text:
In After Effects how can I generate the value of an opposite x position and then send that value to an effect on another layer?
e.g.
my composition width is 4480
I have a layer with a gradient ramp effect with an x start positon of 1026 and I want to generate and store the value of the x position on the other side of the composition which would be 3454.
Then have a duplicate of that effect on another layer get the stored value or have the value sent to it

I think what you're asking to do is simple using Expressions.
If you alt-click on the stop watch of any keyframe-able control you can write an expression to connect that control to another control.
So if you want to control the end of ramp's x position using the start of ramp's x position in your example, it would be:
x = 4480-(effect("Gradient Ramp")("Start of Ramp")[0]);
y = 1080;
[x,y];

The [0] indicates an array - it means "take the x position of the "start of ramp", which has two values, x and y, which can be called as [0] or 2 in the array.
To duplicate this in another layer, duplicate your first layer using cmd+D, then add an Expression to the start of ramp in the duplicated layer:

You can use the pickwhip to select the control you want to enter into the expression

A more robust way of doing this is to avoid hard-coded constants and use x = thisComp.width - (effect("Gradient Ramp")("Start of Ramp")[0]); and y = thisComp.height;. You can use this in any comp and it will be right.


text:
Applying different color keys to one layer in AE
In After Effects, I have an image layer that consists a few colors. Underneath I have several other layers (textures). I want to replace each color of the image
above with one of the textures below.
Is there an easy way to apply multiple color keys to this one image - and to link each color key to a different texture layer?
Thank you

You'll have to make as many duplicates of the layer as there are colours. Apply the appropriate key to each copy, and place the layer you want it to reveal beneath it. On the revealed layer use a track matte, and set it to "Alpha Inverted…". This will hide the keyed layer and use its alpha channel (transparency) to reveal the layer underneath it, but only in the transparent areas.
Your layer stack will look like this, but for any areas not in any of the keys you'll also need a copy of the original layer at the bottom of the stack:

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


text:
When synchronising Video and Audio in FCPX, do the settings matter?
I'm struggling to get a mental model of how FCPX actually works, in particular the relationship between my actual audio and video files, the representation of them in FCP, and what actually gets exported, via Compressor in my case.
As I understand it, FCPX doesn't make changes to the underlying media. Clips contain references to the underlying media with additional meta data, but manipulating a clip leaves the original audio or video file in tact.
However, when you synchronise a Video clip with an Audio clip, you're presented with this UI...

There's a lot of options there, and I'm not sure why. However, all I really want to know is wether those setting actually mean anything when I export my project using compressor. For example, if I have 4k footage and I send my project to compressor and export as 4k, but FCPX has a synced clip with a video format of 720p, does that mean compressor will receive a 720p version of the original media that it then upscales to 4k, or will compressor get the original 4k file?
I'm assuming Compressor gets the original 4k media. It seems crazy to do it any other way. Also, those synchronised clips don't seem to exist in my library. But I'm just really confused by why FCPX presents these options when you synchronise audio and video and I suspect it's because I'm lacking some fundamental knowledge that would help me proceed with confidence.
I realise this is potentially a broad question that may be difficult to answer succinctly, but I'd be happy with a link to some part of the documentation or a blog post that you feel sheds some light on this.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
Effect that detects white object throughout entire video and blurs it, without manually running tracking mask?
Is there a way to track an easily identifiable white object that appears in every frame of a video and apply an effect like blur to the space it occupies for every frame that it appears?
In Adobe Premiere Pro, the object would have to be manually selected in its first appearance, and from there you apply a tracking mask for the blur effect for one entire run through the video to track it all the way through to the last frame,
but I'm instead looking for a tracker that does not have to be manually attached. Instead it should detect the patch of white, or white object, automatically for every frame that it appears, and applies the effect to each detected frame wherever the object is located at that time.
The object is distinctive in color  against the different-colored background and other objects in the video because of its solid color, and moves to different positions each frame (not fixed in one place), that's why it should be possible somehow maybe by color detection

Not really. Color detection, when you’re looking for a white object is really the same thing as what’s known as a “luma key.” So, you can try that, but you’ll quickly see why the VFX industry prefers chroma keys. You could try a machine learning based approach, and both Premiere and Davinci Resolve have ML object removal, but it’s less automatic, and more error prone than you’d expect, and requires certain conditions to be successful at all. Of course, the state of the art is advancing quickly, and this could change in the near future.

What is ML object removal called in Premiere and Davinci Resolve?

In Resolve, it’s just called “object removal”. If memory serves, it’s called “content aware fill” in Premiere.


text:
How to append or join multiple times a video file (single file) to make a 10hour long video of that same file using ffmpeg? is there a way?
I guess i explain what i need in the title but if not i want to make something like this.

Havent checked, therefore only as a comment, but have a look here: https://trac.ffmpeg.org/wiki/Concatenate and search for this text This example will loop input.mkv 10 times

You can use the Windows command line (DOS or cmd) using copy /b 00001.mts+00001.mts K:\Merged.mts as explained in this step-by-step tutorial, where in your case 00001.mts is the identical file repeated over and over again:

https://photography.tutsplus.com/tutorials/3-free-ways-to-join-spanned-avchd-video-files-into-continuous-clips-on-windows--cms-25830

Connecting the same file 6 times instead of twice, you would just replace in
00001.mts+00001.mts+00001.mts+00001.mts+00001.mts+00001.mts


text:
Wearable body gear that automatically evokes video effects during editing?
Consider an arm-cast device programmed to connect with, or be detected by, video editing software during post-production, for the application of video effects wherever the device appears in frame.
If someone in the video wears the arm cast, is filmed wearing it, and the video shoot finishes and recording is stopped, can the video editing software like Adobe Premiere Pro connect to or identify that device within the film, and apply some pre-set special effects to it in each video frame the arm cast appears?
Do wearable clothes or devices recognizable by video editing software exist like this? If so, link some examples

Premiere is not the type of software you’d use for this sort of thing. Cinema4D supports object tracking for 3D postproduction, and I’m sure other 3D apps do too.  But that’s offline, POSTproduction. The hot trend now is doing it real-time. Viacom is a big name in motion capture. Unreal Engine and Unity are big for real-time virtual environments, which can be combined with camera tracking, and possibly also object tracking. Houdini is good at creating procedural geometry to run on UE or Unity.

As far as wearable goes, most trackers for 3D match moving are retroreflective spheres, about the size of a marble, that get fastened to the objects you want to track. With Viacom systems, the balls reflect infrared light that doesn’t interfere with the visible spectrum that other cameras on set are recording.

could you provide a sample link to these reotroreflective spheres?

https://optitrack.com/accessories/markers/

are any $1,500 and under video camcorders compatible with Optitrack markers? or this is exclusively hollywood property

There's a "hand kit" at the bottom of the page, which is like a pair of gloves for the markers.  Since you asked about an arm-cast device, maybe that's close?

If I had to guess, I'd say that the off-the-shelf stuff is mostly expensive, but it hasn't stopped Do-it-Yourselfers, makers, engineers, and tech-savvy people from coming up with homegrown solutions.  This is a small VFX boutique of four young people who developed a pretty good system:   www.hivedivision.net and in this video of their work, you can tell that they use BlackMagic pocket cinema cameras.  The 4K model is in that price range.  https://youtu.be/ysIOi_MP_cs

real aim is a face blurring mask, which means that The Avengers baring balls have to be worn on the face? are these as well accessible to amateurs and their software?

You don’t need all that if you don’t need to do it real-time. If you can record it and then sit down and work on it for a month, you can do it in cinema4D. I’m not sure about blender or maya, but probably those too. For C4D, you don’t need the markers, but you do need a rigid piece of geometry in the real world of which you know the exact dimensions, and a matching 3D model of it. So, if you make a solid mask, that would work fine. C4D is lauded for its ease of use, but that doesn’t mean that it’s easy. Consider hiring someone who knows it, but don’t be afraid to give it a shot, either.

This video shows the actor drawing dots on his face before editing the footage in cinema4D. Can tracking effects be applied post-production even without drawing dots beforehand? If not, how is that drawing dots work in lieu of Optitrack's baring ball markers? https://www.youtube.com/watch?v=Fj5H6-xuqqw

The Viacom systems that use dots use multiple cameras to triangulate the exact 3D location of the markers, which is useful when you need to be very precise.  Drawn dots help with single-camera photogrammetric approaches which use automatic point trackers to "latch on" to an image.  The drawn dots aren't strictly necessary if the image contains enough texture/contrast/detail, and there isn't much motion or lens blur.  Some trackers, like Fusion are good without dots, but can only track one coord system at a time, so moving camera, but not also moving object.  C4d does both but needs help.

OH, wait a minute.  I misunderstood you.  If all you're trying to do is anonymize someone's face by blurring it out, you don't need 3D tracking at all, 2D tracking is fine.  You don't need dots or markers.  Premiere and Resolve would work fine.  But if that's what you want to do, I'm confused about your original question.  What does "arm cast" mean?  Like a plaster cast for a broken arm?  What does that have to do with "real aim is a face blurring mask"?

the difference is wearing a marker device that covers the area that we want edited, but in an automatic way (thus wearing it) so that that editor automatically knows what to do whenever the device appears on screen, rather than 2d motion tracking in an editor.


text:
Displaying map overlay in Final Cut Pro
I often see a map overlay in people's driving videos (showing a map in a corner that moves along the street to match the camera location of the main video as they drive through a street).
How do I create this? I use FCPX on a Mac.
I'm aware of the Relive app, but the video that app creates is in 3D, and moves much faster than the driving speed. I'm looking for a 2D version which show the video moving at the actual driving speed, and shows street names.
If not possible through an app, perhaps I can import the gpx data into a software that creates such an animated video.
I'm grappling for the best way to do this.
Thanks in advance.

With a quick search I found this website, simulating a drive with google maps. When you have your maps simulation you should be able to easily match the speed with FCPX to the footage.


text:
Store video files on USB, SD card, microSD, or external hard drive?
Working with raw .mts (MP4) video scenes that are about 6.5 GB in size each (but automatically  partitioned by the camcorder into separate 10-minute chunks), what arguments are there for not storing them on SD cards?

From experience, USB drives are high-risk storage devices since they
can become corrupted without warning, rendering all data on them
inaccessible.
External hard drives are just too heavy.

This leaves SD cards, they are lightweight. Is it a bad idea to store raw video files on SD cards? How about microSD cards?
Is there a better storage device than all four?

Generally, it’s a bad idea to store data on SD or micro SD cards for any substantial period of time. If you’re a hobbyist, traveling, and plan to transfer to a hard drive when you get home, that’s fine.  But if you’re a traveling media specialist, you want to get your data off of SD/micro SD as soon as possible, for a number of reasons;

Those cards are easily corrupted, because they have very little shielding against electromagnetic or static discharge, and don’t have built in error correction circuitry. They are absolutely higher risk than USB hard drives.
They are easy to lose, because they’re small.
They break.  The plastic wears down over time, especially after several hundred insert cycles. The thin strips of plastic that separate the contact “teeth” of SD cards are especially fragile, and when they break off, they can damage your camera.
They’re made and priced to cycle data. It’s more economical to store long-term data on media designed for that purpose. If you bought a new SD card every time it was full of photos, you’d be throwing money away.
They’re not designed for random access.  They’re designed to write data quickly and sequentially, but reading it quickly isn’t a priority,  and constant random read/writes would not only be very slow, but would also shorten the card’s lifespan.

What you should use instead depends on how you intend to use it; how long you intend to keep the data, how often you plan to read the data, how quickly you need to read the data, and how much money you’re willing to spend.
No, portable hard drives aren’t as reliable as desktop ones, but they are more... portable.  Portable SSDs are faster and more reliable than spinning metal, but they’re more expensive and have lower capacity.  If you really want to protect your data while traveling, you can get portable 2-drive RAIDs, with either SSDs or HDDs, but they’ll be at least double the price of their single-disk counterparts.  If you’re a DIT working on a major motion picture, you might possibly lose your job for not using an actual RAID.  If you’re a digital finisher, you probably have all of the above, plus maybe LTO.  Yes, tapes are still the most economical way to store data long-term, and they have a lifespan of around 30 years.

is it advisable to eliminate the chance of physical loss and corruption altogether by storing raw video files to a server in the basement or even a cloud server?

Absolutely.  If it doesn’t exist in 3 places, it doesn’t exist.

what storage advantage do offline hardware servers have over desktop hard drives?

I strongly advice against microSD cards because they will get lost. They're just too tiny.
There are external SSDs which weigh not much, 50g maybe 100g, I think this is not much weight. Of course you need a way to attach the drive to the camcorder or rig, adding a bit more weight. When filming hand-held, the additional weight and a different center of weight might be an issue which plays a larger role.
Since you mention data loss with USB: this can actually happen at any time with any technology. I've heard people having such a problem with SD cards too and experienced it myself. SD cards don't naturally perform better than USB drives here, because the interface and storage technology is not the problem. The camera's operating system is causing these write errors, especially when using an improper file system. Therefore, using SD cards does not automatically protect you from errors.
Whether you lose access to all data or just the last written file depends largely on the file system, for mass-market cameras they usually use inferior file systems, like the out-dated FAT32. Hence, the fear to lose all data due to one write error is not unrealistic.
Keep an eye on write speed and general compatibility. The camcorder's manual should contain all relevant information. SD cards need to be fast enough to store raw data. SSDs can be faster, but not faster then the USB connection, and camcorder capabilities allow.
High-end cameras use PCI Express as an interface to the SSD for this reason or have proprietary systems. CFast cards are used too. I consider all these high-end systems to be better than the ones you mentioned, but it will be useless to think about it this way if you don't have a camera which could make use of these. You first should ask yourself what exactly you will film, what requirements result, and finally what gear fulfills the requirements.
It's not helpful to find out what's the best storage solution in existance, if it's over the budget and  a simpler solution would work for your case too. If you want to film scenes that are unique or cannot be easily repeated and the budget is low, just try to buy/rent a 2nd camera and run both at the same time for the critical scenes. This way you're not only protected against storage failures but also against any camera failures, because it's highly unlikely that both cameras fail at the same time. Have a laptop on the set to create file backups as needed.

Sorry, didn’t mean to step on your toes. Guess I was answering at the same time as you. Good answer, +1.

No worries, I like yours too and combined we cover a lot of aspects.

This is the first I heard FAT32 being an inferior file system since it seems like the only option to choose when reformatting an SD card (the other option being Quick Format which I never use). I wasn't thinking of storage while recording, for that I trust SD and I make sure it is fast enough. I was mainly just asking about storage for back-up of raw (pre-edited) video files, after recording

Well, in the consumer market, they always use FAT32 because it's compatible with mostly anything since it has been around for so long. Newer file systems have more capabilities, like larger possible file sizes - which is the weak point of FAT32. E.g. exFAT or UDF. Some systems use a virtual layer on top, like Codex' VFS.

Yeah, for backuping on the set, I use a laptop which is present anyway, with it's internal SSD and if that's not sufficient another SSD. There are dedicated copy devices which weigh less but I can't recommend any because I never used one. Not sure if this helps.

if a laptop has an SSD as well as a separate (SATA) HDD, then the SSD is more reliable for saving video?

HDD are prone to mechanical failures esp, when they are moved around. SSDs don't have this issue. So yes, on average the SSD are more reliable in laptops. However, sometimes disks break much earlier than is to be expected and this can happen to any type of disk. So don't overthink it too much and make sure you have a bare minimum of 2 copies (better 3 copies with 1 in a different geographical location) all the time and you're fine. A cloud backup is great too, if your internet connection is good enough.


text:
DaVinci Resolve 17 doesn't show video and shows black screen on imported multimedia
DaVinci Resolve 17 doesn't show video and shows black screen on imported multimedia.
I have VivoBook Pro X580VD, Quad Core model: Intel Core i5-7300HQ bits: 64 type: MCP arch: Kaby Lake, Device-1: Intel HD Graphics 630 vendor: ASUSTeK driver: i915 v: kernel bus ID: 00:02.0
chip ID: 8086:591b
Device-2: NVIDIA GP107M [GeForce GTX 1050 Mobile] vendor: ASUSTeK driver: nvidia
v: 460.32.03 bus ID: 01:00.0 chip ID: 10de:1c8d
Display: x11 server: X.Org 1.20.9 driver: modesetting,nvidia
unloaded: fbdev,nouveau,vesa resolution: 1920x1080~60Hz
OpenGL: renderer: GeForce GTX 1050/PCIe/SSE2 v: 4.6.0 NVIDIA 460.32.03
direct render: Yes
System:    Kernel: 5.4.0-64-generic x86_64 bits: 64 compiler: gcc v: 9.3.0 Desktop: Cinnamon 4.8.6      wm: muffin dm: LightDM Distro: Linux Mint 20.1 Ulyssa base: Ubuntu 20.04 focal

There’s no video on V1, only an audio track on A1.  What happens when you use the edit page instead of the cut page?  If you double-click on the footage in the edit page media pool to view it in the source monitor, will the video play there?

I'm facing the same issue. Tried many thing but it's the same. Anyone got it working?


text:
How can I automate cutting a video along loud beep sounds?
I recorded videos (mp4) of participants in an experiment doing a task at a laptop. There are three tasks, at the beginning and end of which there is a loud beep sound.
I would like to automatically have cuts or extract the parts of the video between the beeps.
So far I've only been able to find this answer:
Automatically cut out sections of a video delineated by a sound.
Can anyone help further? I am able to do a little scripting, but I wouldn't know where to start and I'm hoping that since then there's maybe been a solution with a GUI.
I have a mac, but if necessary could find a pc somewhere.
Many thanks,


text:
How to transition from Final Cut Pro 6 (or 7) to 10
I was a professional video editor in the early to mid 2000's. At the time, I used FCP versions 3 through 6 and was fluid with the program. I worked in the demo commercial business making pretty complicated animations out of layered Photoshop files, managing constant client changes, keeping files organized, knew the keyboard shortcuts, etc. I also had my own art projects. Around 2009, I switched careers (to math education).
Recently, I decided to incorporate some of my video editing skills into what I do now. I picked up FCP 10.5 and was surprised by how different it is. For example, I can't even open any of the my old .fcp files. I've heard of drastic software updates but have never heard of an application's own default file type becoming unrecognizable to itself! This seems more of a symptom than the problem, as the whole file linking method is different. The whole nomenclature for what they call shots, clips, timelines, is different. So much is different! I go online looking for help and find videos of people half my age, who know half the stuff I used to know (but on 6), talking to me like I'm an idiot.
Okay, enough whining.
I want to get up to speed on using FCP 10.5. Does anyone here know of a good tutorial, or set of documentation on this? I'd settle for something on learning about the transition from FCP 7 to X, as that seems to be where most of the changes happened, even though I never used 7. I would also be interested in an effective means of reviving my FCP 6 projects in 10.5, but that's not the main content of this question.
Thanks in advance.

A good starting point would be Apple itself.
Known for tutorials are larryjordan.com and rippletraining.com
A good book is from Ian Anderson


text:
How to change value when passing marker with certain comment
I wanted to change one value when marker with certain comment starts. I've tried something like this, but it doesn't work.
if (marker.comment("R1 L1").time > time){
  value = 40;
}

You need to check how expressions work. An expression sets the value of a property with the first line that returns a value. So for example an expression could just be:
40

since that line returns the value 40. The second line in your expression value = 40 does not return a value, it attempts to set the value property to 40, which doesn't work, because value is read-only.
What you need to do is return 40 if the time is after the marker, and if not return the current value, thus:
if (marker.comment("R1 L1").time > time){
  40;
} else {
  value;
}

Or more tersely, using ternary notation, which uses the form (condition)? <value if true> : <value if false>, thus:
(marker.comment("R1 L1").time > time)? 40 : value

“marker.comment” doesn't work, but “marker.key” does.

I'm not that experienced with expression, so maybe I'm understanding something wrong, but both your code and the code of @stib's answer give me clear error messages. marker.comment is not a function and above that, the code has several more issues.
Using part of the code from this reference I got the following working:
n = 0;
t = 0;
if (marker.numKeys > 0)
{
     n = marker.nearestKey(time).index;
     if (marker.key(n).time > time)
        n--;
}
if (n > 0 )
    t = time - marker.key(n).time;

if(t>0 && marker.key(n).comment=="R1 L1")
    40;
else
    value;

I've created a simple shape and applied the expression for example to the opacity property (100% at start) and added a marker with the comment "R1 L1" and as soon as the playhead passes this marker the opacity changes to 40%. I think this behaves as intended.


text:
Seeking in large HLS input on ffmepg
I'm trying to create an mp4 clip from an HLS input stream that is over 36 hours long.  My ffmpeg command looks more or less like this:
ffmpeg -live_start_index 0 -ss 32:22:19.82667 -i https://example.com/main.m3u8 -t 00:00:55.65625 output.mp4
I don't know why but ffmpeg is non-stop requesting segments even though I'm setting the length of this clip to be 55 seconds. Does anyone have an idea what I'm doing wrong here?

Hey just wondering if you came up with a solution for this? I also found this discussion but there was no definitive answer to why its happening and how to solve it https://stackoverflow.com/questions/38224809/ffmpeg-seeking-in-hls-m3u8-video

I found that using the "HLS protocol" instead of the "HLS demuxer" worked better for seeking.
To use the "HLS protocol" prefix the HLS playlist url with hls+https:// instead of just https:// (which uses the HLS demuxer apparently), and doing that got the seek working for me. It was clearly not downloading the entire file as I noticed it made a fraction of the http requests that it was making before (with -loglevel verbose set)
Do note, if you use the hls protocol, ffmpeg reports this:

Using the hls protocol is discouraged, please try using the hls demuxer instead. The hls demuxer should be more complete and work as well as the protocol implementation. (If not, please report it.)

So maybe I should report the seeking issue to them if they're not already aware


text:
particles with circular motion
I'm traying to create this graphic for my on going project, I tried to guess some techniques but wasn't successful, I was messing around with physics and sphere field in Trapcode Particular but it wasn't quiet right, if anybody would like to share how it might have been achieved, I'd be much appreciated, thanks!


text:
V-mount and D-tap power problems
I might have f-ed up. I’m a producer for an in-house agency and I had the sweet idea of consolidating all battery types and to power everything off of D-tap (p-tap) using v-mount batteries. Here’s what I bought:
Batteries: Here
Vmount plate for camera: Here
Follow focus: Here
Monitor: Here
Wireless transmitter: Here
So I have all of the appropriate d-tap cables and whatnot, and my plan was to power all of this off of one v-mount battery, but it’s looking like I might not be able to do it. When I plugged in everything, I got a spark somewhere on the cage of my c300, but nothing fried. What am I missing? How do large productions run tons of accessories off of one battery? I’m hoping I didn’t get in over my head with this. Any advice or critique is welcome.

I'm no AC, but I've run nearly that much stuff off of 140Wh blueshapes.  No teradek in our case, but it was for an Epic Dragon.  Sparks make me think something's not wired right.  Could you share details about how everything was connected, and what kinds of cables?

I think I might have solved it. I was using an unregulated cable for the monitor. I should be using a d-tap with a dummy battery, but instead I was using the barrel input which is only good for 12v. It’s a good thing my battery was only a quarter charged because I could have fried the whole thing.

To anyone who has similar questions, I think I solved it. Pay attention to voltage inputs to your devices. The blackmagic monitor I was using has a power input of 12v using the two-pin barrel connector. The barrel connecter d-tap cable I was using was unregulated therefore it was pushing out more than 12v. What I need is a l-series dummy battery connected to d-tap regulated down to 8v or so, which do exist. The only reason my entire system didn’t fry was because my battery was only about a quarter charged. If it was full, I would have sent almost 18v to the monitor, probably killing it and maybe some other stuff along the way. Check input voltages on everything you’re planning on connecting to your battery.


text:
ffmpeg prores 4444 banding
Converting an existing clean 8k Quicktime Prores 444 file in FFmpeg yields banding.  It's a lenflare with a completely smooth gradient from center out to edge of frame (no alpha).  If I use AE2020 to convert it to Prores 444, the new file is clean without banding.  Am I doing something wrong?  Here is the command string:
ffmpeg.exe -i file_8k.mov -map_metadata -1 -c:v prores_ks -profile:v 4 -pix_fmt yuv444p10le -color_primaries 1 -color_trc 1 -colorspace 1 -color_range 2 -y file_6k.mov
In this case I'm converting it down to 6k, however other resolutions show the same problem, plus even converting to the same res.

Sorry didn't include my rescale code: -filter:v "scale=5760:-1" however I'm presuming this has nothing to do with the problem.

Share full log.

@Gyan let me know if this qualifies as a log:  https://finalight.com/maindir/webpages/ffmpeg_batch.txt

Have you tried -c:v prores rather than prores_ks I know there were some bugs with banding a while ago with prores_ks.

Will give that a try.  Sorry, long time reply.


text:
how to use -ss and -itsoffset together to precisely delay input start time?
I am rendering a -filter_complex output that has two input videos that are trimmed, and start at various times in the output video. The command looks like this:
ffmpeg \
  -ss 234 -itsoffset 3.5 -t 3 -i video_01.mp4 \
  -ss 23 -itsoffset 3.5 -t 3 -i video_02.mp4 \
  -ss 3 -itsoffset 5 -t 5 -i video_03.mp4 \
  -filter_complex 'color=s=1280x720:color=black:duration=10[base];
[base][0:v]overlay[v_out_0];
[v_out_0][1:v]overlay=x=main_w - 640[out]' \
  -map '[out]' \
  output.mp4

What this command should do, is start video_01.mp4 and video_02.mp4 at 00:00:03.5, and video_03.mp4 at 00:00:05. What actually happens is that video_01.mp4 and video_02.mp4 start at roughly 00:00:03.5, but one appears after the other several hundred milliseconds later. I know this has to do with combining -ss with -itsoffset because the videos start at exactly the right time if I remove -ss from the above command.
I have heard that -copyts -vsync 0 is the solution, but the following command (which adds those args) creates an output that includes all of the input's timestamp. E.g. if video_01.mp4 is a 3 minute video, despite the command appearing to render a 10 second video, the output is 3 minutes. The output is also not playable on vlc or mpv.
ffmpeg \
  -ss 234 -copyts -vsync 0 -itsoffset 3.5 -t 3 -i video_01.mp4 \
  -ss 23 -copyts -vsync 0 -itsoffset 3.5 -t 3 -i video_02.mp4 \
  -ss 3 -copyts -vsync 0 -itsoffset 5 -t 5 -i video_03.mp4 \
  -filter_complex 'color=s=1280x720:color=black:duration=10[base];
[base][0:v]overlay[v_out_0];
[v_out_0][1:v]overlay=x=main_w - 640[out]' \
  -map '[out]' \
  output.mp4

How can I offset ffmpeg inputs in a precise way using -itsoffset?
(side note: I have succeeded offsetting inputs precisely with setpts, but this is slower, probably because it has to rewrite each timestamp)


text:
ffmpeg intermediate transcode for 1920 x 1080 8-bit YUV 4:2:0 @ 25fps source
I have a bunch of footage shot on a Canon 7d I'd like to transcode for editing in Davinci Resolve (I'm exploring alternatives to using Resolve's proxies).
The source footage is 1920x1080 8-bit YUV 4:2:0 @ 25fps.
I'd like to use ffmpeg and either the DNxHD or DNxHR encoders but DNxHD doesn't appear to have a matching profile and errors our and DNxHR outputs 4:2:2 video (which is arguably unecessary in this case) and doubles the original file size.
DNxHR
ffmpeg -i "input.mov" -c:v dnxhd  -profile:v dnxhr_sq -pix_fmt yuv422p -c:a pcm_s16le "output.mxf"

DNxHD (errors "maybe incorrect parameters")
ffmpeg.exe  -i "input.mov" -vcodec dnxhd "input.mxf"

My questions are as follows:

Are either DNxHD or DNxHR capable of outputing to 4:2:0? Would doing so keep file sizes down?
Can DNxHD transcode my source? If yes, how should I ammend the above ffmpeg parameters?

Are either DNxHD or DNxHR capable of outputing to 4:2:0?

No. Running ffmpeg -h encoder=dnxhd will list encoder properties, including
Supported pixel formats: yuv422p yuv422p10le yuv444p10le gbrp10le

Can DNxHD transcode my source? If yes, how should I ammend the above ffmpeg parameters?

The DNxHD encoder only supports a limited number of preset profiles. Each profile is specified of a frame size, interlacing mode, bitrate and pixel format (which also includes chroma sampling scheme).
FFmpeg will automatically convert the input to a matching pixel format, but the rest has to be manually set.
So, for a 1920x1080 8-bit YUV 4:2:0 @ 25fps source,
ffmpeg.exe  -i "input.mov" -c:v dnxhd -b:v 115M "input.mxf"

Try to encode with a non-matching to prompt an error message with the list of supported profiles.

Thanks, that worked. Interestingly, your dnxhd command above produces an output file with the exact same size as my dnxhr command.


text:
ffmpeg - one input, two outputs - separate instances
I've been struggling with a ffmpeg-related issue for a few days now.
What I am trying to accomplish is to grab AV signal from a single input (/dev/video0), then save it into two files simultaneously.

Output no. 1: raw AVI file, for further editing
Output no. 2: preview mp4 file, to work as a preview within an embedded VideoJS player on an webapp.

Here's my command:
ffmpeg -f v4l2 -standard PAL -i /dev/video0 -f alsa -thread_queue_size 512 -i hw:0,0 -preset superfast -crf 25 -r 25 -aspect 4:3 -acodec libmp3lame -b:v 6M -b:a 128k -channels 2 -ar 48000 /vids/vid1.avi | -acodec libmp3lame  -b:v 500k -b:a 128k -channels 2 -ar 48000 -y /opt/lampp/htdocs/preview.mp4

The command above doesn't seem to work for me. Where have I gone wrong?

*doesn't seem to work * --> what's wrong?

Using this command makes output 1 generate nice and smooth, while output 2 doesn't generate at all.

Remove the pipe character.
ffmpeg -f v4l2 -standard PAL -i /dev/video0 -f alsa -thread_queue_size 512 -i hw:0,0 -preset superfast -crf 25 -r 25 -aspect 4:3 -acodec libmp3lame -b:v 6M -b:a 128k -ac 2 -ar 48000 /vids/vid1.avi -b:v 500k -b:a 128k -ac 2 -ar 48000 -y /opt/lampp/htdocs/preview.mp4
(mp3 is not standard in MP4 so let ffmpeg pick the default audio codec)


text:
Streaming MP4 files through HTTP without HLS or DASH?
I am building a web application that consists of a web client and a server. The web client needs to play a continuous stream of MP4 files to the user, preferably through a player like video.js. The problem is that I need to stream the MP4 files in my own protocol rather than something like DASH or HLS. The reason for this is that I cannot create a manifest file for my chunks and that I need to add more messages to the server to prepare the MP4 files.
In a nutshell, my server needs to fetch some files from some archive storage, convert them to MP4, transcode them and then send them to my client. Fetching the files can take up to 30 seconds. I also do not know all files I have available, so I cannot create a manifest that would tell the client how early this stream goes back in time.
My solution is simply to have logic on the client to fetch the MP4 files from the server and play them to the client. The problem I am facing at the moment is that when I try to play MP4 files one after another in my client player (video.js), there is slight stuttering when a file ends and a new one starts playing. So this doesn't feel like a long continuous stream.
The solution I am exploring at the moment would be to convert the MP4 files to MP4 fragments and stream them, but I do not know how this would work considering that I would try to concatenate fragments from different MP4 files.
How would you go about playing an originally continuous video stream when this stream has been fragmented in multiple MP4 files?

I feel that's more a programming challenge that should go on Stackoverflow than a video production question.

@Matt I am not yet at the programming challenge part. At the moment, I am simply trying to figure out what format I should be sending to my client so that I can merge my chunk together in some sort of byte array to play a seamlessly continuous video. Can I take two different MP4 files, fragment them, and then just join the bytes in my client to play a continuous video? Those are the sort of questions I am facing at the moment.

I'm not sure I get your use case, but it might be useful to take a look at the nginx-vod-module by Kaltura. It features a mapped/remote mode where you can specify, through a JSON file, sequences of clips that are then concatenated and JIT-transmuxed to produce HLS/DASH/progressive download streams.


text:
``Failed``when I try to export video - Davinci Resolve 16 FREE

Everytime I try to export this clip this message appears. I'm not very experient with Davinci and editing videos in general, but I had no problem saving other videos. I've tried changing the settings but as I said before, I'm not familiar with it. I don't know if it helps but I have a MacBook Pro (2015) with macOS Catalina 10.15.7, 2,9 GHz Intel Core i5 Dual-Core.

I think you need to provide more details. What is different with this project compared to those that worked? Are there any logs or detailed error messages? You can edit the question and add the details.

You say “every time I try to export this clip.” For clarification, are you really exporting a single clip? Usually, when resolve fails in the middle of an export, it’s because it has run into a clip that it can’t process for one reason or another, such as a Fusion composition with missing media. To put it another way, it’s rare for resolve to error after successfully processing any amount of a problematic “clip;” it will usually fail on the first frame of the clip that’s giving it a hard time.  What’s going on at that spot, roughly 20% into your timeline?

There are cases where it can fail in the middle of a clip. When it does that, it’s usually caused by a memory insufficiency, or in rare cases, components overheating, power supply problems during intense computation, or other hardware-specific issues. In these cases, the point at which it fails is usually more random.

Older versions of Resolve were a bit "picky" if the source material had minor glitches in it. Maybe try exporting a small section only as "proof of concept".


text:
YT stream key - best practice?
Like so many American workplaces, my campus moved this year to a lot of virtual interactions and events. I work in live events management, so I mostly dealt with a lot of Zooms and Blue Jeans, but one department wanted to put some graphics on top of their faces and livestream and OBS feed up to YouTube. For the most part it worked very well but we had one hiccup that I'm wondering whether I addressed it incorrectly.
They sent me a stream key three weeks in advance and began publicizing the URL of their November 11 event, which would happen at 7pm. That day, I plugged the key into OBS and at 6:30, I began sending the feed. An employee in their department misunderstood her instructions and pressed Go live in her YouTube interface at, say, 6:40 (for a 7pm go). At 6:44 she realized her error and pressed End stream.
From YouTube's perspective, we had streamed our four-minute event , and it was over. I couldn't find any way (in the ten minutes I had between 6:50 and 7pm, once I got logged in with their YT credentials) to tell YT I pressed stop accidentally, please let me send content to that URL again
Now, this didn't matter very much in the big scheme, because, as you may have noticed, this was at 7pm EST on November 11. Our link hiccup was overshadowed by YT's massive failure at exactly that moment.
I'm wondering, though, as a relative novice - what's a best practices for live streaming content in this way? Is there a way I could have pushed my content through to the original URL (barring the big collapse)? The system I was part of (here's a stream key, you only have one shot at it) seemed sort of fragile and I wondered whether I'm misunderstanding my role in it.
(And yes, of course, we're doing some of these again this spring, so I'm trying to lay groundwork.)
Thanks in advance for insights / opinions / name-calling.

Is there a way I could have pushed my content through to the original URL (barring the big collapse)?

That's not possible unfortunately, once you stop the live event the content that was ingested is made available for on demand streaming and no more live content can be streamed to YouTube.
If you think about it, it would be difficult to do otherwise, because multiple sequences of the stream would need to be stitched together and that could be confusing for users who watch the recording.
The thing that YouTube tolerates by default is the fact that you might stop and resume ingesting content after you press the Go Live button but before stopping the event. I say "by default" because on Facebook, for example, the default behaviour is actually the opposite: if you accidentally stop streaming in OBS or have a network issue, the stream is stopped automatically and you cannot resume it. (I've seen this happen a number of times, it's a quite common problem.)

The system I was part of (here's a stream key, you only have one shot at it) seemed sort of fragile and I wondered whether I'm misunderstanding my role in it.

The stream key is simply a string that you use to authenticate with YouTube, and YouTube actually allows you to reuse the same key between live streams!
What you should do in your case is simply make sure that the Go Live button is pressed at the right time :)
If it's pressed too early, there's no point in stopping the stream! Going live 20 minutes before the event is perfectly fine and it's actually a very common and recommended practice. While users wait, you can show a placeholder message like "We'll be live at 7 PM". This allows you to check that everything is fine in practice with actual YouTube apps (cough November 11 cough), and also gives users a sense that everything's fine and the event is going to start.

Thanks for your thoughtful, thorough answer. One question, which my campus client posed to me: would we get more control (like, URL-level control) with a paid account at Vimeo or any similar service?

I don't have direct experience with Vimeo but it seems to be very similar to YouTube: you still have to create an event, go live and then stop it. You might have more control and customization options with other services like JW Player, Dacast or IBM Video but... Is it worth it?

Nope!
Thanks again.


text:
Video: Woman pulled from in front of a subway train. Fake or not?
I have found a video allegedly filmed on Wednesday, Feb. 10, 2021,  at 15:35 PM, EET, in Bucharest, Ro, Dristor 1 subway station, showing a woman jumping on the tracks and then pulled out from in front of the train just less than 1 second before impact.
This is the video:

See:

The scene seems a fake but I do not know how to demonstrate it.

No signs to be fake.

It is very difficult to say, because quality is quite bad. It is pretty obvious that it was an interlased video that was then converted to be progressive. That is why you have many ghostly images appearing during the fast motion of the object.
I do not know if this is 'fake' or 'true'. The only strange thing which i have managed to spot came at the frames 315-318 of the video.
I was looking at the reflections, because they are often difficult to fake correctly. At at this moment we see the reflection coming from the part of the train with no window. In other frames during the metal part the reflection would disappear, but here it is visible, and is a little too perfect to be expected.
Now, it is possible that we are seeing the ghost of the previous/next frame due to deinterlasing, but then why does this reflection appear on several frames?
This is not something conclusive, but it did raise 32% of one of my eye brows.


text:
Can I use Apple Compressor software to convert mkv files to mp4
I use Final Cut Pro X. I am planning to buy Compressor software too which gives me options in exporting my video. Can this same software be used for converting mkv files to mp4 because Final Cut Pro X doesn't support mkv files.

Try Handbrake, VLC or a smart tool for Mac lie DumboFab.

No Compressor does not take .mkv files. At least not my 4.5.1 version.

I think Handbrake can do this, and it's free:

Supported Input Sources: Handbrake can process most common multimedia
files and any DVD or BluRay sources that do not contain any kind of
copy protection.
Outputs:
File Containers: .MP4(.M4V), .MKV and WebM Video Encoders: H.264 and
H.265 (Including hardware acceleration support), MPEG-4 and MPEG-2,
VP8, VP9 and Theora Audio Encoders: AAC / HE-AAC, MP3, FLAC, AC3,
E-AC3, Opus and Vorbis Audio Pass-thru: AC-3, E-AC3, FLAC, DTS,
DTS-HD, TrueHD, AAC, MP3 and MP2 tracks


text:
VLC doesn't play mp4v video converted with VLC to h264/h265
VLC reports the original video as:
Codec: MPEG-4 Video (mp4v)
Video resolution: 8192x8192
Frame rate: 7.549296

I am using the Convert / Save option to convert the video using the following profile:
Encapsulation: MP4/MOV
Video Codec: H-265 (also tried H-264)
Bitrate / Quality: Not Used (18 in h264)
Frame Rate: Same as source
Custom options: crf=18

Specifying the quality in the Quality input only works for h264, hence the custom options with crf=18.
After converting the video shows fine on YouTube and in PowerDVD but NOT in VLC! When playing the video the stream is reported as:
Codec: H264 - MPEG-AVC (part 10)(avc 1)
The rest, like resolution and frame rate, are as of the original video.
When the video is being played the Statistics window shows that video frames are being decoded but Displayed remains 0. Why would VLC be able to decode the video but not display any frames?
I tried different settings for Hardware-accelerated decoding but it didn't help. I have other videos which report the same codec H264 - MPEG-AVC (part 10)(avc 1) but they are usually using mkv encapsulation rather than mp4 (and upon further inspection, some other details in the codec metadata).
This is MediaInfo for the original video:
ID                                       : 1
Format                                   : MPEG-4 Visual
Codec ID                                 : mp4v-20
Duration                                 : 1 min 11 s
Bit rate mode                            : Variable
Bit rate                                 : 45.2 Mb/s
Maximum bit rate                         : 85.9 Mb/s
Width                                    : 8 192 pixels
Height                                   : 8 192 pixels
Display aspect ratio                     : 1.000
Frame rate mode                          : Variable
Frame rate                               : 7.549 FPS
Minimum frame rate                       : 3.429 FPS
Maximum frame rate                       : 24.000 FPS
Compression mode                         : Lossy
Bits/(Pixel*Frame)                       : 0.089
Stream size                              : 383 MiB (100%)

This is MediaInfo for the converted video:
ID                                       : 1
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Format profile                           : Baseline@L6.2
Format settings                          : 1 Ref Frames
Format settings, CABAC                   : No
Format settings, Reference frames        : 1 frame
Codec ID                                 : avc1
Codec ID/Info                            : Advanced Video Coding
Duration                                 : 1 min 10 s
Bit rate                                 : 114 Mb/s
Width                                    : 8 192 pixels
Height                                   : 8 192 pixels
Display aspect ratio                     : 1.000
Frame rate mode                          : Variable
Frame rate                               : 7.544 FPS
Minimum frame rate                       : 3.428 FPS
Maximum frame rate                       : 24.006 FPS
Original frame rate                      : 7.549 FPS
Color space                              : YUV
Chroma subsampling                       : 4:2:0
Bit depth                                : 8 bits
Scan type                                : Progressive
Bits/(Pixel*Frame)                       : 0.225
Stream size                              : 978 MiB (100%)
Writing library                          : x264 core 155
Encoding settings                        : cabac=0 / ref=1 / deblock=0:-1:-1 / analyse=0:0x11 / me=dia / subme=0 / psy=1 / psy_rd=1.00:0.15 / mixed_ref=0 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=0 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-1 / threads=24 / lookahead_threads=4 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=0 / weightp=0 / keyint=250 / keyint_min=7 / scenecut=0 / intra_refresh=0 / rc=crf / mbtree=0 / crf=18.0 / qcomp=0.60 / qpmin=10 / qpmax=51 / qpstep=4 / ip_ratio=1.40 / aq=0
Language                                 : English
Codec configuration box                  : avcC

I noticed that for the original video VLC shows
Decoded format: Planar 4:2:0 YUV

even though it's missing in the MediaInfo data for that file. But VLC shows it as empty:
Decoded format:

in the converted file, even though MediaInfo shows:
Color space                              : YUV
Chroma subsampling                       : 4:2:0

Not sure if the addition of Decoded format after conversion would prevent VLC from playing the video, but the fact that VLC cannot play back the video which it produced is highly suspicious. Any ideas?


text:
Problem with retaining aspect rato
(Before you ask, resolution and aspect ratio need to be like this for a reason)
I tried using this to make sure the aspect ratio stayed the same, because for some reason it doesn't
ffmpeg -i input.mp4 -c:v mpeg2video -aspect 16:10 -an -b 6000K -minrate 6000K -maxrate 6000K output.m2v
Now that command works for 4:3 but not 16:10, it just ignores it basically. So I tried using this, SAR is what the base file is and the DAR should be the -aspect command right?
ffmpeg -i P3CT001_01.mp4 -vf scale=640:368,setsar=sar=10/11 -aspect 400/253 -c:v mpeg2video -an -b 6000K -minrate 6000K -maxrate 6000K output.m2v
Well same issue here, it seems it doesn't like when the last number (So the 10 in 16:10) is more than one digit. Also trying that first command seems to change the resolution when set to 16:10
This issue does not happen with mpeg1


text:
How can I know my if footage is rec.709 or not right out of the camera?
I just recorded a video (a talking head) using my Canon EOS 4000D (known as Canon EOS Rebel T100 in the U.S.) at 1920x1080p24.
(Maybe informative/Important, that I want to color edit/grade it in Adobe Premiere Pro etc.)
The main question is, how do I know if my footage color space right out of the camera is Rec.709 or not?
Is it 8 bit? 10 bit? 14 bit? 444? 422? 420? RGB444? YCC422? what more?
All I know is my file type is MOV (Video: H.264 inter frame - IPB).
P.S. I used the built-in Portrait Picture Style.

Canon DSLRs always record video in sRGB, which shares the color primaries with Rec.709. Latter also refers to a Gamma of 2.4 (Or sometimes 2.2). So you can basically treat the video as Rec.709. The footage is most likely 8 bit 420, but I can't 100% answer you that one.

Knowing the details about what format your camera recorded is often as simple as consulting the manual.  However, some cameras shoot multiple formats, and often, editors are given footage from unknown or unreliable sources.  One of the best tools for discovering the full details of an A/V file is the command line utility, mediainfo.
Depending on whether or not your computer comes pre-installed with mediainfo, obtaining your answer may be as simple as opening the command line interface, and typing:
mediainfo /PATH/TO/YOUR/FIlE

If this returns a "command not found" error, then you will need to install mediainfo according to your operating system requirements.  On MacOs, the easiest way to install is through https://brew.sh
If the command line isn't your thing, there are GUI-wrapped versions available in both the Microstoft Store, and Apple App Store, caveat emptor.
The default output is the total information known to the operating system about the media file, which may be overwhelming.  Theres a good explanation of how you can return only relevant information here.
For example, to return only the colorspace, you would type:
mediainfo --Output="Video;%ColorSpace%" /PATH/TO/YOUR/FILE

It's important to mention though, that not all metadata is created equally.  Different camera manufacturers will include different details, and when video files get transcoded, the metadata is often altered.
However, mediainfo is one of the most comprehensive tools available for discovering these sorts of details about a media file.


text:
Clip super loud after embedding
With Premiere Pro 14.8.0 on Mac OS I have a simple project. In one wequence I have 1 single video and one audio:

The audio is nice and normalised, sounds perfectly all right.
Then I embed this sequence in an other sequence:

As you can see, Premiere does not show waveform any more, and although the volume adjustment is on 0 dB and I have no audio effects at all, also haven't touched the mixers, the sound in the second sequence on this clip is crazy loud, you can barely recognise it from the distortion. Even with -80dB it's pretty loud and distorted. All the other clips in the second seq are OK.
What can be the reason for this, is this a bug?

Restart did not help, but deleting the clip from the second sequence and then adding it once again solved it. I'm pretty sure this was a bug after all.


text:
Transition / Cut Advice for Video Idea
I have an idea for a film project that I would like some advice on.
I want to use my GoPro with the handgrip attachment to "interview myself" on a ski chair lift.
Here is what I mean by that: I want to ride a two person chair lift and on the first ride, with the camera pointed at me, I am going to record myself asking all the questions. On the next ride I am going to wear a different outfit and sit on the other side of the chair and record all the answers. Then I want to edit the clips together to make it seem to the best of my ability that they both occurred on the same chair ride.
I could just standard cut / jump cut the clips, but it will be pretty obvious to the viewers what I did and seem discontinuous. I would like to somehow edit the transitions to create the effect that there are really two of me on the same chair (it will be obvious to my viewers that it is the same person, because they all know me, but it will be funny because I am wearing different outfits and I will talk / behave differently for the two different characters).
What I am not trying to achieve is some sort of photo shopping technique to get two of me in the same frame at a given time, but somehow pan back and forth in a smooth way to make it seem as close to being one continuous clip as possible.
Imagine that two people were actually on the lift, and I pointed the camera at myself to ask the question, then turned it to aim at the other person for the answer, then back to me for the next question. This is what I want, but I have to edit it since there is (obviously) only one of me.
Just to help people who aren't familiar with what a ski lift might look like, here are three screen shots from a video of a friend and I essentially doing what I described above (but with two people instead of ong)

Camera being aimed at me for a question, camera was being held by my friend sitting next to me

Halfway between panning from me back to my friend holding the camera

Camera fully panned back to my friend holding the camera
Obviously picture two is unachievable since it has both people in one shot, but I am thinking I might be able to take advantage of the black pole that is in the middle of the chair?
I hope my question is clear, please let me know if I can improve it in any way. Let me know what creative ideas you might have to achieve this goal!
I typically use adobe rush or adobe premier pro for editing.
There is a park near my house that has two swings with a similar pole in between them, and I was thinking I could practice on that before filming on the ski lift.

You could use black screens as section dividers, e.g. one screen could feature a large question mark and the other one an exclamation mark as text.
The idea is to drag the black screens across the video frame from side to side at the same speed you're panning. Make the animation so that it looks like the black screen is attached to the middle pole.
Step by Step:

show the black question screen for a second or two
cross dissolve to you asking the question, the camera being fixed on you
begin panning
as soon as the pole comes into view, move the black answer screen from off-the frame into view, at the same speed as the panning, so it looks like the pole drags the screen with it.
this screen will cover the empty lift seat while you pan
the black answer screen comes fully into view
in the background cut to the other video track
Cross dissolve again and show you sitting in the other seat and answering the question.
start panning again
and so on

You could start the speech tracks just before the dissolve effects start, this is a common technique that simulates typical human dialogue where we perceive someone started speaking first and only then turn our eyes on that person. Research J and L cuts if you want to know more about this.
Also record some ambient sound from the lift ride and environment, that can be played continuously on loop in the background.

It would be fairly easy to use a wipe centred on the black pole in the middle of the ski lift. A wipe is a standard transition found in most, if not all NLEs, that crops the outgoing picture from one side to progressively reveal the incoming picture. Wipe effects commonly have the ability to soften the edge,a nd apply a coloured border, both of which could be useful here, a blurry black border would match the pole as it passes across the shot.
If the pan was quick and reasonably consistent in speed motion blur will help smooth out any mismatch in framing or timing. To do the wipe, count how many frames it takes for the pole to pass from one side to the other. Make the cut in the middle of these frames and then apply a wipe effect to the cut (Premiere, like most NLEs, let you do this by dragging the effect onto the cut). Set the length of the wipe to the same number of frames as it took for the pole to pass across the screen, and make sure the direction and angle match.
When shooting you will want to practice the camera movement so that it is reasonably consistent between shots. One or two frames won't matter, but if one pan is 12 frames long and the other is one second long they wont match. Quicker will be better, because the motion blur and speed will mean you won't see exactly what's going on. There is a cutting technique called a whip pan, where you move the camera super fast (or apply movement in post) to cut to somewhere else. It might be of use to you here.

Hi @stib. Thanks for your answer. Can you describe in just slightly more detail how to do the wipe? I am brand new to this!

edited for you.


text:
How do you edit videos to slide on and off the screen?
Hi I’m trying to edit a group of videos so that they continuously slide on and off the screen. I was wondering if there was a faster way to do this instead of individually adjusting the position key frames of all my videos.
The type of motion I’m referring to is like 1:51 of this YouTube video

Thanks and any help would be appreciated!


text:
Merging all files in a folder with an avidemux batch file
I`ve been trying to create a batch file that merges all files in a folder using avidemux. Ideally, it would be awesome if this works to do some changes as well (basically rescaling the video).
I have tried with this .bat file but it does not do what I intended:
set avidemux="C:\Program Files\Avidemux 2.7 VC++ 64bits\avidemux.exe"

set videocodec=mp4

for %%f in (*.mp4) do %avidemux% --video-codec %videocodec% --force-alt-h264 --load "%%f" --append "%%f" --save "%%f.avi" --quit

What this does is just open each file individually and save it individually, not actually merging them.
If there are any one-click solutions for this kind of issue it would be also appreciated.

Ok I have found a solution using ffmpeg instead of avidemux. I made the following batch file. In this case, I had to know the folder where the ffmpeg executable was, and also i managed to convert the resolution to a different one
for %%f in (*.mp4) do (
    echo file %%f >> list.txt
)
F:\ffmpeg\bin\ffmpeg.exe -f concat -safe 0 -i list.txt -vf scale=320:240 output.avi
del list.txt

This did the trick!

This is based on https://stackoverflow.com/questions/28922352/how-can-i-merge-all-the-videos-in-a-folder-to-make-a-single-video-file-using-ffm

If this solves your problem perfectly, then please mark your answer as accepted (click the check mark on the left).

select all files in the folder, then drag and drop all at once into the avidemux window.  No code required.  You can't file>open then select all, just drag and drop all the files you want to append together.


text:
Adobe After Effects: Equal spacing between layers when each layer is a different size?
I am working in Adobe After Effects (version 17.7.0 Build 45).
I have the following:

How can I get equal spacing between the three layers when each layer is a different size? Let's say I want 60 pixels between each layer?
In other design software, it is easy, when I drag and drop, it tells me. Here's Figma for example:

How can I get the same in Adobe After Effects? I already know about the Align tools in Adobe After Effects, but they do something different. For example, I couldn't say "I want 60 pixels between each layer".


text:
Using FFMPEG, how to join two videos with an intermediate crossfade transition?
Using FFMPEG, I need to join Video 1 and Video 2 with an intermediate transition Video T .

Video 1 has a duration D1 .
Video 2 has a duration D2 .
Video T should have a duration DT .
The resulting video should have a duration D1 + DT + D2 .
Video T should start with a copy of the end frame of Video 1.
Video T should end with a copy of the start frame of Video 2.
Video T should be a crossfade from its start frame to its end frame.
Video 1 and Video 2 are MP4 files and have the same encoding parameters.
Video 1 and Video 2 contain audio, that should remain in the resulting video.
Video T should have no audio.

How can Video T be generated, using FFMPEG simply ?
How can Video 1 and Video 2 be joined with the intermediate Video T, using FFMPEG simply ?
Note : I would prefer to perform the entire operation, through a single FFMPEG call.
Note : I would prefer to avoid setting offsets, since D1, D2 and DT may vary.

Why do you need a video T at all?

Video T needs to be within the resulting video, but it does not need to be saved separately.

Video T is needed, to obtain a crossfade transition from Video 1 to Video 2.

You just need to crossfade directly between 1 and 2. Maybe apply tpad to extend the streams if you want.

Indeed I probably need to use tpad, to extend Video 1 and 2.  Thank you for the hint !

But is it possible to crossfade without setting offsets, since D1, D2 and DT may vary ?


text:
How to input noise values in dBFS for ffmpeg silence detect
I used the silencedetect of ffmpeg with noise value of -30dB to get the silent parts of a small video file & used those timestamps to trim & re-encode the silent parts of the videos.
I had used the audio peak meter in Shotcut(a video editor software) to see that anything below -30dB can be considered as silence.
When I opened re-encoded output video file in Shotcut, I saw that there were still some sections of video that were below -30dB & longer than the silence duration value I had passed into the ffmpeg command.
On closer inspection, I realized that the audio peak meter shown in Shotcut measures in dBFS & the noise value I entered in ffmpeg is in dB.
My knowledge of audio signal is very basic & hence I looked up what's dBFS. I understood that dBFS stands for dB Full Scale & is somehow related to the maximum possible volume in a WAV format.
My question is, how to pass the value in dBFS to ffmpeg instead of in dB?
I checked the ffmpeg documentation & it does not say that we can pass values in dBFS.

@PaulB.Mahol Nope, you're wrong. Check also here where OP already asked the same question: https://sound.stackexchange.com/questions/50418/how-to-input-noise-values-in-dbfs-for-ffmpeg-silence-detect

@PaulB.Mahol there's no app, I just used the timestamps derived from silencedetect filter into a second ffmpeg command that did the trimming. So, there isn't much chance for error other than manual data entry errors. I checked there weren't any of those errors.


text:
video not showing full screen
I have video from multi videos, when I import it in after effect, one of them not showing full screen.
I think when see image will understand my problem
in video player:

in after effect after imported:

Any advise?

Make sure the size of your comp in After Effects is the same as the size of your original video clip. Make sure the clip in your layer is set to scale 100%.

Also if you want to automatically resize the clip to fit the composition hit ctrl-alt-shift-G or ctrl-alt-shift-H or if you're still on a mac cmd-alt-shift-G/H

Still not working, the primary video has 2 video which merged, one appears full and the other not :(

upload some screenshots showing your comp, the comp settings, the video's dimensions etc.


text:
ffmpeg: can't loop over files in folder to remove audio track f was unexpected at this time
I have a folder with .avi files:
dogs
  dog1.avi
  dog2.avi
  ...

Each .avi file has 2 audio tracks. I want to remove the first track.
I can do if for one file like this:
ffmpeg -i dog1.avi -map 0 -map -0:a:0 -c copy dog1-changed.avi

However I need to do it for all files.
I tried (after cd dogs):
for f in *avi; do ffmpeg -i "$f" -map 0 -map -0:a:0 -c copy "${f/%.avi/-changed.mkv}"; done

However it gives
f was unexpected at this time

error.
How do I fix it?

Are you using Bash or something else? And which version? Is the string replacement causing the issue (is it fixed if you use a literal string as output file name?) Anyway, this may not be an ffmpeg question but a scripting question. But I can't say for sure as of now.

@Matt I'm using Windows 10 Terminal. I'll try the fixed output name

Windows Terminal can integrate many different shells. You probably meant the command prompt (because that's giving me the same error like you) and you're using the wrong syntax for this, to me it looks like Bash syntax and it works in Bash. You could install the Bash, and use your command as is or you rewrite it in command line syntax. Anyway, it's now obvious your question is off-topic. If you need further assistence you can ask on https://stackoverflow.com/ but please read the documentation for either the Command Line or Bash first.


text:
Why does my ipad/macbook video camera quality not match logitech hd c270 quality?
I am trying to write a program that takes a video of someone's face, extracts the RGB values, and then uses the color change (imperceptible to the human eye) to map onto heart rate. When I use a logitech C270 HD WEBCAM recording .avi video files, my program works really well because the RGB data is very rich with little noise.
When I switch to using my macbook webcam or an iphone/ipad camera, the RGB data looses its richness and becomes more noisy (lower signal to noise ratio). Why is this? I would think apple cameras would be similar or better quality than the $40 logitech.
The biggest difference I see is that the logitech .avi files run 184410 kb/s and the mac .mov or .mp4 files are ~7000 kb/s.
I know for sure the logitech files are uncompressed. I'm pretty sure that the apple mov or mp4 files are uncompressed (I didn't do any compressing, but maybe its done automatically on the device?).
Any ideas how I can get my mac or iphone/pad to match the quality (interms of kb/s) of the logitech?

If they're mp4s they're compressed, probably with h.264. Pretty unlikely that the logitech is uncompressed too—720p uncompressed video data rate is ≈500mb/s. So both compressed, but the difference as you said is the data rate. Also this: https://tidbits.com/2020/04/08/the-2020-macbook-airs-facetime-hd-camera-is-still-lousy/

Thanks, this is helpful. I see that all mp4's are compressed. Is it possible to record uncompressed or > 150000 kb/S video on any smartphone or tablet? edit: this seems like a separate issue, will start new post.


text:
Software to manage digital assets
Over the years I have accumulated enough digital assets (mainly videos and photos) for it to become a massive problem in terms of organizing it all and then being able to find it.
I am wondering what people are using out there, regardless of the platform (even though I am deeply invested on Linux)
Here are the requirements I consider essential:

Being able to identify duplicates and save storage
Ability to apply multiple tags and comments to make searching easier
Ability to "publish" or otherwise make visible through a controlled web server only a subset of these assets
Easy way to export or otherwise create backup copies
Intuitive GUI front end

I have been searching around without any luck so I am keen to hear from other in this forum.

I recently discovered that what I should look for is DAM Software. Digital Asset Management/

Adobe provide two useful sidekick tools to manage video filles.
Adobe Bridge is a digital asset management app fully efficient with photo and video.
Adobe Media Encoder is a is professional video converter with watch folder options, and ProRes support for Windows and Mac.
These software are not available on Linux, but their metadata and files are useful on every modern system.


text:
After effects - how to put multiple sources on the same layer line? or how to reduce the scrolling of the layers panel?
Competitor software can put multiple footage in the same layer. I think this is Pinnacle, but I've seen this also in Magix (I am not a professional, this is the kind of consumer software I've used in the past):

Instead, it appears this is not possible in After Effects. Am I wrong? Is there a way to do this?
As a result, nearly half of what I have on my screen is just gray lines. Either that or endless mouse wheel scrolling. I have over 5 million pixels on my screen, but they are just used for gray. I think this is horrible UI, and I'm looking a way to improve my user experience. What are my options?

This is totally making me go cross-eyed and giving me headaches. I just can't believe this is what you folks have to deal with. There's got to be a better way. Thank you.
P.S. I cannot pre-compose otherwise I lose the ability to snap. Tried that – didn't work for me. Any suggestion?

After effects isn't an editor, so it's a bit of a pain if you try to treat it like one.
But there are ways to reduce the pain if you have a lot of clips:
Pre-comps
I know you said you don't want to use them, but this is often the most useful solution, as it reduces many layers to a single nested layer. If you need to snap to specific items in your outer comp - copy them inside, and set them as Guide Layers (Menu --> Layers --> Guide Layer).  This will make any Guide layers with this logo  invisible when you render that comp, or any outer comps, but you can still see them in the viewer, and still use them for timings.
Shy layers
You can checkbox any layers you don't need to use often as "Shy" layers by using this icon next to your layer   This means that you can hide them in your layout by pressing the bigger version of that icon:
, but they will still render on screen and in your render.

Video editing (cutting) is best done with Premiere Pro and animation with After Effects. Both are complex software tools that require lots of training. You should invest more time in training or maybe choose different products, if they simply don't fit to your style of working.
Create a sequence in Premiere where you can easily have as many clips in a track as you want. Create a new sequence where you insert this sequence (this is called nested sequence). Then right click on the inserted sequence and select Replace With After Effects Composition. When After Effects opens you will see that you get a composition with only one layer.


text:
Under the hood process of the "create shapes from vector layer" option in After Effects
I'm just curious to know what actually happens when After Effects converts an AI file to shapes. I should note that I do have Overlord but sometimes I am working on projects on my university computer and I am unable to load extensions. I find myself working more and more path animation projects but every time import and convert my AI files to shapes I have to manually dive into each shape group and zero out its parameters before animating. I try to set up my projects in AI in a way so it's already the way I need it to be. It would be nice to actually understand how AE handles this process of converting files. Thanks for your help

No ide of what's going on under the hood, but FYI You can install extensions without admin permission: http://andrewmacfarlane.com/blog/2017/04/how-to-install-after-effects-scripts-extensions-and-plug-ins-without-administrator-access/


text:
How to scale video without stretching it?
I am using this command to scale video ffmpeg -i input.avi -vf scale=720:480 output.avi. I want to add black background instead of stretching the video.

Guys i need this. Else my product manager is gonna fire me. There is no sprints in my company only 'i want this feature by this evening'

I'm sorry for you, but this SE site is not that active and you may not get an answer in time. If you're in a hurry try posting on stackoverflow as they seem to accept ffmpeg questions too and may respond faster. I can't help you since I know too little about ffmpeg. Maybe this question helps you, as it's a bit similar: https://video.stackexchange.com/questions/21839/adding-blurred-background-to-portrait-videos-with-ffmpeg

Check out this similar question: https://superuser.com/questions/991371/ffmpeg-scale-and-pad


text:
Trouble When Combining two video fields into one (to create an interlaced video)
I'm having trouble with the command found here: Combining two video fields into one (to create an interlaced video)
ffmpeg -i tf.avi -i bf.avi -filter_complex vstack,il=l=i:c=i -c:v ffv1 out_i.avi
It seems to combine the fields correctly, the output, however, appears to be progressive. To test, I used
the video 'in_i.mxf' (XCDCAM HD 422, 1080i25) and separated the fields in tf.avi and bf.avi, using this:
ffmpeg -i in_i.mxf -vf field=top -c:v ffv1 -an tf.avi -vf field=bottom -c:v ffv1 -an bf.avi
That's the result of 'ffmpeg -i in_i.mxf -i tf.avi -i bf.avi -i out_i.avi':
Input #0, mxf, from 'in_i.mxf':
  Metadata:
    operational_pattern_ul: 060e2b34.04010101.0d010201.01010900
    uid             : 25e9aa02-7405-4800-809e-0700022483ea
    generation_uid  : 25e9aa02-7405-4800-811e-0700022483ea
    company_name    : CANON
    product_name    : XF105
    product_version : 1.00
    product_uid     : 060e2b34-0401-010d-0e15-005658460100
    modification_date: 2016-01-15T14:48:13.000000Z
    material_package_umid: 0x060A2B340101010501010D43130000000A25E9AB0274058000008500022483EA
    timecode        : 13:13:46:14
  Duration: 00:00:10.08, start: 0.000000, bitrate: 51874 kb/s
  Stream #0:0: Video: mpeg2video (4:2:2), yuv422p(tv, bt709, top first), 1920x1080 [SAR 1:1 DAR 16:9], 50000 kb/s, 25 fps, 25 tbr, 25 tbn, 50 tbc
  Metadata:
  file_package_umid: 0x060A2B340101010501010D43130000000A25E9AA0274058000008500022483EA
    Side data:          cpb: bitrate max/min/avg: 50000000/0/0 buffer size: 17825792 vbv_delay: N/A
Stream #0:1: Audio: pcm_s16le, 48000 Hz, mono, s16, 768 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D43130000000A25E9AA0274058000008500022483EA
Stream #0:2: Audio: pcm_s16le, 48000 Hz, mono, s16, 768 kb/s
Metadata:
  file_package_umid: 0x060A2B340101010501010D43130000000A25E9AA0274058000008500022483EA

Input #1, avi, from 'tf.avi':
  Metadata:
    software        : Lavf58.67.100
    timecode        : 13:13:46:14
  Duration: 00:00:10.08, start: 0.000000, bitrate: 98506 kb/s
  Stream #1:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p, 1920x540, 98889 kb/s, SAR 1:1 DAR 32:9, 25 fps, 25 tbr, 25 tbn, 25 tbc

Input #2, avi, from 'bf.avi':
  Metadata:
    software        : Lavf58.67.100
    timecode        : 13:13:46:14
  Duration: 00:00:10.08, start: 0.000000, bitrate: 98381 kb/s
  Stream #2:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p, 1920x540, 98763 kb/s, SAR 1:1 DAR 32:9, 25 fps, 25 tbr, 25 tbn, 25 tbc

Input #3, avi, from 'out_i.avi':
  Metadata:
    software        : Lavf58.67.100
    timecode        : 13:13:46:14
  Duration: 00:00:10.08, start: 0.000000, bitrate: 201187 kb/s
  Stream #3:0: Video: ffv1 (FFV1 / 0x31564646), yuv422p, 1920x1080, 201979 kb/s, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 25 tbn, 25 tbc

It might be just a metadata problem? Any ideas how to optimize?

Use the setparams filter to mark the frames as interlaced.
ffmpeg -i tf.avi -i bf.avi -filter_complex vstack,il=l=i:c=i,setparams=field_mode=tff -c:v ffv1 out_i.avi

Thank you very much Now, my NLE detects it as interlaced, at least when switching to a well supported codec, Prores. However, ffprobe shows 'top coded first (swapped)', instead of  'top first' and, tbn and tbc show 12800 (default), instead of 50. Not clear if this has any negative impact. I assume I have to create a new thread on this?


text:
How to automatedly synchronize video recording with pre-recorded music track?
When they film music videos ---ones that require the artist to lip sync in cooordination with a pre-recorded song--- do they synchronize

the moment that the cameraman hits the record button on the
video camera

with

the moment that the audio of the pre-recorded song starts playing?

What extra equipment is required to do this syncronization in an automated way, instead of with clapboards or flashing hand signals at people?
The idea is to minimize the divergence in syncing the video and audio files within a video editor upon import during post-production. Is there an automated way to have perfect synchronization during both recording as well as editing?

Music videos are often the easiest type of video to sync because they rarely (but sometimes) contain any live sound from the set. Usually, the people in the video are lip-syncing to a recording of their own music, which they’ve rehearsed many times, and have no problem repeating.
In postproduction, all an editor needs to do is replace the camera scratch audio with the original recording.  This is easy when camera scratch audio records the on-set playback to which the talent is lip-syncing, because the editor can either align the audio waveforms visually, or use software to sync the audio waveforms, automatically.  All of the major NLEs are capable of waveform synchronization, but third-party alternatives are also available.
In cases where there is no camera scratch audio, aligning visual cues to the music manually is also straightforward and effective.
But in cases where audio is recorded on set, with second system sound (an audio recording device other than the camera), usually the camera and audio are synced by “jam syncing” their internal timecode clocks together. Usually, also the camera slate (aka “clapperboard”) serves as a visual+audio sync cue.  Low budget sets will often only use a slate, and zero budget shoots will use a simple hand clap. Of these methods, only jam-syncing timecode provides an automated way to re-assemble the files.
In a nutshell, jam-syncing tells all synced devices to set their internal clocks to the same time exactly once, and then trusts that the devices are capable of keeping time accurately.  For a short music video, you are unlikely to experience significant drift between clocks, but for longer recordings, the inaccuracies between clocks can introduce sync errors.  In these cases, highly accurate timecode generators are often used to broadcast timecode continuously to all cameras and audio recording devices.  Ambient Recording’s Lockit box and Timecode Systems’ Timecode buddy are two names in this field.  For Jam-syncing, Tentacle Sync devices are also popular.


text:
I want to convert .mp4 to .ts using H264 at constant framerate 25fps
I've been trying to do this conversion for a couple of days reading through forums
ffmpeg -i in1.mp4 -vcodec libx264 -s 720x576 -vf "fps=25"-vsync cfr -b:v 2300k -acodec aac -b:a 128k out1.ts
I've tried the below flags found in other forums
-r 25
-vf fps=25
-filter:v fps=25
-filter:v fps=fps=25
I then read the file using mediainfo and keep getting the same result;
Frame rate mode                          : VFR
Frame rate mode                          : Variable
Frame rate                               : 46.875
Frame rate                               : 46.875 FPS (1024 SPF)

what is the .ts video format, and how does it compare to .mts?

@user610620 Please don't start a side-topic discussion in the comments. The difference between ts and mts is irrelevant here.

Seems like an XY problem. That is, you have problem X, but you erroneously think solution Y works well. The error here is likely that you probably don't want a .ts file.

Do not use ts, use mp4. MPEG-TS (.ts) and mkv default to VFR, while mp4 defaults to cfr. https://trac.ffmpeg.org/wiki/ChangingFrameRate
That is this bug. https://trac.ffmpeg.org/ticket/4768


text:
Best Systems for Storing and Organizing Videos/ Projects?
I’m just getting into video recording/ production and am looking for recommendations on best systems to upload, store, organize, and edit videos. Also want to make sure that the videos are backed up in multiple places. Currently using a Sony Alpha A7III. I love shooting video, but the organization part feels more daunting. Any advice on systems for organization or online classes/ tutorials about getting started?

The main goal of SE sites is to help people with their specific questions, not so much to help them get started in general. The reason is that the best strategy to learn something is highly individual. General recommendations are problemtic too, as we would need many more details in order to give a good recommendation. Which system works best is highly opinion based. Such questions are better discussed elsewhere, like in a forum, not here because this format is not suited for such discussions.

Instead, try to describe a specific problem you have, for example "I lose control over which clip belongs to which scene in the script. What can be done to improve that?"

Digital asset management is an entire industry. People with degrees in library sciences go into the field.


text:
Video Production outdoor in driveway? Filming me working on my car?
I've been planning on shooting a video in my driveway of me working on my car; How do I get the best lighting when I'm going to be filming all day?
I'm going to be welding, on the side of my car, replacing rust, and want to document for youtube. I've done so in the past, but the sun changing directions sucks.
I've thought about buying one of these ez-up tents, to get rid of sun glare, and get a soft box lighting kit to add my own light back in. But what are your thoughts on this? Am I on the right track?
I would close all sides, and drape one side over the portion of the vehicle that I am working on.

If the tent you get is white, like the one in the picture, you can point a light up into it, and then the tent becomes a giant soft box. The light loses a lot of energy doing this, because the tent material isn’t designed  to reflect 100% of the light striking it, but the same thing happens to sunlight going in the other direction, and any sunlight coming through the material will diffuse and contribute to the total amount of light. A setup like this runs the risk of being too soft, pushing into flat territory, so you’d want to add a second light to use as your key, and use tent as fill.
If you don’t want to have to buy a second light, you could try rolling up one of the sides of the tent, and using ambient daylight (not direct sunlight) to add contrast to the image.  The amount of contrast will vary through the day, however, and will require you to roll up/down the sides of the tent, assuming the tent sits in direct sunlight all day.
For close-up shots of work being done to the car,  an LED panel would be easier to position, and get in the way less than a large soft box, plus it would double as a work light.  The closer a panel light is to its subject, the softer the light appears, which is why they’re good for closeups.


text:
Tattoo removal video effect
Is there a video editor that has a video effect where tattoos on human skin can be motion tracked and filtered out frame by frame, either by blurring them, or replacing the tattoos with surrounding skin pigment?

You can do it in Premiere Pro. Google for "premiere pro mask tracking", you'll find loads of videos and tutorials. Usually people do it to blur faces, but in the same way it can be done with a tattoo

Assuming that it's not changing perspective or moving around too much, I would use a tracker on the tattoo and a clone stamp from another area of skin.  More elaborate removal could be done with Mocha, or using a mesh warping tracker like Lockdown, which has a demo of tattoo removal in their showreel at 0m24s:

Could you edit with a link to mocha

good idea - added

Might want to also mention AE's new content aware fill.

Could you go in more detail about what clone stamp is and settings for tracking skin pigment to mask the black tattoo with


text:
Premiere Pro: How to sync speed ramped audio with video from linked After Effects comp?
When linking an AE comp through PP, the audio won't sync. This has been an issue forever. I film skate/bmx videos and it's essential that the speed ramp syncs with the audio so you can hear the cool distortion of a slow mo grind. Sometimes I can get by just cutting and stretching audio in Premiere, but that is NOT a solution.
The ONLY thing that I found to work is to unlink the "composition" type from the attached MPEG clip. As soon as you click "replace with AE..." (in PP) and are automatically redirected, immediately delete anything in the timeline. Then, select the MPEG clip ONLY and drag it into the timeline again. There is no linked source info at this point, so your clip will play from the beginning as if you hadn't cut anything in PP. Because of this, in AE you'll need to go to Composition>Compositions Settings and find duration at the bottom. Whatever the AE comp length is will be what your original PP cut length was. Ex) If the original clip is 20s long, but you're cut is only 5s in PP, AE will only play the first 5s of your clip. So, change the duration to any length that you know will contain the part you'd like to edit. Usually, I just increase the time by 10s, and can always add length by going back to comp settings.
Edit your time remapping/speed ramp.
Once finished, go to Export>Add to Render Queue. In your timeline window, click on Render Queue and under "Output to:" change the name of your clip (if you'll have a lot of AE comps in PP). Click "Render" on the right of the window. Then in Premiere, import the clip from wherever you saved it and treat it like an entirely new clip.
There has to be a better way, but I haven't seen anyone come up with something easier so hopefully this helps someone.
Is there any way to keep AE comps linked to a PP project AND keep ramped audio synced?

Adobe Dynamic Link is a great tool, but unfortunately at the end of the day it can be problematic as it has its limitations. As After Effects is almost entirely focused on video, it doesn't surprise me that audio would be one of these limitations.
Before dynamic linking existed, we always had to do round-tripping (sending files to another program, working on it there, and then sending a new rendered copy back to replace in the original program's timeline). Visual effects work in the Adobe Suite that hits these limitations with linking, such as this sound-related one you've run into, just means that you have to resort to this old-fashioned method as you've found.
In fact because dynamic link can cause problems, if I'm doing anything other than basic text or whatnot I only use the "Replace with AE..." tool to send clips to AE. After it's sent over, I hit Ctrl+Z (undo) in Premiere to undo the timeline, breaking the link and getting back the original clip that I just sent in the proper place/time.
Therefore, I'm always exporting a fresh clip straight out of After Effects to drop into the Premiere timeline. There's a few reasons for this:

Dynamic linked clips in the Premiere timeline use a TON of processing power because it's doing the calculations for the dynamic linked clip on the fly, like when you play it back in After Effects without any ram preview cached. You've probably noticed that it can stutter and struggle to make it through a linked clip when you're playing through the timeline, and sometimes slow you down even when you're not looking at it because it's anticipating. For anything remotely intensive, I unlink after sending to AE to avoid this problem, and round trip it back.
Similarly, round-tripping also saves you tons of render time on the video when you're rendering out the Premiere file. Let's say you watch your final render and notice you misspelled something in the credits or a cut is off-time. Re-rendering means it's going to have to recalculate all of the dynamically linked clips again, whereas if you had your individually rendered VFX clips in the timeline, it can breeze through them as it's just a normal video file.
The dynamically linked clip is Premiere's interpretation of the After Effects file, and Tthis can cause some issues and visual glitches with dynamic link rendering just as can happen when dynamic rendering AE files in Media Encoder. These are usually really specific issues with transparency, color science, plugins, and even sometimes referring to the wrong composition or a seemingly old version.

I know it's quite annoying, but you've clearly gotten the basic concept of how to round-trip it without the link. Here's a few things that could help or improve your workflow:

Like you said, you can increase the AE comp time to give you more working room. However to avoid having to do it multiple times, I suggest you just add more time than you know you'll need, and use the "trim comp" tool at the end of your process. Drag the work area range to where your final length should be, right click it, and select trim comp to work area.
To expand on your point on organizing, my suggestion is to create a folder (in your OS explorer) parallel to your footage folder where you can save your new clips. Use a consistent naming convention so that you can always match it with the original clip. For instance, original file: A002_C003.mp4 should be saved as A002_C003-VFX001.mp4 or some other format which distinguishes it as the modified clip, and also allows for revision files to be created without having to go "-VFX-ACTUALfinalfinal2," hahah.

Additionally, I'm sure you'll be able to find some other ways to shave time out of your workflow. If you haven't already, try to learn the After Effects hotkeys as it will save you a lot of time with even these steps you're describing.
I hope I helped at least somewhat! Sorry there's not a more convenient way, but I also recommend reporting this as a bug to Adobe, as it really should be a true functionality.


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How can I have a sliding rectangle overlay between two videos?
I have two video tracks which are synced. I now want to have a vertical rectangle having the height of the video, to slide from right to left. Inside this rectangle, track 1 should be seen. Outside of it, track two. Unfortunately I do neither know the name of this technique, nor how to do it in vegas-pro-18.0.


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Scale from this resolution
I have the following mp4 file:
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:04:43.66, start: 0.000000, bitrate: 1704 kb/s
    Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1080x720 [SAR 1:1 DAR 3:2], 1573 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)

I want to scale it to 1280x720 and also change the aspect ratio to 16x9. I tried some settings from the documentation https://trac.ffmpeg.org/wiki/Scaling but to no avail.

Please provide the command you used, as well as more detail about what went wrong; "to no avail" is a bit vague.

@stib I managed to solve it. The video had bars on the top and bottom, so in addition to using the scale filter I had to use the crop as well: -vf "crop=in_w:in_h-110,scale=1280:720,setsar=1"


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"Calls" trailer on Apple TV - how was it made?
Does anyone have any insights into how this trailer was made?

I'm guessing After Effects - a lot of Trapcode, waveforms, chromatic aberration etc, but what about the moiré patterns in the waveforms?


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Exporting video layers for Premiere-DaVinci workflow
I am editing in Premiere, and sending an XML to a colourist working in DaVinci Resolve. We chose to colour after picture lock in order to reduce the colourist's workload. All of the tutorials I have seen recommend flattening the timeline into one video layer (eg. There and Back Again - Frame.io). However, I have several sections where the layers are neccesary, and their timing is important.  This answer gives a brief overview of a possible workflow, but doesn't address the layers issue.
What are the best settings or workflow to make sure that the layers can be exported for DaVinci and maintain their place in the timeline?

It’s recommended to “flatten” all layers before attempting to conform, but it’s not strictly necessary.  Just make sure you export a reference video, and check all of the footage in resolve by importing it as an “offline reference video”. Resolve’s manual lists supported transformations, transitions, etc, but some things won’t translate 100%, like usually titles and fonts are a little off, re-timed clips might be off, etc. Fixing these issues is all part of the normal conform process. Premiere round tripping is a huge hassle that’s easily avoided by editing in resolve.

This video has a solution using Project Manager to export all clips individually, so that layers can be exported separately.
File > Project manager - Make sure your working sequence is selected.
Under Resulting Project> Consolidate and Transcode,  source: Individual Clips
Adjust the number of handles you want (extra frames on either side of the clip)
Choose your destination path, then OK to transcode.


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MKV file corrupted
I use the movavi screen recorder 10 program for screen recording. However, today, when I finished recording a video, the program stopped responding and I had to close it forcibly. Conclusion: the video has been corrupted. Is there any way to get it back?
OBS: I am completely stupid in informatics. If you can be patient, thank you.

Maybe there are parts of the file intact. But it's better to contact the publisher of your recording tool for support. Maybe they can tell you why this happened so you can avoid it in the future and they know best if there's a chance to recover part of the recording or not.

2 things to try here

See if you can open it up in any video player you have on hand that can read the mkv file as mkv's do not require finalization to be played generally though they will only show the timestamps for the section that is currently playing.
Open it up in OBS and Use the Remux Recordings option to rerender your file and save it properly so all the finalization data is included


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Easiest way to add subtitles
I'm tasked with translating and putting hard subtitles on dozens of videos. This is the only thing I will be doing to the videos and I have 0 experience with video editing. I am a programmer though. What's the most productive process/apps to accomplish this (just downloaded Lightworks)? Most video editing software can do this but isn't exactly optimized for this specific thing.
Right now I'm thinking about using a dedicated subtitle app to create softsubs and then ffmpeg to apply it to video? But as someone who's never done this before it seems easier to use the timeline function of video editors when creating the subs? Any advice please?

For subtitle timing, I would suggest Aegisub and save the subtitles file as *.srt, then you can add the subtitles and export your video with ActivePresenter


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Add a cross-fade to a ProRes clip
I have a ProRes 422 HQ trailer clip that is about 70 seconds. I would like to add a 0.5s cross fade (to black/silence) at the head and tail of the clip. The output file must have the exact same characteristics as the input file.
Where I'm starting at is something like (in ffmpeg):
ffmpeg -i "concat:??|trailer.mov|??" -c copy output.mov

Is there a way to do this with ProRes 422 in ffmpeg. If not, what other tools might work for this kind of thing? Note: all the video files are on a linux server, so it's something I'd need to do via a command-line and not something like Final Cut.
Is this possible to do in Compressor via command line, or what might be the best starting place to try and do this?

Will the fade-in/out add to the duration of the clip or take effect on the first and last 0.5 seconds of the existing clip?

@Gyan It wouldn't add to the duration.

Then the easiest way is to use the fade filter and re-encode the video.

@Gyan on what -- ffmpeg you mean?