text:
How to combine front and rear dash cam video in split screen without gigantic file size?
I have a three camera dash cam (front, rear, cabin). The front is 2160p and the rear is 1080p. I would like to combine two simultaneous videos (front and rear) into one 3840 x 4320 video (stacked vertically, 1080p  upscaled) without producing a gigantic file.
I tried to do this in OpenShot with a custom profile, and it was "successful" in that the video was formatted correctly... but it was 17GB and took 5 hours to render on my 5950x. The source files are 2:00 long and 240MB and 80MB respectively. I would like a video similar in size to the combined size of the source videos.
Any tips on how to combine them without a bloated, rendered vid?

The reason your exported file is huge is likely to be due to the Export settings chosen when you exported. The resolution you're planning to export at (3840 x 4320) is larger than 4K which is realistically the largest format most people use for viewing videos.
I would try re-exporting your final video as an mp4 video with an h264 codec at 3840x2160 resolution with a bitrate of 12Mb/s, and see how the exported video looks in terms of quality and file size.
Quality and file size are a trade-off. For a given codec and resolution & frame rate, larger files (higher bit rate) will result in higher quality files.
I don't know the OpenShot software, but from the look of the manual, you can manually adjust the export settings in this window:

YouTube has a guide to bitrates etc here which is useful for working out export formats even if you don't want to publish to youtube:
https://support.google.com/youtube/answer/1722171?hl=en#zippy=%2Cbitrate

So there's no easy way to just use their existing bitrates and file sizes to infer a reasonable bitrate for the combined video? That's the frustrating part for me. I don't understand why the file sizes aren't marginally additive (obviously somewhat bigger for the upscaling of the 1080p video)


text:
What does Dolly do in AE?
Looks like Dolly works like Scale, just increase the size of the object. So, what really does Dolly?

Dolly moves your camera closer to the object.
Scale makes an object bigger. They're not the same thing.

You're writing about the camera, but the Camera layer is not even created. I just turned on the 3D mode.

In that situation where there is no camera, AE just uses your viewpoint. As soon as you add a camera, AE uses that. You'd have more success watching a beginner's guide to AE than asking each question on here piecemeal.

This is old, but it's a great solid understanding of how AE works, and has a section on 3D stuff: https://www.videocopilot.net/basic/

there is one question left, what does dolly to camera poi tool? Adobe writes that there is POI only for two-node cameras. Looks like this option should work only for two-node cameras

source: Stack Exchange

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

sort: votes


text:
Vocabulary/Industry Term - Raw Video with unusable parts removed?
I'm new to video, so be gentle.
I have a lot of log(Apple, NLOG, GoPro) videos coming from various cameras, and the files are huge, so I'd like to cull them down to just the usable bits but still keep them in the original log format.  For an hour of video, maybe 5 minutes has something of value, and I'm thinking of disk space in future. These are essentially going to be B-roll clips for multiple projects.
Is there an industry term for these kinds of files?  They are original/raw but edited down, so not really.
Also, if anyone else does this...care to share your workflow around Media management?  I'm using DaVinci Resolve but would like to keep these media files organized/tagged/meta data independent of software or OS (MacOS).
I understand the Bin idea in DaVinci Resolve, but it seems to be a per/project thing. I want to do this across projects.

Can't answer for Resolve, but in Adobe Premiere, this process is called Consolidation - you trim the clips you want, copy the project to a new location, but only the trimmed parts of the video are copied. Be warned, as someone who has worked in video for a while, I never ever do this. Storage space is relatively cheap, the chances of disaster are quite high, especially because Premiere's Project Manager panel used to be quite unreliable and slow. Much better to keep everything imho.

Thanks.  I agree, but I just spent $600 to add more disk.  It hurts!

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


text:
Why does my After Effects Comp jump in Premiere Pro Preview
I have an After Effects composition that I imported into Premiere Pro. It has the same resolution and frame rate as my Premiere Pro project, and I can import it without any issues. However, when I preview my After Effects composition in Premiere Pro "Berwang," it starts to shift to the right when I either edit the position or scaling or simply press play.
Take note of how the red line connects to the roof of the church in the first paused preview picture. In the second picture, you can see how far the red line jumped to the right milliseconds after i pressed play.

It seems like the preview is wrong when its paused. When I render the viedeo i get the result of image 2

Not to sound like a downer, but the bridge between Premiere and AE has always been a dumpster fire. I would always recommend rendering your AE comps first and replacing proxies in your Premiere timeline with the renders.


text:
Change Opacity of Layer based on pixel value of another layer in PremierePro/AfterEffects
I'm trying to black out/censor segments of a screen-recording. I basically need something to check the color of a pixel on the video, and if the color does not match, it somehow censors the section of the video.
Example:
The source video needs to have at position 100;150 the color #f3f3f3. If this condition is true, just display the clip normally, if it's some other color, change the opacity to 0 or apply a blur.
(preferably in AfterEffects or PremierePro)

Below is how to change the colour of a shape in after effects based on the background colour at a given position:
Put a null on the position you wish to sample.
Put this expression in the fill colour of the object you want to change:
target = thisComp.layer("BGLAYER");
colorpicker = thisComp.layer("sample 1 null");
target.sampleImage(target.fromWorld(colorpicker.position), [0.5,0.5], true, time)

BGLAYER
is the name of your background layer (eg your video)
sample 1 null
Is the null which is colour picking
You will also need a conditional statement in the expression to switch its opacity on or off - I'm not sure how to do that, but will add it to this answer if I work it out.


text:
Is there a way to erase this white dot through 2 minutes of video?
I recorded a video explaining some complicated things, and when I looked on the big screen, the spotlight is reflecting off my nostril creating a shiny white dot which can be confused with the most worst bogey situation that a human could suffer from, and i was like WHaaaat? Eeewww? It's only a reflection of a spotlight but it looks reeeealy freaky. Is there a way to erase the white dot as it moves through 2 minutes of video?

I don't think it looks that severe, but you'll probably have to do this manually... That's a lot of frames:

Duplicate your video layer.
Turn off the original video layer and select the new one.
Make a small circular mask over the area you want to fix, just slightly larger than the suspicious white area.
Set the mask to None, so it doesn't make a hole for now (we will change this later).
Enable the Mask Path stop-watch on the mask, so that you can animate the position of the mask frame by frame.
Move the mask frame by frame so it always covers the bogey, or whatever was up your nose...
Now set the mask to Subtract, so it cuts a hole.
Open the Content Aware Fill panel from the Window menu.
Click Generate Fill Layer and wait a while.

It will probably work pretty well.. If it doesn't, try adjusting the mask or the alpha expansion - more info here.
If you want to avoid manually moving the mask in every frame:
Instead of step 6, you could try tracking the position of the suspicious white area with a 2D tracker instead, apply that track to a null object, then parent the first frame of your mask to the null instead.
But I suspect a manual move will work better, because the tracker usually needs continuous areas of different contrast.
(Also try coffee instead, it leaves fewer marks)


text:
Loop video for the duration of audio
I have a 10 seconds video clip and 60 seconds audio clip, so when I mux it with
mkvmerge --output video.mkv ./a.mp3 ./a.mp4
The output file shows the video only for the first 10 seconds, and then the last frame is displayed for 50 seconds.
How can I loop the video in automatic mode so that it repeats for the whole 60 seconds with mkvmerge or any other command line tool (I need to automate it as I have to do it for 400 files)?

To merge an audio stream with a repeated video stream
ffmpeg -stream_loop -1 -i 20s.ts -i 120s.mp3 -map 0:v:0 -map 1:a:0 -shortest -c copy output.mp4

-stream_loop -1 : to loop infinity of video input stream
-map 0:v:0 : pick the video of the first input stream
-map 1:a:0 : pick the audio of the second input stream
-shortest : select the shortest length of input streams, which is the audio stream since the video will be looped infinity
-c copy : no video and audio transcodes.

It worked, thanks!


text:
Software for speeding up a video
I want to speed up a video clip in the order of 10x. However, I wasn't able to find a suitable software for that. I tried Movavi but the maximum speed up is 1000%. So I am not able to change the speed by 40x. Any recommendation for that?

What platform are you on? What’s your budget? Do you have any existing video software you would prefer to use?

I am using windows. A trial version is enough I think. If the software is good, I will go to the next steps.

Have you tried to use FFmpeg already? It's a very versatile command line tool.
Here is a dedicated page with a lot of examples on how to speed up/slow down a video with it.


text:
I can’t resize anything in After Effects
I’m currently working on animating a PSD file on after effects. I imported a video into after effects and manipulated it, I’m not sure what I did but out of nowhere the video disappeared. So I went into a subfolder and re added the video there. But once I went back to the whole document, the other video appeared but now I can’t resize them, none of the little square in the corners appear. But when I go into the sub folder it works there, I can resize things. What can I do to be able to resize everything again?

maybe you pressed cmd+shift+H ? This toggles the wireframe views around each object on or off?
Also, you might find this beginner's guide to AE helpful. It's old but it definitely helped me:
https://www.videocopilot.net/basic/


text:
Remove (or reduce) background music, and emphasise the background voice
I have a video with some people talking, but the music cover the people voices.
I can find the music with app like Shazam.
I know that remove the music is impossible. There is a way for reduce the music and emphasize the voice, maybe, with the music track of the song i can apply some filter remove similar sound...
I have installed Audacity and played with equalizer, without any good result.

You already tried EQ unsuccessfully, but there is one more technique worth trying:
Add the original music again to the soundtrack, but with inverted samples. This will cancel out signals. For a bit more theory, check out Wikipedia and the graphics on the top right which illustrates what will happen. The success depends on the mix and applied effects in the video soundtrack.
The basic steps are as follows:

Import soundtrack and import the original music on a separate track (probably that are pairs of stereo tracks)
Sync/align the music track so it matches exactly the music soundstrack. Be aware that the music in the video could have been slowed down or sped up a little bit. Apply the change speed effect on the imported music in this case to make it match.
Try to match the levels of the music track to the music of the video track for best results. Not sure if this can be done automatically in Audacity. Look for a short section on the video track where nobody's talking and compare levels there.
Invert the audio. More on Audacity's invert here.
Mix the track with inverted music to the video soundtrack. (Since both will probably stereo you can try multiple combinations, either add the inverted left to soundtrack left and inverted right to soundtrack right. Or switch them.) I don't know Audacity well enough to tell you how the mixing works. I only ever used it sporadically many years ago.
Music will cancel out or be removed to some degree.

The problem is: if they have applied any effects on the music in the video soundtrack the cancellation may not work well.


text:
How to combine multiple audio tracks without sounding blasted?
Was going to make a combination of 9 covers of people singing the same song. I have it synced already and it is on sync, problem is its just sound like literal ear ache when played.

How to fix?

When you record each track, make sure that the level never goes up to zero on the meter.  If it hits zero, it means that the recording is clipping.  Clipping is when the computer can no longer accurately record the waveform. So instead of recording the shape of the wave, the upper and lower limits of it will be clipped in a straight line. So a tone sound like a sine wave would be clipped as shown below (the black line), instead of looking like the original wave (the grey line):

This results in a very distorted and unpleasant sound.
When you mix multiple tracks together, the combined sound is louder than a single track on its own.  So you will need to make sure that the overall level of your project is also not clipping.  If it clips, you will see the meters in Premiere go red like this when they are clipping:

You need to make sure there is no clipping anywhere in your signal chain, from recording to mixing the final audio.
Assuming the source material isn't distorted, you probably just need to reduce the level of each track in Premiere using the Audio Track Mixer (go to the Window Menu and select Audio Track mixer, and the name of the sequence you're working on).
The Track mixer adjusts the audio on each track.  It is different from the clip mixer, which adjusts audio on each individual clip.
So you might have many clips on a single track, and instead of adjusting each one separately, you can just adjust the whole track once.

If you find it difficult to understand the relationship between the audio level meters and how loud something is, consider using the loudness meter. You can ignore the graphical part of it, pick a target loudness (-24 LKFS is a good target) and adjust the audio tracks so that it measures your target loudness for as much of the piece as possible.


text:
How to change the text box size in After Effects?
I want to use this free preset: https://motionarray.com/after-effects-templates/upbeat-opener-1190720/
It has text like "hello" and "it is a fresh idea". If I want to use different text, then After Effects will crop it. How can I make the "box" bigger?
I'm trying to apply this:
idea -> it is a long long text
I see there is a project view and it has text added there. Can I adjust the textbox there?

To change the length of the text used in this project, you would also need to change the dimensions of each comp used to hold the text.  So for example in "BLOK 1" there is a comp called "Text01" that is 1576x500.  If you want to make it longer you can (using the Composition --> Composition Settings menu item), but then you will also have to adjust the animations in BLOK 1.
E.g. here I have replaced the first word with "length" and the letters "g" and "h" are cropped:

If I change the width of the comp to 1676x700, it is no longer cropped:

But if I go back to the BLOCK1 comp, the text no longer fits nicely into the boxes:

So you would have to adjust the animation on"Shape Layer 1".
If you select the layer and press u you can see it has some animation key frames on it - it is a straight line which changes length and stroke width (thickness of the line):

After a while it becomes easier to make your own animations than it is try to tweak other people's.
I highly recommend this free course to get to grips with the basics of After Effects that you would need to continue tweaking this project.


text:
Bounce effect is not working
I have applied 'bounce effect' following the rules. The first keyframe of scale was 0 and the second one was 100. but the scale gets bigger after second keyframe, increase its size.
Why is this happening? please help.

Bounce expression-

amp =2;
freq = 2;
decay = 4;

n= 0;
if (numkeys > O){
n = nearestKey(time).index;
if (key(n).time > time){
n--;
}}
if (n == O{t = 0;
}else{
t= time - key(n).time;
}

if (n > 0 && t < 1){
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{
Value;
}

Can you add the expression itself, and maybe a full size screen shot too please? Hard to see what's going on

Yes, as usual Like I add expressions. But this one is not working. I dnt understand why the GIF is so small. :(

Add the expressions as text into your answer, and add a single JPG or PNG screenshot (under 2MB)

Done. Kindly check.

I think the reason your shape is growing too large is because you have set the amplitude to above 1, ie greater than 100% of the original size.
I think this is based on Harry Frank's inertial bounce code.
If you use his code, and his suggested values:
amp = .1;
freq = 2.0;
decay = 2.0;
n = 0;
time_max = 4;
if (numKeys > 0){
n = nearestKey(time).index;
if (key(n).time > time){
n--;
}}
if (n == 0){ t = 0;
}else{
t = time - key(n).time;
}
if (n > 0 && t < time_max){
v = velocityAtTime(key(n).time - thisComp.frameDuration/10);
value + v*amp*Math.sin(freq*t*2*Math.PI)/Math.exp(decay*t);
}else{value}

Applied to a scale control with two keyframes of 0% and 100%, you get this effect, which I think is what you're looking for:

Thank you so much.

no worries. If you're after an easier way of doing this - Mograph Motion is a brilliantly useful set of motion tools, and their excite functions give you lots of control over this stuff.. Not free but worth every penny https://www.toolfarm.com/buy/mt-_mograph_motion/


text:
Does Davinci Resolve have a magnetic timeline?
So I just switched from Final Cut Pro to Davinci Resolve. I feel general good since Davinci is more powerful overall. But one thing I do miss is the magnetic timeline. Are there any alternatives in Davinci to get a similar experience to the magnetic timeline in FCP?

Resolve does not have a magnetic timeline, but it does have ripple delete where when you delete a clip it will slide everything over. This is done via the Delete key (not backspace) or ctrl backspace on Windows, and command delete on Mac. Hope this helps!

Thanks so much Logan, I'm on a mac, and I find Shift+Delete will do the trick. I would also like to know if I can make it a default behavior for the Delete key?

Sure! To do keyboard customization,  click on the 'DaVinci Resolve' menu in the top menu bar, then click 'Keyboard Customization'. You can pretty much bind most functions to any key and additionally see what functions are already bound to certain keys.

it's fabulous my man! thanks so much! May I ask an additional question: does Davinci have anything like the skimming feature in FCP?

In DaVinci Resolve there is scrubbing which is basically just dragging the cursor across the timeline and you can turn on audio scrubbing by hitting shift+S. There is also the scrubbing by hovering your mouse over clips in the media pool. If it isn't already on, click on the source viewer menu (3 dots in upper right) and check the Live Media Preview checkbox.

Thanks so much my man! Is it possible, again, to make scrubbing a default behavior for hovering? (in the edit view) I'm using a trackpad so dragging means three fingers. I still prefer one:)

Oh, sorry for the really late response, got locked out haha. Are you talking about in the timeline or in the media pool?

In the timeline. Yes I admit I miss the "skimming" feature. What I want is another final cut but with powerful features from Davinci. I know I'm asking to much lol:

Yeah, unfortunately you cannot scrub through the timeline without moving the play head. There might be a 3rd party plugin you could install, but that may take some digging. Let me know if you find anything! I'll do some research when I get home.


text:
Which text animation is this?
I guess it is an After Effect text animation. Starts at 00:13

I did search a lot here, but did not found it: https://motionarray.com/browse/after-effects-templates/

You don't need a template to do this.
The font is a variation of Zolina according to WhatTheFont:
https://www.myfonts.com/products/bold-zolina-7192
The animation is a series of masks revealing the text, and a stylised dot on the letter "i".  The dot on the "i" is then rotated.
Enter your text on a layer.
Make a new shape layer above it, and draw some paths such that the text is obscured. It might be easier to use a different colour, so you can check you have fully obscured the original text with your paths.
Add a trim path to your shape layers, and animated the end of the trim paths, to make the shape layers grow over time.  You could trim all the paths at the same time, or animate them one by one:

Then set your text layer to be a Track Matte, using the shape layer you created above it:

Do this for all your letters.
Then after that, make a new shape layer for the dot on the "i", and animate it like this - note the position of the anchor point to make the rotation move appropriately:

Wow, that is a comprehensive help, thanks :)


text:
How do I define the vertical position of all subtitles across an entire sequence in Premiere 2024
I'm using the modern subtitling system built into Premiere 2024
I want to adjust the vertical position of all subtitles in my sequence.
My steps:

Double click the subtitle to be altered
Adjust the y position in the Alight & Transform panel in Essential graphics.
Save the Track Style in the Essential Graphics panel
Click Redefine Style in the panel.
Apply to All Captions on Track

None of the other subtitles are adjusted vertically.
Video example:
https://vimeo.com/956604482/f5994c8041


text:
Kodak's h263 MOV files - letterboxed on playback - how to force editors & VLC to use "width" instead of "original width"?
I found a lot of family movies in my old Kodak DX6340 digital camera. Unfortunately, none of the editors (Filmora, Davinci, Movavi, MovieMaker) or any player (except Apple QuickTime Player) can display them correctly - the bar always appears on the right and at the bottom:

I spent many hours looking for the reason and it seems to me that it is because:

Kodak used H263 as the codec H263 codec has a native (one of many)
resolution of 352x288 (does not support 320x240)
Kodak in its camera specifications: (Camera Manual) states that the
videos are 320x240 and that is how they are played when I connect the
camera to a TV with a cable or when I play them on my computer using
QuickTime Player:

The MediaInfo application gives the same size:

And now the most important thing: MediaInfo gives the following data:

With/Height = 320/240, Original Width/Original height = 352/288, Display aspect Ratio = 4:3 So, when I try to open this MOV in movie editors or players - those applications look at the wrong parameters. They should look at 320/240 and 4:3. And they look at 352x288 (additionally - it is not 4:3!) so then they artificially draw this black bar on the right and at the bottom.

Is there any way to force the appropriate interpretation on the MOV header? For example, by modifying this header somehow? If anyone would like to see it on their own, I am attaching this MOV file: link 1
Please do not let me crop/resize the MOV, it has only 320x240, I don't want to lose details (if I can say that 320x240 could have details...;-) ) and do not want to deform (stretch) the picture.


text:
Davinci or Premiere or After Effect. Tag then count the tags
I have videos of hundreds of people walking from right to left. They're not perfectly in a line, but it's quite sparse enough. I'd like to draw a tag on each of their head and count them. How much of it can be automated? Basically, the method I'm thinking about is something like:

Do a face recognition when a person enter the screen.
Put a tag (i.e. draw a physical red rectangle on the head). Step 1 and 2 might have to be done with multiple passes.
Count the tag when a person exit the screen (i.e. count the rectangle).

I have Davinci, but can access After Effects or Premiere if necessary. Thanks.

I think this kind of thing is more commonly done using Python and OpenCV, rather than video editing tools. I don't know of a plugin or process that allows you to continuously track multiple heads in After Effects, although if someone did manage to integrate the code from something like this:
https://data-flair.training/blogs/python-project-real-time-human-detection-counting/
into AE or Premiere, I could see that it could be useful for security & forensics work.


text:
How can I text-to-speech all subtitle fragments at once into another language?
People. Who knows how to use CapCut? How can I text-to-speech all subtitle fragments at once into another language? CapCut allows you to automatically create subtitles for a video and then translate them into another language. CapCut then has the ability to convert each such fragment into a voice. This way, you can re-voice the video into another language. So far, I know how to re-voice each subtitle fragment separately. I select a subtitle fragment, click "Text to speech", select a voice, and it re-voices this fragment. Question: how to make it re-voice all fragments at once, all subtitles, so that I don't have to do it piece by piece? Here is a screenshot. The orange fragments above the video are text subtitles, the green fragments below the video are the voiced fragments. Thank you.


text:
How to convert 32-bit RGB bitmaps to video losslessly?
I have a number of images in RGB bitmap form (8 bits each for red, green, blue; each pixel is 32 bits). I want to convert these individual images to a video, showing each image for 1-2 seconds, using C++ code in my app.
It is important that the images in the video be pixel-by-pixel identical with the original bitmap pixels. Lossless, in the mathematical sense. I am not concerned with file size, etc.
The resulting video needs to be playable on VLC, and preferably on other common media players.
The two approaches I have considered are the ffmpeg library and Windows Media Foundation using the x264 video encoder. From what I read in user postings, ffmpeg H264 encoding cannot be made absolutely lossless, and Windows Media Foundation doesn't support the x264 encoder. I cannot tell whether x264 is completely lossless, either.
I'm looking for advice as to how I can meet my requirements. I have a strong preference for not using any procedure than involves writing intermediate files.

The Quicktime Animation codec can be set to lossless. I think VLC is supposed to support it? Any lossless codec is lightly to be quite burdensome for playback, so it might lag, jitter, have large file sizes etc. It is quite an old codec, there may be a better format to use now.

Might be helpful to say what the overall purpose is? Do you definitely need lossless? Eg, is it for archiving, for scientific analysis?

It's a visualization of scientific data. The final frame rate should be in the range of 0.5-4 frames/sec, so the computational load of playback shouldn't be too great. Also, the image resolution is 640 x 512. The final video will be fewer than 300 frames.

Assume you've seen this - https://video.stackexchange.com/questions/7903/how-to-losslessly-encode-a-jpg-image-sequence-to-a-video-in-ffmpeg

I hadn't seen that, and it's certainly useful. I actually need two different things: a way to get RGB bitmap as input to an encoder, and an encoder and container that will output a lossless version of the input.


text:
Screen record Mac with computer audio and ambient audio soundtracks
I'm making a video trailer for a little arcade-style game that I'm putting up on Steam. This is not a major production, and I'm not going to spend a bunch of money on equipment. But it's a multiplayer game, and in my humble opinion the human sound effects are every bit as delightful as the game sound effects, as the kids yell and exclaim after hitting each other.
So: I want to screen record while recording BOTH computer audio (game sounds) AND ambient audio through the laptop's microphone. I can see how to merge the two streams using Loopback. But wouldn't it be nicer if I could record the two soundtracks separately and mix them later? So I'm looking for recommendations as to how this might be done – inexpensively, with software. By the way, I'm on a Mac.

OBS can screen record, record from a mic and record system sounds, and it's free.
Screenflow can also do this, isn't free, but is easier to use.
Zoom allows you to record system sounds and mic sounds during a call, which might be another free option.
Quicktime can screen record, and mic sounds, but not system sounds unless you use a workaround like soundflower or loopback. This is fiddly.
You could record ambient sounds from another source, eg Voice Memos on an iPhone, and re-sync the audio afterwards with a free video editor like DaVinci resolve or CapCut.


text:
Why does Facebook and WhatsApp refuse to play these clips?
I just received three video clips via Facebook Messenger, but they refuse to play (or show a preview) in many circumstances. Why?
I did a ffprobe on them:
ffprobe version 4.4.4 Copyright (c) 2007-2023 the FFmpeg developers
  built with Apple clang version 15.0.0 (clang-1500.1.0.2.5)
  configuration: --prefix=/opt/local --cc=/usr/bin/clang --mandir=/opt/local/share/man --enable-audiotoolbox --disable-indev=jack --disable-libjack --disable-libopencore-amrnb --disable-libopencore-amrwb --disable-libxcb --disable-libxcb-shm --disable-libxcb-xfixes --enable-opencl --disable-outdev=xv --enable-sdl2 --disable-securetransport --enable-videotoolbox --enable-avfilter --enable-avresample --enable-fontconfig --enable-gnutls --enable-libass --enable-libbluray --enable-libdav1d --enable-libfreetype --enable-libfribidi --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libzimg --enable-libzvbi --enable-lzma --enable-pthreads --enable-shared --enable-swscale --enable-zlib --enable-libaom --enable-libsvtav1 --arch=x86_64 --enable-x86asm --enable-gpl --enable-libvidstab --enable-libx264 --enable-libx265 --enable-libxvid --enable-postproc
  libavutil      56. 70.100 / 56. 70.100
  libavcodec     58.134.100 / 58.134.100
  libavformat    58. 76.100 / 58. 76.100
  libavdevice    58. 13.100 / 58. 13.100
  libavfilter     7.110.100 /  7.110.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  9.100 /  5.  9.100
  libswresample   3.  9.100 /  3.  9.100
  libpostproc    55.  9.100 / 55.  9.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/tmp/arXHwP4h.mp4':
  Metadata:
    major_brand     : mp42
    minor_version   : 1
    compatible_brands: isommp41mp42
    creation_time   : 2024-09-16T18:47:30.000000Z
  Duration: 00:00:28.50, start: 0.000000, bitrate: 1875 kb/s
  Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668), yuv420p(tv, bt470bg/bt470bg/smpte170m), 1024x576, 1586 kb/s, 27.06 fps, 30 tbr, 90k tbn, 90k tbc (default)
    Metadata:
      creation_time   : 2024-09-16T18:47:30.000000Z
      handler_name    : Core Media Video
      vendor_id       : [0][0][0][0]
  Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 287 kb/s (default)
    Metadata:
      creation_time   : 2024-09-16T18:47:30.000000Z
      handler_name    : Core Media Audio
      vendor_id       : [0][0][0][0]

More details: the clips originates on an Android phone and was then transferred to me using Facebook Messenger. On my Mac/Firefox, in Facebook Messenger, the clips are showed like this:

OTOH, in FB Messenger on my Android phone the clips play fine. If I download them to my Mac I can play them in VLC but when I try to send them using WhatsApp it refuses to send them as videos, instead I have to send them as attachments (and they don't play in WA).
Generally I never have this type of problem on neither my phone nor my computer.
What is "special" about these clips that make them incompatible? Can I fix it in ffmpeg or so?

My first impression was about the video codec HEVC or H.265

Stream #0:0(und): Video: hevc (Main) (hvc1 / 0x31637668)

Whatsapp supported video codec would be H.264, my suggestion is to convert the streams by ffmpeg as
ffmpeg -i myFacebook.mp4 -c:v libx264 -c:a aac myWhatsapp.mp4


text:
FX Console crashing AE 2024 when I take a snapshot then open its gallery
What it says... FX Console v1.0.5 is causing a crash every time I take a snap shot then try to view it in the gallery.
Even on a new project with one empty comp.

Which is a shame because I use it all the time. Any workarounds?
MacBookPro M1 Max running Sonoma 14.6.1 with AE v24.6.1

I was running into the same problem as you. I just found a solution that worked for me. I opened FX Console settings, reset settings in there, cleared the cache and then selected a save location folder. Now everything works again. For how long I do not know.


text:
Automatically generate and estimate timing of subtitles from manuscript
I'm looking for a tool where I can paste in my manuscript and get out subtitles. The point of this is that the software should automatically try to estimate how long time it will take for the text to be read.
Do you know of any tools like this?


text:
Importing files at the cursor instead of the beginning of the timeline
I would like to import files at the cursor on the timeline, instead of the beginning as After Effects does now. Would make it much more practical, but I do not see a option to make that happen.
Is there  way to make this happen?

I don't think it's possible. But you can use a single keyboard shortcut to jump any of your selected clips to the cursor point: Press [.


text:
Video of typing text on an angle
I saw this video (https://pin.it/119U75R) and I want to do something like it but I don't know what it's call to search about it, so can you help me how I can search about it?
I would like to make text like typing in this way with an angle.

There are a few different techniques going on in this shot.
First the text was all made in 2D:
The hand-drawn text was probably made in 2D first, then revealed with a mask either line by line or using a plugin like QuickDraw.
The printed text is being animated on character-by-character using text animators.
Then that 2D layer has a paper layer added behind it, some drop shadow added to it as a Layer Style maybe.
Then all of it is placed into 3D, with some camera moves on it (this is an old tutorial, but the whole set is great for getting to grips with After Effects)
There's other stuff going on in that clip, but that's the basics of the text effects.

thank you <3
it's clear


text:
Headphone for recording voice for YouTube
I want to record my voice for YouTube videos. So should I get a headphone with mic like Senheiser GSP 300 or a microphone separately and a monitor headphone..?

The quality of the headphones will only affect how the audio sounds to you, so you don't necessarily need to spend your money on that to improve the audio for a youtube video. I would suggest focussing your money on the mic itself.
This is a great roundup of relatively inexpensive mics, with audio clips so you can hear how they sound.
Gaming headsets tend to have relatively cheap mics in them, and you need to be really careful about the mic's position.  Too close and you get breath noise and popping sounds. Too far away and you get room noise and hissing on the audio.

Thanks @tomh...


text:
Using Secondary HSL in Lumetri on a masked part of a clip
I am grading a clip of video in Premiere CC 2018 using Lumetri.
I have a clip where I have done an overall Basic Correction.
I now want to brighten faces using the HSL Secondary.  There are other areas of my clip which contain similar colours, which I do not want the HSL Secondary to affect.
Currently I do this:

Make the basic grade
Copy my lumetri settings
Paste them onto the same clip again so there are now two sets of Lumetri effects on the clip.
Switch off everything except Secondary HSL on my new copy of
the Lumetri effect.
Mask the area I want to brighten on the second version of Lumetri
Apply Secondary HSL to the masked area.

My question is:
Do I have to use two Lumetri effects on a single clip to achieve this with a mask?

I think the answer might be "yes". Or another answer might be: use a colour grading application.

See below for a very useful answer

You do need a second copy of the Lumetri effect, but you don't need to duplicate the clip, whether or not you keep the extra copy.  Instead of your current workflow, try using Adjustment Layers:

Perform your primary color corrections as you normally would on a single lumetri instance.  By "primary color corrections," I mean white balance, exposure, overall adjustments, and anything that affects the whole frame equally.  No matter what color grading software you use, it's best practice to keep these "color primary" operations logically distinct from operations which require keys, masks, mattes, windows, etc.  One reason for this is that keeping primary adjustments logically distinct allows them to be baked into LUTs (a topic for another discussion).  But as you've discovered, it also helps keeps your work organized so that local adjustments can be accurately targeted.
Add an adjustment layer.  To do this, make sure your project panel is active by clicking in it, go the the File menu, and select New->Adjustment layer.
Drag the new adjustment layer from the project panel to your timeline and drop it on a layer that's above your footage.  In a sense, Adjustment layers are "empty" because they don't contain any video information, but in another sense, they're "transparent" and let you stack effects.  It's because of this transparency that you don't have to duplicate the underlying lumetri primary correction that you performed earlier.  The white balance, exposure adjustments, etc, "show through" to the adjustment layer.
Draw your mask on the adjustment layer, and perform your "color secondaries" there by adding a new instance of the Lumetri effect to the it.  There, you can brighten the faces as you see fit, you can keyframe the movement of the matte if you need to (aka "rotoscoping"), and your color primaries will remain intact.
In this way, you can add as many adjustment layers as you like, and isolate as many different areas of the image as necessary, each with its own unique color transformation.  You can even use mask blending modes to perform boolean operations to the masks, generating complex unions, intersections, cutouts, etc.

There are some limitations and restrictions to Adobe's color workflow, which is why people turn to other software as their grades become more complex.  Tracking multiple masks is problematic, for instance.  However, for basic color work, Premiere is often a simple, quick, and effective solution.


text:
Concatenate two video files with a dip to white with FFmpeg
Is there any way to concatenate two video files with a dip to white (0.03 sec) with FFmpeg?

Assuming input0.mkv is 10 seconds long:
ffmpeg -i input0.mkv -i input1.mkv -filter_complex "[0]fade=t=out:d=0.015:st=9.985:c=white[v0];[1]fade=t=in:d=0.015:c=white[v1];[v0][0:a][v1][1:a]concat=n=2:v=1:a=1[v][a]" -map "[v]" -map "[a]" output.mp4

Note that using your values with typical input frame rate will result in only a few frames being white which will appear as a flash instead of a dip to white, so I recommend increasing the fade duration.
All inputs must have the same parameters (width, height, etc).
See FFmpeg Filters for more info on fade and concat.


text:
Best tool for adding simple graphics such as fading-in text on a video
I need to be able to add small graphical things onto a recorded movie clip. Things like arrows and text. I will need to be able to do simple animation, such as making the arrow elongate, making the text fade in, making an object rotate and such.
I have seen Apple's Motion but I am  not able to use that software.
What other software can do this job?

Why are you not able to use Motion?  You may also want to search for "motion graphics" and see if any of the pre-existing questions cover your needs.

Are you limited to any particular platform?

@AJHenderson I do not have access to Apple software without an Apple computer

@Fridaypants I am not limited more than I hope for a free or cheap (free-trial perhaps) software, since this is for a small project.

Take a look at https://video.stackexchange.com/questions/13082/what-are-motion-graphics.  Not 100% sure it's a duplicate, but seems likely to cover your needs.  If so, let me know and I'll close this one as a dupe.

Adobe After Effects is what I use. It's pretty simple and there are a ton of tutorials out there.
If you need something free there is Hit Film Express, which I hear is decent though I've never used it.
Lastly what editing software are you using? You should be able to do simple things like that in any old editing program out there.

Spencer

Hi Spencer. Thank you for your answer. I am using no special software, just plain and simple Windows Movie Maker. The editing and cutting is easy and effective in that program, but it has no real custom-animation tools except for some small stuff with text animations. I will look into the Hit Film Express and return. I have also heard of Blender, which is an actual 3D animation software but a freeware. It is a bit complicated to start out with though.

Here I am a year later! I'm guessing you're done with your project by now... But anyway I would definitely not suggest Blender or Fusion for something like this as Michael suggest. Blender is a 3D application (though it does other things) and not at all built for this. And Fusion is made for high-end compositing, similarly not really made for this. Fusion can absolutely do what you want and it is free, but the learning curve isn't worth it for simple text animation.

Actually, I ended up using Hit Films  Thank you for the suggestion. It worked like a charm for my purpose, although a bit heavy for my poor laptop

Glad it worked out! And yes, welcome to the world of video production... faster is never good enough, and no matter how much storage you have it's always full.

Blender is wonderful, but only the most dedicated use it for making text annotations.  Davinci Resolve 15 (currently at beta 2) runs on Mac, Windows, and Linux (with constraints).    Its big new feature is the integration of Fusion, a comprehensive 2d and 3d compositing and effects package.  It also offers templates that animate text fades (against backgrounds if you like).  YouTube tutorial videos show these features in detail.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
How to translate face tracking offset values into a 3D null position
I want to put a 2D hat on a video clip of a person, whose head is tilting as he speaks.
I can face-track the face using After Effects CC 2017.
I end up with detailed tracking data, which includes face orientation information.
I can link the orientation information to a 3D null, but how do I link the positional information of the head?
The head appears to only be expressed as a percentage (of what?).
Is there an easy way to connect this percentage data to 3D positional data on a null?
Equally, if I do a simple face track, I get an animated mask.  What's the right way to translate one of the points from that mask into a null that could be parented to another object?

You can access the position of a point in a mask with expressions (in AE CC 2017+) with expressions. To access the first point of a mask called "Mask 1" on layer called "my Layer" you'd use
pts = thisComp.layer("my Layer").mask("Mask 1").maskPath.points();
pts[0]

note that the points are numbered from 0, so the second point is pts[1], etc.
I'm not 100% sure I understand what you';re trying to do, have you tried doing a standard motion track using the inbuilt motion tracker or Mocha?

Finally I found this answer
https://forums.creativecow.net/thread/2/868241
But it's pretty involved.  Is there a better way?

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/3.0/


text:
Is there image degradation when you apply the same chroma subsampling iteratively?
I have digitalized a set of old family VHS tapes. As you know, VHS relied on chroma subsampling. And the capture device creates files with the 4:2:2 tag. Now, when I encode again with ffmpeg to get smaller files but for archival purposes, should I specify '-pix_fmt yuv444p' to make sure the chroma images do not get further degradation, or by using the same subsampling scheme as the source (i.e. yuv422p) the chroma images are not difuminated further due to subsampling?
I am looking for a technical, objective answer. I don't mind if the degradation is subjectively small or something.
To better explain the question, let's say we are transcoding video A into B, where A was done originalyy with a 4:2:2 subsampling and we specify the same 4:2:2 scheme to create B. Then, which one of the following possibilities is true?

Ffmpeg reads some tags inside video A and "knows" it was done using a 4:2:2 subsampling. Then, since the destination image has the same 4:2:2 scheme, it translates directly the chroma images into the destination video without performing any subsampling.
Ffmpeg reads the original chroma image blindly and applies a 4:2:2 subsampling, no matter where the original material comes from.

The first option seems more logical but in that case, what would happen if the subsampling scheme we ask for in the destination video is different than the original? How do you "translate" consistently from, say, 4:2:0 to 4:2:2?
Edit: From my own tests, the accepted answer, and a little bit of thinking about it, it seems clear that using the same chroma scheme does not produce degradation, as long as the resolution and size of the image is kept unchanged. It's difficult to explain without doing some drawings, but there is an analog working with audio. A signal sampled at 44.1 kHz for instance, can be resampled at the same frequency without losing information. If, e.g. a square cluster of 4 luma pixels corresponds to one unique color value (4:2:0), then resampling that image will assign the same color value to that 4 pixels.

VHS does not use sub-sampling. It is an analog format and doesn't sample at all. It does use a form of analog compression by creating color difference channels, then bandwidth limiting them, and frequency shifting the chroma signal below the wider-band luminance signal.

@MichaelLiebman Strictly speaking, yes, but VHS encodes luminance and color with different sampling frequencies, which results in quite a lower resolution for the color image. Both the intended purpose of doing that, and the resulting visual effect in the stored images, are equivalent to what chroma subsampling achieves in digital video.

If the target chroma subsampling is the same as the source subsampling, then any ffmpeg scaling will be a no-op in that regard, so it's not subsampling 'further'.
FFmpeg does not determine chroma sampling scheme from a tag. It is a basic property of the decoded bitstream. If it's 4:2:0, then the decoder will emit chroma planes of half-width and height with respect to the luma plane; for 4:2:2, half-width and full-height. A scaling operation will be carried out if the input and output schemes are different. A scaler will resize each row of the chroma plane to the target width of the output chroma plane and then rescale the resized rows to obtain the target height of the chroma planes. The "translation" is done as per the choice of scaling algorithm - see list at https://ffmpeg.org/ffmpeg-scaler.html#Scaler-Options


text:
Is there a standard target level for spoken audio in a tutorial video?
I record a lot of tutorial videos for my work. I don't use background music or sound effects, just a voice over a screen recording.
One thing I have noticed is each of my videos (so far) has a different overall volume. If people were to listen to the videos in succession, they would be constantly adjusting the volume level. I want to normalize the audio so that it is all at the same level.
My problem is I can't seem to find a standard anywhere for a general decibel level to normalize all my videos to. Is there an ideal audio level that plays at exactly the level a typical viewer would expect for their volume setting?
In other words, if a viewer was just watching, say, a professionally made movie, and then watched my video, ideally they should not have to adjust the audio setting on their computer when switching to my video.

This is too vague to be an answer, so I'm posting it as a comment. In many video (and most audio) programs, you can see a graphic "audio level" monitor that shows green when the volume is good, yellow when it is too loud, and red when it is way too loud. If you can keep your voice over so it is always near the top of the green, with just a few yellow spikes, the volume level will be pretty typical.

^in my experience with FCPX, the waveform cannot be trusted.  When you see red peaks, it can mean either 0 db or -6 db.

"Normalise" (or normalize) is exactly what you need to do. Unless your video is going to broadcast TV you can safely normalise your levels to 0dB using whatever normalisation effect your sound editor has. Do this as the last step before exporting.

There's no single answer - it's a series of trade-offs:
When you record your voice, it should be as loud as possible, but making sure never to go over the maximum level that can be recorded.  This is known as clipping, and sounds distorted.  Too quiet, and your audio will be hissy relative to the noise floor of your setup - too loud and it will clip.
In order to smooth out the overall levels, you can dynamically compress your audio (this is not the same as data compression), either before it is recorded (between the mic and recorder) or after it has been recorded.  This is effectively like having an automatic volume control, where levels over a certain threshold are turned down, so that the overall effect is smoother.  Too much compression can sound pumping and aggressive - like an FM talk-radio host.


text:
Video Editor with custom effect masking and shape/drawing overlays
I've spent a very long time on this and have been unimpressed with 90% of the main stream video editors, so I'd really appreciate some expert advice on this.
I'm looking for a video editor (hopefully within the 100-150 range if possible) that has the following options:

"Effects Masking" - ability to draw custom masks for blurring small segments of text on screen captures. A lot of the editors I see allow you to import a png file for this, but I really would rather have this in the editor, as I have a lot of footage and making a new png for every time the text changes would take forever.
Customizable basic shapes/drawing tools for overlays - NOT cheesy animated overlays; I want to be able to highlight areas of the screen by being able to draw boxes or circles around them.

These seem like basic requirements, but I've had a really hard time with this, so I would REALLY appreciate your help!

Someone on Google+ mentioned that HitFilm Express is free right now: http://community.hitfilm.com/index.php?/blog/1/entry-328-get-hitfilm-2-express-for-free I'll look into it and post as an answer if I find it meets my needs. It looks like an awesome program.

That isn't really rotoscoping, just mask drawing.  Rotoscoping is more on a frame by frame basis generally.  Either way, After Effects will do what you are looking for very easily, but is not in your price range (not even nearly).  Largely, you get what you pay for though and I'm not sure that there are a whole lot of cheaper options that allow you to draw your masks in the editor.

I kinda figured. You can confirm that After Effects can do this, though? Their month-to-month pricing isn't bad for how much I'd be using it.

Oh, and thanks for the correction about rotoscoping. :)

@CullenJ - yes, After Effects can handle what you are talking about and much, much more.  It is even relatively easy to do if I understand you correctly.  It has tools that allow you to draw masks right over the video and you can then leave them there as long as it is valid and use it as a mask for a filter (such as a blur).  It is basically Photoshop for video.

Apple motion can do this, and it's in your price range at $50.  It's not a video editor per-se, more of a motion graphics and compositing app, but then again, so is After Effects.


text:
Finding a highest megapixel camera for PC
How can i have a PC camera/webcam that have high quality as a portable camera, like the Nikon D800 have 35 MP. I can't find a PC camera that have the same Megapixel ? Even the Microsoft Lifecam have only 2MP and it's not my choice :(

This question appears to be off-topic because it is about scientific imaging, not audio-video production.

@AJHenderson ok, it's a bit relevant when i show my purpose. But the main problem is a camera/webcam for PC, so i have edited the question

It's unfortunately still not a good question as it asks to find the highest MP camera which is a shopping question and still off topic as it will change every time a new, higher MP camera comes out that supports tethering with a computer.

Please note that many people take the megapixels specification as proportional to the image quality, but that is incorrect.
Higher megapixel cameras require smaller pixel sensors (as there are more of them on the sensor). Smaller pixel sensors mean less photons are hitting each sensor, thus producing more noise.
High megapixel specs are important mainly if the image is to be printed in large scale (billboards, etc.). But for highest quality small images a lower mega pixel camera may well produce a better image.

Your best bet is a DSLR with a lens mount for the microscope.  It goes in places of the eyepiece and generally does not have the diopter from an eyepiece (so magnification is a bit lower, but you can also zoom in).  Among standard size DSLRs, the highest megapixel one I'm aware of at this time is the Nikon D800 at 35 megapixels, but there may be bigger out there now.

How can i have a PC camera that have high quality as the Nikon D800?

@ĐứcUltraSoft -- As AJ says, the best way to do that is to use the Nikon D800.

@mattdm but i need a camera/webcam directly for computer. It must be show directly in computer instead of a portable camera.

@ĐứcUltraSoft You can connect a DSLR to a computer. This is called "tethering".

@ĐứcUltraSoft - As mattdm already pointed out, a DSLR can be tethered to a computer using drivers for the camera and photos can be taken directly on the computer.  You also want a camera that supports an interchangeable lens system so that you can properly rig it to a microscope, otherwise the effective resolution of the image the camera is seeing will be less than that of the resolution of the camera.  (And honestly, there is a decent chance that it will be anyway, depending on the quality of microscope you are using and the level of magnification.)


text:
Application for Screen-casting for Macintosh
I need to make a Screen-cast. This is, I need to capture my screen and audio from my computer and then after be able to edit this video.
Then I need an app for Macintosh.
Since I just need to do really basic editing tasks I've trying Camtasia and Screenflow, both of them works just fine, but both of these has important lacks imho.
Screenflow: doesn't have vectorial objects like "bubble speeches", "squares", etc.
Camtasia: you can not group or nest the tracks (keep in mind that this is Camtasia for Mac, which has less features that its Windows version)
Then, I'm just wondering what other app would I use.
Should I use Final Cut Pro to get all the features I need?

I know you looked at ScreenFlow. Were you looking at the latest version--ScreenFlow 4? It does have some vectorial shapes (they're called Annotations):

Line (arrow)
Line
Square (filled)
Square
Circle

Now, that doesn't get you speech bubbles and other abstract shapes. For those, you can use a text box with an image fill--unfortunately, you've got to supply your own image in that case.
ScreenFlow also accepts PDF and other image types as layers. This makes ScreenFlow able to import vector PDF's as "shapes" that one can use to add annotations such as the mentioned speech bubbles.

I assume that grouping/nesting is coming in a future version of Camtasia.
If you are going for professional screencasting, there's Claquette.


text:
How does YouTube convert between different videos resolutions?
What algorithm does YouTube follow to convert between different formats?
Does YouTube store different videos (for different formats) on disk or store only 1 and convert from this to appropriate format as requested?

Your title and your question are different. Are you specifically asking about resampling (i.e. downscaling/upscaling) algorithms, or transcoding (converting from whatever format you uploaded to whatever format they then serve)?

Youtube stores whatever you upload and transcodes to other formats using their own versions of multiple compression formats including h.264 and webm.  All transcodes go from the same original file that you upload and are stored after transcoding.  Youtube may change the options used from time to time and save new encodes of the video.  Encodes are generally pre-rendered upon upload and then used from disk as far as I can tell.

They are always pre-rendered. On-demand renderings costs way too much, processing time costs a lot of money in server terms. Disk space is very cheap.

@ProfessorSparkles - they could still theoretically on-demand encode a version when first used and then save it.  I don't believe they do this, but they also don't publish a lot of their process from anything I've seen.

Well it would take up considerably more resources if you take into account that this would have to happen millions of times per day essentially making YouTube one huge ass live streaming site for mostly a single viewer per stream that also streams in a lot of different formats which aren't all that suited for this task. Encoding them in the background with unused resources is much much more cost effective.
But yes in theory its something that would be possible but I highly doubt it happens in practice, its just costs too much money to make sense.

@ProfessorSparkles - I don't want to stray in to a discussion, but that's just it, until someone views a video, you don't know what they want to view.  You can either encode up front for something that someone may or may not ever need or you can encode the first time someone uses it.  It doesn't cost any more to encode it the first time it is used than it does to encode it before someone uses it as long as you are running preemptive encodings whenever the encoders aren't busy.  It would be much more complex to build something to allocate the processing, but it would be more efficient.


text:
Is there a video container which is able to handle segments of different video quality (or even size)?
Let's assume I have a video of 10 minutes length. And I want to reduce its size by having some parts in high bitrate, while other less important parts can be low bitrate. For this I'd cut the original into segments. Leaving the important ones as they are, while transcoding the unimportant parts to a lower quality.

Now, is there a video container format out there which is able to "glue" these different parts together into one file? With good support in players so trusty mplayer will play the video as if it's an ordinary file? And in a standardized/annotated/undo-able way so a simple cli command would untangle the segments into separate parts/files again?
I was under the impression Matroska would be able to do this, via chapters, where each of my segments would be one chapter. (I've read it somewhere where merging videos without transcoding was dicussed). But when I read the actual mkv docs, it seems mkv chapters are more like a textual index pointing into another (video) stream of an .mkv file - and not some low level kind of data block index which would help me with my idea. So mkv looks like a dead end.
Simple editing, or merging (which is possible losslessly, with some remuxing) wouldn't offer me having different qualities in different sections of the video - right?
What I'm looking for is region-of-interest adapted quality, something image formats like JPEG2000 offer for spatial areas, only here applied to video over time.
Any suggestions or ideas?

The accepted answer suggests using the VBR capabilities of a format like mp4. While this works, please leave an answer if you know of a different way of achieving the desired result.

If the only difference is bitrate, then any container which accepts variable bitrate streams, will fulfill your requirement e.g. MP4, MKV..etc
Step 1 is to encode your segments, ideally using the same encoder, to different bitrates with all other parameters being the same e.g. via ffmpeg,
ffmpeg -ss 0 -t 5 -i input.mp4 -b:v 1000k seg1.mp4

ffmpeg -ss 5 -t 7 -i input.mp4 -b:v 3000k seg2.mp4

ffmpeg -ss 12 -i input.mp4 -b:v 500k seg3.mp4

Step 2 is to use ffmpeg to concat the encoded segments in copy mode, using the concat demuxer.
Prepare a text file
file 'seg1.mp4'
file 'seg2.mp4'
file 'seg3.mp4'

and then
ffmpeg -f concat -i list.txt -c copy joined.mp4

Clips with different properties, like resolution, can be joined together as well into one MP4, but compatibility across media players is iffy, and ffmpeg won't do it reliably at present, anyway.

Interesting! I've always had another conception of what VBR is and does, in terms of "granularity". Will try that.   Also, I'll wait a little more until I'll probably mark your answer the as the accepted one

After trying it, and finding it works (both, vbr and even variable size), I've found a minor problem: When I edit-out one segment "as-is" with "-vcodec copy", the concat will report 1. "Auto-inserting h264_mp4toannexb bitstream filter" (seems fine), 2. "Non-monotonous DTS in output stream" (arg!!) for that segment. Is there a way to do a stream copy (no re-encoding), but stripping time-stamps. As I understand it, filtering the output/this segment in such a way would fix this DTS error (although the video plays anyway).

ffmpeg, by default, generates new timestamps, unless you use the segment muxers or supply a flag like copyts. What command are you getting the error with?

Command is what you suggested: ffmpeg -f concat -i list.txt -c copy joined.mp4, and the example segment commands, only the middle one altered to be ... -i input.mp4 -vcodec copy seg2.mp4. Tested with ffmpeg 2.8.1, my Ubuntu avconv doesn't know about concat yet.

Ah. With stream copy, cutting isn't exact. You'll have to insert -avoid_negative_ts make_zero but you'll likely get some repeat with the prior segment.

On the segmenting or the concat step? Tried both. One variant even gave me an added "Packet with invalid duration" error. Sorry for this here becoming a thread... Also, make_zero is the value for the -avoid_negative_ts switch, right. Where're the docs for it?

I had limited success with adding -copyts -start_at_zero on each segmenting, no more DTS warning on concat but video didn't play right.

If you're re-encoding, you don't need those flags. If you aren't those two won't help. Do you intend to segment the entire file?

Let us continue this discussion in chat.

I'm right now pasting commands to reproduce, in chat

Advanced Authoring Format (AAF) and some MXF operational patterns (OP-2a, 2b, 3a, and 3b) should be able mix bit rates. I say "should" because I don't have any good way of testing right now and I don't know of any commercial systems that are making heavy use of those MXF OP's.

Well I can't say I know how it would be done; but RED (www.red.com), their R3D video format uses a debayer process.
I own a RED Epic. It shoots at up to 5K 100 FPS.
When out in the field, and wanting to view the video on say a laptop, the throughput of uncompressed (or near) say 3:1 5K is huge.
So RED uses a debayer process; where the pixels are basically assigned into a grid pattern in terms of how they are both encoded and decoded.
So this eliminates the need for "proxy" files, files which are downres'd for editing because your system simply can't play the file in realtime.
The Debayer is 8 levels. And the RED player (as well as software that supports it such as PPro/After Effects, allow you to playback at 100%, 50% 25% 12.5% and so on.
The unique aspect with RED is when your computer does this, it actually isnt lowering the quality, it's just only displaying the x/100 quality you want.
So perhaps my answer is a bit backwards in thinking: But essentially with RED files you have a 1K, 2K, 3K, 4K, 5K, version- all wrapped into 1 file.
Hope this perhaps helps somewhat, even though it's not an answer to the actual question.

This "answer" does not actually the question that was asked.  It does not address how to handle the problem generally (one cannot transcode from any random video format into RED RAW).  And to my knowledge, one cannot change RED debayer/compression parameters on the fly as a dynamic property of RED media.

More an ex-course into file-formats, but anyway thank you for the effort.

I believe I said clearly that it was not changing the "debayer/compression" parameters; meerly the playback of such. I also specified that the answer does not directly relate to the question, moreso the "concept".


text:
What can be done with .CPI or .clpi files?
In BDAV's M2TS there are .clpi files, in AVCHD the same files are labeled as .CPI. As i understand, some sort of metadata is written into these files. The question is twofold:

What metadata exists in these files? (both 'by the standard' and 'de facto', if there are differences)
Are there any free/libre/open-source software tools that are able to extract this metadata from them?

An example of such a file is here.

@BartArondson, Interesting link, but that is talking about something that is within the m2ts file itself, some sort of switch in a stream, for me CPI files are getting generated by my camcoder, i have definitely set no copyright protection on anything.

As Professor Sparkles has correctly pointed out (I've just checked and confirm) — the MediaInfo tool can extract some metadata from these files. Here is a sample output from one of mine:
General
Complete name                            : /Volumes/CAM_SD/PRIVATE/AVCHD/BDMV/CLIPINF/00119.CPI
Format                                   : Blu-ray Clip info
File size                                : 502 Bytes

Video
ID                                       : 4113 (0x1011)
Format                                   : AVC
Format/Info                              : Advanced Video Codec
Width                                    : 1 920 pixels
Height                                   : 1 080 pixels
Display aspect ratio                     : 16:9
Frame rate                               : 50.000 fps

Audio
ID                                       : 4352 (0x1100)
Format                                   : AC-3
Format/Info                              : Audio Coding 3
Channel(s)                               : 2 channels
Sampling rate                            : 48.0 KHz
Compression mode                         : Lossy
Language                                 : English

Text
ID                                       : 4608 (0x1200)
Format                                   : PGS
Language                                 : English

(But note that it can output more details in the --full mode.)
Also, it may be helpful to note that the AVCHD standard is proprietary and its spec is not publicly available. Attempts to reverse-engineer its components exist, and one of them is in this forum thread (from 2008): http://forum.doom9.org/showthread.php?t=141361


text:
How to change the display ratio of a Theora track inside Ogg?
I have an Ogg Theora file, but unfortunately the display ratio is incorrect on it. I know that it's possible to edit the metadata without reencoding.
What tool can do the job? Preferably something that can be run on *nix.
ogginfo from vorbistools gives the metatada that i would like to edit, but that package doesn't provide anything to change the values, liboggz doesn't seem to do the trick either.
I have attempted to play around with the hexeditor, here's what i've found. Here is my theora packet:
 00000000:  4f 67 67 53 00 02 00 00  00 00 00 00 00 00 00 00  OggS............
 00000010:  00 00 00 00 00 00 70 e4  97 9a 01 2a 80 74 68 65  ......p....*.the
 00000020:  6f 72 61 03 02 01 00 2d  00 24 00 02 d0 00 02 40  ora....-.$.....@
 00000030:  00 00 00 00 00 19 00 00  00 01 00 00 c9 00 00 6a  ...............j
 00000040:  00 03 0d 40 00 80 4f 67  67 53 00 02 00 00 00 00  ...@..OggS......

The 00 00 c9 00 00 6a block is where pixel aspect ratio is being stored, as i understand it the first 3 words are the numerator, and the second 3 denominator.
If i change the values only in the first packet, then avprobe does return the changed values, but then all video players i've tried panic. Any hints on how to change the other packets so that they conform?

The player panic you are experiencing might be due to the checksum in the ogg header. If you recalculate the checksum for the whole header with your new value you might get a valid file again.
http://en.wikipedia.org/wiki/Ogg#Page_structure
Though I dont know all too much about the ogg and vorbis specs. For this kind of low level work its always a good idea to read the specs.
http://xiph.org/vorbis/doc/Vorbis_I_spec.html


text:
Deinterlace by dropping even lines from command line
I want to make an interlaced video with 50fps into a 25fps progressive, in the process i'm also reducing the size of the frame. Currently i am using avconv and there are deinterlacing options, however, they are not documented. So what i am afraid of is that they will actually start bleeding information i am trying to drop into the frames that i am trying to keep.
The only tool that i have found, that does a documented drop of even/odd frames is a plugin for AVIDemux, which unfortunately does not export into Ogg or even encode into Theora. When i attempt to dump into Huff codec (to not introduce quality loss due to reencoding) it demands that i split files at 4 GiB. So i can only use it for small videos.
Is there another tool that can help me?

You could always do the 4gigabyte split and then cut them back together after (assuming Huff codec supports append operations without re-encoding, I'm not familiar with that particular codec.)

@AJHenderson It is a possibility, and i was already looking at that, but it's a hack. I think i would rather try to figure out the avlib's code and create a 'drop-deinterlacer', but i was hoping that something like that already exists.

yeah, makes sense.  I unfortunately have near 0 experience with AVIDemux or avlib.  I'm an Adobe/Windows guy, just a few little things when I was working on writing programs to work with video.

ffmpeg -i input -vf field,scale=123:456 output will do the trick, where 123:456 is your x:y frame dimensions for the output. The field filter just chucks away the fields it doesn't use. Documention on the field filter here. Note that you'll need extra stuff in the command to get good results - e.g. you'll probably want to specify codec details and so on.

Will give you 50 rep for this when the system permits me to.

You could use ffmpeg:
ffmpeg -i input -vf framestep=2 output

This will output every second frame.

That doesn't actually do what is expected with the progressive video. The result is still the same vertical resolution, so it doesn't drop unneeded lines.


text:
Does anybody know about the ".ms" video format, and how I might be able to convert it?
I'm trying to deal with some very old video files from a Mac OS 8-era CD. They have a ".ms" file extension, and can be played with the old "Movie Player" distributed with OS 8. But Movie Player won't export them to .mp4 or anything currently useful, and I haven't found a modern-day player/converter (VLC, etc), on either Mac or Windows, that will open them. I could update my old testing Mac to QuickTime 3, but I've long ago misplaced my QT 3 Pro key(!), and the free version of QT 3 doesn't do exports. Those were the days... BTW, these ".ms" files are not the same as ".dvr-ms" files, so there's no help there.
Any advice? Maybe there are some settings for ffmpeg I've missed? Thanks!
The beginning of the file is:
$ hexdump Breakfast\ Pals.ms | head -n 16
0000000 00e1 3a2c 0034 008c 6a01 bfbf 003c 0098
0000010 aa00 abaf 6044 00a0 5600 af6b 8044 40a0
0000020 6a05 ffbf a04c 61a4 aa00 bfaa c048 82a0
0000030 aa05 ffff c04c 81a8 aa00 ffff e04c a3a4
0000040 aa00 fffb e04c a3a4 aa14 ffbf 0051 a3a4
0000050 ab10 fffe 0051 c2a8 aa00 ffae 0051 c3a8
0000060 ea00 ffaa 0051 c4a4 aa00 ffba 0051 c3a8
0000070 aa00 ffaf 0051 a3a4 aa10 ffff e04c c2b0
0000080 aa15 ffbe e050 e2bc 5951 fefa e050 e2bc
0000090 4150 efd6 e04c c2b8 9544 faaa c04c a2b4
00000a0 a994 ffba c04c 61b0 9100 fee9 8044 60b4
00000b0 5500 ea96 6044 40b0 5500 feaa 4044 40a8
00000c0 a950 feaa 2040 20a8 9500 ffaa 0040 20a0
00000d0 aa00 fffb 003c 0098 a540 faaa 002c 0090
00000e0 a540 fffa 0030 0090 5500 fefa 0028 0088
00000f0 5500 feea 001c 0080 5500 fef9 0010 0080

file is unable to identify it:
$ file Breakfast\ Pals.ms
Breakfast Pals.ms: data

have you tried using file utililty?

Also, do you mind uploading one of the files somewhere?

Duh; should have done that in the first place.  I think this link will work; LMK if it doesn't:  https://www.icloud.com/iclouddrive/0ce4w60ieBGw1yFEE0Vmtg3fA#Breakfast_Pals


text:
How to produce a "broken gif" effect - video example
I am interested in gathering opinons on the best way to create an effect very similar to what might be termed "Broken gif". In this effect the last still shot of the previous scene is used as the colour values for the next one, but all the motion and changes are already unrelated to the depth and other information of that last scene.
Here is a video which makes pretty good use of the effect.

It does look like a duplicate to me as well.

authors: Наталья Ветренко


text:
How to deal with Youtube making videos 'pinkish'?
Often my videos that i upload to Youtube turn 'pinkish' when played there. And unfortunately Youtube allows to adjust Yellow-Blue ratio, but doesn't allow one to play with any other colour after upload.
Sometimes i can counteract this 'pinkification' by using the Youtube editor and increasing both brightness and contrast, but since that implies one extra re-encoding step i would like to avoid that if at all possible (also it doesn't always work).
What i have notice is that this happens more often if the video is shot with just slightly insufficient lighting, where the video (as it plays on my computer) appears just a little darker than it should be.

Is this something that is a common problem or is it just my particular approach to recording that causes that?
Can i expect better quality if i re-encode video locally by increasing luma? Or maybe by decreasing red in RGB?

Additional details:
I am not adding any extra profiles/filters when viewing videos locally. I have tried two separate players (totem and vlc) and both play all the videos equally well. Dark ones are a little dark, but no pinkish colour is added.
The video is recorded by Panasonic HC-V500 and is directly (without any extra reencoding) uploaded to youtube. Recording mode is 1080/50p (i have also tried 1080/50i). The file format is M2TS. Here is the avprobe output:
$ avprobe 00002.MTS
avprobe version v10_alpha1-32-g9a4c10e, Copyright (c) 2007-2013 the Libav developers
  built on Jan  2 2014 23:10:46 with gcc 4.8 (Ubuntu/Linaro 4.8.1-10ubuntu9)
[mpegts @ 0xa5bfb60] Non-increasing DTS in stream 2: packet 2 with DTS 170282, packet 3 with DTS 170282
[mpegts @ 0xa5bfb60] Non-increasing DTS in stream 2: packet 5 with DTS 213482, packet 6 with DTS 213482
(..... some more of these, but they are unlikely to be a cause of anything....)
[mpegts @ 0xa5bfb60] Non-increasing DTS in stream 2: packet 17 with DTS 299882, packet 18 with DTS 299882
Input #0, mpegts, from '00002.MTS':
  Duration: 00:19:09.10, start: 1.957800, bitrate: 25053 kb/s
  Program 1
    Stream #0.0[0x1011]: Video: h264 (High), yuv420p, 1920x1080 [PAR 1:1 DAR 16:9], 50 fps, 90k tbn, 100 tbc
    Stream #0.1[0x1100]: Audio: ac3, 48000 Hz, stereo, fltp, 256 kb/s
    Stream #0.2[0x1200]: Data: [144][0][0][0] / 0x0090
Failed to probe codec for input stream 2
# avprobe output

My monitor is calibrated just fine and i have no problems playing anything else. In fact, as i've said i have no problem playing these exact videos locally before they get converted by Google (Youtube).

Are you using the recommended encoder settings for Youtube and are you applying any ICC profiles to the video when playing it back locally?

What video editing/creation software are you using? And also as AJ Henderson said make sure you are using the recommended encoding settings for YT.

further, has the monitor you are using been properly calibrated?

I've answered the questions by editing the question (ok this sounds like a very poorly structured sentence, but you know what i mean)

One way you could deal with this is to try some tests where you move the color of the video towards green until you get something that looks right when uploaded. (You don't say which editor you're using, but you could use the color board in FCPX or use DaVinci Resolve Lite, or whatever works for your setup.) Green is going to be the opposite of pink on the color wheel. You might be able to figure out the right color transform by taking a screenshot of the pinkish video and seeing if you can correct that. Then apply that same correction to some footage before uploading it and see what happens.

Have you tried transcoding locally with no modifications, and uploading that?  Maybe your camera's h.264 encoder is producing streams that trigger a bug in youtube's h.264 decoder?  Or maybe one of their h.264 colorspace flags is set to something that makes youtube think it needs to do a colorspace conversion?  mediainfo can report on this, I think.
But yeah, I'd try uploading a 10 sec test clip (-t 10) transcoded with ffmpeg:
ffmpeg -i input.mp4 -t 20  -vf scale=-1:480 -acodec copy -vcodec libx264 -crf 24 -preset faster -movflags faststart  downscaled.mp4

The same cmdline should work with avconv, too.  IDK, maybe have to use -a:c instead of -acodec, I forget how avconv differs.
Pick a test clip that will make it easy to see what you're looking for, and preferably low motion for a smaller output file in CRF target-quality mode.  Use a lower crf value if you think compression artifacts will interfere with seeing the problem.
If that works, then try without downscaling (take out -vf scale=...).
If it still has the glitch, then try cutting the frame rate down to 25.  -vf framestep=2:scale=-1:480 -r 25.  Your ffmpeg output will then be bog-standard h.264 high profile 480p25 just like tons of people upload all the time.
If running it through x264 makes it work, you could always do that in future, with -crf 16 or something, and -preset medium, before uploading.
Apparently Youtube is going to xcode it regardless;  I don't think it will use your h.264 stream untouched for the 1080p player, even if it's already at the right bitrate, GOP size, and everything else that it will xcode to.  (point being, don't spend a ton of CPU time making a really rate-distortion-optimal encode before uploading, unless your bandwidth is very precious.)


text:
How to fix invalid bitrate with ffmpeg
I tried to download 3-hour long video (now unavailable) with YoutubeDL and ended up with a 2GB file of 14 seconds with the correct frame size but an insane bitrate:
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'video.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.20.100
  Duration: 00:00:14.08, start: 0.000000, bitrate: 1194942 kb/s
    Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080 [SAR 1:1 DAR 16:9], 1396506 kb/s, 49893.76 fps, 60 tbr, 90k tbn, 120 tbc (default)
    Metadata:
      handler_name    : VideoHandler
    Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 82853 kb/s (default)
    Metadata:
      handler_name    : SoundHandler

I'm guessing all the data is here, but I don't know how to handle ffmpeg to give me the correct output.
What should be the correct parameters to use here?
EDIT : The video is unavailable, but Youtube shows information nonetheless. The video is 9532 seconds long which means a speed factor of 676.99.
Since the audio real bitrate should be 128 Kb/s, another factor of 647.29 can be calculated.
EDIT #2 : Tried to apply a slowdown filter with:
ffmpeg -i video.mp4 -filter:v "setpts=647.289*PTS" video_fixed.mp4

But I only got a still image.
The 4 first seconds seem to be fine then VLC fail to read and displays
avcodec info: Using D3D11VA (Intel(R) HD Graphics Family, vendor 8086(Intel), device a16, revision 9) for hardware decoding
main error: ES_OUT_SET_(GROUP_)PCR is called too late (pts_delay increased to 300 ms)
main error: Timestamp conversion failed for 5250012: no reference clock
main error: Could not convert timestamp 0 for FFmpeg
main error: ES_OUT_SET_(GROUP_)PCR is called too late (pts_delay increased to 1222 ms)
main error: Timestamp conversion failed for 6250012: no reference clock
main error: Could not convert timestamp 0 for FFmpeg
main error: ES_OUT_SET_(GROUP_)PCR is called too late (pts_delay increased to 3115 ms)
main error: Timestamp conversion failed for 8000012: no reference clock
main error: Could not convert timestamp 0 for FFmpeg
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
avcodec error: more than 5 seconds of late video -> dropping frame (computer too slow ?)
direct3d11 error: SetThumbNailClip failed: 0x800706f4

Does the video play fine?

The 4 first seconds seem to be fine then VLC fail to read and displays the following

Here is what i would be doing to try to resolve this:
Check the video with fprobe -show_streams note how many frames there are. From that and the knowledge of the total duration it can be possible to figure out the correct framerate.
Try to reencode with:
ffmpeg -i broken.mp4 -c copy -r (what you have calculated above) try1.mp4

If this doesn't work, try reencoding rather than copying.
If that doesn't work still, maybe it would work to dump all the frames as image files and then reencode them into video with a calculated framerate.


text:
After Effects: how to create a color via expressions
Using After Effects expressions, I can create a color reference by pick-whipping a color control and the result is:
var rgb = rgbToHsl(effect("Color Control")("Color"));

But, I want to avoid using a color control, and simply instantiate a color through code:
var rgb = rgbToHsl([159,27,41,1]);

...but this doesn't seem to work.  Is it possible?

From what I'm reading, it looks like it may just be [R,G,B] where each value is a floating point number between 0 and 1.  I'm looking in the Adobe After Effects Scripting Guide.  Every method I can find that accepts a color value simply uses an array like that.
Update: While certain scripting methods take a 3 parameter RGB value, other expressions require RGBA or HSLA.  In these cases, there will be a forth parameter for Alpha (ie, transparency) where 1 is fully opaque (a good default value) and 0 is fully transparent.  If you get an error with one format, I suggest trying the other and if you get unexpected values, check if the input expects HSL or RGB.

I believe it needs an array of 4, so you'd need to include the alpha value as well.  Thanks for answering.

@itsmikem - for rgbToHsl it does appear it takes a rgba value, so if you need the color in hsla, then you would want to do 4 values with the final being the alpha.  If you just want an RGB color, it only uses 3, but I'm not sure if rgbToHsl will work with that.

Note: I'm new to this exchange, and I posted this to the graphic design exchange, but my question got migrated here. I thought it had been deleted, so I proceeded to post it on Creative Cow.  I got a great answer there, and I'd like to give credit to Kevin Camp, who answered it perfectly:
your rgb values need to be in values 0-1 rather than 0-255. so if you want to stick with entering 0-255 values you just need to divide that array by 255...
var myColor = rgbToHsl([159,27,41,255]/255);

note, i did assume that you wante the alpha component to be full (255) not 1. if i guessed wrong, change the alpha back to 1.


text:
render farm newbie questions
What are the main considerations in setting up a render farm?  We're considering adding an internal render farm to our workflow (we have both Avid and Adobe).  I'm seeing that there are cloud based services, and I'm wondering if it makes more sense to go that route rather than make a significant investment in hardware. Thanks!

Not specific to a render farm, keep in mind that depending on your volume and where the content goes next in the workflow, it may be very inefficient to use a public cloud system. Ignore the hype from the cloud providers when making your decision.

I'm not an economist, but I have built and run a small render farm. I'd make the decision on a ROI basis: will you get back a return from your investment? I can't answer this for you, you'll need to add up all the costs for both options and compare.
Costs for a physical render farm are mostly fixed - i.e. the capital outlay, but you have to factor in depreciation, maintenance and electricity, and the price of housing it. Costs for a cloud-based solution are all on a usage basis.
So a cloud-based solution would work if you only need it occasionally, especially if you need massive render power that would cost a lot to set up and run. Commercial render farms can have thousands of processors, meaning that rendering a sequence takes only as long as it takes to render the longest frame. So cloud farms have the edge in terms of scale. A con with cloud based systems is that you have to trust a third party with your intellectual property. There's also the overhead of sending and receiving the files, depending on your internet connection (a bit of an issue here in Australia).
A physical render farm makes sense if you're using it all the time, and you can afford the upfront cost for the size of farm you need. It has the advantage that it's always available, and using it is (almost) free, so you can use it for things you wouldn't bother sending to a commercial render farm. After all, the more you use it, the more your return.
An inexpensive way of building up a render farm is to retire workstation machines to the farm, thus adding extra value to them. The downside of using older machines is the energy cost - generally they do less computing per watt-hour than newer machines.


text:
Stabilize MP4 from gyroscope metadata? (Insta360)
I just got an Insta360 One R 1-inch sensor and the footage is shaky as hell. I realised that you need their desktop application to actually stabilise in post-production but since I'm on Linux this is not possible.
By probing the MP4 recorded with exiftool it's clear that there is some metadata
$> exiftool -ee -G3 PRO_VID_20210312_225421_00_004.mp4
..
[Doc8914]       Accelerometer                   : -0.2275390625 -1.2587890625 -0.140380859375
[Doc8914]       Angular Velocity                : 0.0109715647995472 0.0351055897772312 0.0297343395650387
[Doc8915]       Time Code                       : 238.231
[Doc8915]       Accelerometer                   : -0.21630859375 -1.263671875 -0.13916015625
[Doc8915]       Angular Velocity                : 0.0109715647995472 0.0606719367206097 0.00416799262166023
[Doc8916]       Time Code                       : 238.233
[Doc8916]       Accelerometer                   : -0.205078125 -1.26513671875 -0.135009765625
..

I was wondering.. is there someway to stabilise the footage by using this metadata on Linux?
When we use vid.stab or similar we usually create this sort of metadata with some analysis. But since we already have this data, there must be a way we can skip that step and use it directly?


text:
Wireless IP Camera
At present I have a software solution that involves 4 analogue cameras connected to an encoder that is plugged into my router. My application then reads the rtsp feed from the ip address from this connection.
The problem I have is that it seems difficult to get installers for my product for various reasons (based here in UK).  If I used wireless digital cameras then it would not need qualified electricians to install these analogue cameras.
But, all the products I have seen for all this is that the wireless cameras uses it's own software to deal with rtsp feeds. I cannot seem to get access to the feed (I am using VLC).
Are there any wireless cameras on the market that I could look in using?
Additional
My C# Desktop app is looking for an rtsp feed from my video encoder that is just a black box that decodes analogue signal and encodes it to a digital output.  I am trying to create a product that will be easy to install but as the industry stands in the UK getting installers to install 4 analogue cameras is difficult. If I can remove the need for installers then that is a great step forward for me.

What is the actual use case?  This is pretty borderline, but I think there may be enough of a possible use case for it to be useful.  If it was just doing slow refresh cameras, then it wouldn't be, but the ability to use wireless IP cameras for video production would require similar things, so it seems useful enough.

@AJHenderson Hi, Thanks for your comment.  I shall edit my question.

Don't have any experience with Wifi Security Cameras but this one here would fit your specs, aswell as the other IP cameras from that company:
http://foscam.us/wireless-ip-cameras/foscam-fi9805w-wireless-ip-camera.html
I have not used their cameras and can't tell you if they are any good.
Actually a lot IP enabled security cameras fit the specs. As long as they have a web interface they offer a stream usable by VLC, you just have to visit their web interface and get the url for the stream. VLC understands more than just RTSP, RTMP f.e. is much more used for web streaming nowadays.

The cameras are so-so.  I got one for use as a baby monitor.  It works ok, but the mic and speaker on it are nearly worthless (might be a defective model, but others with the model I got have similar issues.)


text:
Scroll text up (like in credits) then reverse and scroll text down?
Unsure if this is the right "sub-Stack Exchange" for this question, however I've been unable to find a way to scroll a block of text up then reverse it and scroll down after similar to "The Future of Publishing - by DK (UK)"

Or "Lost Generation"

I've tried with Movie Maker (I have a Windows 8 laptop) but if there's some other program that I can get this done with then I'm happy to try it out.

After Effects or just about any titling software should allow this easily.  You just need to make a layer with all the text on it (or even an image) then you simply need to apply a motion effect to scroll from the top to bottom, put a keyframe in the middle and then the keyframe at the end should bring it back.  This should produce exactly what you are looking for.

Was able to get it working with After Effects, now to figure out a fade area in the top and bottom of the composition so it scrolls and fades in :) Cheers

@dan2k3k4 - the easiest bet, use a mask with a gradient to make the top and bottom edges blend with the background.


text:
How to save the phone rotation into a video?
I recorded a video from an android phone and turned it from portrait to landscape within the first 5 seconds.
I noticed if I play the video in Windows Media Player - it shows up portrait then turns to a 90 degree angle on its' side. However in VLC player, it shows up in portrait and when the film rotates, the position stays fixed so the video always looks correct, I guess because VLC reads the meta data of the film for the rotation angle and adjusts automatically during playback ?
However I need to save this into the actual video... so that it "automatically" turns for other players or for YouTube etc.
I have no idea how to do this?
Edit:
What I mean is that the metadata for current rotation needs to be read and a video saved using this information so that the actual video stays stable when the part in the video where the phone is rotated while filming. Does that make more sense?
Try it out by filming something with your smartphone and then rotate the phone while recording from landscape to portrait or vice versa. Save the video to your PC and play with latest VLC, it stays stable but view in Windows Player and you end up with a rotated video (either it's on the side or something)

Can you provide a sample file?

You mean you want to transcode and make a new video that's actually rotated, instead of just having metadata telling players to rotate?  I wouldn't call this "saving" anything into the video.  More like applying the metadata.

Ah ok I didn't know the correct terms, thanks :)

I may not be able to answer this as fully as someone else, but I'd do the following:

Open the video file in (most) any video editor. (something as basic as Windows Movie Maker will suffice)
Split the clip at the point where the device rotates.
Rotate the newly-created second clip to suit your needs.

You have to get Rotation below ways-
1)MediaMetadataRetriever class  in android.Check below link
http://developer.android.com/reference/android/media/MediaMetadataRetriever.html
This class in Orientation tag supported in Api Level 17(4.2+).
2)
Another way FFMPEG Metadataretrival library import and get rotation.