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Cross-dissolve in real time between end and start point of looping clip
I'm trying to achieve the following: I have a short movie clip that I want to loop for an indefinite amount of time. However, as of now, it doesn't particularly good every time the clip starts over (it just sort of jitters back to the starting point without any form of smooth transition), so I would need a cross-dissolve effect to be applied to it in realtime.
Is there any (preferably free) software solution that could help me accomplish what I want to do here? Preferably, I'd like some kind of free solution that works both across Windows and OS X, but tips relating to the platforms individually are appreciated as well. I don't care whether I need some stand alone software to achieve this (as opposed to using some kind of plug-in for a program that I'm already using, like VLC).

We're going to need a clarification of "it doesn't particularly every time"

@JimMack Oops, I forgot a word there. Thanks for reminding me :)

What platform, OS, player etc are you trying this with? More details will help us help you.

@JimMack I've expanded my question now :)

You can't seamlessly loop a clip that wasn't designed to loop. Some suggestions below, but all require video editing software. No plugin for a player that I know of.
Option 1: Clip has a distinctive/necessary beginning & end that have to be seen, or has audio/narration that cannot be edited or shortened
The best option in this case would be to edit the clip to fade-in from and fade-out to black (and/or an identical image) at the beginning & end.
Now when it loops it at least appears the same (even if the player hiccups slightly). Black works well since most players go to black after finishing a clip.
Option 2: No audio, the clip's start/end location doesn't matter & you want a seamless loop
In this case you could try the following, using whatever software - iMovie, Premiere, After Effects, MovieMaker etc...

Place the entire clip on a timeline.
Duplicate the clip.
Find a point in the clip that has as little motion/change as possible.
On the top copy of the clip, move 1 frame to the left and trim everything after this point.
On the bottom copy, go back to the chosen frame and trim everything before this point.
Move the bottom copy left so it starts at the beginning of the timeline

Your chosen point now starts at 0:00:00

Shift the top copy to the right until it only overlaps slightly with the bottom copy.

The original start/end points are now overlapping somewhere in the middle

Add a cross-dissolve to the beginning of the top copy

The original end point will be obscured by the dissolve.
Experiment w/the length and location of overlap/dissolve to find a suitable result. It could work w/just a few frames, or might require a longer overlap to not look jumpy. How well it works depends on how different the original start/end frames are.
Ensure the dissolve only occurs during overlapping frames or else you'll see clips jumping on & off screen.

Trim the end of the timeline so it stops exactly at the last frame of the top clip.

Your edited video will be shorter by the length of the dissolve.
The new last frame is now exactly 1 frame before the new first frame at the beginning.

Export timeline to your required format

The result of this process is that the beginning and end now only  differ by a single frame, making a loop with minimal jump when you restart playback. The cross-dissolve in the middle takes care of the smooth transition that you don't currently have, at the expense of ~1 second of original length.
You could also flip the directions around so the top clip shows the original "end" point clearly & fades to the "start" of the bottom clip. Either way works...
There still may be a slight stutter no matter what, depending on the delivery platform. VLC is decent about looping, but iTunes and WMP have a noticeable gap even in a clip that should be seamless. If your clip is for DVD there might be a slight pause, but visually it would look the same.
If the video is for web or mobile use, it'll depend on the platform. iOS and Android are horrible about looping videos natively (there's always a noticeable gap while it restarts, if looping is allowed at all). With HTML5 video or Flash you could code it to seek to the beginning immediately before it reaches the end, hopefully preventing much stutter and avoiding the need to go to all this editing hassle...
I hope this helps!

It sure did help. I'm going to go for some version of the cross-dissolve built into the clip itself so that the start of a new iteration of the clip can't be detected.

@Speldosa - You can't say "You can't seamlessly loop a clip that wasn't designed to loop" without knowing the content of the video

I upvoted mc01's answer. But I also want to suggest a couple of alternatives (which is something I do a lot on this forum!).

If possible, you could shoot a new ending and beginning that utilize the skip/jump. It could be a gunshot or part of a quick earthquake.  Or a character could mention that there might be a power outage, or a ripple in the space-time continuum (if something like that fits with the tone of the video). Then, when it occurred, the skip/jump would actually appear as an intentional part of the video.
You mentioned that the clip is short.  Let's assume for this example that it's 3 minutes long. You could make a new edit of the video, where you loop the footage 20 times so it takes up an hour. Each time the footage starts again, you could have complete control over the smoothness of the transition. After outputting it, when you played the footage as a loop, 19 of the transitions would be smooth and flawless; every hour there would be one brief hiccup when the footage restarted at the beginning.

These advices aren't applicable to my specific situation, but they are good tips anyhow. Thumbs up :)

Thank you! I always like to post alternative solutions, even if they're a little crazy.

The issue could be primarily technical or mainly aesthetic. Assuming that the clip is designed to be loopable, it's a technical issue. But if you edit two copies of the clip end-to-start and the transition still looks bad, it's more aesthetic.
On the technical side, I've had success with Windows Media Player looping WMV and FLV clips. This depends somewhat on the bitrate: high bitrates tax the cache and may cause a slight hitch at the transition (usually a freeze on the last frame). But the clip has to be designed to loop, either with matching frames or a good-looking cut.
If it's not technical, you could trim the end of the clip so that it A) ends on a full GOP and B) matches or complements the start of the clip as noted above.
An alternate approach is to create a transition-only clip, like the dissolve you mention, add it to a playlist, and put the playlist on repeat. WMP usually handles playlists seamlessly.

Thanks for the heads-up regarding the bitrate. I'll try to keep an eye on this.

I know this is kind of old but I just had a similar problem and I came up with what I thing is a MUCH better option and doesn't require the compromise of fade in/out. Of course, you must have a simple video editor:
Import the "clip that wasn't meant to loop" and cut in half. Simply reverse the two halves. This makes the start and end frame sequential so when the clip loops back on itself it behaves like it was made to loop. Now, simply overlap the joint in the middle and create whatever cross dissolve makes it look seamless and export!
Of course, this will make your clip start in the "middle" but for many applications it won't matter. If it does matter, simply reimport this new clip and repeat the process to get the proper clip back at the beginning!


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Video with person 'writing on glass' effect
I'm trying to find someone who can make videos similar to one shown here:

At 49 seconds, the actress writes on glass to explain the concept.

Does someone know what this effect is called so I know what to ask for?
Also, if you know how to do this sort of thing, please reply.
Thanks so much,

please update your profile with your website - would like to get in touch.

you have my email under my account...

Desmond, sorry couldn't see your email address - I might not have had enough privilege.

aleks@totalno.si

You could always have her write on actual glass in front of the screen and then flip horizontal.

@Desmond I wouldn't put your email address out there like that. Do something like example[at]example[dot]com. Less spam. Just my two cents worth...

@NReilingh: Do you mean something like this: http://www.youtube.com/watch?v=4Jl0CFgj3IM . My question is, which one would be better?

similar query: http://avp.stackexchange.com/questions/4527/is-there-any-option-for-mirror-imaging-in-video-editing-software

@claws Exactly like that. I prefer the flipped actual writing--it's probably easier for the actor as well. Also it reminds me of this.

I'm late to this party, but if anyone else ends up here, please notice:  Girl's video is different from man's.  Her writing is simply added in post production along with sound effects.  Notice: her motions do not match the drawn characters.  The Man's video is a horizontal flip in it's entirety.  Notice his shirt.  A man's shirt should have buttons on the right side.  His seems to be on the left.  His characters have a right-handed slant, and he holds the pen with a right-handed grip.  But the pen seems to be in his left hand.  It's a horizontal flip.

There is a much better way to do that. That example video is a pretty poor illusion.

It can be done "for real" with with real light. But it looks
different. It has to be dark.
You can use motion tracking to create an animation path.
You can also use manual key frames. There are lots of tutes on the intertubes about that. Here is one:

hahahaha what is this?????? this is nothing like what the op is asking for

The easiest bet is to actually draw on a piece of glass and there are actually boards made for just that purpose for the classroom.  It is probable one of those is being used here and the video reversed to make it readable from the other side.  This seems likely as the video shows the guy left handed and the buttons are on the wrong side of his shirt.
The same look can kind of be achieved using write-on effects and/or animation, but you would still need some prop for the speaker to interact with so that they position their hand in roughly the right area and it still wouldn't like up exactly.
Doing this kind of shot practically is the best way to achieve it.

Thanks! I did notice the left handed writing but I missed the buttons on the shirt, nice catch!

After seeing something similar and wondering how it was done in a video with a guy, girl video looks edited.
I tried this, and think that he actually is writing on glass, is filmed from front, with mirrored letters. After filming just simply flip video horizontal, and text will be mirrored back to normal and guy will be mirrored. Just make sure there is no other text in shot.
Clue: guy on this video is writing with his left hand, but holds pen in right handed way.

Sharp observation on the left hand writing, but what do you mean by holds pen in right handed way?

@BartArondson Most of left handed people I know tend to bend their hand more and almost put their hand above text while writing, so they wouldn't smear text with their approaching hand. :)

Upon closer examination of the sample video, she is not writing what you are seeing, her movement only approximates the motion and if you look close enough you can see it is a mime--take a good look at the "E". She is not moving correctly to get that "E". I don't know what resources you have to work with, but if you want to copy this technique you need to have 2 things:
1) an actor that can closely mimic the correct motion as if she/he is really writing.
2) a good post production video editor so you can animate the writing content on a separate video track and make a composite.
Hope this helps
ps, by the way I think the actor in your example did a marvelous job of miming the motion to trick us into believing she was actually writing the text on glass.

We do this in post, and we can call this "the write on screen/glass effect", we can track her finger and write out what she is writing in the air...and more...

More like pretending she is writing and pretending you are tracking! ;)

indeed, but hey, we ll get some negative points for joking around without a solution... :P

We are using this now. A large pane of glass ( Lexan scratches too easily) in a frame. A black backdrop. There is a string of LED ribbon lights along the top edge of the glass.
Room lights are off. Camera adjusted to bring black levels up...Once recorded, use Premier to horizontally flip the video.
Writing magically apprears.
If we want to see the artist/SME, we can light it. The question I have to that: what is the more critical point? The content or the person?
Take a look. https://vimeo.com/246090021

write stuff up on a smart board and then mirror the person but keep the written stuff as is. on closer observation, we have a habit to start from the left side of the page and in this case, the guy is right handed and his text has been moved to the right and the lady is left handed and her text is moved to the left. Hope this helps

Based on this video

I kind of figured it out how he did that. But the fact that I found this forum is because I thought it was amazing.
I think the way he made the video is

record behind a glass
draw on the glass like a whiteboard
flip the video.

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Why do weathermen and amateurs use green screens when professional movie makers use blue screens?
I've seen a lot of "low budget" green screen setups. However, when I watch things about professional filmmaking, it seems everyone is using blue screens instead. (e.g. I've seen Industrial Light and Magic called "the blue screen boys", and the recent TF2 "Sentry Sabotage" video was filmed using a blue screen)
Is there some technical reason for this distinction or is it merely personal preference/inertia?

Professional film productions use neither only green nor only blue for chroma keying, but switch between both depending on the scene. Each can only be used when there are no objects of the same colour in view, otherwise it takes extra work to un-remove these objects. Blue and green are the usual colours because the human skin, which is what will almost always need to remain visible, is very different from both, but this is not the only thing shown in chroma key scenes!
In most situations, you have neither blue nor green objects in the foreground so both colours will, in principle, work. But they may not work equally well. The main reason why green is predominant in digital productions: digital cameras can resolve green light best, so it's possible to do proper green chroma-keying even with a cheap camera that might have problems to resolve a blue screen accurately enough. But that's not a concern in professional film productions. Analog cameras actually resolve blue better, but the difference is not really significant.
Especially blond hair will sometimes reflect much of the light coming from a greenscreen behind, which can lead to weird and somewhat ill-looking green shades. Blue is less problematic in that aspect. On the other hand, clothing will more often feature blueish colours than greenish ones.

From this green/blue screen guide:

"Green chroma screens have become more and more popular in recent years, largely because green provides a brighter color channel that tends to have less noise than the blue channel. The relative brightness of green makes it a bad choice for shooting blonde hair though, which is a lot easier to key against blue backgrounds."
"The bluescreen has some distinct advantages. When you can’t avoid a lot of spill (for example when you have to put the foreground very close to the chroma material) you can take advantage of the fact that we tend to find blue casts less disturbing than people walking around looking sea-sick with green faces. Also, when shooting for something that will be composited on to outdoor backgrounds and water, a slight blueish cast won’t be a problem."

The Lord of the Rings used green screen.  That's the last behind the scenes I've seen, however I can't imagine it being 'most' if that's the case. Looking at the wiki article there are a couple that use blue but if you think about it I imagine it all comes down to what the actor is wearing and if there are any sets pieces involved.
Green may be best for some situations and blue others.
As for weather forcasters specifically, which color do you see being a problem because of their attire; neon green or blue? =)
[edit] turns out I was wrong, BLUE is older.

Blue is much older than green!

Looking at "behind the scenes" videos from Game of Thrones, it uses both colors in turns. So  yes, both work, you just pick the one that works in the situation you are filming in at that point.

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How to add motion blur in timelapse videos?
I remember watching a video about timelapse photography. There was a moment when the narrator explained that there is a specific trick to make the videos "smoother":

In the timelapse videos which don't use this trick, if people are moving, they suddenly appear at a precise frame, then disappear,
In the videos which use the trick, we have a feeling that they are smoothly moving, like if there was a motion blur.

What is this technique? What is it called? Is it done when taking photos or during post-processing?

After Effects has a frame blending mode called "Pixel Motion," which will attempt to match features in two temporally adjacent frames and smoothly blend between them. This video shows it in action, where it is used to generate filler frames for video footage that was slowed down 10x. As you can see, the results are mixed.
There is no magic bullet for filling in missing data. As the classic computer programming expression says, "Garbage in, garbage out." If you only need to blend between small changes in the scene between frames, this blending mode might help. Otherwise, your best bet is probably to just do a very fast plain fade between each image, which can be achieved with the "Frame Mix" blending mode.

Sure this one is the right answer. I used a lot to do this in After Effects. It's a little trick to set the settings right, but the results then are great. A great tip is : you got different results with motion blur and frame blending on/off. Upvoted! Funny video test!

One solution to the jerkiness of stop-motion animation was developed for some Star Wars sequences, termed "Go Motion".
Basically the idea is that you leave the shutter open a little longer than necessary, and move the objects a bit, to create some motion blur.

For a landscape with people walking across shot, making each exposure quite long, maybe quarter of a second, can help - the background, sun transit and clouds etc will not be affected, but people will be a lightly moving blur.

Drag your shutter, by using an ND filter on your lens by exemple or simply closing your aperture and you'll get this effect =)


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Good open source Video Editors?
Sure, I could Google and find random software. But I rather have the opinion of users that have had hands-on with any open source video editors.
So if you've used one that you like or know of any, please let me know and state whether you've used it or just know of it (and heard good things). Thanks.
I'm looking for Windows software. But you may suggest Linux as well for other people that might stumble upon this.

I tried some and it's hard to find one that is free, well documented and that works perfectly. Especially on Windows. You should tell which operating system you use.

I think you are looking for "free" and not "open source".

@koan Well I'm a developer so I may want to contribute to a video editor that I deem worthy of my time :D

Duplicate of: http://softwarerecs.stackexchange.com/questions/25378/professional-open-source-video-editor

@niutech Isn't it the other way around? I asked this in 2011 :p

VLMC is a non-linear multitrack editor. It's based on VLC and inherits a pretty vast format compatibility from that. The UI is a little rough, but it gets the job done.
Lightworks is a more recent project and seems polished. It's rooted in broadcast editing, so a large number of familiar codecs are unsupported. It supports Matrox codecs, which you have to install separately, so you'll have to convert your video to Matrox AVIs first.
Avidemux is a simple editor, good for trimming and small tasks. In my experience, not very stable on Windows, OK on Linux.

+1 for Lightworks. I switched from FCP to Lightworks a year ago and love it. It's very full-featured; many feature films have been cut on it, including Pulp Fiction and Braveheart, and more recently, The King's Speech and Hugo.

Note that Lightworks is not open-source currently, but open-sourcing it is on the roadmap.

I agree with the Lightworks suggestion, however, to really use it in any modern projects, you need to purchase the pro license for import and export options other than the most basic.

VLMC seems to be a bit dead. Five years on and it's still in alpha.

You might want to see Wikipedia's Comparison of video editing software and list of video editing software. From my personal experience I recommend Kdenlive over any others. It has good support for a wide range of non-linear video editing functions. If you are the real geek, you may want to try out Cinelerra.

Kdenlive is rapidly becoming the most advanced FLOSS video editor. Kdenlive supports Linux and Windows natively. There is also a version for macOS on macports.org, but it is outdated.
I use Kdenlive often on my Linux system. It has an active development team that are very responsive to new feature requests and bug reports. The user community is also very friendly and supportive.

+100 for Kdenlive. I started using it somewhat recently, and it has done everything I've wanted. It has great support, is well developed, and mature features.

I personally run Cinelerra CV and it's "mochup" Cinecutie on my Linux boxes.
Cinelerra (and it's relatives) can do some very sophisticated editing work, but they aren't the easiest to use.  Luckily, there are lots of video tutorials out there to help you.

There is an Linux/Gnome based video editor called PiTiVi which is working close with the GStreamer multimedia framework which is used by most Linux distributions. The PiTiVi project has been slow moving because of their development philosophy which is "upstream first". Challenges they encounter in GStreamer means that they work with GStreamer to solve the issue instead of working around the framework.

If you're on Linux, consider Cinelerra: the most powerful video editor for Linux, Openshot: simple, powerful, and free video editor for Linux, or Kdenlive (also available for FreeBSD and Mac OSX): Free and open source video editor for GUN/Linux and FreeBSD
Openshot and Kdenlive can be installed via apt-get install, however Cinelerra requires a little more configuration

For Linux people:
Kino
It is a non-linear DV editor.  It has many features including capture, editing, FX, and export to other formats.
I've used it for several years without issue.

Kino is "no longer being developed as of 2009" https://en.wikipedia.org/wiki/Kino_(software)

If you are really adventurous why not give Blender a go? It is a 3D animation and compositing/tracking application. It is completely free and open (FLOSS) as well as being totally system agnostic. Run on Windows 32bit or 64 bit, MacOS 32 or 64 bit and Linux 32 or 64bit.
The video editor is rather novel and a bit rudimentary but is supported by a large compliment of addons or python scripts that enhance its usability.

A friend of mine liked VirtualDub quite a bit, which is free. I have not, however, used it myself.

VirtualDub used with AviSynth is a good combination.

OpenShot is easy to use. Only for Linux.

OpenShot Video Editor is a free, open-source video editor for Linux licensed under the GPL version 3.0. It can take your videos, photos, and music files and easily add sub-titles, transitions, and effects, and then export your film to DVD, YouTube, Vimeo, Xbox 360, and many other common formats.

Could you maybe elaborate on why it is easy to use? Is there a good manual? Intuitive user interface? Other good/bad things the software has? Please add some more detail to your answer.

OpenShot 2.0 (currently in late stages of development as of March 2015) is going to be cross-platform.

Better than mearly good is AviSynth: http://avisynth.nl/index.php/Main_Page .
Basically you write a Script and then open the Script in a Player. The Script can change the input in many ways and there are many 1000's of Plugins. There are a few Forks including some 'traditional' looking Editors that use AviSynth under the hood.
After tweaking the Script precisely you simply 'copy' the Script (possibly with Ffmpeg) and render a final version.
Includes capabilities to express exactly (to the pixel and frame) what you want. Not too bad a learning curve and so many examples available. During several years of use I discovered no Bugs but apparently others found a couple that have since been fixed. Open Source and you assistance is welcome.
Often used in conjunction with VirtualDub to provide a GUI.


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What could be causing these strange MP4 video playback corruptions on some machines?
(Note: the video is a screencast hence the desktop icons, that's not actually the desktop of the machine having the error.)

We are using JWPlayer, and we rarely have this issue, but on it is frequently reported by customers and becoming a repeat issue. We've had them update their Flash player to the latest version. What causes this? My guess is codecs or video driver issues but I am not sure how to fix.

".mp4" doesn't tell us anything about the codec. (See this question, asked just recently.)

Does the problem go away when a keyframe pops up?  I've seen this quite a bit, always due to video corruption.  The problem should go away on the next keyframe.  If it doesn't, something else is likely wrong.

@leftaroundabout sadly I don't know anything about the codec, but I was curious to know if it might be a codec issue

You can see what codec it is when you open it in, for instance, VLC.

Put keyframe distance in the encoding options to KEY EVERY FRAME.
When you export in the export options you have keyframe distance, which is used to calculate "intermediate key points/key frames", and the default is 25/30 frames. The player calculates pixels and frames inbetween keyframes. Sometimes it gets lost in calculation because of lost bits or bytes. Having less distance between keyframes reduces the chance of this, and results in more accurate frame rendering.

I've edited your comment into your answer (and removed our now-outdated comments), so that the answer is much clearer. In general this is a better place to put explanation, since it's easier to read and the comments aren't really "part" of the answer anyway - just associated with it. If I've made any error, please do edit the question to fix it.

This has nothing to do really with Codec. Even if the stream is fully corrupt, the media player needs to portray only such things within the UI window.
This could be most likely a device driver or software dependency with player having issue. try alternative players.


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Censoring license plate in a long video
I'm editing a video recorded in a car workshop. The video is about 30 minutes long.
In the background there is a car whose license plate has to be hidden. Unfortunately, the camera moves a lot so it's not possible to censor many frames at a time.
I'm censoring using a mosaic effect over the plate, which has to be added to each frame, but it's taking a very long time.
Can you offer any tips that would help make this process faster?
I'm using Wondershare Filmora 9 for this job.
Thanks.

I am not sure about Filmora 9, but Google Motion Tracking. You just need to roughly track the sign and make a blur bigger than the sign, so it's allways covered. If you want to exactly censor the sign, you need to track the corners. But I'd think filmora can't do that

To make this process faster - you would either need to use KeyFrames or Motion Tracking, but Wondershare Filmora 9 does not support either. There are other free software packages that do support KeyFrames and Motion Tracking like Davinci Resolve.

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text:
What should I be looking for in a low cost color correcting monitor?
I am in the market for a low-cost, color-correcting monitor. Please help me define "low cost." I don't want to skimp out but don't want to buy top dollar either. I know good monitors cost money.
I will be using the monitor for both Video and Photography. What features/specs should I consider a "bare minimum" so, hopefully, I wont need to buy two.

Shopping recommendations are generally off-topic, especially non-specific ones.

@Dave: We don't really allow "shopping recommendation" questions on this site, but I edited your question so you can get some of the information you need to get you started.

In terms of photography - this is a good read http://photo.stackexchange.com/questions/1687/what-should-i-look-for-in-a-monitor-for-photo-processing.

There's a loose binning of monitors into 3 categories:

Consumer equipment [$500 - $1500] Dell U-Series LCDs, Panasonic Viera Plasmas
Entry-Level Monitors [$2500+] FSI, HP DreamColor
High End Monitors [$$ - $$$$] eCinema, TV Logic

Some of the features of non-consumer monitors that you'll want to learn about are:

HD/SDI inputs
Additional outputs
Colorspace and signal type support, such as 4:2:2
"Higher" bit depth, such as 10-bit
LUT programmability

If you're asking for low-cost, without already knowing these monitors, then I strongly suggest you stick to the first category, and use something like the DataColor Spyder calibration puck.  Getting that top 5% of color accuracy comes at a steep price, and since it seems you're just starting out, you probably want to stick with the 95% solution.  Upgrade only when you have specific need for the features.

Consider the Matrox MXO2 products. The Mini model allows you to gain blue gun control of a normal consumer HDTV, solving the big issue with calibration of these large displays. The MXO2 Mini is under $500, other models include features like hardware H.264 encoding and more advanced interfaces.


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High-end graphics cards: is it needed or useless for video editing at i5 machine with quicksync?
I am in search of a graphics card that makes video editing fast.
I think to buy an i5 cpu with a motherboard with quicksync (z68?) and an SSD.
Quicksync on cpu is only for transcoding (h.264 and mpeg2 as I understood).
I suppose that I need a discrete graphics cards with cuda to make faster the rest of video editing.
I don't care about 3D games.
Ofcourse, I will use software that supports the technologies needed.
The differences among the various graphic cards currently are the number of cuda cores (eg 96), the memory size (eg 1GB), the memory-channel size (eg 128bit), the type of RAM (DDR3/DDR5) etc.
Up to what point, adding cuda cores, and more memory to the graphics helps would help my video editing process?

Is it enough to buy a cheap cuda card (under $100)?
Would buying an expensive card with more cuda cores, extra memory, bigger memory
channel size, offer significant advantag over cheap cards?
Could an expensive cuda card even offer no advantage at all, if there are
other bottlennecks at the system?
Does a system with i5, z68    motherboard and SSD disk, 8 GB ram, and windows 7 64 bit have any bottleneck for high-end cuda cards?

First question to ask is:

Does your video editing software actually use your GPU at all in the editing process? If it isn't written to use CUDA then you will not benefit from getting a better video card, other than being able to view it in higher quality on the screen.

For software that can, all of those factors are important:

Memory size is likely to be the most important as working with all relevant data in memory is faster than having to import from disk.
Memory channel size is also important, as is the speed, for ensuring you minimise latency when reading video data.
CUDA cores are probably the least relevant when editing, as this is not a hugely intensive task. They would be much more important when rendering, or carrying out complex image manipulation.

update based on comments
Adobe Premiere Pro does use CUDA, through the Mercury Playback Engine. From this post on the Adobe forums, whether a frame can be processed by CUDA depends on the size of the frame and the amount of RAM on the graphics card (VRAM), which supports my point that the most important is RAM size.

Thanks for your answer, but I did not ask what are the important features in the graphics card. I know them. I need to know what is the limit of adding extra memory, cores, and channel size to the card, after which the rest of the computer cannot take advantage of. I gave example of an core i5 with ssd disk.

@John - the important bit is your software, and what type of editing you are doing. That is what will determine the answer.

I will select the software that can do the job fast. Editing will be with Premiere probably, but I may also find other software also that cooperate with CUDA cards. About transcoding, I ve read about some software that uses quicksync, but I don't remember its name. I can find it easy again if I google


text:
Which container format for ProDVX F150
I need to produce a video that can be played by a ProDVX F150 (a small black box device which plays video from a flash card). It's hard to find real specs for this thing, but webshops say it does:

Playback formats: MPEG1 (up to 8Mb/sec VBR),MPEG2 (up to 8Mb/sec VBR),MPEG4 (up to 8Mb/sec VBR),JPEG,MP3

Based on this (little) info, what container, video codec and audio codec would you recommend? The video is 576p PAL.
Unfortunately I don't have the device at hand for easy testing, otherwise I'd just hit-and-hope with various formats.


text:
Video Assets to test transcode quality
I was wondering if anyone knows from where I could get a few (short) video  assets in high bitrate to check the quality output of a transcoder.
Some context: A few years ago I was working on a VOD project and the person who was configuring the transcoders had a set of 4 videos that really pushed the transcoder (e.g. very clear water ripples, a few bees on top of a yellow flower... and I cannot recall the other 2). I remember this person telling me that he had picked those videos as they pushed different aspects of transcoders, so I was wondering if there's something out there I could reuse.
edit
I haven't found so far a good set of free videos to push the transcoder, but I have found the following sources.

4k media: Has quite a few free high bitrate 4k (30-60 fps) videos.

Here are a few resources I'm aware of.

The Video Quality Experts Group has a variety of test material available.
Big Buck Bunny, with a CC license, is often used as a test asset.
Tektronix at least used sell some test assets to complement their monitoring tools.
SRI has several test patterns and compliance checking assets for sale.

Thanks Michael! ... I still have bad memories of BBB after watching the start sequence a few hundred times long time ago :D.


text:
How do I specify baseline H264 profile using FFmbc?
I am using FFmbc (a FFmpeg derivative) to transcode some video files to H264 (in a mov wrapper).
I want to specify baseline profile (to reduce CPU usage) but can't figure out how.
There doesn't seem to be a simple option to specify this - I understand the profile is derived from whatever options I have specified.
However most examples are for FFmpeg and FFmbc rejects them.
The suggestion to use "-flags2 +bpyramid+wpred+mixed_refs-dct8x8" gives the errors:
[NULL @ 0x101093600] [Eval @ 0x7fff5fbfce20] Undefined constant or missing '(' in 'bpyramid'
[NULL @ 0x101093600] Unable to parse option value "bpyramid+wpred+mixed_refs-dct8x8"
[NULL @ 0x101093600] Error setting option flags2 to value +bpyramid+wpred+mixed_refs-dct8x8.

What am I missing here?

Note: This is for recent FFmpeg, not FFmbc, which doesn't use the same option syntax (yet)

You need to use the -profile:v option, which has been introduced in FFmpeg 0.9 (afaik) and is now standard in 1.0.
ffmpeg -i input.mp4 -c:v libx264 -preset fast -profile:v baseline out.mov

Why? -profile was used (and prioritized) for AAC encoding. It's simply ambiguous, therefore you need the stream specfier :v.

that's for ffmpeg, ffmbc hasn't moved to the newer "-vprofile" style syntax yet.

You're right. Back when I wrote this FFmpeg was about to change the whole thing and everything was a little confusing. +1 to you.

-profile baseline seems to work for me, using libx264. I use the libx264 presets - for example "slow" gives me the options listed below. there's fast, slow, veryslow and placebo (might be more, can't remember).
stib$ ffmbc -i test.mov -vcodec libx264 -preset slow -profile baseline -acodec libfaac -ab 96k -crf 19 test.mp4
...
[libx264 @ 0x101858c00] profile Constrained Baseline, level 3.1
[libx264 @ 0x101858c00] 264 - core 120 - H.264/MPEG-4 AVC codec - Copyleft 2003-2011 - http://www.videolan.org/x264.html - options: cabac=0 ref=5 deblock=1:0:0 analyse=0x1:0x111 me=umh subme=8 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=0 8x8dct=0 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=6 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=0 weightp=0 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=50 rc=crf mbtree=1 crf=19.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'test.mp4'

To set the baseline profile us the following ffmpeg options. Mobile apps like Neighboors by Ring use baseline profile.
ffmpeg -i in_video.mp4 -vcodec libx264 -acodec aac -b:a 256k -vf scale=1280:720 -profile:v baseline out_video.mp4

I also had this issue.  I removed the extra space chars present in preset file and it worked for me.


text:
What is the current status of rolling-shutter-free CMOS sensors on the market?
It is now common to have CMOS pixel matrices inside DSLRs and video cameras. However, when acquiring movies, these sensors suffer from artifacts known as rolling shutter effect, since they are due to the electronic rolling shutter (but surprisingly, CCDs with electronic rolling shutters did not create those artifacts, which gives me hope that there is a hardware solution).
I've read on the web recently (in reports from CMOS lab meetings) that rolling-shutter-free CMOS sensors were now available, and I have also noticed that the "jelly" effect was reduced on recent cameras, but I couldn't find precise information.
Hence, I was wondering if someone knew the current status of global shutter CMOS sensors for the market ? Are they still in the research labs, or embedded in high end devices, coming soon... ?

OK, answering my own question. Sony recently announced a 4K CMOS sensor with an electronic global shutter, see this blog post and the references inside.
So, the status seems to be: reaching the higher end of the market right now (Nov. 2012), the technology does exist. We still have to wait a few years before seeing these global shutters in lower tiers though.


text:
How to force ffmpeg to insert keyframe at first frame when downsampling a framerate of a video with x264 vcodec
I have a mpeg4 video at 25fps. This video contains just one static frame. I'm trying to downsample the frame rate to 1fps and convert the video to x246 (mp4).
I ran the following ffmpeg command:
ffmpeg -i vid.avi -acodec aac -ar 32000 -ab 64k -ac 2 \
-vcodec libx264 -strict -2 -y -r 1 -force_key_frames 0 vid.mp4

FFmpeg then drops a lot of frames until it inserts the first keyframe. Sometimes image appears only after 16 or 20 seconds.
I gather ffmpeg doesn't insert a keyframe at very beginning.
Does anyone know how could I take the first frame of vid.avi and use it as the key frame for vid.mp4?

have you tried it without -force_key_frames 0? Also might want to try changing the 0 to a 1 to have it start on the first frame instead -force_key_frames 1

yes, i tried without -force_key_frames 0 and with -force_key_frames 1, but that didn't help. I'm pretty stuck.

is doing it exactly this way required? I'm going to take a wild guess and assume the following: the audio is the focus of the video. The image isn't a huge concern. Sooo couldn't you extract an mp3 from the video (lossless quality of course) and then, acquire the image, maybe even a screenshot if you're that desperate, then create a new video in ffmpeg using the extracted mp3 and image with the fps set to 1?

The force_key_frames syntax for using the frame number is -force_key_frames "expr:eq(n,0)"

I'm fairly sure the root issue here was something else. Encoders always start with a keyframe.

To force a keyframe at the 00:00:00.000 time code, you should try using the following flag:
-force_key_frames 00:00:00.000

What does this do exactly?

it will force position the keyframe at 00:00:00.000 time code, which was asked with the original request.

Could you please elaborate: Is this applicable to x264 only, or any codec? What does the time refer to - the output file time? I.e. for overlays, how could I put a keyframe to beginning of any overlayed video? Thanks


text:
How would you go about finding out when a digital video was made?
How can you determin when a digital video was made? I know one possibility would be just looking at the meta data but sometimes they are faked or missing. I need some more ideas since I have to write 10 pages about it...
Is there any trick like figuring out what codec was used recording the video, and that this codec is only used by this type of phone, that is only available since then and so the video can not be older than...
I need some ideas in this direction but I am stumped. One idea I have is to analyze the picture quality of multiple copies of the video found online and since every recoding results in loss of quality, you could try to determin which one might be the first since it has the best quality.
But this would only be one method. Any help would be brilliant! I don't expect ready to use answers but suggestions would be wonderful! I am hoping to find something in the line of the Kodak Edge Codes but for digital videos.

Not restricted to digital, but still might help: take a close look at the content. If it's non-fiction documentary style footage you could loosely determine the period in which it was shot.


text:
How to add gradient transparency mask in final cut pro x?
I want to add a gradient transparency mask so that the front layer will slowly transform into the layer below. Can anybody suggest something?
I'm not talking about transition in time, but transition between layers. This is an example of video I want to get:

I think that in old final cut you could do this with black to white gradient and filters.

I don't know if you ever found a solution, but FCPX does have a Graduated Mask that works.
To use it:

Position clip1 over clip2 on the timeline.
Add the "Graduate Mask" filter to clip1.
Animate both "Center" and "Target" properties of the effect to move left to right.

Can you edit your post to explain how to set up the transform as requested? Without that, this doesn't really answer the question.

Nice tip. Here's the explanation. Position clip1 over clip2 on the timeline. Add "Graduate Mask" to clip1. Then animate both "Center" and "Target" properties of the effect to move left to right.

If you're talking a special, unique transition that you can't find in the effect browser, you have to use Motion to create the transition yourself, and publish it to FCPX.  If you're just looking for a slow dissolve, there's already a dissolve transition available.  Just drag it from the effects browser to your edit.
Edit: Here's one I created in Motion.  Delete the .xml extension that google adds to the filename; it should be called "SideBySideGradient.motr", not "SideBySideGradient.motr.xml"  Put this file at ~/Movies/Motion Templates.  If you don't already have a Motion Templates folder in your [home directory]/Movies, create one there, drop this in, and look for "SideBySideGradient" in your FCPX effects browser under the transitions category.  Drag this transition between two clips on your timeline, and VIOLA!
I realize that this is a pretty simple application which might not suit your needs exactly, which is why I encourage you to use motion and try it for yourself.  It's not hard!  If you need help, feel free to ask.

Thank you for answer. I added an explanation to my question. I need a transition between layers and not between clips in time. Do you have any ideas?

Yeah, I was afraid that's what you meant.  The easiest solution is to use Motion.  Apple seriously shifted a lot of functionality over there to keep FCPX simple.  FCPX doesn't even have an 8 point garbage matte anymore.  Kind of a pain, imho.  Another alternative would be to bake the gradient into the alpha channel of Prores 4444 using another application.  Final cut Displays these alphas correctly, but doesn't let you edit them.  Apart from that, you might try kludging together a combination of the gradient generator & the keyer effect.  $50 for motion is your best bet, imho.

made one for you.  see answer above.


text:
Why does After Effects not enable me to work with 60FPS?
For a short student film, I'd like to be able to work with shots that are 60FPS. For some reason I dont see this option:

You could choose a format (HDV, HDTV or DVCPRO) that suits your needs in terms of pixel aspect ratio and frame size and then manually change the framerate to 60 fps. Out of curiosity, why would you want 60fps in your movie? If you want slo-mo footage take a look at this question

Those "options" are just convenient presets. Just select Custom and input the frame rate and any other parameters you want.
Of course, if only some of your shots are 60fps, and your final output is 24 or 30 fps, then set your comp settings to the desired output values, and interpret your footage as 60 fps (if it isn't sensed by AE automatically).


text:
Looking to get Youtube-quality video stabilization from a software based video editing application (on mac)
When I create edited films on iMovie and then export them to Youtube, Youtube's stabilization enhancement greatly increases the quality of many of my shakier action shots. Unfortunately, this same process ruins all of my titles and text overlaid on the screen.
Currently I am exporting the problem (shaky) scenes as single iMovies to youtube, stabilizing them, then downloading them and adding them back into my iMovie project as clips. This saves my text on the screen from being rendered illegible.
I am aware of iMovie's stabilization and have tried it, but haven't gotten even close to the enhancement in watchability of my shaky shots that Youtube's stabilization algorithm/method has given me.
I'm looking for some software that can give me the serious quality improvement that Youtube's can do, without having to use cloud services as a hack like I am now.

A coworker has just turned me on to using Warp Stabilizer. It's a built-in effect in Adobe Premiere CS6. Before using this tool, I also used After Effects to smooth and stabilize motion.
The difference is outstanding. Warp Stabilizer has worked faster, within my workflow, and more reliable than After Effects stabilization has. This has been huge for me. Here's a quick guide that outlines the effect: http://www.premiumbeat.com/blog/premiere-pro-warp-stabilizer/
Another solution is Lock and Load. I've never used it, but I've heard it gets the job done. Might be worth looking into if you do not already own the Adobe Creative Suite. http://www.coremelt.com/products/lock-and-load-x.html

It is worth pointing out that the same Warp Stabilizer is also available in After Effects as well.  It requires less configuration than AE's but AE's standard option or the included copy of Mocha can both do a better job if you have the time to use them right.  That said, I generally use Warp Stabilizer for most stuff because it is good enough for being far simpler and faster.

Adobe After Effects includes stabilization that is of similar or superior quality to Youtube's but it is also not a cheap software package.  I don't know of any particularly cheap software stabilization options that do a high end job.

Is it on only the latest version?

@boulder_ruby - no, it's been there for quite some time, though it generally improves with each newer version.

Creative Cloud makes this fairly affordable actually. Not free but if you're doing enough video work on YouTube to be asking about it - it may be in your budget.

@Ryan - I'd challenge that Creative Cloud makes it unaffordable for everyone.  The long term cost is substantially higher (multiple times higher, even without going in to the concerns of having to pay forever to access your projects).  The short term cost is also much higher if you don't do the 1 year package.  $240 a year for one package isn't what I'd call cheap.

@AJHenderson ya I figured I'd get some heat and almost added "Runs and hides" to the end of my comment. CC has its issues on the pay structure without a doubt but for something like this it is fairly cheap - he could do a single piece license only for AE making it very cheap. You also dont have to pay forever to access only to edit. Could also counter argue because Adobe does do updates fairly regularly. CS4 2008, CS5 2010, CS5.5 2010, CS6 2011. If they're going to put in the money and effort to keep up with new tech/dev tools then CC is actually the way to go

@Ryan - I don't want to get in to a discussion on it, but I kept up to the most recent major version of Master Collection and CC would cost me almost double what I was paying before and I wouldn't actually own a copy of any of it.  Current options are $240 for 12 months of a single app or $75 a month for the MC for 1 month.  There is no single month, single app plan.

MotionBend, http://www.motionbend.com, might be what you are looking for, http://www.fcp.co/final-cut-pro/news/1119-motionbend-takes-video-stabilisation-to-the-next-level-and-adds-fcpx-xml-export. Do you have any examples of videos you are trying to stabilize ?


text:
Compress or convert .mov to lighter format
My camera records videos in .mov format, what can I use to edit out the audio and lower it's size in a Windows environment?

Note that .mov is just a container. What you're really looking to do is change the compression. A QuickTime video file (.mov) can have any number of different codecs used to compress it.

You didn't mention whether you're using a Mac or Windows, but...
You could use a tool like MPEG Streamclip to change the format of the video, or strip off the audio.  Works on both Mac or Windows.

I use a Linux-based OS, but this question applies to Windows users, thanks!


text:
Which cameras produce video that can be edited on a mac without transcoding?
My old video camera is a Samsung HMX-H104. I love its time lapse video modes, but hate the fact that Samsung's bogus codec causes Quicktime (and also iMovie) to play Samsung recorded video at twice their actual horizontal resolution. The only way to make Samsung videos usable is to transcode them in Compressor.
I'm considering getting a new video camera - how do I ensure that I don't end up with another camera that requires transcoding?
Also, if I'm considering switching from iMovie to Kino, Blender or maybe FCP X should that influence my choice of camera?
Update - The codec problem with Samsung cameras goes beyond iMovie. Quicktime player 10 can't play the videos correctly either, and I don't want to optimize my camera choice for just iMovie.

One way is to ask the people in the shop you intend to buy from.
Or (if you plan to buy online), narrow down to a list of potential cameras then ask again here with specific camera names.
Another idea is, if you have a compatible memory card, go to shop, ask to try the camera then shoot some video with your memory card in.
Then you can bring your memory card home and try it out.
I've done this with a digital SLR so I could check out the image quality on my computer.

Not a bad fallback, but I was hoping to learn more about determining which codecs a given camera supports. Camera vendors are a lot more interested in sharing the file wrapper than the actual codec.


text:
How do I prevent Quality loss in the beginning of a video?
My company transcodes videos sent in by users (recorder by our own screenrecording software)
I use FFMpeg to do the work using this command:
 /ffmpeg/ffmpeg -i in.mov -vcodec libx264 -fpre /ffmpeg/ffpresets/libx264-slower.ffpreset   -y out.flv

The purpose is to prepare the video for viewing in browser.
The problem is that the first 10, or so, seconds the quality is really poor.
What can cause this? and how can i fix it?
Preset settings:
coder=1
flags=+loop
cmp=+chroma
partitions=+parti8x8+parti4x4+partp8x8+partb8x8
me_method=umh
subq=8
me_range=16
g=250
keyint_min=25
sc_threshold=40
i_qfactor=0.71
b_strategy=2
qcomp=0.6
qmin=0
qmax=69
qdiff=4
bf=3
refs=5
directpred=3
trellis=1
flags2=+bpyramid+mixed_refs+wpred+dct8x8+fastpskip
wpredp=2
rc_lookahead=50

Exampel of an input video
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '84f42bcb67ac616635ef6f99057bbbc46d418295.mov':
Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    creation_time   : 2012-03-07 13:45:16
  Duration: 00:15:56.00, start: 0.000000, bitrate: 4108 kb/s
    Stream #0.0(eng): Video: qtrle, rgb24, 1680x945, 3401 kb/s, 13.61 fps, 1k tbr, 1k tbn, 1k tbc
    Metadata:
      creation_time   : 2012-03-07 13:45:16
    Stream #0.1(eng): Audio: pcm_s16be, 44100 Hz, 1 channels, s16, 705 kb/s
    Metadata:
      creation_time   : 2012-03-07 13:45:16

Any chance you could post an example, both of input and of the poor-quality output? Would help trying to tweak it (and reproduce the problem).

Fixed by updating FFMpeg to newer version


text:
How to record a video of computer screen movements
Can someone suggest good softwares for making a video tutorial of computer screen, like is done on most computer tutoring sites?
I am looking a software that can capture a video of my blackberry simulator run so that the client can preview the look and feel of an app on the device.
Please suggest software that is freely available and which doesn't add any watermarks.

are you running windows or OSX? Free or paid?

Windows XP Professional registered version

It's called a "screencast"

There are a large number of these, mostly advertised on gaming websites, but I think this question may be too localised.
Google will find you many, 2 seconds found me this:
http://www.anewmorning.com/2009/01/06/5-free-alternatives-to-fraps/
And if you want to find a good one, that link gives some information about each one.

Thanks.Well yes i have googled too.I wanted some experienced users to suggest their opinions in case they are themselves using one.

I used to use Fraps, but find the performance of WeGame is easily sufficient for my COD/MW antics, and is free.

I just tried Cam studio and its working great.

@techie If you can find them on Google but you are looking for the opinions of experienced people, just make sure to say that in your question :)

I love using Camstudio!
It's free I've used it , not the best interface but great to use until you are willing to pony up $300 for Camtasia.
http://camstudio.org/

Yeah absolutely.But i am yet to figure out how can i go about editing the videos.Atleast the free version doesnt support this feature it looks.

Use CamSTudio to make your raw videos then something like iMovie or Windows Movie maker to edit the pieces together.

I use Open Broadcaster Software for that purpose. It is well known for its streaming capability but can also record the screen with high quality and flexibility.
https://obsproject.com/


text:
Does anybody get a strobing effect when filming video with the D90?
I often shoot indoors for interviews with my D90, but I often get a sort of strobing with it.  Check out the attached picture, to help you see it on a picture, I added red marking, so simply look on the curtain on the right of that.

My best explanation so far was the type of lighting in the room, which is common in most offices, similar that was is in the picture:

Does anybody know what is going on?
Similar experience?
Solution?
Explanation?
Thanks for any input.

Many types of artificial lighting flicker at twice the rate of the power source. This is most pronounced with fluorescent lighting, but also happens to a lesser extent with incandescent. Common power sources are 50 Hz (in Europe and most of Asia) and 60 Hz (in North America), which cause 100 and 120 pulses of light each second, respectively.
Other than changing the lighting, one has two options for overcoming this problem:
Frame Rates. Choose a frame rate equal to the lighting pulse rate divided by some integer. This is often the simplest option since most corresponding shutter speeds will appear flicker-free.
Shutter Speeds. Choose a shutter speed equal to the lighting pulse rate divided by some integer. This option often isn’t as straightforward, and can constrain one’s ability to control motion blur. On the other hand, this option typically minimizes flicker under a broader range of lighting and power types.
For example, in North America, the standard 24 and 30 fps settings work with most shutter speeds (since 30×4 and 24×5 = 120). Use the tool below to find other flicker-free shutter speed and frame rate combinations:
http://www.red.com/learn/red-101/flicker-free-video-tutorial


text:
Encoding DNxHD using ffmbc
I have decided to re-encode my footage as DNxHD for editing. I am using ffmbc (downloaded here) to do the encoding. My source footage is HDV 1080i50.
Therefore I think the best format to trancode into would be DNxHD 1080i50. According to this document ffmpeg (which ffmbc is derived from) has a limited selection of formats of which 1080i50 is one.
Here is the command I am using (%1 and %2 are the in and out filenames):
ffmbc -i %1 -s 1920x1080 -vcodec dnxhd -b 185M -mbd rd -tff -acodec copy -threads 0 %2

Questions:

To encode interlaced media I need to specify -tff or -bff. I don't really understand the difference. Which would be the best to choose? Currently I have chosen tff as that is how the source is encoded.
Is there any benefit to doing a two pass encode? My understanding of a two pass encode is that it helps keep the bit-rate constant. Is that helpful for editing. I can do a two pass encode with the following command, but it's so slow I'm wondering if it's necessary?
ffmbc -i %1 -s 1920x1080 -vcodec dnxhd -b 185M -mbd rd -tff -an -f rawvideo -an -threads 0 -y NUL
ffmbc -i %1 -s 1920x1080 -vcodec dnxhd -b 185M -mbd rd -tff -acodec copy -threads 0 %2
My source is actually encoded as 1440x1080i. Can any one comment on the drop in quality when converting to 1920x1080i. (I believe that the image will still be the same size but the source has wider pixels)

1) If you're not going to deinterlace it then stick to the source's field order.
2) I wouldn't bother with the two pass encoding (if indeed it even does anything) - dnxhd will only encode at certain specific fixed bit rates anyway so you're actually pretty constrained for options.
3) You'll see some softening, but it's unavoidable.  ffmbc's filtering is ok though.
What software are you editing in?
And the 185M bitrate might be overkill if your source is HDV.  Try 120M and save yourself a bit of space.

Thanks for that! I'm editing in Premiere Pro CS5 on Windows.


text:
Repairing brightness problems caused by auto lighting optimizer
I've shot a video with my Canon EOS 1100D, but unfortunately forgot to turn the auto lighting optimizer off.
Now the video footage looks really bad because there are random changes of brightness every time the colours change, similar to the changes seen in this video, only that it's even worse for me.
Is there a way to repair the footage and adapt the brightness so that it is equally the same throughout the video? Or is my footage lost?
Keyframing and changing the brightness & contrast would be the last possible option, but it's certainly far from perfect and very much work.


text:
cross platform software to convert video to image sequence
I'm looking for a piece of software I'm even sure it exists.
Here's what I would like this software to do:

be free (ideally open source, but free and closed source is also fine)
be cross platform (at least works on Win and OSX, Linux support would be nice)
import a variety of video formats (mov, avi, wmv, mpg, mp4, ogg, flv, 3gp, etc.)
exports an image sequence from the imported video

Any ideas/suggestions ?

Look at ffmpeg. It will run on just about anything and should do what you want, although it might depend on what your source actually is
Something like this should work :
ffmpeg -i sourcefile.avi -f image2 'img-%03d.jpeg'

(see the image2 section for full reference)

Thanks, I'll have look. The main purpose is to have this software running on the average user's machine. I'll have look to see if I can bundle it and put a minimal gui on top.

If you want GUI you might want to check VLC, it's using some of the same libraries too

For a good GUI based on libavcodec (which a ffmpeg library), take a look at handbrake. Might be a bit too detailed for a very "simple" user, but with some effort it's manegable. It also supports saving of presets, so you can set it up for easy use.


text:
How can I make a video such that the quality degrades if someone tries to record it using screen recording software?
How can I make a video such that the quality degrades if someone tries to record it using cam-studio or similar software? We create music videos which are often subjected to piracy. Although the CDs are encrypted, making it difficult for people to duplicate, anyone can record the videos using camstudio or similar software while playing it on their computer.

Have you considered making a chain of renders until you get one that really shows degradation and then use the render just before this to publish so that when it is pirated it will be obviously degraded?

@filzilla I think you just invented the new Instagram for video...

Rovi does try to add an element of security but the simple truth is that once it is being played, there is actually nothing you can do to prevent it being copied. Unless you control everything (including the screen) then an attacker can just wait until the encryption has been removed and copy the output. So this could be in memory, on screen, by intercepting HDMI etc.
This has been discussed at great length on security.stackexchange.com as it is one of the unsolved issues in security.

yes - you really need to evaluate your situation to ensure that adding a copy protection scheme makes sense. At the end of the day, you are probably just putting money in Rovi's pocket and making life a bit harder for the people that produce your final output. There is also the small issue that music videos are usually intended to promote your band. You might need your head examined if you want to prevent people from seeing them!

HDMI is usually encrypted for this reason.

Securing a computer against its own user is the only way this is possible.  It's only possible with the cooperation of OS vendors, so anything that depends on it will never be portable to Free operating systems.  Your best bet is to push for DRM Helmets for everyone.  http://archive.oreilly.com/1540.html

Rovi, formerly Macrovision dominates this field. Their products can be expensive, and are far from perfect, so there are a variety of competitors out there, but you have to evaluate them (and Rovi products as well) very carefully.


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What software do I need to edit commercials out of recorded sports games?
I have been using HD PVR to capture some of my football games to PC and now I want to edit out the commercials.  So I'm wondering what is the software that will do all these needs:

Allow me to edit out commercials anywhere in the video.
After editing, it keeps the 5.1 Surround Sound.
Burn the video to a Blu-Ray player or save it to disk.
Ability to add menus too my Blu-Rays.
If there are logos on the screen(say ESPN logo), be able tell the software to find all instances and remove it.

The HD PVR allows me to record in .TS, .M2TS or MP4.  Which format is best to allow me to do video editing?

TRY , Corel video Studio Pro.
Simple and meets your needs. Supports, 5.1 sound ,Disk burning (if you have the capability), and add menus. Also provides features to add an overlay above the Logo.
Try the description here $60 or less only


text:
Graphical editor for OggKate
Does anyone know of a graphical editor that let's one create and edit OggKate metadata for a file. I prefer using Ubuntu.
Most of the examples I've found so far uses the commandline.
I've come across "mmg in the package mkvtoolnix-gui", a GUI for mkvmerge.
I plan to capture video recordings through IEEE 1394/Firewire into the DV format, and then export to Ogg Theora. The editor should be able to insert the metadata (geo location, tags, comments). It is specifically metadata, not subtitles.
Link:
About OggKate

From the Xiph Wiki, it doesn't look to me as if such an editor exists.  I would use something like the free Aegisub subtitles editor to enter the metadata text at the correct timings, but enter them as subtitles.  Then export from Aegisub as an .srt file, then perform some search & replace funtions on the .srt file (which is a human-readable text file) to generate the metadata strings you need based on this definition.  Once you have the metadata in the correct format, you should be able to add it to an Ogg file using KateDJ.


text:
Noise reduction in DaVinci Resolve 14 free version
DaVinci Resolve is great for hobbyists because it has a fairly capable free version. Unfortunately, the free version does not include noise reduction functionality. Are there any free tools/plugins that integrate with DaVinci Resolve on OS X and provide some sort of image noise reduction functionality?
Resolve supports OpenFX plugins.

I found the Tuttle OpenFX suite, but available OS X binaries cause Resolve 14 to crash immediately.


text:
Why are there two ways to keyframe-animate geometric transformations?
In DaVinci Resolve 14, there seem to be two ways to use keyframe animations with geometric transformations.
One is on the Edit page, using the Inspector. Here it seems to be possible to smoothen out transitions with curves.

Another is on the Color page, with the Sizing tab.

What is the difference between these?  When should I use one or the other?  Is it possible to transfer the adjustments made with one into the other?
I am new to this software (and also video editing). I originally made adjustments on the Color page, but then wasn't able to smoothen the transitions, so I ended up scrapping them and re-doing the same thing on the Edit page.

The video transform tools in the edit page inspector window (zoom, position, etc) actually translate directly to the color page in the "Edit Sizing" window.  In your screenshot your color page is showing the input sizing window, which instructs resolve how to scale the image as part of the input process (very front end of the image processing pipeline).  If you place your mouse over the Input Sizing menu item, you'll see that there is also edit sizing (inspector on edit page), node sizing (associated specifically with the node you have selected in the color page), output sizing (how things get sent to video monitors), and reference sizing (lets you reposition/scale an image when using the wipe function to compare two clips in the color page).


text:
Windows software to turn a 3gp video on its side before upload?
My camera phone takes video in 3gp format. I've inadvertently taken a video sideways and want to turn it 90 degrees for upload to services such as YouTube and Facebook.
What software package can I use on Windows to do this, or is there another option?  I've looked at the YouTube upload interface and it doesn't have an option to turn the video.

After a bit of research I'm considering ffmpeg transpose http://ffmpeg.org/ffmpeg.html#transpose but have to sit down with it to learn a bit more.

YouTube note: In fact, at this point in time, YouTube does allow a video to be turned on its side after it has been uploaded. The video is then reprocessed.

You could use Windows Live Movie Maker, which is free with Windows Live Essentials.  Here is a tutorial on how to do it.
It looks like Windows Movie Maker doesn't have native support for the 3GP format, but you should be able to download a CODEC for it.
For Mac users, iMovie is the equivalent.

The following will flip a video 90 degrees clockwise:
ffmpeg -i input.3gp -filter:v 'transpose=1' -c:a copy \
-c:v libx264 -crf 22 -preset veryfast output.mp4

To flip it 90 degrees anti-clockwise, use 'transpose=2'. See the documentation for more information. Note that this will require a fairly up-to-date version of ffmpeg.


text:
How can I stitch together several m2ts video files into one large file?
I have recorded several community theater productions with a Panasonic TM900 camera. The settings on the camera were to record at 1080p @ 60 FPS.  However, I noticed that the camera produces  several video files (.m2ts).
While the included Panasonic HD Editor software plays the videos seamlessly that is not the case with other video players such as Windows Media Player.
I want to be able stitch together two or more m2ts video files without losing the quality of the original footage. What software should I use to do this? I do not need fancy editing capabilities though I would like to cut some scenes from the video such as during the play's intermission.
Open source software or at least free software is preferred but commercial software is not out of the question if it works well and it is easy to use.

I believe you can join MPEG ts (transport stream) files simply by joining them together.  In Linux:
cat file1.m2ts file2.m2ts file3.m2ts > joined_file.m2ts

In Windows/DOS:
copy /b file1.m2ts + file2.m2ts + file3.m2ts joined_file.m2ts /b

As long as the input files are split properly, and each new file begins with a key frame (and I would expect your camera does this), this should work just fine. And even if your camera is not careful about splitting right before a keyframe (again, I'd be surprised if it doesn't), as long as you re-join in the exact same order, it ought to work.

While the cat/copy option mentioned generally works, I've found that it can cause problems with some media players, due to timecode issues. I would prefer to use ffmpeg's concat protocol to achieve the same effect (but more reliably in my experience):
ffmpeg -i "concat:in1.m2ts|in2.m2ts|in3.m2ts|in4.m2ts" -c copy output.m2ts


text:
Practical algorithms for rate adaptation
I am interested about reading material on rate adaptation, by which I mean the process of adapting the bandwidth/rate allocated for a streaming application, ranging from services such as YouTube, to Netflix or Skype calls.
I would like to have references to papers or any kind of material where are described practical solutions that adapt the rate of the media to network and environmental conditions.
I am especially interested about algorithms that can be applied from the perspective of the end user.

This is a difficult problem to study in an academic setting because it depends heavily on the real world network routes that occur out in the wild. It is easy to study in industry, but those guys are a lot less likely to publish papers.

This question seems more broadcast and compression specific than AV Production! Inviting experts to a new site proposal Broadcast and Media Technologies which aims to capture more architectural and theoretical views around subjects like this. If this proposal will go through, you will surely get the answer of this. Join and invite others.

You may want to read the spec for Apple's HTTP Live Streaming
and see their recommended settings.
While the standard seems to be quite well thought through, its real-world performance on iOS still needs some improvement. Switching qualities and streams (for ads) often results in less than stellar experiences. Encoder support also needs to be more accessible, I think.


text:
DSLR RAW video: 1080p or 720p?
This question has probably been asked before, but could not find it. With the possibility of recording RAW video on a DSLR, file size matters because CF cards are limited.
File size can be reduced by recording at 720p as opposed to 1080p. First of all, how do I compute the size needed for a certain resolution? I presume it would be

file_size_per_second = height x width x 14 x fps

and the result must be divided by some compression factor, I guess, otherwise the number would be too large.
Now, the second question is: for practical purposes, how does the size of the screen need to be  be in order to be able to notice differences between 1080p and 720p? Or, perhaps, does it also depend on what is being recorded?
I'm asking this question, because I would go for 720p to save some space if it did not affect video quality significantly.

What is your deliverable?

@filzilla You mean, screen size or something else?

@Bob - is there any additional information that you are looking for that my answer doesn't provide?  I updated it with some more details about distances and screen sizes that someone with 20/20 vision should notice the difference at.

Keep in mind that it is 14 bit color and there are 8 bits to a byte.  So the uncompressed data rate would be height * width * 14 bits per pixel / 8 bits per byte * fps.  That said, I'm not sure if they store it completely uncompressed.  RAW images are generally compressed significantly, they are just compressed losslessly.  I'm not sure if the MagicLantern hack uses compression or not though.
As far as screen size for noticing the difference between 720p and 1080p, it doesn't have to be big.  Viewing distance makes a bigger difference, but it's fully possible to tell the difference between 1080p and 720p even on screens that are inches in size as long as they actually support 1080p and are viewed from fairly close.
While I wasn't able to find a CC version, Carlton Bale has a nice graph on his site that shows the screen sizes and distances at which 20/20 vision can resolve the differences.  Note that someone with higher than 20/20 vision would see the differences further out.  It unfortunately only goes from 20 inch displays up though.
In closer, it might be easier to use a pixels per inch measure.  Photographs are typically suggested to be printed at 300dpi or higher when in close.  A 4.7 inch screen at 720p has around 312 ppi.  Uping that to a 1080p resolution at 5 inches or so has a PPI of 415.  At arms length, it isn't going to be noticeable, but when you get in close to it, say watching in bed with it a few inches from your face, the difference will become quite noticeable.
Thinking about it another way, it really all has to do with how big of an area of your vision the screen takes.  So using a 50 inch screen as a guideline, if the display takes up the area of your vision that a 50 inch TV takes when sitting 8 to 10 feet away, then you won't see better than 720p with 20/20 vision.  If it is taking more than that area, then you will easily be able to see the difference.

It looks like currently ML does not use compression for the RAWs from what I can gather from the ML forums.

if I got it right, it would be around 260MB per second. I guess they do some kind of compression to YUV?

@Bob - I guess they must since I think the data rate requirement is somewhere around 100MB a second as I recall.  I guess what they were all describing as "uncompressed raw" might not actually be uncompressed.  I had seen a page on their site somewhere that had a good summary of data rate requirements, but I couldn't find it when I went digging yesterday.

With video, it would be '3 channels' instead of '3 colors'. Most DSLRs use chroma subsamping (4:2:0 is the most common) - so it is only the luma channels that uses the entire 14 bits. The other two chroma channels are reduced to a fourth of the original information. (Cameras that output 4:4:4 video are uncommon and expensive)

@BalaSivakumar - Are you sure on this?  Everything I can find seems to indicate that they are taking the raw image data as shot from the sensor and putting it in a file.  The sensor data is per color I believe.  It has to be processed in YCbCr.  More Detail

@BalaSivakumar - ok, I did some double checking.  It is 14 bits per pixel, but it isn't because of chroma sub-sampling, it is because it is the raw values for each pixel prior to adjusting for the bayer filter.  Each pixel is either red, green or blue in raw data with no other color information.  The correct algorithm for data rate would not have the * 3 though.

@Bob - note the update, after some additional checking I was wrong about the multiple of 3.  RAW only stores the pre-demosaiced values, so each pixel is only one color.

@AJHenderson: You're right. My comment mixed multiple concepts - the 14bpp should be all luma. The color is 'inferred' during demosaicing according to the Bayer (or other) pattern. Thanks for correcting me!

@BalaSivakumar - thanks for making me fact check as well.  It's a better answer now and we're all walking away with better info.

If you are recording RAW then you need to know what that really means, is there any compression or not ? You also need to know the colour space, RGB or YCbCr and if chrominance subsampling is involved.
It's only realistic to assume that the compression is lossless and in a real world example we would be looking at a worst case scenario of not being able to compress any better than the original amount of data. That's also assuming that such compression doesn't expand the data.
It seems that you are considering 14 bit video, as in 14 bit per colour channel. If I assume you are talking about uncompressed video, for RGB and YCbCr at 4:4:4 that means you need
width x height x 3 x 2 x fps bytes per second
To explain the constants:

There are 3 colour channels
You need 2 bytes to store 14 bits - it is unlikely (but not impossible) that the software is going to be packing multiple 14 bits together without gaps in between.

Check QuickTime's v216 format for an example of how 14 bits are typically encoded - 2 bytes.
For YCbCr 4:2:2 you will get 2 pixels encoded in 8 bytes (4 channels = Y0, U, V, Y1; at 2 bytes each) in this case the rate is
(width/2) x height x 8 x fps bytes per second
I'm assuming that your images are an even number of pixels across. Note that in all these calculations I'm assuming there are no padding bytes added to each line for memory alignment A.K.A. 'stride'.
Let's plug in some numbers for 30 fps:

1080P at RGB/YCbCr 4:4:4 = 356 MB/s
720P at RGB/YCbCr 4:4:4 = 158 MB/s
1080P at YCbCr 4:2:2 = 237 MB/s
720P at YCbCr 4:2:2 = 105 MB/s

If the RAW format is very raw, then you may have to recompute for demosaicking of colour filters.


text:
How to get a higher FPS without changing speed video through Adobe After Effects or Premiere Pro CC2014 letting the software create the missing images
I have a video that has been recorded at 7 FPS. I noticed that in the Windows properties of the video file, it is tagged as 25 FPS, and I see that the recorder has inserted each second fake frames (copies of the 7 frames shot in beetween these 7 images) to reach 25 FPS in the recorded video file.
I'd like to convert it to a real 30 FPS video, without changing its duration, letting the software create missing images or replacing fake static ones (with newly interpolated images) to have a smoother play, even if it's not as perfect as what I could obtain with a native 25 FPS record.
For a quick try, I have tried to put 2 effects one after the other, one to accelerate the video at 300%, to make the fake images disapear, and another to reduce the speed at 33%, to force the soft to create interpolated images, all of this in a 25 FPS (for a try at 25) composition in AE, with no success.
Do you know how I can do this ? All tutorials I find on the Web talks about accelerating or reducing speed for slow motion, but for my own I want to keep the speed, just make the whole thing smoother.

It really doesn't matter if it's 7fps in 30fps? You don't want to calculate the motion of the frames in between, right?

@poor:I want the software to generate a 30 FPS video file in wich the key files are each of images taken at 7 FPS (real footage), and insert in beetween new interpolated images.

You have a 25 fps video which just contains repeats of frames captured at 7 fps, right? No interpolated frames? How long is the piece? What codec and container?

@JimMack:yes that's it. It's an AVI container of near 20 secs (for testing, but I have other ones that are longer like 2 min or more), uncompressed YUV as far as I know

@Oliver So 7fps represents real time, and you want the resulting video to also represent real time, but at 30fps. In that case you need to generate intermediate (interpolated) frames that don't currently exist, not repeat frames that do exist, is that right?

@JimMack:yes this is what I want to obtain

I can't give you specific commands but since these are fairly short I'd extract the individual frames into a TIFF stack (or similar), then import them at the correct (7fps) frame rate into your editor. Then I would apply twixtor or an open-source equivalent to raise the frame rate. How well those work depends somewhat on the amount of motion. 7 fps to 30 fps is asking a lot.
You may find ffmpeg / avconv assistance in extracting only the frames that are actually different -- that is, removing the extra inserted duplicate frames.


text:
Is there a way to manage Final Cut project files under Linux or Windows?
I don't have a x86 Mac at hand I'm having trouble organising a large collection of Final Cut 7 projects.
I have tried to run Final Cut under Virtualized OS X.  But I have trouble installing it since VMWare doesn't provide QuartzExtreme driver.
Is there any way to solve the issue or this is hopeless and I need a real Mac?

you could try dual booting.

You can't edit FCP project files on Linux for sure. Sorry :)


text:
Paper camera software filters for post-production?
I have downloaded an android app called Paper Camera that provides real time camera filters such as a variety of 'sketch' and cartoony feels. I find especially interesting their filters 'Contour', which is pretty much B&W contour lines, and 'Sketch Up' which looks like a rough pencil drawing.
What kind of software and what filters could I use to apply similar effects to an already recorded video file?

I'm not sure how that second question is related, other than also being about an Android tablet. If it isn't, it'd fit better as a second question, so that we aren't doubling up on questions and answers.

Yeah I was thinking about doing just that. Thanks! http://avp.stackexchange.com/questions/2791/screen-record-tablet-ink-drawing-on-top-of-recorded-video

Adobe Premiere should do exactly what you want - it has a ton of effects plugins.
As to your second question, any screen grabber video software should let you do this - you play the video and have your wacom sketch overlay running, and just use the screen grabber software to make a video of everything displayed on the screen.

I made a separate question for the second inquiry.

Would Adobe Premiere Elements also offer me such plugins?

I haven't tried Elements, but a quick google comes up with some plugins which appear to do 'sketch' type effects.

authors: Максим Бегунов


text:
FFmpeg/Avconv unable to copy subtitles; Unsupported codec?
I've got an mp4 file with these streams (avconv -i file.mp4 or ffmpeg -i file.mp4):
Stream #0.0(eng): Audio: aac, 48000 Hz, stereo, fltp, 125 kb/s (default)
Stream #0.1(eng): Audio: ac3, 48000 Hz, 5.1, fltp, 384 kb/s
Stream #0.2(eng): Video: h264 (Main), yuv420p, 1280x568, 4027 kb/s, PAR 1:1 DAR 160:71, 23.98 fps, 2997 tbn, 50 tbc (default)
Stream #0.3(eng): Subtitle: c608 / 0x38303663, 0 kb/s
Stream #0.4(und): Subtitle: text / 0x74786574
Stream #0.5: Video: mjpeg, yuvj420p, 667x1000 [PAR 72:72 DAR 667:1000], 90k tbn

I am trying to strip out the first audio stream from the file like so:
avconv -i file.mp4 -map 0 -map -0:0 -codec copy file-out.mp4

# OR #

ffmpeg -i file.mp4 -map 0 -map -0:0 -codec copy file-out.mp4

The problem is, I get this error:
Could not write header for output file #0 (incorrect codec parameters ?): Operation not permitted

So, I checked if something's wrong with the mp4 file itself:
avprobe file.mp4

# OR #

ffprobe file.mp4

And the output says:
Unsupported codec with id 0 for input stream 3
Unsupported codec with id 94213 for input stream 4

I have no idea what that means. (Apparently something's wrong with the subtitles, but I got the video from iTunes.)

What's wrong?
Can I simply force avconv/ffmpeg to do what I asked of it (i.e. strip the audio stream & copy the rest as it is)? If so, how?
Is there a better alternative for remuxing, that's command-line & actively developed?

Apparently I missed the other errors/warnings in the console output before the final error message, like @aergistal suggested:
[mp4 @ 0x2645420] Codec for stream 0 does not use global headers but container format requires global headers
[mp4 @ 0x2645420] Codec for stream 1 does not use global headers but container format requires global headers
[mp4 @ 0x2645420] Codec for stream 2 does not use global headers but container format requires global headers
[mp4 @ 0x2645420] Codec for stream 3 does not use global headers but container format requires global headers
[mp4 @ 0x2645420] Codec for stream 4 does not use global headers but container format requires global headers
[mp4 @ 0x2645420] track 2: could not find tag, codec not currently supported in container

Lack of global headers is not relevant to your muxing problem.

This question has been crossposted (this is discouraged).

The fourth stream apparently is a CEA-608 subtitle stream, which during the days of analog television signal transmission was caption data embedded within the video data. Apparently FFmpeg can extract it but can't mux it to a new container.
As for stripping only the audio, MP4Box may be of help.

So based on your answer & comment, ffmpeg currently doesn't support doing what I asked of it, and if the ticket is patched, it may in the future. No way to force ffmpeg to just do it right?

There may be a roundabout way of doing it: Mux only the AC3 and H264 streams into a new container. Try to extract the caption to a SRT e.g. ffmpeg -i file.mp4 -c:s copy file-out.srt. If this works, mux the SRT along with the streams from the new container into a final container.

I just extracted the 2 subtitle streams as separate srt files and the command ran successfully without any issues. But when I opened them in Notepad++ I see this: http://i.imgur.com/j1MKW8n.png -- Any idea why? I've opened srt files before and they are supposed to show normal text.

Because they are just raw CEA608 data dumped into the output you specified. CCExtractor should be able to produce valid SRTs from them.


text:
How do I assemble a Dynacam Flycam 5000 (AKA ProAim Flycam)?
I bought the Dynacam Flycam 5000 (also sold as ProAim Flycam, and probably some other no-name brands) in a local shop the other month. Unfortunately no assembly instructions at all were included so I have some troubles getting it setup.
More specifically I need to connect the upper part with the weights.
On the plate holding the weights there are a rubber detail.
The lower part of the camera base and handle is way too large to fit the rubber part on the weight plate.
I'm also left with some metal tubing that I guess should be used to connect these parts.
Any help in putting this thing together would be appreciated.
I have found a Youtube video with a time lapse of assembly of this very product. Unfortunately the level of detail is far from helpful since you can't actually tell how these parts are connected.


text:
Selectively blur many but not all of the faces in a video
Shooting videos of Ninjutsu events. Top man insists that there are privacy issues as some of the participants don't want their faces to appear in the resulting video. Would really love to be able to solve this problem because I'm sitting on tons of video that I want to distribute!
Blurring all the faces in the video is not a good solution because first there are the instructors in the the video and second some of the participants would LOVE to see their faces in the video.
So what I was thinking was to blur the faces of those participants who request that their faces be hidden (i.e. opt-out). This means I'd have to be able to tell the software that "this is the face of Dick, Joe and Harry" and have the software identify and blur all occurrences of those faces in the multiple clips of the event.
A less desirable alternative would be to somehow pixelate/blurr/remove everyone EXCEPT for the instructors (i.e. opt-in)
So, my question is:
Do you know a solution to preserve the privacy of some of the participants in a video?
This is a hobby, so preferably the solution would be inexpensive or even free ;)
I'm totally pessimistic - can you surprise me? :)
Update: I ran a test. I figured Google would have the best technology, because of Google Street View. So I uploaded a sample to YouTube and selected to blur all faces. This is a much easier problem than my problem description but the results were very disappointing. First, it was very disconcerting to see the blurred faces but even worse, the blurring was very "temperamental" - sometimes faces were blurred, sometimes they weren't.
So, I figure that if Google can't do it, then  it isn't doable.
However, and here's the moral of the story: Returned to "Top Man" and mailed him that it can't be done. Return mail was a very surprised "who told you this was an issue"!?! So, the moral of the story is: "Always recheck again and again with the client and re-verify the requirements".
As if we didn't know :)
I'm leaving this question open for a few more days, to solicit answers, and then I'll award the "solution" to the best answer. Thanks for helping!

I don't have a solution for you that is free, but this will most likely be a time-consuming and difficult thing to do.  Computer vision simply isn't that advanced and while motion tracking software can track a face once it appears and is marked, it isn't going to be able to identify when else that same face shows up.  Even so, it's still a computationally intense process that will take a lot of time and patience and processing power to get right and that is even when using higher end commercial software.

While its technically possible to have a program detect specific faces and apply a blur on that face. That would require a lot of programming work on your side, there is no free tool or low cost tool that does this automatically for you. This is possible with OpenCV but I highly doubt that this is a viable solution for you in any way, it's a quite complicated task and the result will not be 100% reliable.
The general workflow of blurring out faces would be to semi automatically track the motion of the faces with a 2D tracker in each clip an apply a blur mask to them.
The usual go to software for that is Adobe After Effects or other Motion Graphics video applications like Apple Motion.
Both are no free applications and I never heared of free software that implents 2D tracking together with a video editor. Though there are some really cheap amateur video editing suites out there that even implent face recognition but they all work pretty bad and unreliable without giving you much or no control over whats happening.
For example: http://www.wondershare.com/video-editing-tips/change-face.html
I highly discourage using such software for any work that goes beyond your average random youtube video.
While Adobe After Effects was always unaffordable for hobbyists, Adobe now switched to a subscription based model which makes it very affordable for small projects. You can use the program for free for 30 days (no commercial use) or a monthly subscription for ~30$ depending on the country you live in.
I recommend After Effects because there are ton of beginner tutorials out there for exactly what you want to do and the tracking workflow is quite straight forward. There is also Apple Motion like already mentioned and Nuke and quite a few other applications though After Effects is available for both Windows and Mac and is the easiest to grasp in my opinion.
Edit: I just found out that there is also an automatic face tracker in Adobe Premiere since CS6, this might not yield perfect results but should ease the workflow quite a bit.

Yes, I tried Wondershare Video Editor and, even though I'm very satisfied with their Video Converter Ultimate, the face-off technology of the Video Editor did no better than Google's YouTube.

I do editing work for a Large Surveillance company in the UK who require faces of all Juveniles and Children to be Blurred out. Please be under no illusion there is no easy way to do this and I spent many many hours looking at ways to do it, don't waste your time on free progarmmes.
Firstly I am not a professional Video Editor but have picked up a lot of bits and tips as I go along specifically related to what I do. I have tried many programmes (including demos/trials costing 5 - 10K and the only programme I find to do the task with high accuracy is After Effects.  I looked at AE with Mocha and AE on its on on the Motion Tracking( even for the high cost of CS6 it is still the most cost effective programme for the task and like someone mentioned there is a subscription service (which I will switch to soon).
Motion tracking is great if the subject (face) doesn't move out of view, once it does you loose the tracking and its grief.  The best way I  have found is AE using Motion tracking with keyframing which is simply moving the created Gaussian mask frame by frame. It is a laborious tack but as I have prograssed over the past 6 months I have discovered ways to speed up the process by say moving two or more masks at the same time and to split an adjustment layer which saves time creating a new layer which I found invaluable as it allows me to increase or decrease the size of the mask.
With CS6 it also has the added benefit of Dynamic Link which is brilliant for cross platform editing with Premier Pro or Encore etc. If you take a look at YouTube tutorials on the subject  you will see what I mean.  What ever the Professionals say Ae and PPro is really quite easy to get to grips with the basics and you will very soon add to your knowledge as you go along, there is always that 'wow' I didn't know I could do that with this programme.

I'd have to see your footage to come up with a perfect solution, but I do have some ideas that might help. (They're time-consuming. Sorry. At least they're free!)
First thing is to decide on a solution for each SHOT or even each section of a shot.  For example, you might have a shot that starts pretty stationary, then follows a particular person as they move around. For the start of the shot, you may be able to create a single image (using free downloadable software like GIMP) that is mostly transparent, but has black circles that would cover the faces of people that need to be hidding. Then you lay that over the top of that section of the footage, and those people are blocked out. Once the camera starts tracking the person as they move around, you could use free editing software (Mac computers all have iMovie; Windows computers all have Windows Movie Maker) to zoom in on the person, blocking out people behind them.
You may also find that you have some sections of some shots with nobody in the background! Or the people in the background all don't mind being on camera. Using your free editing software (iMovie or Movie Maker) you can cut those sections out of the shots and add them to your finished video without any further manipulation.

I just created a video tutorial about how to blur videos with 4 ways. I think you may pick up any of them to solve your problem.