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Greenscreen (aka chroma key) effect with a webcam?

This is not the blue screen of death I am speaking of, but the process called bluescreening (also known as green screen, or Chroma Key).

It removes a particular colored background from an image so that it can be superimposed on some other video/still picture. If you have ever seen the weatherman stand in front of the map, then you have seen someone doing a blue screen technique.

I would like to be able to

1. capture video from my webcam
2. send that video to a bluescreen / greenscreen / chroma key program
3. have that program replace the color in the background with a background of my own choosing
4. Once the image is superimposed, pipe it into Skype for video conferencing.

Anyone have a good way to do this?

Split Up a Video Using FFMPEG through Scene Detection

I saw this thread, which almost exactly does what I want, but I'm actually looking for splitting on scene detection.

Automatically split large .mov video files into smaller files at black frames (scene changes)?

For example, let's say I have a woman on screen in from 0:01 -> 0:05, then a man in a different scene from 0:06 -> 0:09, and a second woman on screen from 0:10 -> 0:14

This (ideally) would create three different video clips. I'd really like it down to the frame level, if possible, with autodetection for when the scenes change.

** UPDATED **

Ok, I'm off to a great start. I've done the following using FFProbe:

ffprobe -show_frames -of compact=p=0 -f lavfi "movie=foo.mp4,select=gt(scene\,.4)" > foo.txt

Which gives me a list of timestamps that appear to be exactly right! Now the next step - how do I take this list of timestamps and input them back into ffmpeg to split it? Here's an example of the timestamps.

media_type=video|key_frame=1|pkt_pts=972221|pkt_pts_time=10.802456|pkt_dts=972221|pkt_dts_time=10.802456|best_effort_timestamp=972221|best_effort_timestamp_time=10.802456|pkt_duration=N/A|pkt_duration_time=N/A|pkt_pos=5083698|pkt_size=6220800|width=1920|height=1080|pix_fmt=rgb24|sample_aspect_ratio=1:1|pict_type=I|coded_picture_number=0|display_picture_number=0|interlaced_frame=0|top_field_first=0|repeat_pict=0|tag:lavfi.scene_score=0.503364
media_type=video|key_frame=1|pkt_pts=2379878|pkt_pts_time=26.443089|pkt_dts=2379878|pkt_dts_time=26.443089|best_effort_timestamp=2379878|best_effort_timestamp_time=26.443089|pkt_duration=N/A|pkt_duration_time=N/A|pkt_pos=12736403|pkt_size=6220800|width=1920|height=1080|pix_fmt=rgb24|sample_aspect_ratio=1:1|pict_type=I|coded_picture_number=0|display_picture_number=0|interlaced_frame=0|top_field_first=0|repeat_pict=0|tag:lavfi.scene_score=1.000000
media_type=video|key_frame=1|pkt_pts=2563811|pkt_pts_time=28.486789|pkt_dts=2563811|pkt_dts_time=28.486789|best_effort_timestamp=2563811|best_effort_timestamp_time=28.486789|pkt_duration=N/A|pkt_duration_time=N/A|pkt_pos=13162601|pkt_size=6220800|width=1920|height=1080|pix_fmt=rgb24|sample_aspect_ratio=1:1|pict_type=I|coded_picture_number=0|display_picture_number=0|interlaced_frame=0|top_field_first=0|repeat_pict=0|tag:lavfi.scene_score=0.745838
media_type=video|key_frame=1|pkt_pts=2627625|pkt_pts_time=29.195833|pkt_dts=2627625|pkt_dts_time=29.195833|best_effort_timestamp=2627625|best_effort_timestamp_time=29.195833|pkt_duration=N/A|pkt_duration_time=N/A|pkt_pos=13485087|pkt_size=6220800|width=1920|height=1080|pix_fmt=rgb24|sample_aspect_ratio=1:1|pict_type=I|coded_picture_number=0|display_picture_number=0|interlaced_frame=0|top_field_first=0|repeat_pict=0|tag:lavfi.scene_score=0.678877

How to losslessly combine multiple AVI files into a single file?

I would like to combine multiple movie clips with .mov and .avi extension into a single file. Is there any free software in the market that is good and able to perform that?

Preferably that should work without any loss in quality.

How can I crop a video to a part of the view?

I have a video that shows the following

and I would like to crop it to this:

How can I do it?

How to convert a 16:9 movie to a 4:3 letterbox version?

Suppose you have a 16:9 aspect ratio wide-format movie file and you want to make a version ideal for playing on a 4:3 device. Since you don't want to clip any of the image or distort the picture, so you want to make a letterbox version.

That is, you want a 4:3 movie with black bars at the top and bottom surrounding the moving image rectangle, which has true 16:9 dimensions.

Can you tell us how to do this in Windows or Linux, using free command-line or GUI tools.

What is an efficient way to do a video crossfade with FFmpeg?

Doing a crossfade between two pieces of video content is actually quite complicated in FFmpeg. There is no “crossfade” filter like there is for audio.

What’s an efficient way to do it?

How can I join multiple .mpg movie files?

I create a lot of these small clips on my digital camera. These are in .mpg format and before I share them with others, I would love to just join, clip a few seconds here and there.

I use Google Picassa to create new start and end points, but I dont know a good way to join mpgs yet.

Whats the best free software i can use for this?

How do I export only a single clip from a Premiere Pro sequence?

I'm cutting a video in Premiere Pro CS4 and need to slice a long sequence into smaller parts. I've successfully sliced the parts, like this:

I even set the sequence markers to the current selection. Now I want to export this selection only.

If I press Cmd-M, it opens the Media Encoder, but doesn't respect the current selection. It wants to export the whole sequence again, and I'd manually have to mark the clips again.

How can I export only the parts I marked?

How to save mplayer's output when watching in ASCII mode (with aalib)

I was helping out a friend working on a presentation where he wants to show some videos he has taken but converted to ASCII art. I can do that quite easily with mplayer on a Linux box using aalib (-vo aa). But that only plays the movie, transcoding it live. What I would like to do is to convert those videos to ASCII art and save them in files so that they can be played in a loop on some regular video players (be that vlc, wmediaplayer, whatever).

I have played around with mplayer / mencoder trying to dump streams, videos, piping it to fifos, standard output and so on but I just can not seem to find any way of doing this.

Has any of you done this before and if yes, how?

Thanks a lot!

Free Chroma key tools [closed]

I want to create an educational introductory video, where the tutor stands and explain a subject, and the background is an illustration of that subject. This is done using a technique called Chroma Key, where a blue or green curtain is placed in the video background, and replaced with another image or video at post-production.

Is there a free tool that can help me merge my videos using Chroma key?

Clarification: I prefer open-source solutions which work well under Ubuntu.

Reference: This question deals with Chroma key, but it's about real-time video (which I don't need) and the answers suggest proprietary software.

Automatically split large .mov video files into smaller files at black frames (scene changes)?

I have 65 .mov video files named tape_01.mov, tape_02.mov, ..., tape_65.mov. Each is about 2.5 hours long and takes up many gigabytes. They are digital copies of what were VHS tapes (my family's "home movies").

Each 2.5-hour .mov video file contains many "chapters" (in the sense that sometimes the scene ends in a fade to a black screen, and then a new scene fades in).

My main goal is have the 65 large files sliced into smaller files by chapter. And I want that to be done automatically via detection of the black frames between "scenes".

Could I use ffmpeg (or anything) to pass in the 65 original filenames and have it automatically iterate over each video and chop it down, naming the resulting pieces tape_01-ch_01.mov, tape_01-ch_02.mov, tape_01-ch_03.mov, etc? And I want it to do it without re-encoding (I want it to be a simple lossless slice).

How can I do this?

Here are the steps I want:

1. Iterate over a folder of .mov files (named tape_01.mov, tape_02.mov, ..., tape_65.mov) to export them as mp4 files (named tape_01.mp4, tape_02.mp4, ..., tape_65.mp4). I want the compression settings to be easy to configure for this step. The original .mov files should still exist after the .mp4 files are created.
2. Iterate over the mp4 files: for each mp4 file, generate a text file that specifies the start time and duration of black segments between "scenes". Each mp4 can have 0 or more of these black scene breaks. The start time and duration should be precise to a fraction of a second. HH:MM:SS format is not precise enough.
3. I'll then be able to manually double-check these text files to see whether they correctly identify scene changes (black segments). I can adjust the timings if I want.
4. Another script will read each mp4 file and its txt file and split (in a super fast and lossless way) the mp4 into as many pieces as necessary based on the lines of the text file (the timings indicated there). The splits should happen in the middle of each black segment. Here is a sample mp4 file (with audio removed for privacy purposes) that has fade-to-black scene changes. The original mp4 files should remain untouched as the smaller mp4 files are created. The smaller mp4 files should have the naming scheme of tape_01_001.mp4, tape_01_002.mp4, tape_01_003.mp4, etc.
5. Bonus! It would be awesome if another script could then iterate over the small mp4 files and generate one .png image for each that is a mosaic of screenshots like this person is trying for: Meaningful thumbnails for a Video using FFmpeg

I'd like these scripts to be shell scripts that I can run in Mac, Ubuntu, and Windows Git Bash.

Is there a way to add a "fade to black" effect to a video, from the command line?

I have a script to encode videos (using mencoder), but is there a way to add a simple "fade out/in to black" from the command line, preferably free (as in open source).

It could be either on Windows or Ubuntu Linux.

How do I trim a video using Handbrake?

I can't seem to figure out the solution to a very simple problem. I want to trim a video in Handbrake and keep the video as is (resolution, encoding, etc), just chop off the first few seconds, but I can't find out how.

How to split an m4v file?

I downloaded a TV season on iTunes (.m4v files), however the files are clustered into 3 episodes each. I'd like to chop these up so that each episode is in it's own file. Googling around a while didn't provide any promising leads.

What's the easiest way to split these files up?

Update: Yes, the files are DRM'd.

Lossless universal video format

I am trying to find the most suitable lossless video format for 1280x720 25fps video. The video has 4 minutes. Sound will be 320 kbps mp3, that is not a big deal. Ideal conditions:

• Lossless (can be perceptionaly lossless)
• Container + codec can be played on most platforms
• Container + codec can be played on modern DVD players (supporting other formats than DVD)
• Size is less than 700 MB

Is that even possible? Have been struggling three days already, without any satisfying results, even getting 12 GB files (seems a lot - 3 GB/minute).