Convert a video to transparent using ffmpeg

Question

Want to convert the black part in the video to transparent so can be used in modern browsers to overlay

Presently doing things using html canvas

Solution

Use

ffmpeg -i video.mp4 -filter_complex
"[0]split[m][a];
 [a]geq='if(lt(lum(X,Y),16),0,255)',hue=s=0[al];
 [m][al]alphamerge,format=yuva420p"
-c:v libvpx output.webm

See here for how to use this file in Chrome.

As of now, VP8 alpha playback is behind a flag, so you have to either enable it in about:flags or set the command line flag --enable-vp8-alpha-playback when you start Chrome. When the flag is enabled, alpha playback also works with MediaSource.

Comments

[somya bhargava]

Using html canvas have created two videos one grayscale and one with rgb just copying the rgb value from grayscale video to the alpha value of rgb video means in bytes R, G, B, A putting R,Gand B from video with color and A value from color of grayscale video

[Gyan]

Which format? I only know of VP8/VP9, which at present, support alpha channel for web playback. See basic approach here.

[somya bhargava]

Input files mp4 and output any format