[FFmpeg-user] alpha channel "overlay" or "movie"

[Carl Eugen Hoyos]

angelfilo <at> gmail.com <angelfilo <at> gmail.com> writes:

> I actually can't understand why this output:
> 
> > Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'video2.mov':
> >    Stream #1:0(eng): Video: mpeg4 (Simple Profile), yuv420p
> 
> loading video2.mov in After Effects I clearly see the alpha channel.

While I am not the ultimate expert in video codecs, 
I am pretty sure the MPEG-4 ASP specification does not 
mention transparency.

Carl Eugen