Aurelien Jacobs <[EMAIL PROTECTED]> added the comment:
If you decode the 2 video streams and blend them together, you should get the
same
result as with the flash player.
But I don't think that this blending belong to lavc/lavf. If the only purpose
was
to display the video as in your screen capture, it wouldn't have been encoded
with an alpha plane. This would just be a straight video. If there are other
purpose, then the plane needs to be available separately.
So if you want this video to be displayed correctly by ffplay, you need to:
- add some information in the AVStream to link the aplha video stream to
the "normal" video stream.
- add an option to ffplay to set the background color (it seems flash player
is using white, or maybe this information is also stored in the flv file)
- modify ffplay so that when it decodes a video, it also decodes the linked
stream (if any) and blend them.
Another solution might be to improve the swscaler so that it takes 2 video
streams and merge them in a single YUVA stream. But that may be somewhat ugly,
and that still requires to add support for alpha plane in ffplay.
Anyway, I don't really intend to implement this, so you can open a new feature
request or simply do it yourself.
______________________________________________________
FFmpeg issue tracker <[EMAIL PROTECTED]>
<https://roundup.mplayerhq.hu/roundup/ffmpeg/issue166>
______________________________________________________
