[FFmpeg-user] Faster codec with alpha

[Carl Eugen Hoyos]

2016-12-02 16:51 GMT+01:00 Joshua Grauman <jnfo at grauman.com>:
> Hello all,
>
> I am using the following command successfully to generate a screencast. The
> video comes from my program 'gen-vid' which outputs the raw frames with
> alpha channel. The resulting .avi has alpha channel as well which is my
> goal. It all works great except that my computer can't handle doing it
> real-time. So I am wondering if there is a different vcodec I could use to
> achieve the same result that was less demaning on the cpu? I am willing to
> sacrifice some compression for more speed, but would prefer not to have to
> store all the raw frames without any compression. Storing the alpha channel
> is also a must. It is preferable if the compression is lossless. Does anyone
> have any other suggestions for compression other than png that may be
> faster? Thanks!
>
> ./gen-vid | ffmpeg -f rawvideo -pixel_format bgra -video_size 1920x1080
> -framerate 30 -i - -vcodec png over.avi

utvideo is faster than png, consider to change gen-vid so it outputs rgba to
slightly increase speed, this will also slightly increase performance with png.

Carl Eugen