[FFmpeg-devel] [PATCH] libavdevice: Improve example in deprecation message for opengl and sdl

[Nicolas George]

Alexander Strasser via ffmpeg-devel (12024-04-14):
> When piping ffmpeg into ffplay both programs write a status line in
> the terminal. That causes flickering and invisibility of one or the
> other status line.

The suggestion of piping to ffplay to replace opengl is inadequate: the
muxing, pipe, demuxing steps introduce a significant latency, and ffplay
tries to maintain the timing, so the latency is never reduced.

Compare:

ffplay -f x11grab -framerate 5 -video_size 284x92 -i :0+1138+0
ffmpeg -f x11grab -framerate 5 -video_size 284x92 -i :0+1138+0 \
  -f nut -c:v rawvideo - | ffplay -loglevel warning -
ffmpeg -f x11grab -framerate 5 -video_size 284x92 -i :0+1138+0 \
  -pix_fmt yuv420p -f xv :0

(since at least xv was not broken)
(replace 284x92 and +1138+0 with an area of your screen where something
is happening)

The first two ones will have a delay of about five seconds, the last one
is almost instantaneous.

Either we find options to make ffplay display frames as fast as
possible, or we must document to the user that no adequate replacement
exists.

Or we make a point of fixing the devices that were broken.

Regards,

-- 
  Nicolas George