[FFmpeg-user] New To FFmpeg streaming question
barsnick at gmx.net
Sun May 24 22:44:39 CEST 2015
On Fri, May 22, 2015 at 19:45:34 -0500, Orion Fyre wrote:
> > ffmpeg -i "udp://@188.8.131.52:4454?fifo_size=640000&overrun_nonfatal=1" -vcodec libx264 -preset slow -crf 20 -c:a libvo_aacenc -b:a 128k -vf scale="trunc(oh*a*2)/2:480" http://localhost:8080/myTest.mp4
> Your scale expression doesnt make sense. Its scale="width:height". For the width part of the expression you're usin 'oh' which stands for 'output height'. Did you mean to use the expression:
Orion: Actually, it does make sense:
oh in effect refers to the 480. So the width is a function of the
output height. Perfectly fine.
In the expression you recommended:
the width is a function of the output width - now, that's impossible.
If you had tested your recommended expression, you would have seen:
Error when evaluating the expression 'trunc(ow*a*2)/2'.
Maybe the expression for out_w:'trunc(ow*a*2)/2' or for out_h:'480' is self-referencing.
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