N00b Still Confused with the FFMPEG Command Syntax ('-crop x:y') [Archive]

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audiohominis

29th December 2010, 20:24

Forgive me guys, I'm not very bright but would you kindly provide the exact command line for adding a crop signal to h264 bitstream, I keep getting error.
I don't suppose this is correct ha:
ffmpeg -i input.mp4 -vcodec copy crop=0:8 output.mp4
What am I missing?
Thanks

J_Darnley

29th December 2010, 22:11

You need a patched version of ffmpeg (http://forum.doom9.org/showthread.php?t=152419) and you need to use the correct bitstream filter with -vbsf

audiohominis

29th December 2010, 23:05

That's the one I'm using, actually.
Is this command correct though?
Thanks

b66pak

29th December 2010, 23:10

nope....
ffmpeg -i infile -vcodec copy -acodec copy -vbsf h264_changesps=crop=x:y outfile
_

audiohominis

30th December 2010, 01:13

:thanks:

audiohominis

8th January 2011, 01:59

Oddly enough, it added over 7.5KB to a short 43.7MB clip, was it supposed to? Could that snowball into considerable amounts with longer clips?

roozhou

8th January 2011, 09:25

Oddly enough, it added over 7.5KB to a short 43.7MB clip, was it supposed to? Could that snowball into considerable amounts with longer clips?
No unless you are using incorrect timebase. e.g. Your video is 23.976 fps but you are using 1/1000s timebase. The PTS increment will alter between 41 and 42 so this adds ~8bytes per frame overhead.