[FFmpeg-user] mpeg2 bufsize question

Dave P lists.davep at gmail.com
Wed Jan 18 16:24:35 CET 2012

On Tue, Jan 17, 2012 at 18:11, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> Dave P <lists.davep <at> gmail.com> writes:
>> I recall reading on here somewhere that -f vob was for program
>> streams.
> I believe it tries to conform to the DVD standard (at least that is what I would
> expect) and this standard is certainly not written for 1920x1080.
> -f mpeg (or .mpg as output filename) forces mpeg program streams.
>> I get the same result without it. Muxrate values ranging from 2M to 25M still
>> generate errors.
> I can now reproduce your problem (I originally tested with an Apple trailer that
> starts with a still and only outputs the warnings / errors later).
> I suspect the bug is that -bufsize (which is the right option) does not work
> correctly with -qscale, a work-around is to change (current) line 377 in
> libavformat/mpegenc.c "stream->max_buffer_size =" to a significantly larger
> value, I tested "10*" successfully on mentioned trailer.
> (The line is the one following the warning message "VBV buffer size not set".)
> Carl Eugen

I did some tests with similar command lines from the original message.
 Some editing programs complain about files produced with "-f mpeg" as
having mpeg2video in mpeg1 system streams.  It's not a problem for
ff-based players/decoders, though.

c:\ffmpeg_x64\bin>ffmpeg -formats | findstr "mpeg"

 DE ffmetadata      FFmpeg metadata in text format
 DE mpeg            MPEG-1 System format
  E mpeg1video      raw MPEG-1 video
  E mpeg2video      raw MPEG-2 video
 DE mpegts          MPEG-2 transport stream format
 D  mpegtsraw       MPEG-2 raw transport stream format
 D  mpegvideo       raw MPEG video
 DE yuv4mpegpipe    YUV4MPEG pipe format

c:\ffmpeg_x64\bin>ffmpeg -formats | findstr "vob"

  E vob             MPEG-2 PS format (VOB)



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