[FFmpeg-user] Encoding to mpeg2video results in buffer underflows

[Roger Pack]

On 12/30/12, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> Jonathan Isom <jeisom <at> gmail.com> writes:
>
>> ffmpeg -i mpeg2video_underrun.mp4 -b:v 8000000 -qmin 1 -qmax 5
>> -c:v mpeg2video -c:a ac3 -f mpeg mpeg2video_underrun.mpg
>
> This command line shows the following warning:
> VBV buffer size not set, muxing may fail

I think I've seen this before.
http://ffmpeg.org/pipermail/ffmpeg-user/2012-January/004329.html may
also be related.  Does some default need to be set here?