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

[Jonathan Isom]

On Fri, Sep 28, 2012 at 5:08 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> Jonathan Isom <jeisom <at> gmail.com> writes:
>
>> Attached is 2 logs. 1 is from a ATSC mpeg2 stream, the other a h264
>> mkv video.  Fresh build from today from a live ebuild on gentoo that
>> uses no patches.
>
>> Problem affects mplayer and vlc as well(system ffmpeg).
>
> (I don't think I understand this sentence.)

I meant that mplayer and vlc use the system's ffmpeg libraries and are
affectd by same bug.

>> command line used:
>> ffmpeg -i test.mkv -t 60 -s 720x480 -target ntsc-dvd -b:v 8000000 -b:a
>> 224000 -c:v mpeg2video -c:a ac3 test.mpeg
>> ffmpeg -i 3031_20120927210000.mpg -t 60 -s 720x480 -target ntsc-dvd
>> -b:v 8000000 -b:a 224000 -c:v mpeg2video -c:a ac3 test.mpeg
>
> (More unrelated comments:
> Why did you compress the output:
> To make reading it more difficult?

I thought that a 32k and 148k log files would be too much for the list
as text files.  Some lists have a limit.

> Some of the build options look _very_ strange, consider
> using ./configure && make or at least something more
> similar.

This better.  Results about the same related to buffer underflows.

ffmpeg version N-44854-gbad603c Copyright (c) 2000-2012 the FFmpeg developers
  built on Sep 28 2012 17:40:04 with gcc 4.7.1 (Gentoo 4.7.1 p1.3, pie-0.5.3)
  configuration: --prefix=/usr --libdir=/usr/lib64
--shlibdir=/usr/lib64 --mandir=/usr/share/man --enable-shared
--cc=x86_64-pc-linux-gnu-gcc --disable-static
  libavutil      51. 73.101 / 51. 73.101
  libavcodec     54. 61.100 / 54. 61.100
  libavformat    54. 29.105 / 54. 29.105
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 18.100 /  3. 18.100
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 16.100 /  0. 16.100
Hyper fast Audio and Video encoder

Unrelated but have you, the developers , thought about adding a report
bugs to link in the above to a page that gives instructions or such.

> -s 720x480 -c:v mpeg2video -c:a ac3 look unneeded)
>
> I can reproduce the problem here, if I haven't opened a
> ticket in the next days please remind me.
>
> If you want to help, consider uploading a sample.

Input or output.  I am probably wrong but I think I'd have problems
with just about any file going to mpeg2video.

> Thank you, Carl Eugen

Thanks to you as well.

Jonathan
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