[Ffmpeg-devel] [Bug] m2p -> mpg hangs on audio

Michael Niedermayer michaelni
Fri Feb 9 14:44:59 CET 2007


Hi

On Thu, Feb 08, 2007 at 04:02:41PM +0100, Matthijs Douze wrote:
> Hi
> 
> On a x86-64 linux box, I am trying to transcode a mpeg 2 video to mpg with
> 
> ---------------------> snip
> 
> cpl_x64 $ ./ffmpeg_g -i ../begin.m2p -y -ar 32000  o.mpg
> FFmpeg version SVN-r7868, Copyright (c) 2000-2006 Fabrice Bellard, et al.
>   configuration: 
> --prefix=/scratch2/cornwall/douze/compil/ffmpeg/cpl_x64/installed
>   libavutil version: 49.3.0
>   libavcodec version: 51.32.0
>   libavformat version: 51.8.0
>   built on Feb  7 2007 12:39:35, gcc: 4.1.1 20060724 (prerelease) 
> (4.1.1-3mdk)
> Input #0, mpeg, from '../begin.m2p':
>   Duration: 00:00:00.8, start: 0.294367, bitrate: 9986 kb/s
>   Stream #0.0[0x1e0]: Video: mpeg2video, yuv420p, 720x576, 6000 kb/s, 
> 25.00 fps(r)
>   Stream #0.1[0xa0]: Audio: pcm_s16be, 48000 Hz, stereo, 1536 kb/s
> Output #0, mpeg, to 'o.mpg':
>   Stream #0.0: Video: mpeg1video, yuv420p, 720x576, q=2-31, 200 kb/s, 
> 25.00 fps(c)
>   Stream #0.1: Audio: mp2, 32000 Hz, stereo, 64 kb/s
> Stream mapping:
>   Stream #0.0 -> #0.0
>   Stream #0.1 -> #0.1
> Press [q] to stop encoding
> 
> <------------------ snap
> 
> It hangs. Specifying -an works. Removing -ar hangs. It hangs also on 
> 32-bit boxes (where I also get "Compiler did not align stack variables." 
> messages, as both gcc 3.4.1 and 3.4.3 seem to ignore __attribute__ 
> ((aligned (16)), but this is another problem).
> 
> With gdb:
> 
> ---------------------> snip
> 
> (gdb) bt
> #0  pcm_decode_frame (avctx=0xa123c0, data=0x2b7cc38ad010,
>     data_size=0x7fffe7b3749c, buf=0xa11f8a "", buf_size=1)
>     at /scratch2/cornwall/douze/compil/ffmpeg/libavcodec/pcm.c:404
> #1  0x000000000046cb62 in avcodec_decode_audio2 (avctx=0xa123c0, 
> samples=Variable "samples" is not available.
> )
>     at /scratch2/cornwall/douze/compil/ffmpeg/libavcodec/utils.c:945
> #2  0x0000000000414445 in output_packet (ist=0x9fcc50, ist_index=1,
>     ost_table=0x9fe810, nb_ostreams=2, pkt=0x7fffe7b37600)
>     at /scratch2/cornwall/douze/compil/ffmpeg/ffmpeg.c:1072
> #3  0x0000000000417b39 in av_encode (output_files=0x987dc0, 
> nb_output_files=1,
>     input_files=0x987c80, nb_input_files=1, stream_maps=0x987e60,
>     nb_stream_maps=0) at 
> /scratch2/cornwall/douze/compil/ffmpeg/ffmpeg.c:1941
> #4  0x000000000041d014 in main (argc=7, argv=0x7fffe7b37c58)
>     at /scratch2/cornwall/douze/compil/ffmpeg/ffmpeg.c:3936
> 
> <------------------ snap
> 
> pcm_decode_frame is called with
> 
> buf_size=1992
> buf_size=1995
> buf_size=1
> buf_size=1
> buf_size=1
> ...
> 
> it loops with this unusable buf_size. The example file is available here:
> 
> http://lear.inrialpes.fr/~douze/ffmpeg_bug/begin.m2p
> 
> Any idea ?

implement an avparser for pcm audio (see parser.c)

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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