[FFmpeg-user] acodec copy creates file with unplayable audio?

[Roger Pack]

Hello.
I noticed with this file:

http://rogerdpack.t28.net/incoming/sintel.mpg

and this command:

$ ffmpeg -y -i sintel.mpg -t 60 -vcodec copy -acodec copy out.mpg
ffmpeg version N-43577-g045f8dd Copyright (c) 2000-2012 the FFmpeg developers
  built on Aug 15 2012 14:10:50 with gcc 4.7.1 (GCC)
  configuration: --enable-memalign-hack --arch=x86 --enable-gpl
--enable-libx264 --enable-avisynth --enable-libxvid
--target-os=mingw32
--cross-prefix=/home/rogerdpack/dev/ffmpeg-windows-build-helpers/builds/mingw-w64-i686/bin/i686-w64-mingw32-
--pkg-config=pkg-config --enable-libmp3lame --enable-version3
--enable-libvo-aacenc --enable-libvpx --extra-libs=-lws2_32
--extra-libs=-lpthread --enable-zlib --extra-libs=-lwinmm
--extra-libs=-lgdi32 --enable-librtmp --enable-runtime-cpudetect
  libavutil      51. 69.100 / 51. 69.100
  libavcodec     54. 52.100 / 54. 52.100
  libavformat    54. 23.100 / 54. 23.100
  libavdevice    54.  2.100 / 54.  2.100
  libavfilter     3.  9.100 /  3.  9.100
  libswscale      2.  1.101 /  2.  1.101
  libswresample   0. 15.100 /  0. 15.100
  libpostproc    52.  0.100 / 52.  0.100
[mpeg2video @ 01C2F6A0] ac-tex damaged at 40 7
[mpeg2video @ 01C2F6A0] Warning MVs not available
[mpeg2video @ 01C2F6A0] concealing 1035 DC, 1035 AC, 1035 MV errors in I frame
[mpeg @ 03361800] max_analyze_duration 5000000 reached at 5024000
Input #0, mpeg, from 'sintel.mpg':
  Duration: 00:14:47.58, start: 0.233367, bitrate: 4132 kb/s
    Stream #0:0[0x1e0]: Video: mpeg2video (Main), yuv420p, 720x480
[SAR 32:27 DAR 16:9], 7000 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 59.94
tbc
    Stream #0:1[0x80]: Audio: ac3, 48000 Hz, 5.1(side), s16, 448 kb/s
Output #0, mpeg, to 'out.mpg':
  Metadata:
    encoder         : Lavf54.23.100
    Stream #0:0: Video: mpeg2video, yuv420p, 720x480 [SAR 32:27 DAR
16:9], q=2-31, 7000 kb/s, 29.97 fps, 90k tbn, 29.97 tbc
    Stream #0:1: Audio: ac3, 48000 Hz, 5.1(side), 448 kb/s
Stream mapping:
  Stream #0:0 -> #0:0 (copy)
  Stream #0:1 -> #0:1 (copy)
Press [q] to stop, [?] for help
frame= 1638 fps=0.0 q=-1.0 Lsize=   32396kB time=00:01:00.00
bitrate=4423.1kbits/s
video:28947kB audio:3281kB subtitle:0 global headers:0kB muxing
overhead 0.520095%

It seems to succeed...

However, the output doesn't seem to have "playable audio" for mplayer or VLC.

If I use

$ ffmpeg -i sintel.mpg -y -vcodec copy -acodec copy yo.avi

The file yo.avi is playable.

In fact, if I convert it from "bad" .mpg to an .avi (with -vcodec
copy...), the resulting file also works fine.  So ffmpeg is able to
read the audio ok.
MediaInfo seems to reveal it having an audio track.
Any ideas?
Thanks.
-roger-