[Ffmpeg-devel] An MPEG2/AC3 audio that ffmpeg cannot properly identify (or play)

matthieu castet castet.matthieu
Wed Sep 21 21:48:40 CEST 2005


Ronen Mizrahi wrote:
> Hi,
> I have an MPEG2 file recorded from an Australian DVB-T broadcast. When 
> running ffmpeg -i on it this is what I get:
> ffmpeg version 0.4.9-pre1, build 4723, Copyright (c) 2000-2004 Fabrice 
> Bellard
>  built on Sep  7 2005 17:43:26, gcc: 3.2.3 (mingw special 20030504-1)
> Input #0, mpeg, from 'd:\testmedia\Avril Lavigne test 2.MPG':
>  Duration: 577014:01:50.9, bitrate: N/A
>  Stream #0.0: Video: mpeg2video, 720x576, 25.00 fps
> Must supply at least one output file
> As you can see the audio stream is not identified, I know this is not 
> the latest build, but if I am not mistaken not much has changed with 
> regard ot mpeg2 and I tested also MPlayer and latest release of VLC and 
> both of them fail to play the audio. Mplayer Classic on the other hand 
> (as well as Windows Media Player or any other directshow based player) 
> can play the audio just fine.

It works with a recent version of mplayer :

$mplayer http://www.tversity.com/ffmpeg/test.mpg
MPlayer dev-CVS-050915-22:30-4.0.2 (C) 2000-2005 MPlayer Team
CPU: Advanced Micro Devices Athlon 4 /Athlon MP/XP Palomino (Family: 6, 
Stepping: 2)
Detected cache-line size is 64 bytes
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 0
Compiled for x86 CPU with extensions: MMX MMX2 3DNow 3DNowEx SSE

Failed to open /dev/rtc: Permission denied (it should be readable by the 
Playing http://www.tversity.com/ffmpeg/test.mpg.
STREAM_HTTP(1), URL: http://www.tversity.com/ffmpeg/test.mpg
Resolving www.tversity.com for AF_INET...
Connecting to server www.tversity.com[]:80 ...
Cache size set to 320 KBytes
Cache fill:  5.00% (16384 bytes)    Win32 LoadLibrary failed to load: 
avisynth.dll, /usr/lib/win32/avisynth.dll, /usr/local/lib/win32/avisynth.dll
MPEG-PS file format detected.
VIDEO:  MPEG2  720x576  (aspect 3)  25.000 fps  10000.0 kbps (1250.0 
Trying to force audio codec driver family ffmpeg...
Trying to force audio codec driver family ...
Opening audio decoder: [liba52] AC3 decoding with liba52
Using SSE optimized IMDCT transform
AC3: 2.0 (stereo)  48000 Hz  192.0 kbit/s
Using MMX optimized resampler
AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
Selected audio codec: [a52] afm:liba52 (AC3-liba52)
Opening video filter: [pp]
Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
VDec: vo config request - 720 x 576 (preferred csp: Mpeg PES)
[PP] Using external postprocessing filter, max q = 6.
Could not find matching colorspace - retrying with -vf scale...
Opening video filter: [scale]
The selected video_out device is incompatible with this codec.
Also try adding the scale filter, e.g. -vf spp,scale instead of -vf spp.
VDecoder init failed :(
Opening video decoder: [libmpeg2] MPEG 1/2 Video decoder libmpeg2-v0.4.0b
Selected video codec: [mpeg12] vfm:libmpeg2 (MPEG-1 or 2 (libmpeg2))


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