[MEncoder-users] Invalid AC3 file

Thu May 1 06:00:48 CEST 2008

Hi all,

I was trying to convert what I believe to be a valid AC3 file I
demuxed out of a matroska file.  I believe it is valid since it plays
just fine in VLC and in windows media player classic using ffdshow.  I
would attach the ac3 but it is 54 megs.  I was wondering if this is a
known bug in mplayer/mencoder or if anybody else has experienced this
issue?  Here is the output from mplayer.

>> mplayer "the.big.bang.theory.s01e14.720p.hdtv.x264-ctu.ac3"
MPlayer 1.0rc2-4.2.1 (C) 2000-2007 MPlayer Team
CPU: AMD Athlon(tm) 64 X2 Dual Core Processor 4200+ (Family: 15, Model: 43, Step
ping: 1)
CPUflags:  MMX: 1 MMX2: 1 3DNow: 1 3DNow2: 1 SSE: 1 SSE2: 1
Compiled with runtime CPU detection.

Playing C:\the.big.bang.theory.s01e14.720p.hdtv.x264-ctu_convert\the.big.bang.theory.s01e14.720p.hdtv.x264-ctu.ac3
.
libavformat file format detected.
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 32 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Video: mpeg2video)
[mpeg @ 00E1E768]Could not find codec parameters (Video: mpeg1video, 1195x1092,
78579 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 224 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 80 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 96 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 32 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 128 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 48 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 80 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Video: mpeg1video, 2939x3081,
12960 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 128 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 80 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 224 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 96 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 80 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 56 kb/s)
[mpeg @ 00E1E768]Could not find codec parameters (Video: mpeg2video)
[mpeg @ 00E1E768]Could not find codec parameters (Video: mpeg2video)
[mpeg @ 00E1E768]Could not find codec parameters (Audio: mp2, 320 kb/s)
LAVF_header: av_find_stream_info() failed
MPEG-PES file format detected.
MPEG: FATAL: EOF while searching for sequence header.
Video: Cannot read properties.
==========================================================================
Opening audio decoder: [mp3lib] MPEG layer-2, layer-3
ADecoder init failed :(
ADecoder init failed :(
Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
Unknown/missing audio format -> no sound
ADecoder init failed :(
Opening audio decoder: [libmad] libmad mpeg audio decoder
Cannot sync MAD frame
ADecoder init failed :(
ADecoder init failed :(
Opening audio decoder: [hwmpa] MPEG audio pass-through (fake decoder)
Cannot sync MPA frame: 0
ADecoder init failed :(
ADecoder init failed :(
Cannot find codec for audio format 0x50.
Read DOCS/HTML/en/codecs.html!
Audio: no sound
Video: no video

Exiting... (End of file)

The file information from the AC3 parser filter for media player
classic is here if that helps anyone:

- Connection media type:

Audio: Dolby AC3 48000Hz 6ch 384Kbps

AM_MEDIA_TYPE:
majortype: MEDIATYPE_Audio {73647561-0000-0010-8000-00AA00389B71}
subtype: MEDIASUBTYPE_DOLBY_AC3 {E06D802C-DB46-11CF-B4D1-00805F6CBBEA}
formattype: FORMAT_WaveFormatEx {05589F81-C356-11CE-BF01-00AA0055595A}
bFixedSizeSamples: 1
bTemporalCompression: 0
lSampleSize: 1
cbFormat: 18

WAVEFORMATEX:
wFormatTag: 0x0000
nChannels: 6
nSamplesPerSec: 48000
nAvgBytesPerSec: 48000
nBlockAlign: 1536
wBitsPerSample: 0
cbSize: 0 (extra bytes)

And the information from the original matroska file using mkvinfo is here:

>>mkvinfo "the.big.bang.theory.s01e14.720p.hdtv.x264-ctu.mkv"
+ EBML head
|+ Doc type: matroska
|+ Doc type version: 1
|+ Doc type read version: 1
+ Segment, size 586014961
|+ Seek head (subentries will be skipped)
|+ EbmlVoid (size: 4027)
|+ Segment information
| + Timecode scale: 1000000
| + Muxing application: libebml v0.7.7 + libmatroska v0.8.1
| + Writing application: mkvmerge v2.0.2 ('You're My Flame') built on Sep 20 200
7 09:25:45
| + Duration: 1181.600s (00:19:41.600000000)
| + Date: Tue Apr 29 01:23:53 2008 UTC
| + Segment UID: 0xec 0x71 0x83 0xea 0x2f 0xe9 0x33 0xc0 0x7d 0x38 0x66 0x06 0xc
c 0x91 0x3f 0x14
|+ Segment tracks
| + A track
|  + Track number: 1
|  + Track UID: 3668660603
|  + Track type: audio
|  + Enabled: 1
|  + Default flag: 1
|  + Forced flag: 0
|  + Lacing flag: 1
|  + MinCache: 0
|  + Timecode scale: 1.000000
|  + Max BlockAddition ID: 0
|  + Codec ID: A_AC3
|  + Codec decode all: 1
|  + Default duration: 32.000ms (31.250 fps for a video track)
|  + Language: und
|  + Audio track
|   + Sampling frequency: 48000.000000
|   + Channels: 6
| + A track
|  + Track number: 2
|  + Track UID: 1
|  + Track type: video
|  + Enabled: 1
|  + Default flag: 1
|  + Forced flag: 0
|  + Lacing flag: 0
|  + MinCache: 1
|  + Timecode scale: 1.000000
|  + Max BlockAddition ID: 0
|  + Codec ID: V_MPEG4/ISO/AVC
|  + Codec decode all: 1
|  + CodecPrivate, length 39
|  + Default duration: 41.708ms (23.976 fps for a video track)
|  + Language: eng
|  + Video track
|   + Pixel width: 1280
|   + Pixel height: 720
|   + Interlaced: 0
|   + Display width: 16
|   + Display height: 9
|+ EbmlVoid (size: 1024)
|+ Cluster

If anybody has stumbled across this problem before, I would be happy
to know about it.  Any help is appreciated. If I've posted this to the
wrong list, than I apologize.

Thanks,
Justin