[MEncoder-users] Strange output format of mencoder

Sat Dec 11 21:58:51 CET 2010

On 10/12/2010 1:12 p.m., briconaut at gmx.de wrote:
> Hi,
> I've been using mencoder to transcode videos for my iPad for some time
> without any problems. Recently some of the transcoded files were not usable
> anymore. Neither itunes nor the ipad could play them, but playing them with
> mplayer on my debian box still works. To understand this behavior, I took a
> good and a bad file and compared the output of 'mplayer -identify' of both
>   the original and the transcoded file. While the original '-identify' output
> of the files is really similar, the '-identify' output for the transcoded
> files appears to be radically different (at least to my untrained eye).
> I'm posting the '-identify' output and my transcoding command below in the
> hope that someone might be able to answer these questions:
> - What is the difference in the input files that makes mencoder produce two
> so apparently different output formats?
> - How can I detetct this difference? The '-identify' option apparently
> doesn't show the crucial piece of information.
> - How can I encode my 'bad' files to get them to play just like the good
> ones.
>
> Thanks for any help and suggestions in advance,
> Thomas.
>
> My system:
>     Debian/Lenny on 2.6.32-bpo.5-amd64
>
> My mencoder version:
>     MEncoder dev-SVN-r26940 (C) 2000-2008 MPlayer Team
>     CPU: Intel(R) Core(TM)2 Quad CPU    Q9550  @ 2.83GHz (Family: 6, Model:
> 23, Stepping: 10)
>     CPUflags: Type: 6 MMX: 1 MMX2: 1 3DNow: 0 3DNow2: 0 SSE: 1 SSE2: 1
>     Compiled with runtime CPU detection.
>
> My transcoding command:
> mencoder -sws 9 \
>     -of lavf \
>     -lavfopts format=mp4 \
>     -vf 'scale=1024:768,dsize=1024:-2,harddup' \
>     -ovc x264 \
>     -x264encopts
> 'bitrate=800:vbv_maxrate=1000:vbv_bufsize=2000:nocabac:me=umh:subq=6:frameref=6:trellis=1:level_idc=30:global_header:threads=2'
> \
>     -oac faac \
>     -faacopts 'mpeg=4:object=2:br=160:raw' \
>     -channels 2 -srate 24000 \
>     file.avi -o file.mp4
> (Comments on how to do this better/right are welcome, I got this command
> from google...)
>
> Output of '-identify' on the original 'good' file:
>     Playing good.avi.
>     AVI file format detected.
>     ID_VIDEO_ID=0
>     [aviheader] Video stream found, -vid 0
>     ID_AUDIO_ID=1
>     [aviheader] Audio stream found, -aid 1
>     VIDEO:  [XVID]  624x352  12bpp  23.976 fps  1033.3 kbps (126.1 kbyte/s)
>     Clip info:
>      Software: MEncoder SVN-r32669-4.3.2
>     ID_CLIP_INFO_NAME0=Software
>     ID_CLIP_INFO_VALUE0=MEncoder SVN-r32669-4.3.2
>     ID_CLIP_INFO_N=1
>     ID_FILENAME=good.avi
>     ID_DEMUXER=avi
>     ID_VIDEO_FORMAT=XVID
>     ID_VIDEO_BITRATE=1033336
>     ID_VIDEO_WIDTH=624
>     ID_VIDEO_HEIGHT=352
>     ID_VIDEO_FPS=23.976
>     ID_VIDEO_ASPECT=0.0000
>     ID_AUDIO_FORMAT=85
>     ID_AUDIO_BITRATE=125776
>     ID_AUDIO_RATE=0
>     ID_AUDIO_NCH=0
>     ID_LENGTH=1255.00
>     ID_SEEKABLE=1
>     ==========================================================================
>     Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
>     Selected video codec: [ffodivx] vfm: ffmpeg (FFmpeg MPEG-4)
>     ==========================================================================
>     ID_VIDEO_CODEC=ffodivx
>
> Output of '-identify' on the transcoded 'good' file:
>     Playing good.mp4.
>     libavformat file format detected.
>     ID_VIDEO_ID=0
>     [lavf] Video stream found, -vid 0
>     ID_AUDIO_ID=1
>     [lavf] Audio stream found, -aid 1
>     VIDEO:  [avc1]  1024x768  24bpp  23.976 fps    0.0 kbps ( 0.0 kbyte/s)
>     ID_FILENAME=good.mp4
>     ID_DEMUXER=lavfpref
>     ID_VIDEO_FORMAT=avc1
>     ID_VIDEO_BITRATE=0
>     ID_VIDEO_WIDTH=1024
>     ID_VIDEO_HEIGHT=768
>     ID_VIDEO_FPS=23.976
>     ID_VIDEO_ASPECT=0.0000
>     ID_AUDIO_FORMAT=255
>     ID_AUDIO_BITRATE=0
>     ID_AUDIO_RATE=24000
>     ID_AUDIO_NCH=2
>     ID_LENGTH=1255.13
>     ID_SEEKABLE=1
>     ==========================================================================
>     Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
>     Selected video codec: [ffh264] vfm: ffmpeg (FFmpeg H.264)
>     ==========================================================================
>     ID_VIDEO_CODEC=ffh264
>
> Output of '-identify' on the original 'bad' file:
>     Playing bad.avi.
>     AVI file format detected.
>     ID_VIDEO_ID=0
>     [aviheader] Video stream found, -vid 0
>     ID_AUDIO_ID=1
>     [aviheader] Audio stream found, -aid 1
>     VIDEO:  [XVID]  624x352  24bpp  23.976 fps  1454.3 kbps (177.5 kbyte/s)
>     Clip info:
>      Software: Nandub v1.0rc2
>     ID_CLIP_INFO_NAME0=Software
>     ID_CLIP_INFO_VALUE0=Nandub v1.0rc2
>     ID_CLIP_INFO_N=1
>     ID_FILENAME=bad.avi
>     ID_DEMUXER=avi
>     ID_VIDEO_FORMAT=XVID
>     ID_VIDEO_BITRATE=1454256
>     ID_VIDEO_WIDTH=624
>     ID_VIDEO_HEIGHT=352
>     ID_VIDEO_FPS=23.976
>     ID_VIDEO_ASPECT=0.0000
>     ID_AUDIO_FORMAT=85
>     ID_AUDIO_BITRATE=154368
>     ID_AUDIO_RATE=0
>     ID_AUDIO_NCH=0
>     ID_LENGTH=2848.30
>     ID_SEEKABLE=1
>     ==========================================================================
>     Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
>     Selected video codec: [ffodivx] vfm: ffmpeg (FFmpeg MPEG-4)
>     ==========================================================================
>     ID_VIDEO_CODEC=ffodivx
>
> Output of '-identify' on the transcoded 'bad' file:
>     Playing bad.mp4.
>     libavformat file format detected.
>     ID_VIDEO_ID=0
>     libavformat file format detected.
>     RAWDV file format detected.
>     ID_VIDEO_ID=0
>     ID_AUDIO_ID=0
>     VIDEO:  [DVSD]  720x480  24bpp  29.970 fps    0.0 kbps ( 0.0 kbyte/s)
>     ID_FILENAME=bad.mp4
>     ID_DEMUXER=rawdv
>     ID_VIDEO_FORMAT=DVSD
>     ID_VIDEO_BITRATE=0
>     ID_VIDEO_WIDTH=720
>     ID_VIDEO_HEIGHT=480
>     ID_VIDEO_FPS=29.970
>     ID_VIDEO_ASPECT=0.0000
>     ID_AUDIO_FORMAT=RADV
>     ID_AUDIO_BITRATE=0
>     ID_AUDIO_RATE=0
>     ID_AUDIO_NCH=0
>     ID_LENGTH=43.41
>     ID_SEEKABLE=1
>     ==========================================================================
>     Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
>     Selected video codec: [ffdv] vfm: ffmpeg (FFmpeg DV decoder)
>     ==========================================================================
>     ID_VIDEO_CODEC=ffdv
> _______________________________________________

Are you 100% sure you used the same command line to produce that bad 
output file?

The bad output file seems to have DV Video which is not what using x264 
as a ovc creates.
Also the bad output file has the wrong fps to the original.

I suspect you either used a different command line to make bad.mp4 or 
bad.mp4 is a file
totally unrelated to the source file you claim it came from.