[MEncoder-users] mencoder is unable to select libmpeg2/mpeg12 decoder

[Cristian Manea]

I use this command to encode interlaced DVD to progressive H.264 with
MEncoder:

mencoder vobfile.vob -vf crop=704:464:12:8,yadif,hqdn3d=2:1:2 -nosound -ovc
> x264 -x264encopts
> crf=18.0:preset=slower:tune=film:profile=high:level_idc=30:threads=auto -of
> rawvideo -o encodedstream.264


The problem is that when I open vob files or dvd titles with mplayer and
mencoder, ffmpeg is selected to decode the mpeg2 stream, but in the output
it says that this codec is not compatible with the source format:

Could not find matching colorspace - retrying with -vf scale...
> Opening video filter: [scale]
> The selected video_out device is incompatible with this codec.
> Try appending the scale filter to your filter list,
> e.g. -vf spp,scale instead of -vf spp.


So I tried selecting another codec using "-vc mpeg12" in mplayer first, and
it wasn't able to start playback. I then tried "-vfm libmpeg2 -vc mpeg12"
and it didn;t work either. The output in both cases was:

MPlayer SVN-r33953 (C) 2000-2010 MPlayer Team
>
> Playing dvd://5.
> libdvdread: Encrypted DVD support unavailable.
> libdvdread: Attempting to use device /dev/loop0 mounted on /mnt/iso for CSS
> authentication
> libdvdread: Could not open input: Permission denied
> libdvdread: Can't open /dev/loop0 for reading
> libdvdread: Device /dev/loop0 inaccessible, CSS authentication not
> available.
> There are 6 titles on this DVD.
> There are 1 angles in this DVD title.
> audio stream: 0 format: ac3 (stereo) language:  aid: 128.
> number of audio channels on disk: 1.
> number of subtitles on disk: 0
> MPEG-PS file format detected.
> VIDEO:  MPEG2  720x480  (aspect 2)  29.970 fps  8000.0 kbps (1000.0
> kbyte/s)
> ==========================================================================
> Forced video codec: mpeg12
> Opening video decoder: [libmpeg2] libmpeg2 MPEG 1/2 Video decoder
> Selected video codec: [mpeg12] vfm: libmpeg2 (MPEG-1 or 2 (libmpeg2))
> ==========================================================================
> ==========================================================================
> Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
> AUDIO: 48000 Hz, 2 ch, s16le, 192.0 kbit/12.50% (ratio: 24000->192000)
> Selected audio codec: [ffac3] afm: ffmpeg (FFmpeg AC-3)
> ==========================================================================
> AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
> Starting playback...
> Movie-Aspect is 1.33:1 - prescaling to correct movie aspect.
> VO: [xv] 720x480 => 720x540 Planar YV12
> MPlayer interrupted by signal 11 in module: decode_video
> - MPlayer crashed by bad usage of CPU/FPU/RAM.
>   Recompile MPlayer with --enable-debug and make a 'gdb' backtrace and
>   disassembly. Details in
> DOCS/HTML/en/bugreports_what.html#bugreports_crash.
> - MPlayer crashed. This shouldn't happen.
>   It can be a bug in the MPlayer code _or_ in your drivers _or_ in your
>   gcc version. If you think it's MPlayer's fault, please read
>   DOCS/HTML/en/bugreports.html and follow the instructions there. We can't
> and
>   won't help unless you provide this information when reporting a possible
> bug.
>
>
I'm using Debian Stable and I have a package called "libmpeg2-4" that was
already installed. What seems to be the problem with this mpeg2 decoder ? Is
there another decoder that I should select when encoding DVD's to H.264 with
MEncoder ? I don't know of any other mpeg2 decoder, but I would like to
solve that incompatibility: "The selected video_out device is incompatible
with this codec"