[MPlayer-users] DTS and Dolby Digital passthrough works for VOB but not AVI files

[Ulion]

2007/11/24, Steve Vanspall <steve at vanspall.id.au>:
> Hi,
>
> I have a Sound Blaster live card with SPDIF Digital Out and passthrough
> capabilities.
>
> I use Mplayer to play video's in mythtv using the following command line
> options.
>
> mplayer -ao alsa:device=iec958 -fs [video_file]
>
> Now I know when the digital signal is being passed through properly
> because my receiver lights up with Dolby Digital or DTS.
>
> To test this out I have a set of Xvid's with Dolby Digital and DTS
> encoded sounds. Infact they are those DD/DTS intros you see before a
> movie sometimes.
>
> After encoding the xvids (from vob files) I double checked the audio
> encoding and sure enough they still read as Dolby Digital or DTS.
>
> Now the problem I have is that these Xvid encoded avi's do not pass
> through the digital signal.
>
> So I had the idea of trying to play the original vob files. so I played
> one Dolby Digital fiel and one DTS file. Sure enough both these files
> registered correctly on my receiver. So passthough works just not with
> AVI's.
>
> Can anyone suggest why?
>
> belowis the output for the dts files. The first is the Xvid file (the
> one that doesn't pass through dts signal) the second the original vob
> file (the one that works).
>
> Any help would be appreciated
>
> Steve
>
> -------------------------
> mplayer -ao alsa:device=iec958 -fs dts_digitalexperience.avi
>
> AVI file format detected.
> VIDEO:  [XVID]  720x416  12bpp  25.000 fps  2894.8 kbps (353.4 kbyte/s)
> Clip info:
>  Software: VirtualDubMod 1.5.4.1 (build 2178/release)
> xscreensaver_disable: Could not find XScreenSaver window.
> GNOME screensaver disabled
> ==========================================================================
> Opening video decoder: [ffmpeg] FFmpeg's libavcodec codec family
> Selected video codec: [ffodivx] vfm: ffmpeg (FFmpeg MPEG-4)
> ==========================================================================
> ==========================================================================
> Forced audio codec: mad
> Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
> AUDIO: 48000 Hz, 2 ch, s16le, 1509.8 kbit/98.29% (ratio: 188719->192000)
> Selected audio codec: [ffdts] afm: ffmpeg (DTS)
> ==========================================================================
> AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
> Starting playback...
> VDec: vo config request - 720 x 416 (preferred colorspace: Planar YV12)
> VDec: using Planar YV12 as output csp (no 0)
> Movie-Aspect is 1.73:1 - prescaling to correct movie aspect.
> VO: [xv] 720x416 => 720x416 Planar YV12  [fs]
> gnome_screensaver_control()00 ct:  0.000 185/185 13%  0% 10.5% 4 0
> Exiting... (Quit)
>
>
>
>
> mplayer -ao alsa:device=iec958 -fs vob_dts_digitalexperience.vob
>
> MPEG-PS file format detected.
> VIDEO:  MPEG2  720x576  (aspect 3)  25.000 fps  9800.0 kbps (1225.0 kbyte/s)
> xscreensaver_disable: Could not find XScreenSaver window.
> GNOME screensaver disabled
> ==========================================================================
> Opening video decoder: [mpegpes] MPEG 1/2 Video passthrough
> VDec: vo config request - 720 x 576 (preferred colorspace: Mpeg PES)
> Could not find matching colorspace - retrying with -vf scale...
> Opening video filter: [scale]
> The selected video_out device is incompatible with this codec.
> 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))
> ==========================================================================
> ==========================================================================
> Forced audio codec: mad
> Opening audio decoder: [ffmpeg] FFmpeg/libavcodec audio decoders
> AUDIO: 48000 Hz, 2 ch, s16le, 1536.0 kbit/100.00% (ratio: 192000->192000)
> Selected audio codec: [ffdts] afm: ffmpeg (DTS)
> ==========================================================================
> AO: [alsa] 48000Hz 2ch s16le (2 bytes per sample)
> Starting playback...
> VDec: vo config request - 720 x 576 (preferred colorspace: Planar YV12)
> VDec: using Planar YV12 as output csp (no 0)
> Movie-Aspect is 1.78:1 - prescaling to correct movie aspect.
> VO: [xv] 720x576 => 1024x576 Planar YV12  [fs]
> gnome_screensaver_control()00 ct:  0.040 152/152 16%  2% 12.0% 7 0
> Exiting... (Quit)
>
> -----------------------

I think both two log showing that dts is not passthroughing, it's try
to decoded with ffdts.
To passthrough, you need to specify '-afm hwac3' to your mplayer cmdline.

-- 
Ulion