AC3/5.1 SPDIF passthough not working for MPEG4 videos

[tbonessc]

On version 5 when I played mpg4 videos that had AC3 audio Sage would pass the 5.1 sound to my receiver through SPDIF just fine.
In version 6 it is only passing stereo, is there something I need to do to set this up again?
HD recordings and DVD both pass 5.1 fine in the new release, this is just limited to mpeg4 so far.
For HD and DVD I have Sage set to use the Nvidia Audio decoder.

I checked the AVI's in Windows Media Player, the 5.1 sound is passing correctly via SPDIF using AC3Filter.

[Zladotimov]

That's because v6 now uses MPlayer for playing video media, which has internal codecs for most popular streams, including AC3. That also means that whatever codec you select in the menu, won't get used during playback.
You can force mplayer to use your own codec by changing the appropriate settings in the sage.properties file:
mplayer/use_for_all_mpeg4_playback=false
You can also set mplayer to redirect the AC3 stream to spdif by adding the following to the properties file:
extra_mplayer_args=-afm hwac3 On my system this completely screws up video playback, so I used the first option.
There is no mention anywhere in the manual on how mplayer can be configured through the properties file..

[tbonessc]

Thanks. I'll give those options a try.

[tbonessc]

Well I had to use mplayer/use_for_all_mpeg4_playback=false as well, but it works again.
extra_mplayer_args=-afm hwac3 had no sound at all.

[JDizzy]

Originally Posted by tbonessc

Well I had to use mplayer/use_for_all_mpeg4_playback=false as well, but it works again.

I too had issues and had to change this setting.
I not only was getting no passthrough, but also ws getting no picture.

This fixed it for me
JD

[drpixel]

If you are trying to playback MPEG4 files with AAC audio, -afm hwac3 will not work, as it will simply pass thru an AC3 signal. What you really need to have happen is for something to transcode the AAC to AC3. FFDShow and AC3Filter v1.0 and higher do this, but mplayer does not.

My solution was to get a sound card that encodes 6 channel audio to 5.1 on the fly. This feature is called Dolby Digital Live and can be found on several higher end sound cards. I have the AuzenTech HDA X-Plosion 7.1 DTS Connect, which also encodes in DTS. This will take anything 6 channel and output it properly.

Another thing you'll need to do to get 6 channel sound to work with mplayer is to add '-channels 6' to the extra_mplayer_args setting. Be sure to remove the '-afm hwac3' flag when you do and set 'mplayer/use_for_all_mpeg4_playback=true'

Hope this helps

[jamesnw]

I have been trying to play a mkv file (Matroska) and had no problems with the video output. The audio, however, was being decoded in software rather than being sent as an AC3 stream to my A/V receiver. I turned mplayer debugging levels on using the extra_mplayer_args=-msglevel all\=9 option in Sage.properties to determine what the problem was. Apparently mplayer is used to play Matroska files regardless of the mplayer/use_for_all_mpeg4_playback=false setting. This probably makes sense since Mastroka is not the mpeg4 container. Anyways, since I am forced to use mplayer I added the option that was suggested above extra_mplayer_args=-afm hwac3 which enables hardware DTS and AC3 pass-through. I ended up losing all sound output at this point as some of you have mentioned before. The issue turned out to be the mplayer/audio_renderer=dsound option. According to the SageTV log file, mplayer could not open my audio device when I configured the extra "-afm hwac3" option. After fiddling around with a standalone copy of mplayer I determined that the audio renderer "win32" (which is WaveOut rather than DirectSound) worked properly. Once I configured mplayer/audio_renderer=win32 in Sage.properties the AC3 stream was properly passed over the S/PDIF interface and my world is now a little bit better

In short, try these two settings:

extra_mplayer_args=-afm hwac3
mplayer/audio_renderer=win32

Good luck!

[ToxMox]

Hey thanks jamesnw I was having the same problem with mkv files in Sage and your solution worked like a champ!

[camus]

Ditto on the thanks jamesnw. :cheers:

[Justintoxicated]

Originally Posted by jamesnw

I have been trying to play a mkv file (Matroska) and had no problems with the video output. The audio, however, was being decoded in software rather than being sent as an AC3 stream to my A/V receiver. I turned mplayer debugging levels on using the extra_mplayer_args=-msglevel all\=9 option in Sage.properties to determine what the problem was. Apparently mplayer is used to play Matroska files regardless of the mplayer/use_for_all_mpeg4_playback=false setting. This probably makes sense since Mastroka is not the mpeg4 container. Anyways, since I am forced to use mplayer I added the option that was suggested above extra_mplayer_args=-afm hwac3 which enables hardware DTS and AC3 pass-through. I ended up losing all sound output at this point as some of you have mentioned before. The issue turned out to be the mplayer/audio_renderer=dsound option. According to the SageTV log file, mplayer could not open my audio device when I configured the extra "-afm hwac3" option. After fiddling around with a standalone copy of mplayer I determined that the audio renderer "win32" (which is WaveOut rather than DirectSound) worked properly. Once I configured mplayer/audio_renderer=win32 in Sage.properties the AC3 stream was properly passed over the S/PDIF interface and my world is now a little bit better

In short, try these two settings:

extra_mplayer_args=-afm hwac3
mplayer/audio_renderer=win32

Good luck!

jamesnw, Kind of hard to follow what exactly I need to change to get mkv files to have 5.1 sound, but not pass through SPDIF. I'm using the analog output on my Sb X-fi card. I am however only getting 3.1 surround when playing mkv files back and not 5.1 like I do in VLC player. Which setting exactly do I need to change? I want my x-fi card to decode the sound and output analog signal to my Logitec Z5500's

Do I not use the first line and simply use this second one?
mplayer/audio_renderer=win32

??????????

[jamesnw]

I think the latest version of SageTV fixes most of the issues with mkv. Check out the change list for it.