Beginners guide to Mediaportal Codecs and what to use. (3 Viewers)

[jameson_uk]

Right some fundamentals

• There are only two ways of getting audio from the PC to a received
  • Decoded audio
  • Bitstreaming
• HDMI (via LPCM) and analogue are the only methods of passing multi-channel decoded audio
• S/PDIF (can be optical, coax or HDMI connection) can only pass DD/DTS or stereo decoded audio
• If you set your PC to 5.1 and output multi-channel LPCM then it does output six channels of audio but only two of them actually have sound
• Pro-Logic is still valid and is just a way of upmixing stereo to 5.1

What I think you are looking to do is output multi-channel audio as multi-channel but output stereo audio from video files as 5.1 (music adds another layer of complexity here)

If that is the case then HDMI and bitstreaming solves most audio types

• DD
• DTS
• DTS-HD
• True HD
• Multi-channel audio in any format decoded to LPCM

All this leaves is stereo.

As I mentioned above to get multi-channel audio out over HDMI you have to setup your speaker in Windows to be 5.1/6.1/7.1 but in doing so this means that stereo audio tracks get output as is (ie. in 5.1 / 6.1 / 7.1 but with only the Front L/R channels have audio). Your receiver will not know this is a stereo track as the connection is multi-channel (it can not differentiate between this and a film where for some reason all other channels happen to be silent).

So you have a number of options

• Convert the stereo to 5.1 on your PC and output it as LPCM
• Get the amp to recognise that this is in fact a stereo track and for it to flick over to Pro-Logic

I think for the former you still need to add a post-processing filter (AC3 Filter or FFDShow) to upmix the audio.
The latter is possible using MPAR in exclusive mode however this means you need to decode all audio to LPCM (which in theory should make no difference to the quality anyway) as this will negotiate a new connection so your amp will know that a stereo connection is stereo, 5.1 is 5.1 etc.

The mixing options in LAV are only for down-mixing (ie. convering multi-channel audio a pro-logic encoded stereo signal) (http://forum.doom9.org/showthread.php?p=1620752#post1620752)

So I guess the point here is the MP is not doing anything with the audio but you can use codecs (filters) to achieve this.

 

[Atomic7431]

Although I note that you can switch between straight and mixup on the amp by pressing the "sur" button, it would be nice to have everything change automatically, depending on the audio source.

I have done some further tests here and, if you start a movie and make sure you press straight on the remote and that it says straight and not 5 channel stereo enhanced, now the surround should be working for movies as you have seen already.
Next go and play a tv channel and hit the sur. decode so it says pro logic ||. Now when you go to watch a movie dont press anything and it should auto be on the straight input and the surround should be as you would expect. When you now go watch a tv channel you should see it say pro logic || again.
Hope this helps further, for this to work like this follow the screen shots i posted earlier in the thread and you will have hd audio via mpar and pro logic || when on a tv channel.
About to see if the settings on the amp are remembered when turning the amp on and off.

Update : turning the amp on and off a minute or so later and the audio options were still remembered on the amp and working as expected.