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[GaryM]

My HTPC is linked to my receiver via spdif. That is at present the only connection available to me as they are in adjacent rooms.

I would like to try using videoclock, and therefore need to turn off bitstreaming in MC.

From Windows (7) normal audio and system sounds are played OK via the spdif connection, so I guess if MC can output the right format I can pass the 5.1 to the receiver via the spdif connection. BUT, I assume that to use Videoclock MC needs to decode AC3, and then resample, then re-encode?

Can anyone advise on how to go about configuring MC to do this?

Thanks...

At some point the audio needs to be decoded (to PCM), converted to analoge (DAC), and amplified.  It's not so much an argument of what is "better" (as the output should be identical) but more where you want to apply any desired DSP features.

1) Advantage of Decoding in the HTPC:  If you want to add an DSP effect (have a look at the stuff in Player --> DSP Studio) on the PC side you need to decode not bitstream.  The main argument however is the "VideoClock" feature (Tools --> Options --> Audio for Video, DVD, & TV --> VideoClock).  Like with Reclock, VideoClock gives the ability for MC to resample the audio to keep it perfectly in time with the Video Frame presentation so that you don't get any dropped or inserted video frames.  The result is perfectly smooth presentation of the video with the audio being insync.

2) Advantage of Decoding in the Receiver:  [flame suit on] You get the little DTS, DD etc lights comming on.  [/flame suit off]

[jmone]

Sorry GaryM but you are out of luck if you want to use S/PDIF and VideoClock for Multi Channel Audio, as the S/PDIF is limited to either 2.0Ch PCM or up to 5.1Ch in DD/DTS.  You really only have std options for Multi Channel decoded audio:
1) HDMI (which by the sound of it you don't have on you receiver and/or PC).  This is my preferred option as the PC just decodes the Audio to PCM and you receiver then does the DAC and Amplification.
2) Analog Output (which you should have on both).  How "good" this sounds depends on the DAC in your Audio Card as the PC will now do both the decoding and DAC, with the receiver doing the Amplification.  That said for movie sound tracks you are already limited to only DD/DTS now anyway (so no HD Audio).

[GaryM]

So MC can't re-encode the 5.1 that it decoded from the DVD AC3 signal? I thought I had read somewhere it could?

.....as the S/PDIF is limited to either 2.0Ch PCM or up to 5.1Ch in DD/DTS.  You really only have std options for Multi Channel decoded audio:

[jmone]

Nope

[raym]

So MC can't re-encode the 5.1 that it decoded from the DVD AC3 signal? I thought I had read somewhere it could?

Umm, yes it can. DSP studio under "channels" - output 5.1 and enable the AC3 option. As long as you don't bitstream, you can take advantage of videoclock and then "repackage" to AC3 at the final stage for spdif connections. This is exactly what I do for one of my htpc's where hdmi isn't an option.

[GaryM]

Thanks for the confirmation. Despite jmone's advice I thought I'd give it a go last night and my configuration was just as you describe. It seemed to work okay.

[jmone]

Thanks - I learnt something new today!