How do I make my reciever change PCM into 5.1? Also - best video option? (mirror?)

Hello -
I have purchased all the things I need to get my HTPC up and running. My connection is as follows:

Video - ATI 4870 X2 connected via DVI->HDMI cable into my 50" panny plasma

Sound - Have my Yamaha 5990 receiver connected to my Sound Blaster via SPDIF out to Optical in on the receiver.

Everything works great - except my receiver decodes the audio as "PCM". On certain movies I have, I know they should have 5.1 sound (mostly WMVHD and MKV files), but since my receiver is only picking up PCM, its only outputting to 2 speakers. Can someone give me some insight on how to fix this?

My other question is, I want to have my computer hooked both to my Plasma TV and my monitor (so for the nights the TV is being used by the family, I can still use the computer ). What is the best option for this? I was thinking "mirrored display", but I've heard that games won't work that way, are there any other negatives?

Thanks!

Your computer isnt outputting the DD/DTS bitstream to the receiver.

HDMI can handle 7.1 channels in PCM though, but i dont know if that ATI card can.

thanks for the reply - the thing is, I'm not using HDMI for audio, I'm using my sound blaster via optical out. any thoughts on that?

Thanks

I've been fighting the 5.1 thing on my own HTPC and receiver with mkv's. I have a weird setup though, as I'm using 2 sound cards, one for 6 channel analog and the other for SPDIF. If I play an mkv in SageTV, it comes out the 6 channel analogs and ends up playing in a "6 channel stereo effect". If I play it in Media Player Classic Home Cinema, then it will play through the SPDIF and play in 5.1. Try using MPC HC and see how that works.

i would think it has to do with which player you are using. as said, MPC HC seems to output 5.1 fine. VLC however, doesnt work at all. vista media center works fine though.

i did install AC3 filter at the get go, and in it's settings i selected something along the lines of "direct spdif passthrough" which seemed to do the trick. like i said though, VLC has its own set of issues regarding 5.1.

It must be VLC then, thats what I use most often (except for WMVHD files). I updated my soundblaster drivers just to be safe but no luck - even out of windows media center.

I am running Vista 64bit, so I will give MCH a try and see if that fixes it. Thanks for all the info

Install AC3Filter and use the "prefer ac3filter" setting in the configuration page and set the AC3/DTS to passthrough. If you have ffdshow or a codec pack that includes ffdshow, make sure you set the ac3/dts codecs to "disabled" in the configuration. Now, you can also set AC3Filter to encode your PCM streams into AC3 so your receiver gets even stereo sources as 5.1/7.1 DD streams. In this case your computer would be encoding a stereo signal into a 5.1/7.1 format and sending it to the receiver over SPDIF. However all native AC3/DTS streams would be passed directly to the receiver "as-is". I spent a long time learning the in's and out's of this SPDIF game recently and while confusing at first, it's essentially very simple once you grasp the big picture of codecs/pass throughs.

I had a similar problem with my Denon 988 receiver and Xonar D2X sound card. The signal (digital via coaxial) from the D2X to Denon defaulted to PCM until I changed the card's encoder setting to Dolby Digital Live or DTS Connect. I get 5.1 with either setting. Hope this helps!

jonesad said:

thanks for the reply - the thing is, I'm not using HDMI for audio, I'm using my sound blaster via optical out. any thoughts on that?

Thanks

Click to expand...

Use the HDMI for audio. Or can you not do that?

In terms of software I prefer to use AC3filter. But that's just me.

Well, I'm starting to think maybe this is a problem with my configuration (Vista 64bit & sound blaster).
I tried installing both AC3Filter and the Vista 64 codec pack and follow some tips posted here, but no luck.

The closest I can get is setting my SPDIF out to my "default" audio device, and then certain movies will play in DTS (or dolby digital), but the sound is JACKED UP (lots of clicking/etc). If i set my speakers to default, then it sounds fine but only plays back PCM. Whats odd, in my control panel>sound>manage audio devices, when I test "DTS" and "Dolby Digital", they both work perfect and I can clearly see my receiver decoding as DTS or Dolby Digital (with no sound problems). So I know it can take them, and i know my computer can output them...but only in when I click the "test" button.

I have a unique set up in that I have my computer hooked up to a monitor/speakers in my office, and then use my DVI port 2 out to my TV, and my SPDIF out to my reciever. That way, when the TV is being used by someone else, I can still use the computer on my monitor/speakers.

Thanks again for all the help - I think this is one battle that I might just give up on.

jonesad said:

thanks for the reply - the thing is, I'm not using HDMI for audio, I'm using my sound blaster via optical out. any thoughts on that?

Thanks

Click to expand...

S/PDIF can only carry up to 1536kbps of data. That equates to 2 channels of 16-bit/48KHz PCM, or full-bitrate DTS/AC3 (/E-AC3 up to 1536kbps). You have to set your application to pass through the audio via S/PDIF. If it doesn't, the audio is decoded as normal to 5.1 channel PCM (or whatever the source is), but only 2 channels can be sent. In that case, you have to use on-the-fly AC3 encoding available through such software as ffdshow unless you want to downmix all 6 channels to 2.

jonesad said:

It must be VLC then, thats what I use most often (except for WMVHD files)

Click to expand...

VLC relies on its own internal filters. It doesn't care what else you have installed.

cre3d said:

If you have ffdshow or a codec pack that includes ffdshow, make sure you set the ac3/dts codecs to "disabled" in the configuration. Now, you can also set AC3Filter to encode your PCM streams into AC3 so your receiver gets even stereo sources as 5.1/7.1 DD streams.

Click to expand...

ffdshow does a better job of passing audio through S/PDIF yet you recommend disabling DTS/AC3 in favor of AC3Filter. Sounds a bit redundant.

jonesad said:

Well, I'm starting to think maybe this is a problem with my configuration (Vista 64bit & sound blaster).
I tried installing both AC3Filter and the Vista 64 codec pack and follow some tips posted here, but no luck.

Click to expand...

Stay away from codec packs unless you know what you're doing. All you need is MPC-HC if that's what you're using. You can set whether DTS or AC3 is passed-through via S/PDIF or not, and for other formats that can't, you can set it to downmix them to 2.0 so they can be sent over S/PDIF as PCM.

Snowknight26 said:

Stay away from codec packs unless you know what you're doing. All you need is MPC-HC if that's what you're using. You can set whether DTS or AC3 is passed-through via S/PDIF or not, and for other formats that can't, you can set it to downmix them to 2.0 so they can be sent over S/PDIF as PCM.

Click to expand...

Snow - thanks for the info, can you maybe help guide me through this? I have now uninstalled everything (the codec pack, and AC3Filter) so I don't have any extra stuff installed. I downloaded MPC-HC (both 32 bit and 64 bit), and so far still no luck. I do not see anything in the options for passing through S/PDIF. The only audio options I can find are in View>Options>Audio Switcher (this is also the panel that opens when I right click on the video and select Audio>Options). What am I missing?

Options, Internal Filters. On the right side, check both DTS and AC3, double click on either DTS or AC3 (takes you to the same config window), choose SPDIF for DTS and AC3. For those WMV files, a different method will have to be taken, but I'll save that for another post.

YES!!! That works like a charm, thanks man! Can't believe I went through everything else only to uninstall and then use MPC-HC. I'm ready to learn about those WMV's now, if you care to teach

thanks!

Snowknight26 said:

ffdshow does a better job of passing audio through S/PDIF yet you recommend disabling DTS/AC3 in favor of AC3Filter. Sounds a bit redundant.

Click to expand...

How does it do a "better job" of passing it through? I and many others prefer to have AC3Filter handle all audio processing for AC3/DTS streams. Setting ffdshow's AC3/DTS codecs to disabled simply allows for AC3Filter to do it's thing. You could just as easily forgo AC3Filter and let ffdshow handle everything, personal preference.

To help with codecs and troubleshooting you need to get graphedit. It shows you exaclty what codecs/filters your video files are using when playing.

Just because you install a codec doesn't mean it's being used.

And if you discover that the codec/filter you want to be used is not being used you use another app called radlight filter manager to adjust the merit/priority of the codecs/filters.

jonesad said:

I'm ready to learn about those WMV's now, if you care to teach

Click to expand...

For this you'd need an additional piece of software such as ffdshow. Assuming you're using the 32-bit MPC-HC, download the 32-bit version of ffdshow (xvidvideo.ru is a good site for the latest builds) and install it as usual. If you're using 64-bit MPC-HC, get the 64-bit version of ffdshow. Once that's done, there are only a small nubmer of changes you need to make.

In ffdshow's audio configuration under the Codecs panel, change Uncompressed to all supported (down the bottom). This ensures that the WMAudio Decoder DMO (the audio decoder for WMA, which is what I presume will be used) can connect to ffdshow. Then, on the left side, select and check Mixer then change the output speaker configuration to '3/0/2 - 5 channel' and select LFE. This forces any potential 7.1 channel audio to be downmixed to 5.1 (for the next step). Next, under Output on the left side, check AC3 (S/PDIF encode mode) and Encode only 5.1 channel streams (leave it at 640kbps). While you're here, might as well check AC3 and DTS under Pass-through as ffdshow will be used over MPC-HC's internal AC3/DTS decoder.

Now, for part two, in MPC-HC, go to Options, External Filters, select Add Filter, choose ffdshow Audio Decoder, then select Prefer. Now ffdshow will be exclusively used for audio that it can decode.

All these steps ensure three things: audio with more than 6 channels gets downmixed, uncompressed 5.1 (6) channel audio (WMAudio Decoder decodes to PCM or raw/uncompressed audio) gets encoded to AC3, and AC3 gets sent over S/PDIF.

Edit: If you only the audio decoding part of ffdshow, add ffdshow Video Decoder to the External Filters list, but set it to Block.

cre3d said:

How does it do a "better job" of passing it through?

Click to expand...

Supports more formats and allows pass-through over HDMI as well.

Archer75 said:

To help with codecs and troubleshooting you need to get graphedit. It shows you exaclty what codecs/filters your video files are using when playing.

Click to expand...

Just do note though that programs such as MPC-HC don't strictly follow DirectShow filters' merits (such as allowing of non-global merits through the use of the Prefer and Block options), allowing for more flexibility in which decoders are used - basically meaning that just because graphedit renders the content one way doens't mean that all applications will, too.

subed, thx