Question about ac3filter and the Hauppauge remote

[jbarr]

Can SPDIF-based volume be controlled by the Hauppauge remote while using ac3filter and SPDIF passthrough?

I built an HTPC with 5.1 onboard sound with a SPDIF optical output connected to a Sony 5.1 home theater system. I've been running audio through the SPDIF connection, and have the SageTV settings as follows:

Audio Renderer: "SoudMAX HD Audio"
MPEG2 Audio Decoder Filter: "SageTV MPEG Audio"

I am able to use the Hauppauge remote to control the SageTV volume. Audio goes through SPDIF, but the actual sound, though displaying as "digital" on the Sony, is apparently simple 2.0 stereo. While it does sound good through the Sony home theater system, it is definitely 2.0 audio. But the important thing is that I have control over the audio with the Hauppauge remote.

OK, so I next installed ac3filter, configured it, enabled it, and full digital audio suddenly ROCKED our home theater system--it made me literally jump! It sounded amazing in full digital glory, and it worked extremely well...almost: I lost the ability to control audio with the Hauppauge remote through SageTV. I could only control it using the Sony's remote.

So, how can I configure things such that I can get full ac3filter audio while still being able to use the Hauppauge remote to control the audio levels?

[ke6guj]

You may want to try volumetracker. I think it will do what you want.

I found the official link to volumetracker at http://www.chrisnet.net/code.htm

Here is the description...

Volume Tracker - Great for systems using Digital Audio Out, such as SP-DIF. With Digital Audio output, only the wave volume effects the output level, not the master volume. Yet multimedia keyboards and remote controls only adjust the master volume. This app tracks the wave volume to the master volume by monitoring changes to the mixer control. Works on 2000, XP and Windows Media Center.

[stanger89]

If you have AC3Filter (or any other filter for that matter) configured for Passthrough, you can't control the volume since it's just passing the bitstream through as-is.

To control the volume you have to decode the audio to PCM, only then can you apply the volume control. Of course S/PDIF can only carry stereo PCM, so then you lose the 5.1.

Basically you can have 5.1 or volume control, not both.

[bcjenkins]

Or get a learning remote, eg. Harmony, and use the volume buttons to control the receiver.

B

[jbarr]

Bummer. Thanks for the replies.

It's OK that I only get 2.0 Stereo from SageTV recordings, as long as volume is controllable through SageTV. Stereo is OK, so that's a no-brainer. But my real goal is to be able to ALSO play DVDs, physical and ripped, with 5.1 or Dolby Digital, all managed through SageV. Would it be possible to achieve this given my setup?

[stanger89]

The only way I know of to get 5.1 and volume control is to decode it in the PC, and run the 6 analog channels into your receiver.

Only other way is something like bcjenkins mentioned, ie to control it on the reciever.

[GKusnick]

I hesitate to contradict Stanger, but the later versions of AC3Filter do have an option to decode the AC3 to PCM, apply volume controls and whatnot, and then re-encode it as AC3 for transmission via SPDIF. To enable this option you have to disable SPDIF passthough and check the "Use AC3 encoder" checkbox. There's some generational loss in the re-encoding (not noticeable to me), but it does allow you to send 5.1 channel AC3 to the receiver and still control the volume from the PC.

The catch is that I haven't figured out how to make it work with the remote. AC3Filter doesn't respond to the system volume control but has its own gain controls on its property pages. It may be possible to configure Hip or Girder to work these controls, but I haven't explored that.

[stanger89]

Originally Posted by GKusnick

The catch is that I haven't figured out how to make it work with the remote. AC3Filter doesn't respond to the system volume control but has its own gain controls on its property pages.

That's mostly what I was getting at, Windows can't control the volume of a bitstream (which AC3Filter outputs either in passthrough or re-encode mode), only PCM.

The "best" (meaning most likely to succeed) way to do this is probably to get one of the soundcards that does encoding to DD/DTS in the drivers. It would theoreticaly be possible for Windows to control the volume on the PCM before it's sent to the driver.

But that's a hardware fix, and IMO the better hardware fix is to control volume on the receiver and use a learning remote if necessary.

Oh, and you could also probably use the current remote with Girder and a USB-UIRT (or serial if your RX supports it) and remap the Remote's volume control to change the receiver volume instead of the system volume

[Humanzee]

So for what ever reason we are in the habit of using windows media player to watch DVD's. In WM the volume does work with the spdif output and 5.1 output. In sage the volume is pinned at zero. This is in vista. Does WM do something unique to allow the volume controls to work with spdif? I thought that the volume worked in VLC too but I could be wrong about that.

[stanger89]

Originally Posted by Humanzee

In WM the volume does work with the spdif output and 5.1 output. In sage the volume is pinned at zero. This is in vista. Does WM do something unique to allow the volume controls to work with spdif?

It probably decodes the audio and outputs stereo.