5.1 audio from OTA HD or QAM ?

[korben_dallas]

I did a quick forum search, but I'm unclear about something. Are people getting 5.1 audio from OTA HD or QAM recorded shows in Sage?

[GKusnick]

Yes, I get 5.1 from those OTA programs that have it. I use AC3Filter version 1.11 and it took some fiddling to find the right combination of settings, but it does work.

[thatdude90210]

I just recently got a HDhomerun so I didn't even notice I wasn't getting 5.1 audio. This post got me to to play around with some Audio Renderer & MPEG2 Audio decoder filter combos and found that with just the right combo, I do get 5.1 audio.

I can get 5.1 with either AC3filter or SageTV MPEG Audio Decoder. For Audio Renderer, it only works with SoundMAX Digital Audio (it's the onboard sound via coax digital).

It's weird but when I use AC3filter, I get 5.1 with HD content, but get no sound at all with regular SD content. Maybe I need to play around with AC3filter config.

With SageTV audio decoder, I get 5.1 with HD, and sound works ok with SD.

[korben_dallas]

Either of you guys, are you getting 5.1 via the PC speakers, or sending it to a receiver?

[Jesse]

Hi,

It's weird but when I use AC3filter, I get 5.1 with HD content, but get no sound at all with regular SD content. Maybe I need to play around with AC3filter config.

I had this issue in the bedroom with OTA HD and DVD rips. I use the tv for sound and it will not do 5.1. There is indeed a setting in AC3filter to convert 5.1 to standard 2.0 (ie stereo).

korben_dallas: Optical to the receiver.

HTH

Jesse

[avonnied]

there is a screen on the ACFilter config that deals with the passthrough options..

you don't want to passthrough MPEG audio unless your receiver can decode that

just uncheck MPEG in hte passthrough and it will encode the MPEG audio to something the receiver can decode..

leave Dolby and DTS checked, that way your OTA Digital's Dolby encoded audio will be passed through directly to the receiver

[GKusnick]

Originally Posted by korben_dallas

Either of you guys, are you getting 5.1 via the PC speakers, or sending it to a receiver?

SPDIF out to receiver.

I actually don't use the SPDIF passthrough option in AC3Filter; instead I have "Use AC3 encoder" checked so that I can adjust the gains and use DRC and such. (SPDIF passthrough ignores all of those controls.)

[thatdude90210]

Using digital coax from mobo to a receiver, and it tells me if I'm getting 5.1 with indicator lights.

Btw, Sage didn't seem to let me change anything using ac3filter config, even if I copy over ac3filter and ac3filter.cpl to Sage's folder. I had to use Radlinker to increase ac3filter's priority to finally get Sage to use it. Now I can finally increase the sound gain, the volume was just too low, and mpeg sound is working too.

[Fuzzy]

Part of the problem is that Sage is bundled with ac3filter (an older version, I believe). You should first unregister that filter (regsvr32 /u "c:\program files\sagetv\sagetv\ac3filter.ax"), then install the newest ac3filter (1.11) from ac3filter.net. You will then be able to select ac3 filter in sagetv.

As for configuration, there are a few options you can choose from. The simplest option is to go into the ac3filter config, and set it up as follows:
'3/2+SW 5.1 channels' with use SPDIF checked
[x] Use AC3 encoder
[x] Restrict SPDIF to 48kHz
[x] Disallow PCM output in SPDIF mode
Use AC3Filter for : All selected
SPDIF passthrough : Only AC3 and DTS checked
merit set to prefer AC3Filter
Use Wave out as default Audio Renderer.
This will make it so that AC3Filter will always output 5.1 audio on the digital output. Sage really only ever outputs AC3 (HD & DVD), DTS (DVD only), and MPEG Audio (SD) This setup lets AC3Filter handle everything, by just sending the AC3 and DTS to the receiver, or if it is MPEG Audio, it encodes it to AC3 and sends it to the receiver (though usually just with signals on Left and Right, since it is just a stereo source). Also, there is no volume leveling or DRC (Dynamic Range Compression - makes quiet sounds louder, and louder sounds softer... leps to eliminate 'commercial shock') on AC3 or DTS sources.

Now, for a more advanced method. Since most stereo broadcasts these days use Dolby Pro Logic surround processing, I would like to get that out and use it. This is what I use, and it seems to work really well. I have the most recent ffdshow installed. What I do is set AC3 Filter to work with PCM (uncompressed audio), AC3 and DTS only. This lets MPEG audio (along with any other supported audio compression) to be handled with ffdshow's audio decoder. I then set up ffdshow to work with all formats EXCEPT AC3 and DTS. I set Sage up to use 'default' for audio decoder (that way it will use either ffdshow or AC3 filter, whichever is appropriate). To get that Dolby Pro Logic out, i use ffdshow's 'Dolby Decoder'. This will turn any stereo signal into a Surround signal (Left, Right, Center, Surround). I use ffdshow's LFE Crossover to pull the lows out of the signal and put it on the LFE channel. I then use ffdshow's 'Mixer' set to 3/2 - 5 channels, with LFE selected, with 'Voice control' and 'Expand stereo' checked. Then set ffdshow to output 16 bit integer and connect to 'any filter'. This will make ffdshow output a 5.1 PCM signal. This PCM signal is then seen by AC3 filter, which takes over from here. AC3Filter then encodes the 5.1 PCM signal into 5.1 AC3 to be sent to the receiver. The sound for stereo sources now really fills the room, without using any cheap reverb effects. Even better, this works for all playback, including the music library. It will still take some tweaking on your end, to determine the right settings for the LFE Crossover, and Voice and surround levels, but it really worked great with the default settings for my particular setup.

Another option that I can't really use, would be to have ffdshow also handle the AC3 and DTS decoding as well. This would let you run them through some of the ffdshow filters as well, to help clean them up. The reason I cannot do this is I am limited by CPU power. If I am watching an HD show, my CPU is about 90-95% tapped out, so i don't have room to decode and reencode the AC3, so I have to just pass it out. A CPU upgrade is in my future, and I will be able to use this then.

[millers_35]

I am also trying to get 5.1 audio with my hdhomerun recordings. Here is what graphedit looks like for the filters(everything in sage is set to default).



The Nvidia Audio Decoder is setup to passthrough to reciever via an SPDIF cable. And here is what my settings for AC3Filter look like.






I have AC3Filter setup the way Fuzzy has explained above(Thankyou very much for the explanization) Except for using ffdshow to decode AC3 and DTS.
I was wanting to get the Dolby Pro Logic from SD shows(which this seems to be working fine just need to do a little more tuning).

The soundcard I am using is a Audigy 2 ZS using the spdif out. Also in the soundcard properties I have it set to SPDIF Passthrough.

Anyone see anything right off the bat that could be causing my problem?

Thanks,

Miller


edit: I just noticed that if I play the video with the player in graphedit it works fine but when I play it with sage if does not.

In my properties file I have:
always_use_dshow_player=true
mplayer/use_for_all_mpeg4_playback=false
not sure if these pertain to what I'm doing or not.

[Fuzzy]

My first guess would be the NVidia Audio Decoder. It shouldn't really be needed, as all it is doing is passing the ac3 on to AC3filter. Try selecting AC3Filter in Sage, and see if that fixes the issue.

[korben_dallas]

Originally Posted by millers_35

IThe soundcard I am using is a Audigy 2 ZS using the spdif out. Also in the soundcard properties I have it set to SPDIF Passthrough

The Audigy cards (I have 2) have built-in Dolby decoders and pass-through. So you shouldn't need AC3Filter at all. Make sure Nvidia is set as the default audio decoder (check Windows Media Player > DVD > advanced options), and is set to receiver + S/PDIF.

[Fuzzy]

- You are correct that AC3Filter may not be needed if you are going to simply pass teh CA3 out the port. There does have to be a directshow filter to receive the AC3 from the splitter filter, and pass it to the sound card. This can be Cyberlink, Nvidia, ATI, Intervideo, whatever decoder filter you choose, and they all have some sort of passthrough ability. However, AC3Filter fills this role as well, and appears to use less resources that the others, if all you are doing is passing it through.
- AC3Filter's strength is in it's ability to encode NON AC3 sources INTO AC3, to send to an external receiver. (Some NVidia built in sound chips have this capability as well). It also gives you the ability to Decode the AC3, modify it in some way (DRC, Volume Leveling, individual channel levels, etc) and then reencode it to AC3 to send to the receiver. This is very important for me because I have noticed great variances between multiple HD channels, DVD's, and analog broadcasts volume levels.

[MTuckman]

Fuzzy,

Thanks for your step by step instructions. I finally got around to reinstalling myLive! 24-bit External and set up AC3Filter and ffdshow as you suggest and it works great! I am especially happy with the non-HD shows, ffdshow does a great job of expanding the stereo into the 5.1 signal.

The only problem I am having is with some of the HD shows, where my receiver is indicating it is getting a Dolby Digital [2/0] signal, and is only using the L/R channels.

Is there something else I need to do to get these signals to be processed much like the non-HD shows? Some of the HD shows are being processed as [3/2], but a lot aren't.

Any suggestions?