Encode PC Games to AC3 into SPDIF passthrough?!

djdynamite123

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Feb 13, 2011
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Since my receiver can only encode DTS/AC3, i have to use ffdshow to encode AAC 5.1 HD content on the fly with GOM Player.

Surely u should be able to do the same with PC games? using AC3Filter, FFDshow or something? please reply, thanx.
 

mmntech

Lifer
Sep 20, 2007
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No analogue 5.1 RCA inputs? That's odd. I've never seen one like that. Must be one of those home-theatre-in-a-box deals.

Most computers will output an appropriate AC3 signal via digital out or HDMI without additional software or tweaks beyond drivers. What are your specs?
 

Blurry

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Mar 19, 2002
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Sorry - don't think you can do this without a dedicated card the supports Dolby Digital Live or DTS Connect, such as the Auzentech Prelude 7.1, etc.

Basically these soundcards convert your audio into a 640kbits (DD) / 1.5mbits (DTS) 5.1 stream that feeds into your receiver.
 

djdynamite123

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Sorry - don't think you can do this without a dedicated card the supports Dolby Digital Live or DTS Connect, such as the Auzentech Prelude 7.1, etc.

Basically these soundcards convert your audio into a 640kbits (DD) / 1.5mbits (DTS) 5.1 stream that feeds into your receiver.
really? yes you can http://forums.whirlpool.net.au/archive/1000547 Iv'e managed to do it easy as jelly, but there is a full second delay which i dont know whats causing it, guess AC3Filter needs altering some more.
 

Soundmanred

Lifer
Oct 26, 2006
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I've never seen this work without a DDL card or bitstreaming over HDMI to a compatible reciever.
You can do DD/DTD over S/PDIF for video and audio files, but games are a different story.
 

djdynamite123

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I've never seen this work without a DDL card or bitstreaming over HDMI to a compatible reciever.
You can do DD/DTD over S/PDIF for video and audio files, but games are a different story.
Well you can do it, read that link, it's easy, i just need to figure out why im getting the delay, since i get no delay using a encoding on the fly with acc to ac3 using ffdshow and media players.
 

Soundmanred

Lifer
Oct 26, 2006
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Well you can do it, read that link, it's easy, i just need to figure out why im getting the delay, since i get no delay using a encoding on the fly with acc to ac3 using ffdshow and media players.

I don't see anywhere on that link where it's "easy".
I do see where he says it stutters, and may or may not work at all.
It's probably delayed due to having to process the audio into a stream your reciever can use.
What reciever are you using?
 

Ross Ridge

Senior member
Dec 21, 2009
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Well you can do it, read that link, it's easy, i just need to figure out why im getting the delay, since i get no delay using a encoding on the fly with acc to ac3 using ffdshow and media players.

Probably because when playing media files the video gets synchronized with audio, either stream is delayed as necessary, but there's no mechanisim to do that with games. It's expected that sounds cards and video cards will render audio and video without much of a delay.

You'd be better off checking to see if your receiver has an analogue multi-channel input. Better quality than AC3 and easier than jelly.
 

Modelworks

Lifer
Feb 22, 2007
16,240
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The delay is because your cpu is processing the audio and since the cpu cannot even begin to work on the conversion until it receives the data from the game there will always be a delay. Even gaming sound cards that do the conversion in hardware have problems with delay when used with games, it isn't terrible but it is still there . If you are playing back video the video can be told to wait until the audio is ready .

The only converters I know of that can do real time conversion without delay start at about $500 and are designed for broadcasters showing live events. Those contain some very fast DSP chips designed for that purpose.