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which to pass over SPDIF?

post #1 of 11
Thread Starter 
Hello, i am back again for somenew help with my HTPC. If you read my last thread, i was struggling to get audio to pass through over the HDMI on my graphics card.

well i finally figured this out. there was a jumper underneath the fan shroud of my video card. shorting pins 1-2 was optical audio input (via the SPDIF input on the card that sticks out on the back) and the 2-3 was coaxal (via the wires from the graphics card to the SPDIF_O header on the motherboard) now, after being so proud of my self for finally figuring this out, i decided to watch my brand new bluray copy of Iron man on my brand new bluray HTPC well, about 5 seconds into the first scene, i just had to shut it off. the audio quality was horrible!

long story short, i bought a new sound card. the model i bought was the HT-Omega STRIKER 7.1 as i had heard many good things about it. now, ive installed the sound card and gotten the optical input into my graphics card for sound over HDMI. the audio control panel has several options for the SPDIF output. this is what i have questions about. First and foremost, will my graphics card be able to translate the optical input into HDMI audio without losing surround? i thought the easiest thing to do would be just to run the audio cable straight into the receiver in the next room (i already have the cables and everything) but i realized that my receiver HDMI inputs are for audio and video and there's no way to get HDMI Video and SPDIF video at the same time. But i could also just run the HDMI cable straight to the tv. Would it be easier to do that (Run SPDIF to the receiver, and have the receivers audio turned to that input, and run HDMI directly to the TV)? if i did that would i experience sync problems?the second question is, should i use DTS: Interactive or Dolby Digital Live? my third question is, if im using DTS interactive or DDL (Dolby Digital Live) i will not have to screw around with stuff like AC3 filter or FFDshow to get unaltered DTS/DD pass through to the receiver right? Thanks and sorry for the disgustingly long post
post #2 of 11
Thread Starter 
bump? this post isnt to long is it?
post #3 of 11
Thread Starter 
anyone?
post #4 of 11
No, the post isn't too long. You just might have too many questions packed into that paragraph and it's scaring people off. But I'll take a shot at part of it (because I like martinis - Hendricks Gin, bone dry and shaken with olives. )

I have HDMI with stereo audio running from my HTPC to my TV. (My audio card will supply stereo for HDMI, which is all my TV will accept via HDMI, so it works out fine.) I use this mode when I'm just watching TV - live, recorded or downloaded. But I also have SPDIF from the motherboard going to my audio receiver. If I want to watch a movie or listen to music I switch from HDMI stereo audio to SPDIF 5.1 audio. I haven't had any sync issues, but YMMV. Some TVs have a audio sync control that delays the picture slightly to allow the audio to catch up. And some audio receivers have an audio sync control that delays the audio slightly to allow the picture to catch up. I'm not sure if your equipment has either delay, or whether you'll even need it. Like I said, mine is synced up enough that I can't perceive a problem. All you can do is try it out.

Good luck.
post #5 of 11
It would be very helpful if you give the model number of :

- motherboard
- graphics card (GeForce?)
- software player
- receiver
- TV

Basic flow of audio from Iron Man would be:

- Dolby TrueHD -> LPCM (decoded by the software player) -> Dolby Digital 5.1 or DTS (encoded by the software player [or the sound card]) -> HDMI signal (muxed with video by the graphics card) -> Dolby Digital 5.1 or DTS (demuxed by the receiver) -> LPCM (decoded by the receiver) -> processed by the sound processor -> analog

IMO the sound card is a waste of money. Necessary processes in the above can be done by the software player and the S/PDIF transmitter integrated in the onboard audio codec. But if you choose a latest Radeon HD 4xxx card, you even don't have to rely on the inferior DD/DTS (it's lossy!), you can output lossless 7.1 LPCM over HDMI directly to your receiver:

- Dolby TrueHD -> LPCM (decoded by the software player) -> HDMI signal (muxed with video by the graphics card) -> LPCM (demuxed by the receiver) -> processed by the sound processor -> analog
post #6 of 11
Thread Starter 
i had the audio working fine with the onboard, its just the quality was crap used to be an audio phile back in the 80's, but then the kids came along. funny how that changes things. but anyway, i just wasnt sure if my video card (9600gt) would do anything to the audio signal before it sent it out over HDMI
post #7 of 11
Quote:
Originally Posted by martini161 View Post

i had the audio working fine with the onboard, its just the quality was crap used to be an audio phile back in the 80's, but then the kids came along. funny how that changes things. but anyway, i just wasnt sure if my video card (9600gt) would do anything to the audio signal before it sent it out over HDMI

The video card does not do any change to DD/DTS.

If I were you, I would sell GeForce 9600 GT and HT Omega Striker, and buy Radeon HD 4670. If your receiver support HDMI audio, there is no reason to use DD/DTS. Multichannel LPCM is simpler and much better.
post #8 of 11
Thread Starter 
well considering i got the 9600gt for free ill stick with it and i really like the audio quality of my striker extreme as well
post #9 of 11
Never mind. I thought "striker extreme" as a mb.

Anyway, as the video card does not modify at all DD/DTS audio, sending DD/DTS through HDMI is a simpler solution imo.
post #10 of 11
Thread Starter 
Quote:
Originally Posted by renethx View Post

Never mind. I thought "striker extreme" as a mb.

Anyway, as the video card does not modify at all DD/DTS audio, sending DD/DTS through HDMI is a simpler solution imo.

oh no, i wish i had a striker extreme mobo and yes, thats what i had thought about the audio as well. but is there any one thats better? (ddl or dts: interactive)
post #11 of 11
Quote:
Originally Posted by martini161 View Post

oh no, i wish i had a striker extreme mobo and yes, thats what i had thought about the audio as well. but is there any one thats better? (ddl or dts: interactive)

DDL or DTS Interactive is just the name of a real-time DD or DTS encoder. Input is LPCM and output is DD or DTS. CyberLink PowerDVD and ArcSoft TotalMedia Theater also have a real-time encoder (not called DDL or DTS Interactive though).
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