will sblive resample?, 24/96 through Coax Options

[lexor]

say I have a receiver that is capable of 24/96, and is connected to 5.1 speaker set, and I connect my computer to the receiver through Coax digital out on SBLive! 5.1. I am trying to play back a 24/96 WMA Pro 5.1 (came from DVD, so it is actually that, and not upsampled and channels aren't expanded from 2.0 stereo)

now if I connect sblive to 5.1 Computer speakers (analog connect from sblive) it will down-sample, as it always does.

if as above, I'll connect it to receiver through coax, will sblive still interfere and resample? you can give an answer or tell me how I can checked it.

[jrbamford]

if you send the 5.1 info as AC3 over coaxial (something transcodes it to this from wma?!) then i guess it will be left, but i thought AC3 only went up to 40khz!?! dunno what DTS goes up to, i thought that was more about less lossy compression...

not got much experience with this, but have seen people talking about using the media chip on an nforce which is one of the only ones available that can encode dolby digital AC3 in realtime... these seem to be the only options with WMA surround... I've got the terminator2 HD version in windows media, i listened in plain stereo, but others on avsforum spoke about this AC3 output option and managed to get it working well...

[lexor]

weired, what I did was extract ac3 -> convert to 6 wav for audio (to avoid desync), then multiplex it with video using WME 9, setting audio input to those 6 wavs and choosing to encode at WMA 9 pro 24/96 5.1 so it's not in AC3 anymore, that thing is gone.

also how was playback on T2? mine was jerkey as hell (in high rez mode) had to choose that smaller sized wma source. (the high resolution looked sweet, though it was more of a slide show)

p.s. I'm sure it was just a typo on your side, but nforce doesn't encode AC3 in real time, it decodes it for playback.

[lucpes]

The SB Live only supports 16bit & up to 48kHz so there's no way to play that file in 24/96 (unless you find a way to pass the WMA file to the receiver to decode it - highly unprobable & most likely unpossible)

[lexor]

The SB Live only supports 16bit & up to 48kHz so there's no way to play that file in 24/96 (unless you find a way to pass the WMA file to the receiver to decode it - highly unprobable & most likely unpossible)

oh, thanx for clarification, what confused me is the fact that term coax is used very loosely by many people in some forums I visit, it kinda given me this nagging feeling that since it's a digital out, it might output a digital stream of data from the file without processing it, and the processor in receiver will do the job (like for DVD). Now that I think about it I really don't see how receiver would know how to decode wma.

p.s. unpossible? watch simpsons to much?

[AstralStorm]

Additionally SB Live's digital output resamples everything to 48kHz, just like analogue one.

/EDIT\
Corrected.
\EDIT/

This post has been edited by AstralStorm: Aug 17 2003, 23:38

[CosmoKramer]

p.s. I'm sure it was just a typo on your side, but nforce doesn't encode AC3 in real time, it decodes it for playback.

Yes, it does.

[jrbamford]

yeah it does, its the MCP chip out of the XBOX... realtime dolby digital creation from a games perspective.. luckily for movies in wma 5.1 you can decode the wma and encode into dolby digital to get 5.1 playback on traditional recievers...

I own the Terminator 2 HD dvd.. there is only one version of the video and yes it did struggle a little... even my 2.8ghz P4 couldn't hack it... more importantly you need a top of the range (radeon 9700 and above) graphics card to get good performance with it

[Pio2001]

Additionally SB Live's digital output resamples everything else to 48kHz, just like analogue one.
It is bit-identical only with that input frequency.

Has anyone checked that the digital out is bit exact in this case ? I thought that the SB Lives ran SRC a all input frequencies, including 48 kHz.

[AstralStorm]

I don't know whether it was bit identical or not and can't check it now - I don't have the card anymore.

(PC-AV Tech tests show uneven frequency response, so...)

This post has been edited by AstralStorm: Aug 17 2003, 23:40

[lexor]

ughm... darn it!

I just checked and the best I can do is to encode 24/48, to avoid resampling of frequency, but I can't get it to 16/48. the other alternative is 16/44.

so which one should I opt for? (i.e. does the least harm to original ac3)

thanx for all your great help guys!

[AstralStorm]

This won't be half as bad as resampling frequency, only slight truncation noise,
unlikely to be very noticeable.

[Patsoe]

Additionally SB Live's digital output resamples everything else to 48kHz, just like analogue one.
It is bit-identical only with that input frequency.

Has anyone checked that the digital out is bit exact in this case ? I thought that the SB Lives ran SRC a all input frequencies, including 48 kHz.

I thought so too, after reading the info at the kx-project site. But they are actually speaking about the digital input only.

[Pio2001]

(PC-AV Tech tests show uneven frequency response, so...)

I did test the SB Live digital output (when I had one) with the level meter of my DAT Deck, and found very different results than PCAV tech : perfectly flat response until 24 kHz, plus or minus 0.5 dB.