Audio Processing in Vista Explained - Page 3

Amir,

Will Vista be able to use a mic calibration file like those used by TrueRTA or Room Eq Wizard? I have a LinearX M31 cal mic, others use the Behringer ECM8000. It will be very interesting to try the Vista room eq. How many filters can Vista use to "flatten the room response" for a main channel? Were does it quit (what freq) doing this eq for the subwoofer (since you say it does not really replace a BFD)?

Multiple bass crossover points (one for each channel type -- center, L/R mains, side surrounds, and rear surrounds) would be very nice.

This will push me to replace one of my PCs with an upgrade that has a HDMI video card (with GPU support for VC-1). I'm hoping I'll still be able to use my M-Audio Firewire 410 since it handles a mic input so well and has 8 analog outs.

Thanks for the very nice audiophile features in Vista.

Bob

Amir, any comments on this:


Thanks!!

Amir,

Thanks for the feedback. A few comments:
It's understood and understandable that ripping CDs to a hardrive is not supported by the redbook standard for CDs. I suspect this capability simply wasn't considered at the time the redbook standard was released in 1980.

In defense of the MS engineer I spoke with at CES, we both understood during our chat that MCE relies on WMP for ripping and playback. My bad for not making this clear.

Your advice concerning remedies are both valid, but I stand by my opinion that Vista's upcoming media center would benefit from native error correction (understanding that this functionalily would likely come from the underlying WMP 11). The value would come from users not having to leave the MCE interface to conduct a (IMO) fundamental AV management task: Accurate CD ripping. Addmittedly, it would not be rocket science for myself or others on this forum to leverage third party apps for this purpose, but it would detract from the eloquence of the product. To Microsoft's credit, it is clear they care about audiophiles and sound quality (the development of a lossless codec, the features mentioned within this thread, etc.). In my mind, accurate ripping is simply another relevant component of the ultimate goal of high sound quality.

In Windows XP or MCE's Windows Media Player 9/10/11, if you select "Properties" on the CD device in "Options... Devices"... you can enable "Use error correction" for both CD ripping and direct CD playback.

In my experience, modern CD/DVD mechanisms with undamaged source CDs will yield clean rips no matter what the application is. Applications like Exact Audio Copy, and it's aggressive "Secure Mode", are not as important as they were in the early days. As always, your mileage may vary. "Bad rips" generally cause audible glitches (pops, clicks, etc.) that are not in the source material... and not generic "worse sound quality." I stream WMA Lossless rips to my Roku SoundBridge with external DAC for playback on high-end audio gear and the sound is identical to my overpriced CD transport and the original CD.

The room correction is very exciting. How would this work with spidf out for various apllications (2 channel to 7.1) to a good processor like a Lexicon? Will 24/192 be supported? What level of distortion will be added by the various correction you will be including in Vista?

I use wma11 (beta) now to listed to wma losselles CD collection over a newtwork with no major problems via my Lexicon DC-1 to my ML Vantage speakers in stereo and then use TT for 7.1 using DTS of Dobly digital converted to 7.1 by my lexicon.

How will this change in Vista

Joel

Too bad! If you check hdmi.org FAQ you'll see the initial HDMI 1.0 standard already supports the full 8 channels (7.1) 24bits 192KHz multi-channel PCM. PC display card is starting to switch to HDMI interface so it's sad to hear the up-coming major Windows OS release still won't support the basic feature.

regards,

Li On

"Jeol, can you clarify if you are talking about playing stereo material instead of multi-channel? If the source is stereo, then yes, PCM out from S/PDIF will enjoy all the enhancements from Vista. If the source is compressed like DD track from a DVD, the answer is no. We don't decompress, correct and then recompress on the way out from S/PDIF (S/PDIF can not carry multi-channel uncompressed audio). "

I listen to stereo over SPIDF so I guess it would be PCM and Vista enahancement will lead to improvements for me.

With respect to DVd's it seems I will need to have a good card act as my preamp with 8 cables out to my amp (or a preamp that will take the input for DVDs. Is that correct?

Will Vista handle 24 bit/192 hz from a DVD to an output over analogue out cables?

what are your anticpated specs for the processing in terms of THD, cross channel, S/N etc for the PCM case-the high end stereo audio application via PCM out or anlogue RCA cable out?

I use balanced XLR inputs to my amp so the anlogue 8 cables out could be a chore.

Joel

will vista allow a bit perfect output will volume at 100% or do we still need to use some sort of kernel streaming or asio for that ?

what will be mandated on the audio side to have non donwsampled audio (ex: logo compliant drivers ? WHQL drivers ? special audio chipset )

is watermarked audio still in the talk for hd-dvd and BRD ?

Yup, talk about missing the boat...

But I am not sure that 8ch PCM over HDMI (or lack of) is a microsoft issue (alone). Hardware vendors need to enable it and AFAIK there are no solutions that do so yet. The toshiba laptop with HDMI does not output audio, the current video cards only do spdif over hdmi, and there no mobos or audio cards with 8ch hdmi out. I could be wrong of course, and would like to be, so if anyone knows otherwise please speak up.

Now if for some reason vista's new drc/eq features were specifically limited to analouge output, that would be dissapointing (amir?) In fact, the main reason i never got serious about DRC on the PC was not wanting to get a good soundcard, the av-710 works just fine for me now.

"Now if for some reason vista's new drc/eq features were specifically limited to analouge output, that would be dissapointing (amir?)"

'twould be fine with me.... whatever floats the boat

Amir,

Does your room correction software take into account whether a speaker is dipole or monopole. ?

joel

Or omnipolar (Mirage OMNISAT)?

Do you mean Vista doesn't care if the output is analog or digital, as long as the digital is PCM? It will not send any multichannel codecs like WMA, DD/DTS or the new HD audio codecs after applying any DSP, correct? This would also include any of the bass management features...?

So for the vast majority of cases, people who currently connect their soundcards to an A/V receiver via S/PDIF, will they will be limited to stereo/2-channel? At least this seems to be the case until there is a connection like HDMI that will support multichannel PCM. Unless, you are willing to use a good soundcard and output analog directly to your receiver/amps.

If the idea of using a soundcard hooked up to your receiver with a bundle of analog cables is unappealing, you might be interested in products like the ones we are developing. It is a new kind of multichannel amplifer, with a built-in soundcard. So you just connect our product to your PC with a FireWire (or possibly USB2) connection and the speaker cables to our binding posts.

In other words...

You can use a digital connection (S/PDIF to your A/V receiver), correct?

And, since you can only send 2 channels of PCM or multichannel DD/DTS over S/PDIF, you will be limited to 2-channel PCM because Vista's audio processing will not encode the multichannel stream to DD or DTS, right??

Sorry for the confusion. Maybe I'm a little confused.

Will cards like the X-Mystique be able to re-encode this processed multichannel data?

Ozy

Ok, HDMI 8 channel PCM output is out of the question now. What's the next best thing for a digital connection?

- AV receiver with a USB connection and act as a sound device to a PC, will this setup pass processed multi-channel PCM from the PC to the AV receiver? If so, which AV receiver has the feature?
- re-encode to WMA Pro lossless over SPDIF to external decoding. If so, which AV receiver supports the feature? There is 1 or 2 Pioneer receiver accepts WMA Pro over SPDIF, will it do "lossless" WMA Pro? How's WMA Pro decoding support from other brand/model?

regards,

Li On

Amir

This is indeed exciting news, I have been following the driver developments by looking at the WinHEC slides over the last few years and had been thinking that what you describe would be possible in the new infrastructure, I had no idea you would actually go ahead and do it.

One thing that I'm still not sure about is the best way to build a possible DScaler for Vista. For video I have a set of filters that work fairly well within the DirectShow framework except for a noticable and slightly inconsistent (between 4-10 fields) latency. I can probably play with time stamps and try to give a fixed delay of say 100ms. However this is still too large if the audio is being routed separately.

One possible solution is to try to do the same sort of thing for audio and add control over the delay. My early attempts to processing within the DirectShow framework were pretty disheartening, the latency was around half a second doing a DD decode on an incoming spdif signal. What I'd be very interested to know is what MS suggest as the best, lowest latency way of getting incoming sound off the card, through a set of directshow filters and back to the sound card (via your new filtering/processing). Ideally we should be able to do all this processing with a latency of no more that 50ms. Can you suggest the right technologies to play with?

John

amir care to take a look at my questions please ?

Maybe I missed it, but did Amir ever answer this. This is my only concern as well. Anyone using DVD and CD playback from the same box is going to be annoyed if they have to change the sample rate for each format every time they switch between the two. This would be the same as we have now.

Is there an option to have it simply leave the stream alone and just pass it to the outputs?

Is it possible to completely sidestep ALL of these features or shut them off completely? (e.g. completely gone, never accessed, never used)

90% of the features listed are of no use to me, and I will be VERY annoyed if MS assumes that I want them and makes them non-defeatable, or worse, says they are defeatable but they continue to run in the background anyway. Every time I install XP (without an image) it takes about an extra 40min to make all the changes that I require to have a usable system.

What we have been asking for from the start is for CDs to play at 44.1 and DVDs at 48 with 0 human intervention. That shouldn't be too hard since any $30 APEX can figure out how to do that.

Can the Vista room correction software handle multiple listening positions? That is accept input from 2 or more postions and then optimize for all listeners or is it restricted to one?

Joel

Amir,

The audio improvements in Vista are pretty interesting. Will we be able to get a chance to hear a technical demo of these various DSP features at a trade show like CES?

Thanks,

- Steve O.

Amir addressed this one:


Also:


Li On, that's the rub right now, no good way to get discrete multi-channel digital out (esp. if processed by the pc). Any receiver I've seen (except for a couple of flagship ones) are not addressing this. Even for ones that support HDMI, anything other than 2-channel LPCM is an option in the HDMI spec, and as a result only a couple of high-end offerings accept anything above 2-channel (and if I remember correctly are even then capped a 5.1). Even if I had one of these rare ones with a USB input or multi-channel HDMI, we need a driver solution for Vista.

I'm sure I'm not alone in trying to plan my next-generation HTPC, and once again the audio is hard to nail. My hopes are:

- that as the HD formats get out in the field that receivers with HDMI inputs will get better at accepting 8-channel LPCM (even if technically they don't implement HDMI 1.3, but just actually support the multi-channel features available in the earlier HDMI specs).

- that a sound card vendor (or even better yet a video card vendor) steps up to the plate and gives us an HDMI solution. With all this great stuff in Vista, I'd hope ATI or Nvidia see the opportunity to write some driver code to capture the digital audio in Vista and pipe it out the HDMI connector (perhaps even using the lip sync features in HDMI 1.3?). Leveraging the Vista feature set effectively adds a sound-card capability by only writing a driver (assuming you do the DA downstream, which I think is where many of us want to be doing it).

In the meantime I'll be using analog outs, and contacting the folks at Orangeware and see if they want to make a firewire driver for Vista that will output the digital streams to my Denon i-link receiver.

I may also take a look the that DTS-connect card (X-plosion, I believe), and see how the quality is if the room-corrected streams are re-encoded and sent over spdif (that's pushing it, I think I'll just accept analog until the picture is clearer).