the underlying reason for this is that the kernel mixer of vista isn't bitperfect anymore unlike its predecessors from XP and 2000. In vista either kernel streaming (non-WaveRT version) or wasapi (both WaveRT/non-WaveRT versions) is thus required to get bitperfect PCM sound and thus supported.

Thanks for the quick reply, so as I'm running XP I can just use your drivers and there's no need for the kernel streaming plugins to be used as well.

One other quick question if you don't mind, I'm running some HTPC software called Meedio to playback all my media - when I first playback one of my MP3s my Amplifier lights up 44.1KHZ PCM fine (and sounds SO MUCH BETTER than the original drivers), I then go and play say a DivX video it lights 96KHZ and go back to music and it stays at 96KHZ - it still sounds pretty good to me even like this but presumably something is upsampling my music to 96KHZ which will be compromising the quality I guess - any ideas on this or is it solely down to the Meedio s/w?

you've described basically one of the ways in which the sample rate of the kmixer is selected - you can either shutdown and restart the application in order to force the kmixer to reset or disallow higher sample rates.

OK, so even using your drivers its not always possible to eliminate kmixer then?

I guess the divx file is 96KHz hence why it plays like that (which you would want ; playback same as source), but you really want the application to then switch back to 44.1KHz for MP3 - if I disallowed 96KHz in your provided control panel than that would mean kmixer would have to downsample the divx back to 44.1KHz ?

there's a directshow filter called 'reclock' which can bypass the kmixer - I haven't tried it since mplayerc / foobar2000 suffice for my needs.

if the application re-initializes the soundcard between stopping one media file and playing another one, there shouldn't be a problem with resampling unless some other application is blocking the kmixer.

Thanks for your help, much appreciated.

I believe I've got around the issue by invoking Windows Media Player to play my audio and Meedio to play video - everything seems to switch sample rate correctly on my Amp then.

Out of interest if I blocked everything in the control panel except 44.1KHz, would this affect when I play DVDs with DD/DTS 5.1 Soundtracks at all (ie passthru)?

Problem with the current release... Previously I was using 1.08 I think and I don't remember it happening. This is in XP.

Whenever I resume my desktop from hibernation it forgets the volume slider and mute settings. The volume is turned all the way to the maximum and some analog input is not muted. So I get a really loud, high-pitched buzzing noise from my headphones that are always plugged in. As soon as I touch the slider it remembers where it was at, and as soon as I touch a mute checkbox it remembers that as well. The graphic for the slider and checkboxes are correct in the volume control panel thing, just not the actual volume/checkboxes.

I see no responses have been logged since the middle of last month, so I hope this will not go unanswered.

I want to know if there is any way to get the echo effect that is normally applied by the manufacturer drivers with your homebrew. I purchased this card primarily for it's echo effect. I run karaoke (i know, i know...) from my HTPC. I currently have to run two sound cards in my setup one for bit-perfect (a realtek integrated) and a Xtreme sound 7.1 for echo on the mic. Usage... I disable Realtek, when I want to use the Cmedia for analog purposes.

I would like to have one card for all solutions. Can I somehow run the manufacturer mixer and get echo to work with your driver?


Thanks for all your help. This solution would bring my HTPC/karaoke dream to fruition.

Mhh, I've had the hope to have these things working... I'll take a look at it.


No, but this really ought to be done in user mode and not in a driver. There's most likely software out there which is able to do this kind of processing much better than C-Media's driver.

Any suggestions on software to do this besides Xear 3d?

nopes, sorry, I'm not really a karaoke guy.

leto, the bug with the wrong volume after hibernation / standby should be fixed.

Great! Probably won't be able to test it out until Sunday or Monday though.

I'll thank you in advance in case it works, and if not I'll be sure to let you know.

Hibernation works fine for me now. Thanks.

Hi guys, did alot of reading but must have missed it.
I have a cmi8738 card with spdif bracket. I have hooked up coaxial out to my pioneer home threatre system.
How come I cant get seperate channels. its like stereo in all speakers. system plays stand alone DVDs sweet.

Im using homebrew drivers. Media player classic with ac3 filter, when switched to passthrough, no single channels. I have a ac3 audio test "front right" "centre" etc still coming from other speakers.

With pass through can I change the volume etc? I have my projector screen in front of my sound system
is there a mixer to adjust..?

with 2 channels music videos I get the same in all speakers , which I think is good its more ac3.

cheers

aj

anyone know??


whoo hoo

Vidman,

-Make sure only spdif is hooked up to decoder/amplifier, so there's no analog route
-My receiver has a stereo mode, converting all multichannel input to just stereo. check yours!
-make sure your player software has something like "spdif passthrough" enabled. try different players.
-Does your receiver have DTS/AC3 indicator that lights up?

What happens on this AC3 test file?
http://dither123.dyndns.org/alladinAC3.flac
It's AC3 data, in wav container, ran through lossless codec.

will try this, will get back

cheers for reply..

v

Hi,

I installed the drivers and tried to get them to work, but I came upon some problems. The digital output works fine when I play MP3 files in winamp and stereo sounded movies in VLC. When I try to play a movie in VLC which has AC3 sound, my Logitech Z-5400 recognizes it as Digital audio but it stutters very badly ! What did I do wrong ?
In the configuration screen I set channel configuration to 2.0 otherwise it doesn't work at all. Did I forget something ? I only tried VLC to play the video file. When I use media player it doesn't recognize the AC3 audio at all and just plays it in stereo.

nothing - ac3/dts passthrough in vlc is somewhat broken. A good alternative is media player classic in conjunction with ffdshow.

Yeah it works perfectly now ! I have to crank up the volume a lot on my speakerset but that's not so bad. It works Thanks !

Hi all

I tried to use dogbert's drivers instead of the offcial ones for my Terratec Aureon 5.1 PCI card (the official driver didn't allow me to get SPDIF output at all). With the open source driver, I can get SPDIF passthough, but only 2 channels

Any advice to get some real 5.1 ?

Regards

Julien

Hi Dogbert,

a question and a request

my analog channel configuration is set to 5.1 but now I can't set the config to stereo anymore. When I select stereo and press apply the config jumps back to 5.1 (running non wavert 1.17 on vista x86). Is this a (known) bug?

and...

Is it possible to add an option to route the line-in to spdif? At the moment I use Audacity to record and monitor the sound, that works but its not very efficient. This feature would really help in setting up my split surround set.


thanks!

Only stereo PCM and compressed multichannel audio data (dts/AC3) can be transmitted over the SPDIF port. As a consequence, "regular" multi-channel PCM data from games and so on can only be output through the analog jacks because my driver avoids any kind of signal processing in order to be bitperfect.
So unless preencoded dts/ac3 data from a DVD / AVI / ... is passed through, stereo PCM is the only supported format for the SPDIF port.



Microsoft decided to deprecate the API which is responsible for changing the channel configuration in Vista. The reason for this was to force the IHVs ("independent hardware vendors") to develop software embedded in Vista's sound applet instead of delivering their own tools.
I'm not going to support this crapfest anytime soon because I want to keep my driver backward compatible to XP / 2k.


mh.. I don't think the hardware supports this, but I might be wrong. I'll take a look at it when I've got a bit more free time.

hello guys, first of all i´d like to thank dogbert for these great drivers!

many issues have been fixed (install in the beginning ) and passthrough works great for me! *thumbs up*

the only thing im constantly fighting with is the microfone.
With your drivers i cant get voice tools like ventrilo working properly.
when i start ventrilo it says: "Failed to open input device. Another program might have it open already"
If i set up direct sound input i get an "createcapturebuffer error" and if i try the regular CMI8738/8768 Wave device input i get an "open input wave device failed" error.


im using the latest driver, but tried the 1.1.7 ones too.

what can i do?

thx in advance

Hi,
there is no "request feature tread", so I decided to post here: Well, passthrough is excellent and is exactely what we were looking for. One nice additional feature would be a "monitor output, a.k.a. second zone" on analog ports, if it is possible at all...
Many thanks.

what OS do you use, what version do you run (32 or 64 bit), and do you have any other programs opened which might use the soundcard while Ventrilo is running?


uhm... what input port should be monitored onto what output port exactly?

Here it is:
- application (media center) plays a DVD;
- your WaveRT driver bypasses Vista's internal DSPs, renders audio stream into cmedia chip;
- chip outputs to SPDIF endpoint;
- SPDIF is hooked to audio receiver, which decodes AC3 audio to 5.1 speakers;
All of above is excellent.
Now, if I want to use stereo headphones and dont want to mess with default playback device changing?
I thought it would be greate, if it is possible to force cmedia chip to do what it was originaly designed for but at the same time with SPDIF passthroug:
- route the same DVD audio stream into Vista DSPs;
- use software decoders;
- downgrade to 2 chanels;
- output via analog connectors.

Well, it contradicts with Vista's idea of endpoints, as it outputs same source twice (but in different form). Again, it only make sense if it can be done in parallel and at the same time as SPDIF passthroug.
Hope this time I explained better

Yep, now it's crystal clear - I'm afraid the hardware is limited to one playback stream at a time so that an AC3 stream and a decoded stereo stream can't be played simultaneously.

Hi d0gbert or anyone who might help
I'm desperate to get my dts audio files to play on my htpc via spdif, but no joy.
Came across your drivers bought an aureon 5.1 new clean install of xp sp3 (3311).
Stereo plays well but dts gives me static (when flac, receiver says pcm 44) or nothing (when wav, receivr says dec. err).
I'm using foobar 0.9.5.1 kernelstreaming or not doesn't change a thing.
I reinstalled vista sp1, xp sp2, xp sp3 so many times, used onboard alc889 (including dts interactive!), used an audigy2 used a m-audio 2496 and now this one, it drives me crazy.
Also using two recievers to compare (denon/sony) and of course they behave different.
This really seems the hardest thing to do.

Hints anyone?
Really, any help appreciated.

PS: Interesting: When I enable windows sounds they play as 96kHz...

are your receivers capable of decoding DTS? have you tested them against other DTS files?

foobar with KS is bitperfect if no prior DSP plugin processes the sound.

yes the sony is doing well with dts interactive and the denon avr3805 has all logos up tp 192 kHz, but doesn't even play with the onboard dts interactive. The denon is the target but i'm testing against the sony de-695 right now.

I have no dsp active and it's a plain vanilla installation with only the grafx driver, your driver and foobar installed. ok touscreen driver and irtrans are present also, but that's it.

well, make sure that the volume in foobar is set to 0dB and there is absolutely no signal processing, and if it still doesn't work, try winamp with its KS plugin.

Foobar is at 0 db... winamp with ks plugin...no audio
installed kmplayer, configured spdif, dvds play their dts track fine, just not my audio files
and I tried many of them, also dts cds don't play.
As if only 48kHz is working...

have you tried 48kHz DTS files in .wav format? do your receivers specifically support 44.1 kHz DTS?

ac3 files can be packaged as .wav, too - maybe it's worth a try to test some 44.1kHz ac3 files. If this doesn't work, the hardware (soundcard) might be defective.

Solved! What a relief!
Your comment "do your receivers specifically support 44.1 kHz DTS?" made me check my receivers documentation and I found
- Sony str-de695 has a default decoding setting "PCM" that needs to be changed to "AUTO"
- Denon AVR3805 has a per input setting 'Auto Surround" that needs to be enabled

both work flawlessly now.
Some of the older flacs need to be reencoded it seems, peace of cake.

Thank you so much for the drivers and your support.
You just made my easter weekend!

Great . Happy easter then!

Dear Dogbert,

I got a question:

If i understood this and this articles correctly, WaveRT driver supposes to work on WASAPI interface. That shall lead to almost any windows audio processing not having effect on audio stream. So, by using your drivers, I was expecting to have Vista volume slider no effect. Lets say for Windows media player, I expected it to decode (if encoded at all) the file into pcm and then to output it straight onto SPDIF.

In reality, when I play AC3 or DTS files, it really does pass to SPDIF without Vista volume interfearance, but if I play WMA file - Vista volume is effective. This somehow doesnt seem pure "pass through".

Could you please clarify that?

Best regards.

In Windows 2k, XP and Vista, there's the so called "passthrough" mode which can be called from the WaveOut / DirectX interface - this enables dd/dts streams to be sent to the soundcard's driver and subsequently ot the spdif without any processing by the kmixer. All the common video player and their codecs use this, and it is limited to 48kHz streams. Also, the passthrough mode is based on a rather quick&dirty hack job than on a thorough design.

The so called "exclusive mode" of Vista is a feature of a new API called "WASAPI". Applications which use this mode can read and write directly into the sound driver's buffers without after-processing from the kmixer. This works for both WaveRT- and non-WaveRT-versions of the driver, but it has to be specifically supported by the application.

Afaik, WMP does not support it out of the box - it still uses WaveOut / DirectSound and it hence can't be bitperfect unless the "passthrough mode" is employed because the kmixer of Vista isn't bitperfect anymore.

I've recently written a small article on the subject: http://code.google.com/p/cmediadrivers/wiki/Bitperfect

All right, I got the point. In other words, to use WaveRT, application has to call for that. Apparently this is not the case for WMP (WMC) and generally speaking any other existing today application (with very few exclusions).

Questios remains: how to get bitperfect SPDIF output for other than DD or DTS content? It is clear that application "X" can be used for that. But, could there be a way to "enforce" it by your driver, be it even such "dirty pass throug" way?

Regards.

s/WaveRT/exclusive mode of WASAPI


The driver has no effect on whether the kmixer is bypassed or not. However, there is a DirectShow filter which can be used to force kernel streaming for all media: ReClock. It might be worth a try - the windows media player and windows media center both use the DirectShow API to build a filter graph in order to play the media, so ReClock might be set up in a way that it is always prioritized as output sound renderer. I haven't personally tested this though.

Dear Dogbert,
Thank you very much for your answers.
ReClock is outdated and messes alot with recoding, hence can't be bitperfect.
I was just thinking (as not programmer of cours):
- Wavert option of a driver is called by application;
- driver presents its capabilities to OS:
Now, what would happen if driver will say "I am ONLY capable of wavert and nothing else"?
Is it possible at all?
Will OS somehow still try to render all audio to such driver?

Regards

yeah, but it shows that a DirectShow filter can in fact utilize KS/WASAPI's exclusive mode and hence potentially make WMP/WMC bitperfect.


WaveRT is another flavour of the WDM - in essence, it is knitted around a somewhat different sound buffer handling than the regular WaveCyclic/WavePCI designs. This has nothing to do with bitperfect.
WASAPI is an application interface. The kernel audio mixer can be bypassed when an application uses its "exclusive mode".
The driver presents input and output pins in so called pin factories which can be instantiated by the OS. There is (almost) no differentiation between a pin getting instatiated by kmixer or by an application using WASAPI/KS.

Means, driver can absolutely not force aplications (OS) to bypass mixer

You don't plan, by chance, to develop such DirectShow "exclusive mode" filter?
It looks (for non-profesional) much simple comparing to what ususal filters do, in fact, instead of doing anything, this filter has to say "do nothing, go to exclusive" (if I got it right).
Extending your driver reach to PCM streams will be much appreciated by the comunity, I beliave.

Many thanks for all explanations.
Best regards.

the wikipedia article gives a rough description on how DirectShow works: http://en.wikipedia.org/wiki/Directshow
and nope, I'm not planning to develop such a filter - I'm currently packed with other stuff.

Any hope for other cmedia's chips support, 8788?

Regards

the 8788 is fundamentally different from the 8768/8738, so that's a no, too.

Thanks for the driver.

Been playing with it for a week with my Asus A7S333 motherboard. Haven't built a spdif RCA plug yet, so it's only analog playback for now. Couple of questions I like to ask.

1) the "enable pcm/dac" option works (i.e. if blank then no analog out). However if I blank the "enable spdif out" option --- there is no analog sound even if the "enable pcm/dac" option is on. Don't know if you notice that.

2) I plug my cd-rom's spdif out into the motherboard's spdif-in (I split a 4 pin soundcard cable into 2) and tried to record sound thru spdif-in --- but there is no sound. The CD-ROM has its own playback, volume buttons and headphone jacks on the front panel. I tried it with window's sound recorder and nero's soundtrax and wave editor. I tried it with every possible combination of your driver's control panel --- inverse,.... --- no sound.

I know it's 100 times easier and better to just rip the music cd thru IDE cable. Just curious if I can make the spdif-in works --- before I spend the time and money to make the spdif RCA plug.

Nope, I haven't noticed that - but I'll take a look at it when I've got some time.


yeah, the SPDIF-in recording is a bit buggy - sometimes, the recording won't start, and only a reboot can "fix" that.

I was wondering if it was somehow possible to send trackmarks over an optical output. If you copy a CD to a MD using a TOSLINK connection for example, the MD recorder knows when a track begins and ends even for gapless CDs. This is currently not possible if you are using a computer as source.

Try the reboot method, it didn't work.

Don't know if it's a voltage issue (0.5 vs. 5v) for spdif signal on the motherboard or a hardware issue for my cd-rom (it's a 2x cd burner) or whether I am actually doing it wrong.

How does one do a spdif-in recording of a music CD from a cd-rom correctly?

1) press the physical play button on the cd-rom or play it in some sort of windows media player software.
2) what software to record (window's sound recorder???)

All I get from pressing the physical playback button on my cd-rom and press record on the "windows sound recorder" is either 0 seconds, or 0.1 seconds or 0.2 seconds.