Has anyone been able to get 24bit output before I rush out and buy a cheap generic 8768 card (sweex 7.1)?
The driver might have failed to install - the x64 version of vista doesn't allow unsigned drivers, and since I'm not able to sign the drivers by myself or cash out ~500 usd to msft, you will need to disable this policy by pressing F8 each time you boot and selecting the relevant item in the menu.
I'm still tempted to try a 8768 card for 24bit output later next week...
Maybe we can also test it without a DAC? If we use a card with proven 24bit capabilities and feed the 8768 SPDIF output to the 24bit card's SPDIF input?
Hi again,I tried the Winamp Kernel-streaming plugin with your drivers,but I couldn't pick any output in the ks-settings, there was nothing to choose from.Any idea, what this could be about?
AFAIK the CMI8738 had a demo program on the CD that was able to play 24 bit wav files.If I'm correct, you might use it to reverse-engineer 24 bit spdif mode....
I've seem to run into some trouble with the drivers. After replacing an 8738 with an 8768 card using kernel stream output started failing (error opening device). I replaced the card with the previous 8738 but that didn't help. At the end I had to revert to the original Terratec Aureon 5.1 drivers which still worked. Is there a way for to troubleshoot what's happening? The debug log of the Winamp kernel streaming plugin only says that it can't create a render pin which doesn't help much either. Also Foobar and Reclock don't work with kernel output anymore so it doesn't seem to be application specific. Thanks!edit: and a happy 2007!
Certified driver!?I have a CMI 8738 sound card. Windows Vista (32bit) automatically installed a driver for this device. I'm a simple man, all I need is just the simple 2 channel speaker output and microphone input. I don't need SPDIF or other advanced features. But as you see in the screen capture, the maximum microphone input level is 0DB! I can't record my voice. What is wrong? Do you have the same problem or my sound card is out of order? This sound sound card works fine under Windows XP.
The WMP stream properties state that the samplerate of the 32kbit stream is 32khz, which is below the 8768 (and my DAC's) capabilities. Is it the chip automatically choosing the samplerate in this case?
I am wondering why I have to switch to 2 channel or earphone mode in driver configuration in order to activate the S/P-DIF with the original driver!? Are rear and center/subwoofer outputs and S/P-DIF using the same port within the microcontroller?
officially, the 24 bit modes are only supported by the 8768 chip.
For instance, 32 kHz can easily be upsampled to 96 kHz because the 'missing' two samples are simply filled by copying the original sample.
Two datasheets I have (CMI8738_4ch_spec.pdf v1.3 and cmi8738_6ch_datasheet.pdf V1.5) both claim 24 bit SPDIF in/out.
Proper sample rate conversion isn't that easy!The method you suggest would result in massive energy content for frequencys above 16kHz due to aliasing, which at higher volumes might even damage tweeters.Lineair interpolation would already be better, but going from 11.025 to 44.1, I would still hear ill effects of it. Proper resampling requires lots of calculations using FIR filters.
Ok, found a problem within 6-channel-mode (3/2+SW in AC3Filter).