WASAPI error 6 channel PCM

[ionutm80]

Hi guys,

I really need your help on a matter that has created me headaches.

I have read several forums posts regarding the best settings one could have for a HTPC but I couldn't find a solution to my issue so I decided to ask for help here since I have streamlined my issue with ReClock.

Hardware specs: Intel Core I5 3470S, GTX 750 TI, 8GB DDR3 1600 HyperX Fury, 120GB Intel SSD, USB 2.0 Asus Xonar U7 soundcard, Logitech Z906 speakers

So to summarize I have an Win 10 HTPC which I'm using to play my media collection with the following set-up:
- MPC-HC with external filters added: lav-source, lav-splitter, lav-video, lav-audio, ffdraw
- lav-video:Intel QuickSync decoding (leave all NVidia resources for madVR and SVP and anyway CUVID is not working for me in Win10), HW Adaptive deinterlacing ON Force Film Mode
- lav-audio: left unchecked everything in bitstreaming since I'm going to decode everything and sent 6 channel analog audio to my speakers
- madVR: chroma:BCB75AR, image up:Lanczos3AR, luma doubling NNEDI 32 neurons, image down: CRARLL, enable exclusive fulscreen exclusive mode, Smooth Motion OFF
- SVP level 4G

... and now comes the problem, since my TV (to which the HTPC is connected) only accepts 60Hz signal I thought that by using SVP to interpolate frames up to 60fps I would be on the safe side with the frame drops as shown by madVR OSD. Unfortunately it was not the case and the stats showed 1 frame repeat every 35-45 seconds. By the way the dispaly shown in madVR stats was 60.0022 Hz while composition rate was 60.000 Hz (movie 23,976 by source filter) so my NVidia card did not output a perfect 60Hz resolution ...

So I thought that I should try ReClock, with first attempt using DirectSound set for PCM (did I mention that I'm decoding everything with lav-audio and then sent 6 channel PCM from Xonar U7 to the Logitech speaker with 3 Stereo cables?) leading to perfect playback and O dropped frames in madVR (the stats however says that I'm dropping 1 frame every 5-7 hours ). Settings in Asus Xonar U7: 24bit, 96KHz, same in Win audio settings, in ReClock: Sampling Rate 96KHz, format:24 bit padded into 32.

Being very happy with my set-up I continued to read about best settings for HTPC and I have found that most people recommend WASAPI instead of DirectSound in ReClock for best audio experience (bypassing Win mixer and talking directly to the audio hardware). So I said why not and set WASAPI exclusive for PCM ... but no matter what settings I choose for sampling rate and format (48/96/same as source KHz, 16/24/24 padded into 32/ same as source) I get the same error message:

"the format is not supported by the hardware / driver, xx KHz, 6 channel PCM audio".

Could it be a driver issue of Xonar U7, of Win 10, me being too stupid to make the correct settings?

Thanks a lot in advance for any feedback

 

[el Filou]

Sorry if the question sounds dumb, but you did check that Exclusive Mode was enabled in the Xonar properties in Control Panel, right?

Regarding the difference between DirectSound and WASAPI, I think that in theory if in ReClock you select a fixed sampling rate and bit depth that is the same as the one set in Windows Control Panel (say, 24/96), set the device volume to 100% and disable all "enhancements", you should get the same result with DirectSound as with WASAPI as long as no other application is playing audio of course. Using WASAP Exclusive instead of DirectSound might possibly shave off some latency, though.

 

[ionutm80]

Hi and thanks for feedback,

Both settings regarding exclusive mode in audio control panel in Win 10 are checked, volume set to 100%, all enhancements disabled.
I have put 24bit/96KHz in both Win Audio Control Panel and Asus Xonar Settings and 24 bit padded into 32 / 96KHz in ReClock (should I put 24bit straight also in ReClock?). Another question, the Asus can go up to 192KHz, would it be worth to increase to that?
I have also tried with the drivers from Asus for Win 8.1 x64 the WHQL ones that are claimed to be the best so far and I get the same error.
But if you consider that there is no perceivable diff in quality between DS and WASAPI by setting the same bit/KHz everywhere then I think that I can live with DS.

 

[el Filou]

EDIT: OK sorry you can forget what I've written below, I've found DTS WAV files to test and it doesn't work.
Even when setting the exact same output format and number of speakers as the input, disabling all Enhancements, muting System Sounds and putting all volumes at 100%, DirectSound doesn't play bitperfect (on my system at least). That means Windows 10 is STILL messing with the audio even when it doesn't actually have any work to do on it. I'm actually a bit disappointed.
Note that it's not the same result as when choosing a different sample rate though: I hear silence instead of noise and from time to time my AVR actually detects the DTS inside the PCM stream but can't play it, so it means the processing it's doing is not as destructive as resampling/mixing. I guess it must be changing the volume slightly or something like that.

Well, sorry for getting your hopes up for nothing.
It's still weird why your sound card driver wouldn't accept WASAPI Exclusive from ReClock.
Could you try to play audio-only test samples in a player like Foobar2000 with WASAPI Exclusive to see if that works?

====== rubbish theory proved wrong below this line ======

What I'm saying is theory but I don't see what could change the audio in that specific case if all the parameters are the matching.
DirectSound was not bitperfect under XP most of the times because it was up to the sound card driver to decide the output format and how it dealt with input streams so you didn't really know what the sound card driver was going to do with it (for example later HDMI drivers for my Radeon on XP upsampled everything to the highest reported format which is 192 KHz which is not well supported by most AVRs' DSPs), but starting with Vista DirectSound is just a software wrapper really and the Windows Audio manages everything itself and outputs what format you configured, so if the output from ReClock matches exactly the output configured in Windows there shouldn't be any way for the Windows mixer to mess with the audio.

I wanted to test that theory on my HDMI output but unfortunately I can't easily find any DTS-in-WAV test sample anymore which is what I used to test bitperfectness (bitperfection? ) before. I'll keep looking when I have some time, if you know where to find one I could try to verify if that theory is correct.

I don't know much about 24-bit Vs. 24-bit padded to 32, I only know my sound cards accept one or the other but never both. 24 padded to 32 is converted back to 24 by the sound card when outputting anyway so it shouldn't matter.

 

[ionutm80]

Hi and thanks again for your reply,

I already start to think that is my audio card that is probably not accepting WASAPI exclusive.
I've tested ReClock with WASAPI exclusive on a laptop (Realtek HD Audio) and an Intel NUC D34010WYK and in both cases it worked. On the NUC I even had SVP puting the movie at 60Hz and ReClock still did its magic ...
Anyway I've found a post on jRiver saying: "[t]he only way to prevent a Creative Labs X-Fi based card or Asus Xonar card from resampling all incoming audio is to use ASIO and the driver that came with the card. With these cards, WASAPI exclusive will not change the master clock of the card." So in fact even if WASAPI would be accepted, the U7 would still be resampling the sound to whatever is checked in the sampling settings.
http://yabb.jriver.com/interact/index.php?topic=78291.0

 

[ionutm80]

Ok, after a lot of searching on the internet I have finally found the solution for my problem and it was fairly simple:
- in Win Sound set the speakers for 5.1 (I have completely neglected this ...)
- in ReClock I had to tick the "16 bit integer for 16 bit sources" (seems DTS-HD MA track in my Blu-Ray rips was 16 bit ... as shown by LAV Audio and ReClock), use built -in estimator for both media and dvd but leave assumed frame rate unknown (it will switch to automatic when playing a movie and correctly detect the 60Hz after SVP interpolation), set matching speaker config.
- LAV Audio, tick "Use Legacy 5.1 channel layout"
... and now I have silky smooth playing with WASAPI exclusive audio through my Asus Xonar U7 + Logitech Z906, 1 frame drop every 3-4hrs / even 1.2 days in madVR, 59.94Hz with SVP on my 60Hz screen and green ReClock icon doing its magic for the difference