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Topic: peculiar behavior of f2k + WASAPI + different AVRs (Read 554 times) previous topic - next topic
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peculiar behavior of f2k + WASAPI + different AVRs

A friend of mine replaced his old Yamaha AVR with a new Anthem AVR.  I myself use a Denon AVR that's maybe 5 years old about the same vintage as his yamaha was.  We have identical foobar configurations , and in the case I'm about to discuss, we're playing identical files played on different laptops -- his runs Windows 8.1, mine runs Windows 10.  We are both set up for bit-perfect  output to our AVRs, using the default f2K components plus  SPDIFER 1.0, WASAPI 3.3 (push or event modes), and an HDMI connection from laptop to AVR. In this configuration  DTS and AC3  (Dolby Digital) files are *not* decoded before output.  They are sent as raw bitstreams for the AVR to decode.  This means that if there is any corruption of the bitstream, the AVR outputs white noise.

This setup works perfectly for me. E.g. my AVR lights up with 'DTS 96/24' when I play that kind of .dts file, and sound is normal surround.

However, he found initially that he could not play. dts (or .ac) files.  The output was noise.  I double checked that his foobar volume was at maximum, there was no DSP active, made sure the .dts and .ac3 boxes in SPDIFER were checked (they are, by default).  His Windows 'Sound' settings were identical to mine too (except his playback device was a different AVR model, of course; but as with mine, its Properties showed it was capable fo DTS decoding up to and including DTS-MA) IOW, everything was the same as my setup, which works.  Yet his still did not, for these files.  So I figured it's some weird issue with his Anthem AVR, right?  Or maybe Windows 8.1 vs Win 10? 

But, no, here's the peculiar part.  As a final test I tried VLC on my laptop, configuring it properly for bit perfect  (nondecoded) .dts output (in the Audio menu: output mode = Windows Multimedia Device, HDMI/SPDIF passthrough = Enabled, Device = AVR model*) .  Once again, it worked, my AVR lit up 'DTS 96/24' as before.  Then I set VLS up identically on his laptop.  *And it worked.*  His Anthem AVR lit up with the proper DTS 96/24 decoding logo, and the correct surround sound output.

So now I'm, stumped.  Why would VLC work, but foobar not work?
 
Btw, my fiddling with his laptop was by remote -- he lives several states away.  So could not do the other obvious test,, I.e., use his laptop with my AVR, and vice versa.


*NB, a few layers down in Audio settings in VLC, there's a setting for the Windows Multimedia Device  called 'Output back end', choices are 'Automatic', WASAPI, DirectX, and Disable.  I leave it on Automatic, and I presume , because the output is proper surround sound detection + DTS info display**, and not noise, that it's using WASAPI.  Maybe I should test this too?

**NB2 If by accident these laptops were actually decoding DTS to PCM before it was output to the AVR, the DTS info would not display.  The AVR displays would read something like 'Multi Channel PCM' instead. So I know we haven't made that mistake.