WASAPI Exclusive Mode - for audio output without resampling

[cake0815]

hi


when i play a blu ray, dvd or another movie with 48.000 hz audio, vlc will resample it to 44.100 hz.
same with high res audio files (88,2k, 96k, 176k, 192k etc)
everything will be resampled to windows default settings (44.100 hz)

i tried this with 3.06 and 4.0 git.

(i made a posting here)
https://forum.videolan.org/viewtopic.php?f=14&t=148149


changing the default windows settings to 48.000 is also not ideal because then everything is resampled to 48.000.
i tried "Windows Multimedia Device Output" like Lotesdelere suggested but it didn't work since vlc has no exclusive wasapi output.

powerdvd, dvdfab media player and mpc be have an exclusive output mode
and can play movies and audio files 1:1 like they were encoded.


i am sure the vlc devs will agree, that audio quality is best 1:1 without resampling.
hope exclusive mode can be added to the wasapi plugin for 4.0 (or next 3.x).
it would greatly improve audio quality of vlc.



thx and greets

[Rémi Denis-Courmont]

VLC has supported S/PDIF pass-through for years, and now also HDMI pass-through. By definition, that's always exclusive, so there is separate setting for exclusive mode there.

[cake0815]

thx but it doesn't work.
vlc still plays everything with 44.100.
i have a usb dac which shows incoming frequencies.


i want this:
44.100 movies to be played with 44.100 hz
48.000 movies to be played with 48.000 hz

88,2k flac file played with 88,2k
96k flac file played with 96k
192k flac file played with 192k


i tried this already:
using Windows Multimedia Device Output in the audio preferences
enable S/PDIF / HDMI pass-through

i also tried disable resampler in vlc like Lotesdelere suggested ( this had the effect that vlc plays only 44,100 hz files everything else is silent).


what EXACTLY do i have to do that vlc will do that ?
(play all files 1:1 automatically with their frequency)
(like i said powerdvd, dvd fab media player and mpc be are doing this)

thx

[Boogie7910]

I have same issue. Help

[Rémi Denis-Courmont]

I think it should be obvious but you cannot do 1:1 through a DAC. And as a corrolary, S/PDIF and HDMI pass-through cannot work through a DAC.

I suppose that, in theory, if you turned off the OS mixer and resampler, and if the input audio codec was lossless, you could do 1:1 PCM through a digital output. But that seems very niche, and VLC does not support that.

[racebit]

I also have the same issue, which is critical to me.
Chord DACs (like Chord Mojo) are recommended to use bit perfect, so for all my CDs (ripped to WAV) I use foobar2000 with ASIO4ALL via optical TOSLINK.
However now I want bit perfect also for all my music videos and concerts.
So I was forced to switch to MPC BE (thank you cake0815 for pointing it), after using VLC exclusively for about 15 years.
Now my DAC reports 44.1K or 48K accordingly to what file I play, while with VLC my DAC always reports 96K which is the rate I have configured in Windows audio device.

With MPC BE (WASAPI mode), If we select only Exclusive mode it still does not work, we need to select also "Bit-exact", which seems is what is missing from VLC.
Looking forward to return to VLC once this is available.

[Rémi Denis-Courmont]

There's no such thing as "bit exact" mode in WASAPI. There are normal and exclusive modes, are all.

Just don't enable any audio filter, and leave speed and volume at exactly 100%, and VLC won't mess with the audio bits.

[racebit]

Thank you for your quick reply Rémi. Unfortunately I missed it until now, I though a post would automatically subscribe me to the thread, but it is not automatic.

I think the problem is not VLC messing with the audio bits. It is Windows that is messing (a lot) with the bits by re-sampling from the original sample rate to the Windows default sample rate (configured on the device windows profile). So windows is just making up all the values it sends to the DAC (via optical port) by guessing what values would be there if the sample rate was different.

That happens with MPC-BE as well: Even in WASAPI Exclusive Mode, Windows resamples audio from original sample rate to windows configured sample rate. But in MPC BE there is a check box "Bit-exact" and when I have that checked, Windows no longer resamples. I know because my DAC reports the sample rate it is receiving from the optical port.

With VLC (or with MPC-BE with Bit-exact off) no matter the file audio sample rate, the DAC always receives the windows sample rate. But with MPC-BE with Bit-exact on, the DAC always receives the same sample rate as the file.

So, I don't know what MPC-BE is doing there (on that "Bit-exact" option) to tell Windows to not resample, but it works fine. Unfortunately with VLC that does not work, which is critical to many including me.