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Author Topic: Kernel Streaming and 32-bit float output [HELP NEEDED]  (Read 4924 times)

Matt

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Kernel Streaming and 32-bit float output [HELP NEEDED]
« on: May 13, 2010, 05:22:06 pm »

32-bit float output with Kernel Streaming is causing us some grief.

There are two ways to report an audio format, let's call them "new" and "old".  We try to open Kernel Streaming with the new format first, and then try the old format if that didn't work.

The issue is that two soundcards I have accept 32-bit float in the new format, but then treat it like 32-bit int.  The sound is terrible.

Could anyone that wants to help set their DSP Studio to 32-bit output and try Kernel Streaming playback.  Does it fail to start, play correctly, or play distorted?  What is your hardware?

We're trying to figure out what (if any option) we need in the program to handle this.  Thanks for any help.
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Matt Ashland, JRiver Media Center

Matt

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Re: Kernel Streaming and 32-bit float output [HELP NEEDED]
« Reply #1 on: May 14, 2010, 07:27:45 am »

bump
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Matt Ashland, JRiver Media Center

Alex B

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Re: Kernel Streaming and 32-bit float output [HELP NEEDED]
« Reply #2 on: May 14, 2010, 10:02:50 am »

I guess 32-bit sound devices are rare. Mine can barely handle 24-bit.

In general, isn't 32-bit float only useful with DSP and pro audio editors as an internal format. Isn't a DAC always finally using integer values when it adjusts the output voltage?
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Matt

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Re: Kernel Streaming and 32-bit float output [HELP NEEDED]
« Reply #3 on: May 14, 2010, 10:18:55 am »

I'm not suggesting using 32-bit output always.  We're just trying to make it so the program does something good if you do use 32-bit output with Kernel Streaming.  A failure to open with a suggestion to use 24-bit would be fine.

But my cards are opening but handling the data incorrectly.  I'm hoping others will try the same to see if the problem is the same with all hardware.

Thanks for any help.
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Matt Ashland, JRiver Media Center

Alex B

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Re: Kernel Streaming and 32-bit float output [HELP NEEDED]
« Reply #4 on: May 14, 2010, 11:16:41 am »

I see. I just tought that maybe you could output 32-bit int if that works with those cards.

When I set the format in DSP Studio to 32-bit and output to Kernel Streaming MC doesn't show an error message and the audio signal is badly distorded - completely unusable. The card is Terratec DMX 6Fire 24/96.

Surprisingly Terratec's ASIO driver can handle MC's 32-bit setting just fine. Apparently it converts the signal automatically.

WASAPI exclusive doesn't work with 32-bit. MC correctly shows the "playback could not be started" message.

The OS is 32-bit Windows 7.
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mojave

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Re: Kernel Streaming and 32-bit float output [HELP NEEDED]
« Reply #5 on: May 14, 2010, 04:11:17 pm »

It will play, but I get static and distortion with kernel streaming and 32 bit with a Creative X-Fi Elite Pro.
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Matt

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Re: Kernel Streaming and 32-bit float output [HELP NEEDED]
« Reply #6 on: May 17, 2010, 10:50:37 am »

This was our solution, in build 43:
Changed: Disabled 32-bit floating point output support for Kernel Streaming -- most (all?) cards claim to support it than treat the data as 32-bit integers so the sound is heavily distorted.

If there's ever a card / driver with legitimate 32-bit floating point support in Kernel Streaming, we'll revisit this.

Note that these same cards know to reject 32-bit floating point data when using WASAPI.

And with ASIO, the card specifies the delivery bit-depth (usually 24-bit integer).
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Matt Ashland, JRiver Media Center
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