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[TheLion]

I take it that the bitdepth setting in DSP Studio->Output Format is ignored when using ASIO. In that case the output bitdepth is set " because ASIO automatically delivers audio to the soundcard in the highest bitdepth that it supports."

I discussed that issue with the developers over at Prism Sound (my DAC/audio interface is the Orpheus). They strongly recommend 24bit as input, although 32bit input is also supported - in which case it gets downconverted to 24bit before it reaches the DACs. They tell the Orpheus is showing slightly better performance/less distortion when fed with 24bit data.

So in my case I want JRiver MC to always output at 24bit to my ASIO audio interface. How can I make sure it does so?

[Matt]

The ASIO driver picks the bitdepth.  Technically, we create buffers and the buffers have a ASIOSampleType.

I'm not aware of any way to configure this from our side.  If you enable the diagnostic popup in ASIO options, you can see the buffer type used when creating buffers.  You'll have to look the number up using the link above.

[TheLion]

I see, Matt. Diagnostics show "Buffer Type: 18 (480 samples)". I didn't find the information which output bitdepth is represented by that?

[Matt]

I see, Matt. Diagnostics show "Buffer Type: 18 (480 samples)". I didn't find the information which output bitdepth is represented by that?

That's ASIOSTInt32LSB, which is 32bit integers.

If they think 24bit input is better, they should update their ASIO driver.  Any good ASIO player (including Media Center) can deliver audio in any ASIO format they request.

[TheLion]

Matt,

I got the following statement from Prism Sound regarding this issue:

"Orpheus packs samples according to the 61883-6 FireWire audio specification. 24-bit samples are placed inside a 32-bit sample frame, bit-shifted to look like a 32-bit sample. Arguably, this is done for reasons of efficiency, but it must be done this way to comply with the standard. 
 

The ASIO driver reports this accurately. ASIOTInt32LSB type specifies that each sample is a 32-bit integer. However, Orpheus discards the bottom 8 bits, so only 24 bits of each sample is used."

So it is a "fake 32bit int" output that is used for my ASIO connection. Is this of any consequence regarding how you deal with this output format? I guess you downsample the internal 64bit fp stream to 32bit int in my case. Wouldn't it be better to downsample to 24bit int and place it into an 32bit int container just like the Prism Orpheus expects? Or is the result exactly the same?

Thank you!

[Alex B]

Down-sampling is actually quite incorrect term for the bit depth reduction process. In this case the top, aka most significant, 24 bits are not altered at all, no "samples" are analyzed and no recalculating or averaging is applied to these 24 bits. The bottom bits are simply removed from the data. It does not matter if the least significant 8 bits in the 32-bit container have zero values or if they contain something else when this data is discarded.

[pcstockton]

So in my case I want JRiver MC to always output at 24bit to my ASIO audio interface. How can I make sure it does so?

That kind of defeats the whole point of ASIO, which is to provide a bit-perfect signal to your soundcard.  Dont get caught up in bit counting.

-patrick

[jesseinsf]

I take it that the bitdepth setting in DSP Studio->Output Format is ignored when using ASIO. In that case the output bitdepth is set " because ASIO automatically delivers audio to the soundcard in the highest bitdepth that it supports."

I discussed that issue with the developers over at Prism Sound (my DAC/audio interface is the Orpheus). They strongly recommend 24bit as input, although 32bit input is also supported - in which case it gets downconverted to 24bit before it reaches the DACs. They tell the Orpheus is showing slightly better performance/less distortion when fed with 24bit data.

So in my case I want JRiver MC to always output at 24bit to my ASIO audio interface. How can I make sure it does so?

Does your ASIO driver have its own control panel separate from MC? If so, just change the bitdepth there to 24 bit. I have an Asus Xonar Essence STX card that has it's own control panel for ASIO that is separate from MC. If I set the bitrate in the Manufacturers ASIO control panel to 32 bit then MC sees the output as 32 bit (same goes if I set it to 24bit or 16 bit). MC will see the exact bitrate setting that I choose in the manufacturers ASIO control Panel.

[TheLion]

The control panel of my audio interface doesn't have a bitdepth option. Thanks