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Author Topic: ASIO input word width is always 32 bits?  (Read 1133 times)

gvl

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ASIO input word width is always 32 bits?
« on: April 19, 2018, 12:04:21 pm »

I'm routing a stream from an ASIO input through JRiver (File/Open Live/ASIO Line-in) and the input shows up as 32 bits in the audio path. The stream is most certainly not 32 bits as it is coming from Chromecast Audio via optical SPDIF, it is 16 bits. I then run it through the upsampler (SoX currently) and out to a 24-bit DAC, getting a warning message in the audio path that can't output full input bits to the device. Is this normal, or more importantly, is there a possibility this may somehow affect sound quality? I'm on version 23.
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RD James

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Re: ASIO input word width is always 32 bits?
« Reply #1 on: April 19, 2018, 01:26:46 pm »

I believe ASIO only works with 32-bit data. It shouldn't affect quality at all.
If you are outputting to a 24-bit DAC via ASIO, there is an option in the audio device settings which is "Device only uses most significant 24-bits" that tells Media Center to dither to 24-bits rather than 32-bits.
I'd also recommend setting Options > Audio > Advanced > Dither Mode to TPDF, if it is not already.
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gvl

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Re: ASIO input word width is always 32 bits?
« Reply #2 on: April 19, 2018, 01:45:02 pm »

I believe ASIO only works with 32-bit data. It shouldn't affect quality at all.
If you are outputting to a 24-bit DAC via ASIO, there is an option in the audio device settings which is "Device only uses most significant 24-bits" that tells Media Center to dither to 24-bits rather than 32-bits.
I'd also recommend setting Options > Audio > Advanced > Dither Mode to TPDF, if it is not already.

I'm outputting with Wasapi to 24 bits so dithering should be taking place even though it is a moot point if it has any audible effect at these levels. The concern was that the 16-bit data that's apparently being padded with 0-s to 32 bits is being send to SoX or JRiver's default resampler as true 32 bits and it may have some undesirable effects during processing.

Perhaps the same thing happens anyway when JRiver sees 16 bit data and it pads them with 0s before sending onto resampling or maybe it happens inside SoX to the same effect.
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Hendrik

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Re: ASIO input word width is always 32 bits?
« Reply #3 on: April 19, 2018, 01:46:40 pm »

Audio data in Media Center is always processed at full 64-bit for full accuracy, so a few extra 0's on the input data don't really change the quality at all. We would be adding those anyway!
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~ nevcairiel
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gvl

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Re: ASIO input word width is always 32 bits?
« Reply #4 on: April 19, 2018, 01:54:53 pm »

Audio data in Media Center is always processed at full 64-bit for full accuracy, so a few extra 0's on the input data don't really change the quality at all. We would be adding those anyway!

Got it, thanks for confirming!
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