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Author Topic: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC  (Read 2805 times)

michael123

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Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« on: February 19, 2018, 10:22:09 am »

I have around 30 albums in DSD128 rate, when playing these back, the only way to playback is to convert everything to PCM.  Or, to define two zones.

I described this issue few times.  It should discover what are capabilities of the DAC (i.e. what are PCM rates it handles natively, and what are DSD rates), and give out options - everything in the same screen - to define how to handle the signal. Similar to what we have today for PCM, but sadly it excludes the DSD.
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JimH

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #1 on: February 19, 2018, 10:57:33 am »

You could use Bitstreaming if the DAC can handle the format:

https://wiki.jriver.com/index.php/Audio_Connection_Type
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RD James

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #2 on: February 19, 2018, 11:13:59 am »

While I agree that it should be an option, you are better off converting everything to PCM anyway.
You can't perform DSP if you are bitstreaming DSD, which means losing things like the Volume Leveling feature that keeps playback volume consistent across all albums, the ability to use DSP like the room correction / convolution features (and more), and you have to trust that your DAC is doing a good job with playback.

For example: the DSD spec calls for playback to have a 6dB boost applied.
In my library, that would push 65% of the tracks into clipping if the DAC does not have additional internal headroom. My DAC has 3dB of headroom, which would still mean that 5% of the tracks would be pushed to clipping.
By default, Media Center does not apply that 6dB boost to DSD to PCM conversions, and if you have run audio analysis and use the Volume Leveling feature, it will prevent all clipping.

The DSD spec also calls for a soft low-pass filter at 50kHz, while that does nothing but allow considerable amounts of spurious noise to be sent to the amplifier.
Media Center's default filter cuts off at 24kHz instead, filtering out all of that junk ultrasonic noise, which should reduce distortion (you can also select 30kHz or 50kHz filters if desired).

You could use Bitstreaming if the DAC can handle the format:

https://wiki.jriver.com/index.php/Audio_Connection_Type
The issue is that bitstreaming in Media Center DSD is all-or-nothing.
My DAC will bitstream DSD64, but it results in me being unable to play DSD128 tracks.
Other DACs may handle up to DSD128 so DSD256 tracks will not play etc.
 
Roon's settings appear to use "up to DSD64/128/256" rather than "DSD Bitstreaming On/Off".
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Awesome Donkey

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #3 on: February 19, 2018, 11:25:01 am »

If there's a way to detect DSD128 or above, you *could* potentially create a new zone and use ZoneSwitch with it (e.g. turning off bitstreaming and doing a PCM conversion for DSD rates not supported by the DAC). I suppose you could create a DSD field and change it for 64/128/256/512/etc. and setup ZoneSwitch that way? Not sure as I don't have any DSD128 files to test this with.
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michael123

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #4 on: February 19, 2018, 11:37:27 am »

You could use Bitstreaming if the DAC can handle the format:

https://wiki.jriver.com/index.php/Audio_Connection_Type

Jim

The bitstreaming option is a binary in JRiver - that's either all or nothing.
We need to have it per specific rate - DSD64, DSD128, DSD256
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michael123

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #5 on: February 19, 2018, 11:40:03 am »

If there's a way to detect DSD128 or above, you *could* potentially create a new zone and use ZoneSwitch with it (e.g. turning off bitstreaming and doing a PCM conversion for DSD rates not supported by the DAC). I suppose you could create a DSD field and change it for 64/128/256/512/etc. and setup ZoneSwitch that way? Not sure as I don't have any DSD128 files to test this with.

Yes, we have zones. It is very inconvenient and disturbing. Quite frequently - especially if you have JRemote open on your tablet - results in playing simultaneously in two zones


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dtc

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #6 on: February 19, 2018, 12:49:22 pm »

MC's handling of multiple DSD sample rates could certainly be improved.

First, as noted, there are no separate settings for each DSD sample rate as there are for PCM sample rate.  MC has added the capability for playback and conversion for higher sample rate DSD, but the UI and user flexibility have, unfortunately, not been updated. This has been discussed in the past, but it does not seem to be a priority, unfortunately.

Second, conversion from DSD to PCM requires the user to know that the initial conversion  to PCM is done at 1/8th the origin DSD sample rate. It is then up to the user to specify the appropriate PCM to PCM conversion to get to the final desired rate.  That frequently trips up new users.

The simple solution would be to simply extend the sample rate table in Format Output  to include the DSD sample rates and allow the user to specify No Change or the final PCM sample rates.  Then, for example, the user could specify No Change for 1x and 2x DSD and, for example, 352 Khz for 4x and 8x DSD. Unfortunately, my understanding is that that might not be easy to do internally.  But it would certainly make the process a whole lot simpler for the user.

In addition, a user specified boost for DSD to PCM conversion would be nice. The Scarlet Book specifies that DSDs be mastered to -6 dB maximum, but since SACD players usually  went to +3 dB, some SACDs were mastered to -3 dB. It would be nice to have a variable boost to handle both situations.
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RD James

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #7 on: February 19, 2018, 02:00:35 pm »

If there's a way to detect DSD128 or above, you *could* potentially create a new zone and use ZoneSwitch with it (e.g. turning off bitstreaming and doing a PCM conversion for DSD rates not supported by the DAC). I suppose you could create a DSD field and change it for 64/128/256/512/etc. and setup ZoneSwitch that way? Not sure as I don't have any DSD128 files to test this with.
You could switch based on sample rate, but Zone Switch is a bad solution for this. Too many issues with Media Center result in "just use zone switch as a band-aid" as a 'solution'.
Zone Switch doesn't handle conflicts well, and prevents playlists from containing files in different formats if any of those are sent to another zone.

In addition, a user specified boost for DSD to PCM conversion would be nice. The Scarlet Book specifies that DSDs be mastered to -6 dB maximum, but since SACD players usually  went to +3 dB, some SACDs were mastered to -3 dB. It would be nice to have a variable boost to handle both situations.
Disabling the 6dB boost (which is the default) and using Volume Leveling or Peak Level Normalization after analyzing the tracks is a much better solution for this anyway, since that prevents there ever being clipping on playback.
 
I just realized that my numbers for affected tracks was wrong, as R128 requires an additional 1dB of headroom.
So it's actually 82% of my SACD library which could be pushed to clipping with a 6dB boost, and 15% with a 3dB boost (which Roon seems to have as an option).
When the number of affected tracks is so significant, I don't know if the option should even exist.
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michael123

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #8 on: February 20, 2018, 10:38:04 am »

@JimH What do you think?
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michael123

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #9 on: February 20, 2018, 11:02:16 am »

this is how it looks in Roon (two screenshots, but it is the same screen, just need to scroll down)

Note that Roon detects device capabilities automatically.
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tyler69

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #10 on: February 20, 2018, 12:27:59 pm »

I think something similar has been discussed already a few times: https://yabb.jriver.com/interact/index.php/topic,92777.msg639048.html#msg639048
and I understood that such changes would imply lots of effort with regard to coding.
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michael123

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #11 on: February 20, 2018, 12:30:34 pm »

I think something similar has been discussed already a few times: https://yabb.jriver.com/interact/index.php/topic,92777.msg639048.html#msg639048
and I understood that such changes would imply lots of effort with regard to coding.

I disagree that that's a lot of coding.
Anyway, we pay year over year for MC. That might be a nice feature for next version to justify an upgrade
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Hendrik

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #12 on: February 20, 2018, 12:31:50 pm »

I suppose being able to limit the maximum DSD sample rate for bitstreaming might be simple enough to add, similar to the Roon option. I'll put it on the list for a future change.
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michael123

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Re: Playing back DSD128 as PCM, but DSD64 bitstreamed to DAC
« Reply #13 on: February 20, 2018, 12:34:59 pm »

I suppose being able to limit the maximum DSD sample rate for bitstreaming might be simple enough to add, similar to the Roon option. I'll put it on the list for a future change.

Exactly!
Hallelujah :)
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