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Author Topic: MC22 - DSD over PCM (DoP) issues  (Read 7206 times)

cl_rwong

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MC22 - DSD over PCM (DoP) issues
« on: January 25, 2017, 09:21:34 am »

I am new to the software (trialling this for development purposes), using version MC22.0.54 (just updated to 22.0.59) with an Amanero COMBO384 USB to I2S DSD Converter module.
Analyzing the output of the Amanero initially using a scope and test equipment (AP2700), but will be applying to DAC at later date.

I am attempting to output DoP (x1) by using MC22 to convert either an MP3 or .DSF on the fly, however the output is not as I would expect (expecting a I2S format playing at 176.4kHz or 192kHz for the given DSD64 file). I appear to see native DSD on the output of the Amanero module. On occasions when I have managed to get a 176.4kHz I2S output having played a .DSF file, it appears that this has been a cobversion to 176.4kHz PCM (output decoded as standard PCM and it sounds normal).

Is this option available during the trial period (still have about 15 days of the trial period) or is it only available on the paid for version.

I have installed various ASIO drivers (foo_dsd_asio, COMBO384_ASIO, Amanero USB Driver (WASPI)).
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Matt

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #1 on: January 25, 2017, 10:33:08 am »

If you play using Options > Audio > Bitstreaming > DSD, then the files will get delivered in their native format if they're DSD.

It's a little strange, but ASIO uses a native DSD format.  If your ASIO driver isn't supporting that nicely, switch to WASAPI and we'll deliver DoP.

You can convert all your files to DSD in DSP Studio > Output Format > Output Encoding.
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Matt Ashland, JRiver Media Center

JohnT

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #2 on: January 25, 2017, 10:55:12 am »

Just to clarify the settings Matt was talking about...

If you play using Options > Audio > Bitstreaming > DSD, then the files will get delivered in their native format if they're DSD.
It's a little strange, but ASIO uses a native DSD format.  If your ASIO driver isn't supporting that nicely, switch to WASAPI and we'll deliver DoP.



Alternatively, leave the Bitstreaming option at None above and use our DSP Studio to convert ALL files to DSD in DoP format:

Quote
You can convert all your files to DSD in DOP format using DSP Studio > Output Format > Output Encoding.

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John Thompson, JRiver Media Center

cl_rwong

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #3 on: January 25, 2017, 11:54:15 am »

Matt/JohnT,

Thanks for the responses.

I have followed JohnT's pictures, and configured:
Audio Device -> Digital Output (Amanero Technologies USB Driver 1.0.57 [WASAPI]
DSP Studio -> Output Encoding -> DSD in DoP
Bitstreaming -> none

Whether I play an .mp3 or a .dsf file, what I see on the output of the Amanero module appears to be native DSD, and not 176.4kHz PCM encoded DSD (also tried the alternative method suggested by JohnT).

However, just can't get the DoP to work (on the fly).

I have also tried
Audio Device to a Combo384 ASIO1.03
    Device Settings with DSD Stream in DoP format checked
DSP Studio -> Output Encoding -> none
Bitstreaming -> None

I see a PCM stream at 352.8kHz (double what I expect when playing a .dsf file that should be DSD64), and the audio sounds normal as if it has just been up-sampled to 384kHz and not encoded in DSD.

It might be the drivers I have that are the issue
Digital Output (Amanero Technologies USB Driver 1.0.57) [WASAPI]

the other I have are:
Combo384_ASIO1.03 [ASIO]
foo_dsd_asio [ASIO]
ifi (by AMR) HD USB Audio [ASIO]

Or should I try MC21 (currently using using MC22.0.59)
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Matt

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #4 on: January 25, 2017, 12:22:02 pm »

I think you need to enable bitstreaming to get DoP working.  At least give it a try.
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Matt Ashland, JRiver Media Center

cl_rwong

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #5 on: January 26, 2017, 12:45:23 pm »

Hi Matt,

enabled the bitstreaming as well, therefore had

Audio Device -> Digital Output (Amanero Technologies USB Driver 1.0.57 [WASAPI]
DSP Studio -> Output Encoding -> DSD in DoP
Bitstreaming -> yes (DSD)

Output of Amanero still looks like Native DSD and not 176kHz PCM
When I probe the DSD flag from the Amanero card, this is indicating DSD.

Do you know where I can get a wav/mp3 encoded in DoP format to confirm that the Amanero card can support DoP (assume it should interpret this as 176kHz PCM).
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dtc

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #6 on: January 26, 2017, 02:00:56 pm »

First time I have seen this card, but I looked at the description and according to the manual on your device, it sounds like header 7 is set on if it is receiving DoP. Repeating FA05 MSBs are the signal it sees as DoP and sets the signal accordingly. Is that what you are using to determine if it is DSD or not?

Header 7
DSD ON
Out
This line is “1” when a DSD stream is detected. ( FA05 in the PCM
envelope MSB )
LVCMOS 3.3V
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cl_rwong

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #7 on: January 27, 2017, 11:13:34 am »

Hi dtc,

It is also the first time I am using this board. I am evaluating it for development work (this is the first of three modules I am trying).

Yes, I am scoping pin 7 on the header and when I send a standard PCM file, the signal is low, and when I configure DoP via DSP studio, the DSD_ON signal is asserted.

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dtc

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #8 on: January 27, 2017, 12:42:53 pm »

That sounds like for a  DSD file MC is sending a DoP signal and the board is identifying it as DoP. Seems like it is working as it should.
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cl_rwong

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #9 on: February 07, 2017, 10:06:09 am »

Hi dtc,

I would have thought the DoP format would be 'identified' as a standard 176.4kHz pcm file, not as a DSD native format, and it would be then a configuration of the receiver to 'decode' the received data as DSD.

However, it could potentially be an issue in how the driver has been implemented for the Amanero brd.

When the DSD_ON signal is asserted, it automatically converts the output to DSD native, whereas what may actually be required is a 2nd indicator to help differentiate between Native DSD and DoP. The Amanero brd has a Flag for DSD64/DSD128, but not DoP.

I have managed to get my hands on some DoP files, and these (after disabling all formatting and bit-streaming) appear to work as I would expect. The output looks like a standard 176.4kHz pcm format (DSD_ON = low), and when I attempt to playback the out decoded as PCM, i get the 'very' noisy/hissy and attenuated (-55dB) version of the expected output (a 1kHz tone).
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dtc

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #10 on: February 07, 2017, 06:12:03 pm »



The Amanero brd has a Flag for DSD64/DSD128, but not DoP.


Again, I have no experience with that board, but here are some thoughts.

I think that is backward. From what I read, Header 7 is set when DoP is detected. The board  needs  to differentiate between PCM and DoP and it seems it does so by looking for the FA05 MSBs and sets 7 accordingly. 

I am not an Apple guy, but since I believe the board works with usb from an Apple computer, I do not think the DoP determination is made on the PC/MAC side, since there is no special driver for Apple. As far as I know, IOS just thinks it is sending a PDM stream. That means the DoP determination is made on the board, which does not explain why your DoP files are not detected as  DoP. There is an old form of DoP which uses a different MSB value. Is is possible your DoP files are using the old format? Can you you look at them and see if they have FA05 in the MSB?

Again, no real experience here, just trying to understand what is going on.

FWI, Vinyl Studio can write out DoP files. I have not tried them, but it has that capability. It is $29 and has a free trial.

Edit - I am assuming it works with Apple. Documentation says no drivers available.

Edit - Found references that indicate that it is supported natively by IOS up to DSD 128, which means DoP. And there are no IOS drivers. So, I think my above discussion stands.
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cl_rwong

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #11 on: February 09, 2017, 09:03:36 am »

Hi dtc,

There might have been some misunderstanding somewhere in the message trail.

A summary of what I have been trying to do/done:
with default settings (DSP studio output format = none, Bitstreaming - yes (DSD))
Play a .dsf file - I observe Native DSD on the output of the Amanero module as expected
   DSD_ON is asserted
Play a .mp3/.wav file - I observe I2S (PCM) on the output of the Amanero module as expected
   DSD_ON is not asserted

with DSP studio output format = DoP, Bitstreaming - yes (DSD) or None)
Play a .dsf file - I observe Native DSD on the output of the Amanero module
   DSD_ON is asserted
Play a .mp3/.wav file - I observe Native DSD on the output of the Amanero module
   DSD_ON is asserted

This could be where I have a misunderstanding of what I expect to see, as I am expecting MC to convert the .dsf file and package this in DoP, therefore what I should see is on the output of the Amanero is I2S (PCM) at 176.4kHz (or 352.8kHz for DSD128).
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dtc

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #12 on: February 09, 2017, 11:04:15 am »

Here is my understanding, although it is based on the very minimal documentation on this board. I may be completely wrong.

I think the confusion is what the board uses for its inputs and its output. My conjecture is that it only accepts PCM and DoP and does not accept native DSD.  If the board sees a DoP file, it sets DSD_ON to high and then converts the signal to native DSD for output. It does not output DoP. That would explain why you never see DoP on output.

If the Output Formating option in MC  is set to output DoP, then MC is sending DoP and the board is seeing the DoP indicator (32 FA05 MSBs) and it then converts that to native DSD for output.

If you are using WASAPI and the board sees DSD then it must be in DoP format. WASAPI does not work native DSD.

If you have a correctly formatted DoP file, if MC outputs it exactly, then the board should detect the FA05 MSBs, set the DSD_ON flag and covert it to native DSD for output.  If it does not, I suspect the DoP file is not correctly formatted. Older DoP files used a different header - not FA05.

If I am correct in the above, then MC is performing as expected.
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cl_rwong

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #13 on: February 10, 2017, 12:45:39 pm »

H dtc,

That was a worry I had that the Amanero brd was automatically converting to DSD (and you have mentioned one of the issues I have found with the module in that documentation for the module is a bit lacking).

however, I would like to believe that the Amanero can received Native DSD, as configuring DSP Studio to output DSD does result in the Amanero model transmitting Native DSD.

I can try another module (XMOS based), which hopefully works as expected.

I am still trying to get some properly formatted .wav files. I believed I had some from colleagues, but need to confirm.
I will still be trying to get this working over the next few weeks.

Thanks for the assistance and hopefully I get some success at some point.
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dtc

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Re: MC22 - DSD over PCM (DoP) issues
« Reply #14 on: February 10, 2017, 05:54:58 pm »

If the board is receiving native DSD, then you must be using ASIO for that. WASAPI does not send native DSD.

I created a DoP file from a 2X DSD using Vinyl Studio. It created a 352 KHz DoP file and I played that using MC 22. It played fine and my DAC recognized it as DSD. So that process works.
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