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[Matt]

DoP is the emerging standard for bitstreaming DSD to a DAC.  JRiver was part of the formation of DoP.

When we first added DoP support in MC17, it was only allowed with the 'WASAPI - Event Style' output mode.

I was resistant to adding support for DoP to ASIO output because the ASIO specification defines its own way to handle DSD with ASIO v2.2.  However, several DAC makers requested we allow DoP also with ASIO.  I think this makes their lives easier because they can add DoP support to the firmware and don't need driver updates.

So with 18.0.175, JRiver adds the ability to use DoP with ASIO.

This method is required for Lynx hardware among others.  Also, with some other hardware DoP will have less noise (a click) when entering and leaving DSD mode than with the native ASIO v2.2 method.  So even if your DAC works with the ASIO method, you might try DoP to see if it works better.

Part of what made this change possible was the improved audio bitdepth system in MC18.

Another important change to DoP bitstreaming is that now DoP markers are laid down at the end of the chain instead of the beginning.  This is mostly an internal detail, but the new system makes it (basically) impossible for a DAC to fall out of DoP mode when we're playing to it, even in the rare event of a data shortfall.

[AndyU]

I have found a slight issue with DoP in MC 18.0.183 which maybe relates to these changes - see this post.

[Matt]

MC 18.0.191 also adds DoP support when using WASAPI without event style (required by some hardware), and also when using Kernel Streaming.

In other words, DoP now works on all hardware direct outputs:
WASAPI (either mode)
ASIO
Kernel Streaming

[6233638]

I was wondering if you had any suggestions about sending DoP to my new DAC, as I'm just used to setting up WASAPI for PCM via HDMI.

When I first got it, I thought it was silent when switching between DSD and PCM, but it seems that it is only silent some of the time.
Sometimes it's perfectly silent when starting or stopping DSD playback, other times it makes a click when starting, when stopping, or both.

Kernel Streaming clicks every time, and ASIO clicks maybe 50-75% of the time.

WASAPI seems to be less likely to click (maybe 25% of the time) as long as the Play a little silence on DoP stop option is enabled. Otherwise it seems to happen about as often as ASIO.
For some reason, this option also seems to help with removing the click as the start of playback, not just the end.
And even with that option enabled, sometimes it will click as soon as I press the stop button, before it has finished playing silence. (I assume - because the stop button is still in the "active" state)


I'm also a bit unsure about setting ASIO buffers. There are the buffer settings inside Media Center, which default to 500ms. (which seems huge)
There's also the Use large hardware buffers option, which doesn't appear to do anything here, and I can't find any information about what it's supposed to do on the Wiki.
In the ASIO driver panel, I also have options for USB Streaming Mode, and ASIO Buffer Size.

It seems that as long as I set the ASIO Buffer Size (from 64 to 8192 samples) to the minimum setting recommended for the current USB Streaming Mode (from "minimum latency" to "extra safe") in the driver, it doesn't make a difference whether I set Media Center's buffer to 5 seconds or 0.02 seconds. (20ms)

Because it doesn't seem to be consistent, I am unclear on whether this buffer size is impacting the frequency of clicks when starting or stopping DoP.

And as long as I have Streaming Mode set to "Safe" or "Extra Safe" (which require a minimum of 4096/8192 sample buffers for 192kHz, respectively) CPU load doesn't seem to impact playback at all. (for example analyzing 4 multichannel DSD tracks at the same time, which causes my mouse cursor to start skipping around)

Are there any recommendations for this, or is it just "figure out what works" ?

[Matt]

There's a little discussion of buffer sizes here:
http://yabb.jriver.com/interact/index.php?topic=75191.msg509675#msg509675

The 'Use large hardware buffer' simply tries to set the hardware buffer size (the number you're describing that's normally like 1024, 2048, etc.).  Some hardware allows the player to set this buffer size, but other hardware ignores it when we set it.  Normally a large hardware buffer is good, since a small difference in latency is not relevant for playback (unless you're doing loopback).

Someday I hope to write a wiki to detail this all a bit better.

[6233638]

Thanks. I just wasn't sure if I should be setting the Media Center buffer to match or exceed the ASIO buffer (i.e. above 185ms) or since the ASIO buffer is set to 8192 samples externally, if there was any reason to keep the Media Center buffer above 20ms.
I guess the "Use large hardware buffer" setting isn't doing anything here, because high sample rate material is still completely unplayable if I reduce the buffer to 64 samples in the driver for example. (if Media Center had control, I assume it would be increased)

It seems that the noise I'm getting with DoP playback over ASIO is (mostly) related to my track change settings rather than the buffers though. (which seems to be a bug)