Author Topic: ASIO Output plugin behavior  (Read 725 times)

garson

  • Posts: 138
ASIO Output plugin behavior
« on: 28 May '16 - 15:35 »
I guess my questions are intended for Ian, but feel free to share opinion.

I've been using ASIO output plugin for years and never had issues with it. But recently I started to use digital (otpical) output on my soundcard. In order to activate it in XMPlay I figured out that I need to change it in Output->ASIO and to click on "..." box. My soundcard is 7.1 (and outputs 9 and 10 are left and right on digital output).

Here are my questions:
1) I noticed that when I choose L 1/2 I get stereo output (left and right) and when I choose R 1/2 I get just right channel. I tried this on my other computer with Asus Xonar soundcard and behavior is same. I don't see logic in this, L should be left channel and R should be right channel (and it is). Is this a bug or desired behavior?


2) Other thing I noticed is that I can't choose more than one option from the list. So if I want digital output I need to choose L 9/10, that way I don't have analog output from soundcard.
   For example, in MPC-HC with multichannel asio renderer (image below) I can choose channel mapping whatever I like. I can choose analog stereo output and digital in the same time. Also L is just left channel, R is just right channel.  It would be nice to have this in xmplay's asio plugin, for example to add tick mark in front of each channel.

Thanks.
 





saga

  • Posts: 2179
Re: ASIO Output plugin behavior
« Reply #1 on: 29 May '16 - 12:47 »
Quote
1) I noticed that when I choose L 1/2 I get stereo output (left and right) and when I choose R 1/2 I get just right channel. I tried this on my other computer with Asus Xonar soundcard and behavior is same. I don't see logic in this, L should be left channel and R should be right channel (and it is). Is this a bug or desired behavior?
The option selects the base channel, i.e. the first channel to which (the left channel's) audio is sent. The next channel in order then receives the data of the right channel. So in your example, if you pick R 1/2 as the base channel, then the right channel of the first stereo pair receives the left channel data, and the left channel of the second stereo pair receives the right channel data. Since you probably don't have anything connected to the second stereo pair, you only hear one channel playing.
ASIO has no notion of "channel groups", hence XMPlay cannot know which channels belong together, or which channel is a "left" or "right" channel.

garson

  • Posts: 138
Re: ASIO Output plugin behavior
« Reply #2 on: 29 May '16 - 15:49 »
Quote
1) I noticed that when I choose L 1/2 I get stereo output (left and right) and when I choose R 1/2 I get just right channel. I tried this on my other computer with Asus Xonar soundcard and behavior is same. I don't see logic in this, L should be left channel and R should be right channel (and it is). Is this a bug or desired behavior?
The option selects the base channel, i.e. the first channel to which (the left channel's) audio is sent. The next channel in order then receives the data of the right channel. So in your example, if you pick R 1/2 as the base channel, then the right channel of the first stereo pair receives the left channel data, and the left channel of the second stereo pair receives the right channel data. Since you probably don't have anything connected to the second stereo pair, you only hear one channel playing.
Ok, thanks for clarification, saga.
ASIO has no notion of "channel groups", hence XMPlay cannot know which channels belong together, or which channel is a "left" or "right" channel.
That is ok, I just would like option to map channels like in Multichannel Asio renderer so I can have sound on digital output as well. I believe that's "doable".