Re: Four channel output with ChannelMergerNode

On Sat, Apr 27, 2013 at 7:54 AM, Michael Barton
<michael.barton10@gmail.com>wrote:

> Hi all,
>
> I've been trying to get a DJ app style 4 channel output (1 stereo main, 1
> stereo cue) test working in Chrome Canary. I get audio out for the main but
> nothing for the cue channel..
>
> Code I'm trying out:
>
> ctx = new webkitAudioContext();
> ctx.destination.channelCount = 4;
> merger = ctx.createChannelMerger(2);
> merger.channelCount = 4;
> merger.channelCountMode = "explicit";
> merger.channelInterpretation = "discrete";
>

You want those attributes to be set on the ctx.destination and not the
merger, otherwise each input of the merger gets upmixed to 4 channels, and
since you have two inputs each with four channels it will output 8 channels.

For the merger you might want to set the attributes as: 2, "explicit",
"stereo"


> merger.connect(ctx.destination);
>  main = ctx.createGainNode();
> main.connect(merger, 0, 0);
>
> cue = ctx.createGainNode();
> cue.connect(merger, 0, 1);
>
> I've checked the hardware using a couple of other programs and that's
> working so I don't think the sound-card itself is broken.
>
> Any suggestions on how to debug this would be greatly appreciated.
>
> Thanks,
>
> Michael
>