ChannelMergerNode - not working for me like web audio api about labsound HOT 6 CLOSED

Thanks for the report. This is a great test.

from labsound.

thanks and I did find a silly thing - forgot to say musicClip->start(0);
But then the problems started (and more like what I'm seeing in my main application), here I reworked the test a bit
ac.connect(splitter, musicClipNode); gain->gain()->setValue(1.0f); ac.connect(gain, splitter, 0, 1); ac.connect(merger, splitter, 1, 0); // A ac.connect(merger, gain, 0, 0); // B ac.connect(context->device(), merger, 0, 0); musicClipNode->start(0);
If I comment out // A or // B I get some output. If I leave them both in, it crashes on the second one, something about an index / array out of bounds.
And of the output I get with just one, it sounds monophonic - equal in both ears. I was expecting it to be left front or right front.

from labsound.

for reference, I see that channel merger is supposed to generate a single output with as many channels as inputs, unless a different output channel count is specified in construction.

LabSound doesn't have that constructor variant, but it does have

    void setOutputChannelCount(int n) { m_desiredNumberOfOutputChannels = n; }

The constructor starts with a single channel output instead of numberOfInputs, so that's an error

ChannelMergerNode::ChannelMergerNode(AudioContext & ac, int numberOfInputs_)
    : AudioNode(ac, *desc())
    , m_desiredNumberOfOutputChannels(1

so that explains the mono output.
Subsequently, I see that the processing loop increments outputChannelIndex and does not test against the actual number outputChannels.

I think I understand the spec to say

let a = number of input channels
let b = number of output channels

if a == b copy 1:1
if a < b copy 1:1 up to a, then zero the other channels
if b < a copy 1:1 up to b, then ignore the other channels

if that matches what you think it should do, we can go with that

from labsound.

It matches, lets go with it - thanks for taking it on

from labsound.

Ok, pushed to top of tree. It's crash free, and the splitter & merger are now working to spec. I modified the sample to swap the left and right channels (so front left comes from the front right speaker, and vice versa) to make it obvious it's working.

from labsound.

This is in the 1.2 release. Please reopen the issue if you encounter problems!

from labsound.