Re: [Jack-Devel] ALSA PCM substreams

On 12/03/2013 10:31 AM, Fred Gleason wrote:
>> Any idea where the whole `substream' concept is documented?  I'm still fuzzy on what it's intended to solve.
>
> For cases where an application needs to play multiple PCM streams simultaneously out of the same physical output (and doesn’t want to muck around with mixing them in software).  That said, I’ve only seen one card (outside of the high-end pro-audio domain) that actually has this capability.

Thanks!

>> Even if it's hardware mixing, I think it still makes sense for JACK to open them.
>
> I disagree.  It sounds like the caiaq driver is just getting this wrong.  If the two subs are producing output at two different physical ports, they should be implemented as separate PCMs.  I’d file a bug report.

I disagree about two PCM's.  What I want is _one_ PCM. :-)

Unfortunately... these drivers have been out for a while and making big 
changes like this likely break userspace.

-gabe

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