Re: using AUMatrixMixer & format conversions
Re: using AUMatrixMixer & format conversions
- Subject: Re: using AUMatrixMixer & format conversions
- From: William Stewart <email@hidden>
- Date: Fri, 24 Oct 2008 11:31:48 -0700
Yep - we give you the blocks you need, but the notion of having a
general set of mixers for different sample rates is a fine one. And we
use this ourselves - primarily because a sample rate conversion is an
expensive operation, so doing as few of these as you need to is one
thing you should consider
On Oct 24, 2008, at 1:28 AM, Brian Willoughby wrote:
On Oct 23, 2008, at 19:32, William Stewart wrote:
No SRC - the matrix mixer assumes that all of its inputs and
outputs are at the same sample rate
On Oct 23, 2008, at 1:30 AM, John Clayton wrote:
but they all have to be of the same ASDB format, right? I saw
somewhere else on this list that the mixer is pretty much just
doing channel mapping, which implied that it wasn't performing
format conversion.
Yes, but No. ASBD format in that it is float 32, same sample rate.
No, in that num channels is a part of the ASBD, so that is as
different as you want.
Ultimately, you'd need to decide upon the sample rate that you are
going to mix at, and then add an AUConverter unit on each input
that doesn't conform to that sample rate. The AUConverter unit can
do any number of channels In to Out, but I would set it up to just
do an SRC (and keep the num channels the same)
I presume that if there are many of the same SRC conversions needed,
it might be better to have two mixers and one AUConverter, so that
similar sample rates are converted together. e.g. if the QuickTimes
movies are roughly half and half 44.1 kHz and 48 kHz, then you might
want a subgroup mixer for the 'other' rate which runs through an
AUConverter before being mixed with everything at the final rate.
Brian Willoughby
Sound Consulting
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