Re: Two AUHALs, one ring buffer, and one AU filter. But no sound.
Re: Two AUHALs, one ring buffer, and one AU filter. But no sound.
- Subject: Re: Two AUHALs, one ring buffer, and one AU filter. But no sound.
- From: Robert Grant <email@hidden>
- Date: Thu, 1 Jul 2004 17:27:13 -0400
Hi Chilton,
What you're trying to do is not impossible. You can pass the audio from
the input device (the iMic) through your buffer to the output device.
The syncing issue is that the two devices may be running at slightly
different actual sample rates - even though they're both set to 44.1
kHz (for example) - meaning that you're eventually going to get subtle
audio glitches.
It sounds like you need to build things bit by bit:
Get input working with your render proc
Then start putting it in the ring buffer.
Then start pulling from the buffer using the render callback from your
Output Unit.
Then insert your filter.
Trying to do it all in one go seems to be adding confusion...?
Best,
Robert.
On Jul 1, 2004, at 3:13 PM, Chilton Webb wrote:
Hi,
Back story: I'm trying to transmit audio through a USB mic, through an
AU filter, and out the default output. Thus far, it turns out you
can't connect the AUs all together (devices run in parallel, so data
doesn't get passed back and forth properly, or so I understand), and
you can't use a single block of memory (this crashes deep inside the
filter AU, no idea why). I'm trying the ring buffer theory now, where
I write to one part of a buffer and read from another, so the buffer
can be used by both input and output threads.
I've successfully created a ring buffer, and as far as I can tell from
the debugger, it's getting and setting data in the buffer. I'm looking
into that closer now, as it's still not producing any audio. But
during all of this, a few people have suggested that this is just
impossible, due to timing issues. Is that true? If not, is a ring
buffer the right way to do this?
Thank you,
-Chilton
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