Re: How to get feed samples to QT in realtime? (like CoreAudio)
Re: How to get feed samples to QT in realtime? (like CoreAudio)
- Subject: Re: How to get feed samples to QT in realtime? (like CoreAudio)
- From: Kevin Boyce <email@hidden>
- Date: Mon, 14 Mar 2005 09:07:11 -0500
On Mar 14, 2005, at 2:09 AM, David M.Cotter wrote:
using CoreAudio, I can set up an output, set up an render callback,
then start the output. then the output "pulls" samples from the render
callback, and from there I have access to the samples. eg: I can use
FillComplexBuffer() and whatnot to get the decompressed data from an
MP3. lovely. at that point I can massage the data how I see fit
before sending it along to CoreAudio.( as long as I do it very very
fast)
is there any way to play QuickTime audio this way? eg: is there a
QuickTime AudioUnit?
Not so far as I know, but Kurt Revis has written a very nice QT audio
player class called QTSoundFilePlayer <http://www.snoize.com/>. I'm
using it, and it works very nicely (except that the "current time"
reporting; if you need accurate times let me know and I'll send you my
mods).
see, I was going with CoreAudio cuz it's new and modern, and because
Apple told me to. but it doesn't play AAC (why?), OGG, or LAME MP3's
(another why?). But QuickTime does.
Note that nothing other than iTunes is allowed to play protected AAC
(boo!), though you can certainly do unprotected AAC with
QTSoundFilePlayer.
Oddly, it doesn't work with Ogg either. I'm not sure why, since
iTunes, Amadeus, and QT Player all play Ogg files just fine (after
installing the Ogg component). But for some reason QTSoundFilePlayer
returns a "didn't fill buffer" code at the first call to
GetMediaSamples. Apparently the Ogg component is missing certain
operations. Or something.
However, all this should be doable with pure CoreAudio, I should think.
Maybe the AudioFile API has what you need and I should shut up, but I
haven't explored that yet.
-Kevin
--
Kevin Boyce
"Burn the land, and boil the sea; You can't take the sky from me."
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