Re: MTCoreAudio, CAAudioFileWriter and conversion
Re: MTCoreAudio, CAAudioFileWriter and conversion
- Subject: Re: MTCoreAudio, CAAudioFileWriter and conversion
- From: William Stewart <email@hidden>
- Date: Tue, 11 Oct 2005 12:55:07 -0700
There are some simple examples in the latest release of the CA SDK.
One of these is called ConvertFile, and this uses the
ExtendedAudioFile API directly to write a file. This is, as Doug
described previously, asynchronous, so safe to call from any thread.
If you are just targeting 10.4 or better, then I would use that API
directly - its very simple (as you can see from that code) and clear
Bill
On 11/10/2005, at 9:34 AM, Michael Thornburgh wrote:
if you're using an MTAudioBuffer as i described earlier, then on
the read side feeding your audioFileWriter, the buffer is probably
blocked waiting for more data. i wouldn't be surprised then if the
audioFileWriter->Stop() can't actually do anything.
if audioFileWriter->Stop() is synchronous (that is, it doesn't
return until writing has completed and the file is closed), simply
reversing the order of these two operations should fix that
problem. that is:
audioFileWriter->Stop();
[[self recordingDevice] deviceStop];
if audioFileWriter->Stop() is not synchronous, then you will need
to somehow otherwise synchronize the actual stopping/closing of
your output file before doing -deviceStop, so there will still be
audio samples filling the buffer and keeping it from blocking.
-mike
On Oct 11, 2005, at 6:17 AM, Olivier Destrebecq wrote:
In my stop recording message i do the following:
// stop recording
[[self recordingDevice] deviceStop];
audioFileWriter->Stop();
I assume this is enough...
thanks
Olivier Destrebecq
http://otusweb.spymac.com/portfolio/
On Oct 11, 2005, at 2:09 AM, Jens Alfke wrote:
On 10 Oct '05, at 5:45 PM, Olivier Destrebecq wrote:
My code run, the file gets created, but then when i try to open
it with Quicktime, it tells me it cannot open it. Also if i add
code to try to convert to AAC before writing to disk i get an
error. I include the code in this email for your review.
The code you showed us doesn't ever close the output file. Are
you just killing the process after recording enough audio? As far
as I can tell, an AIFF file has to be explicitly closed after
writing the data, so that the writer can either add a necessary
trailer or update the header. Otherwise the file isn't openable.
email@hidden wrote:
My question would be: in minimal lines of code, how would one
save a sampled sound buffer (which MTCoreAudio provides) into an
AIFF file.
It's really easy using CAAudioFile. You call CreateNew() on the
file object, repeatedly call its Write() method passing in a
buffer list, then call Close().
--Jens
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