Re: Silent m4a AAC recordings
Re: Silent m4a AAC recordings
- Subject: Re: Silent m4a AAC recordings
- From: William Stewart <email@hidden>
- Date: Mon, 31 Oct 2005 11:53:14 -0800
There's also some comparisons between these two APIs in the latest SDK.
In the Simple Examples directory, there's a ConvertFile example. This
has two versions - they both "work the same" for the user, but show
you two different approaches to getting there.
The ExtAF path uses the ExtAF API - this does alot for you of course
using the AudioFile and AudioConverter (and AudioFormat) APIs
The other shows how to use both the AudioFile and AudioConverter APIs
directly. I've tested writing m4a's with AAC and this works fine
Bill
On 31/10/2005, at 10:12 AM, Dominic Feira wrote:
Okay,
I see the key difference between a correct recording and the ones
that I am making. The stsz atom in my recordings contains all
zeros. Now as far as I understand this information should be
coming fromt he AudioPacketDescriptions that I get from the audio
converter and then pass into the AudioFileWritePackets function.
I'm going to see if I can find the difference between the afrecord
example and my code. Thanks for your help.
Dominic Feira / Code Monkey / Ambrosia Software, Inc.
On Oct 31, 2005, at 12:31 PM, Olivier Destrebecq wrote:
Dominic,
<file removed>
Here you go. probably not much to here in the audio.
hope this help, also you can use the /Developer/Examples/
CoreAudio/Services/AudioFileTools/afrecord.cpp to figure things
out, that's what i used...
Olivier
http://otusweb.spymac.com/home/
On Oct 31, 2005, at 12:09 PM, Dominic Feira wrote:
Thanks for the response.
I have verified that AudioFileClose is being called and does not
return an error. Could you send a m4a file that you have created
to me? When I compare the file created via CA with one that I
create with QuickTime (i.e. the old method) the CA file seems to
be missing some atoms.
I would use ExtAudioFile, but Panther compatibility is a
requirement. Even though there isn't an AAC encoder on Pather, I
will be using CA for AIFF encoding as well.
Dominic Feira / Code Monkey / Ambrosia Software, Inc.
On Oct 29, 2005, at 11:21 AM, Olivier Destrebecq wrote:
I'm using extended file. And i found that i needed to close the
file before it would actually write to disk...
Maybe that is your problem too.
Olivier Destrebecq
http://otusweb.spymac.com/portfolio/
On Oct 28, 2005, at 4:52 PM, Dominic Feira wrote:
Hello.
I am currently trying to figure out how to record to an m4a
file. I am using 100% AudioFile routines, not the CAAudioFile
or ExtAudioFile.
So far I've managed to record only silence. Interestingly, the
recording is the correct length. The AudioConverter appears
to be working correctly. If I dump the output of the converter
I can watch the data. It drops to zero properly if I silence
the input source. So, that leads me to believe the problem is
on the AudioFile side of things.
If I switch the file format to AIFC and set the
audioconverter's output format to something appropriate a
valid (non-silent) recording is produced.
I have found references to this problem while searching through
the archives, but no solution. Has anybody ever figured this out?
Dominic Feira/ Code Monkey / Ambrosia Software, Inc.
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
40umich.edu
This email sent to email@hidden
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden
--
mailto:email@hidden
tel: +1 408 974 4056
________________________________________________________________________
__
"Much human ingenuity has gone into finding the ultimate Before.
The current state of knowledge can be summarized thus:
In the beginning, there was nothing, which exploded" - Terry Pratchett
________________________________________________________________________
__
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Coreaudio-api mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden