Re: Modifying afrecord sample file
Re: Modifying afrecord sample file
- Subject: Re: Modifying afrecord sample file
- From: Bruno Blondeau <email@hidden>
- Date: Mon, 17 May 2004 00:46:01 +0200
Well, the afconvert.cpp doesn't seem very easy to understand for a
CoreAudio beginner. It seems I have to dig into CAAudioFileConverter
and so on... I have tried to find similarities with afrecord but this
is far from easy for someone who doesn't have a clear understanding of
the audio formats and who is just looking at something to plug in his
applications (so as to play, record,...). The examples in this folder
are great, as they can be reused nearly directly (so as to play a file,
so as to convert a file...), but there lacks something which could be
reused to record files in a compressed form, and which could be reused
by people who don't need to have a complete understanding of CoreAudio.
I'm not writting a real audio app. I would like to have a simple API to
play/record files. QuickTime isn't easy, but still easier than
CoreAudio it seems... and I would like to avoid using QT if possible,
as it seems to be an unnecessary layer.
Is there any shorter sample code which would show how to handle these
compressed formats? Something which would be more like the afrecord
sample?
Bruno
On 14 mai 04, at 21:43, William Stewart wrote:
for any of these - have a look at the afconvert code in the same
project... it shows you how to set up a desc for AAC (and handle
setting things like desired bit rate, etc).
Bill
On 13/05/2004, at 2:50 PM, Bruno Blondeau wrote:
I'm trying to modify the afrecord.cpp sample file so as to use AAC
encoding instead of the PCM/AIFF one.
Could anyone explain me what to change?
const int kNumberBuffers = 3;
const unsigned kBufferSize = 0x8000;
CAAudioFile file;
CAAudioFileRecorder recorder(kNumberBuffers, kBufferSize);
CAStreamBasicDescription dataFormat;
dataFormat.mSampleRate = 44100.; // later get this from the hardware
dataFormat.mFormatID = kAudioFormatLinearPCM;
dataFormat.mFormatFlags = kAudioFormatFlagIsBigEndian |
kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked;
dataFormat.mFramesPerPacket = 1;
dataFormat.mChannelsPerFrame = 2;
dataFormat.mBitsPerChannel = 16;
dataFormat.mBytesPerPacket = dataFormat.mBytesPerFrame = 4;
file.PrepareNew(dataFormat, 0.);
file.Create(recordFileName, kAudioFileAIFFType);
recorder.SetFile(file.GetAudioFileID());
Record(recorder);
Also, I've heard MP3 encoding isn't available. Is this still true?
What about QuickTime encoders? (Qualcomm, QDesign...)
Would it be possible to modify afrecord to use them and generate a
quicktime readable file? (there doesn't seem to be a kAudioFile******
for these formats)
-- Bruno
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