Reading audio with Extended Audio File Services (ExtAudioFileRead)
- by Paperflyer
I am working on understanding Core Audio, or rather: Extended Audio File Services
Here, I want to use ExtAudioFileRead() to read some audio data from a file.
This works fine as long as I use one single huge buffer to store my audio data (that is, one AudioBuffer). As soon as I use more than one AudioBuffer, ExtAudioFileRead() returns the error code -50 ("error in parameter list"). As far as I can figure out, this means that one of the arguments of ExtAudioFileRead() is wrong. Probably the audioBufferList.
I can not use one huge buffer because then, dataByteSize would overflow its UInt32-integer range with huge files.
Here is the code to create the audioBufferList:
AudioBufferList *audioBufferList;
audioBufferList = malloc(sizeof(AudioBufferList) + (numBuffers-1)*sizeof(AudioBuffer));
audioBufferList->mNumberBuffers = numBuffers;
for (int bufferIdx = 0; bufferIdx<numBuffers; bufferIdx++ ) {
audioBufferList->mBuffers[bufferIdx].mNumberChannels = numChannels;
audioBufferList->mBuffers[bufferIdx].mDataByteSize = dataByteSize;
audioBufferList->mBuffers[bufferIdx].mData = malloc(dataByteSize);
}
UInt32 numFrames = fileLengthInFrames;
error = ExtAudioFileRead(extAudioFileRef,
&numFrames,
audioBufferList);
Do you know what I am doing wrong here?
