Apple

On Nov 8, 2011, at 3:13 PM, kamaldeep tumkur wrote:

Try with:
asbd.mFormatFlags = kAudioFormatFlagIsBigEndian | kAudioFormatFlagIsSignedInteger;

It's usually the ASBD with these kind of things, in my short time with CoreAudio.

On Tue, Nov 8, 2011 at 8:53 AM, Jon August <email@hidden> wrote:

Hi,

Just joined this list and can't find a way to search archives, so I apologize if this is a common question.

I'm working through some example code in Core Audio and I'm getting kAudioFormatUnsupportedDataFormatError when I try to write an AIFF file or MP3 file. Everything works if I use CAF. Am I missing a framework? Code below.

Thanks,
-Jon

//
// main.m
// CAToneFileGenerator

#import <Foundation/Foundation.h>
#import <AudioToolbox/AudioToolbox.h>

#define SAMPLE_RATE 44100
// 1
#define DURATION 5.0
// 2
#define FILENAME_FORMAT @"%0.3f-square.aif"

// 3

int main (int argc, const char * argv[])
{
@autoreleasepool {

if (argc < 2) {
printf ("Usage: CAToneFileGenerator n\n(where n is tone in Hz)");

return -1;
}
  double hz = atof(argv[1]);
assert (hz > 0);
NSLog (@"generating %f hz tone", hz);
NSString *fileName = [NSString stringWithFormat:FILENAME_FORMAT, hz];

NSString *filePath = [[[NSFileManager defaultManager]
   currentDirectoryPath]
stringByAppendingPathComponent: fileName];
NSURL *fileURL = [NSURL fileURLWithPath: filePath];


AudioStreamBasicDescription asbd;
memset(&asbd, 0, sizeof(asbd));

asbd.mSampleRate = SAMPLE_RATE;
asbd.mFormatID = kAudioFormatLinearPCM;

asbd.mFormatFlags = kAudioFormatFlagIsBigEndian;
asbd.mBitsPerChannel = 16;

asbd.mChannelsPerFrame = 1;
asbd.mFramesPerPacket = 1;

asbd.mBytesPerFrame = 2;
asbd.mBytesPerPacket = 2;

AudioFileID audioFile;
OSStatus audioErr = noErr;

// ## FAILS HERE ##

audioErr = AudioFileCreateWithURL((CFURLRef)fileURL, kAudioFileAIFFType, &asbd, kAudioFileFlags_EraseFile, &audioFile);

// ## FAILS HERE ##

assert(audioErr == noErr);


// Start writing samples

long maxSampleCount = SAMPLE_RATE * DURATION;
long sampleCount = 0;

UInt32 bytesToWrite = 2;
double wavelengthInSamples = SAMPLE_RATE / hz;

while (sampleCount < maxSampleCount) {

for (int i=0; i<wavelengthInSamples; i++) {
SInt16 sample;
if (i < wavelengthInSamples/2) {
sample = CFSwapInt16HostToBig(SHRT_MAX);
} else {
sample = CFSwapInt16HostToBig(SHRT_MIN);
}
audioErr = AudioFileWriteBytes(audioFile, false, sampleCount*2, &bytesToWrite, &sample);
assert(audioErr == noErr);

sampleCount++;
}
}
audioErr = AudioFileClose(audioFile);

  assert(audioErr == noErr);
NSLog(@"wrote %ld samples", sampleCount);

}
return 0;
}

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References:
	>kAudioFormatUnsupportedDataFormatError (From: Jon August <email@hidden>)
	>Re: kAudioFormatUnsupportedDataFormatError (From: kamaldeep tumkur <email@hidden>)
	>Re: kAudioFormatUnsupportedDataFormatError (From: Jon August <email@hidden>)