Re: AudioFileWriteBytes() fails with error code -40
Re: AudioFileWriteBytes() fails with error code -40
- Subject: Re: AudioFileWriteBytes() fails with error code -40
- From: Alex Wiltschko <email@hidden>
- Date: Tue, 6 Apr 2010 00:03:40 -0400
I've gotten this fixed. Problem was, I wasn't casting to the proper endianness.
On Mar 26, 2010, at 10:15 PM, Hamilton Feltman wrote:
> status = AudioFileWriteBytes(audioFileID, NO, 0, &numBytesToWrite, &holdingBuffer);
>
> This line looks suspect. holdingbufer is already a pointer and this code is taking the address of it.
>
> HTH,
> Hamilton
>
> On Mar 20, 2010, at 9:34 PM, Alex Wiltschko wrote:
>
>> I'm trying to write raw audio bytes to a file using AudioFileWriteBytes(). I get an error of "-40".
>>
>> This is a function I'm calling from an NSTimer, after properly initializing the audio file. Here's what I'm doing:
>>
>> void writeSingleChannelRingBufferDataToFileAsSInt16(AudioFileID audioFileID, AudioConverterRef audioConverter, ringBuffer *rb, SInt16 *holdingBuffer) {
>> // First, figure out which bits of audio we'll be
>> // writing to file from the ring buffer
>>
>> UInt32 lastFreshSample = rb->lastWrittenIndex;
>> OSStatus status;
>> int numSamplesToWrite;
>> UInt32 numBytesToWrite;
>>
>>
>> if (lastFreshSample < rb->lastReadIndex) {
>> numSamplesToWrite = kNumPointsInWave + lastFreshSample - rb->lastReadIndex - 1;
>> }
>> else {
>> numSamplesToWrite = lastFreshSample - rb->lastReadIndex;
>> }
>> numBytesToWrite = numSamplesToWrite*sizeof(SInt16);
>>
>>
>> // Then I copy the audio data (stored as floats) to a holding buffer (SInt16)
>> // that will be written directly to the file.
>> // The copying looks funky because it's from a ring buffer.
>>
>> UInt32 buffLen = rb->sizeOfBuffer - 1;
>> for (int i=0; i < numSamplesToWrite; ++i) {
>> holdingBuffer[i] = rb->data[(i + rb->lastReadIndex) & buffLen];
>> }
>> // Okay, now we actually try to write the audio from the SInt16 buffer "holdingBuffer"
>> // to the audio file. The NSLog will spit out an error -40,
>> // but also claims that it's writing bytes. No data is written to file.
>>
>> status = AudioFileWriteBytes(audioFileID, NO, 0, &numBytesToWrite, &holdingBuffer);
>> rb->lastReadIndex = lastFreshSample;
>>
>> NSLog(@"Error = %d, wrote %d bytes", status, numBytesToWrite);
>>
>> return;
>>
>>
>>
>> What is this error -40? By the way, everything works fine if I write straight from the ringBuffer to the file. Of course, when I play the AIF file, it sounds like junk, because I'm writing floats, not SInt16s, but AudioFileWriteBytes doesn't complain. _______________________________________________
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