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POAudio buffer size is incorrect on a mac
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copied!<p>After a while,developing with the audio unit, i know there is some bug that is well known to devs who works with audio buffers in low level .</p> <p>The bug is that the buffer size on a mac is wrong and show 512, instead of 1024 , where the same software on a iDevice , shows 1024 .</p> <p>Question is , there is a way to solve that so i can get on a mac also 1024 bits buffer? its a little bit hard to work like that, because simulation is different from device.</p> <p>This is the callback function where i check the buffer from the mic input :</p> <pre><code>static OSStatus recordingCallback(void *inRefCon, AudioUnitRenderActionFlags *ioActionFlags, const AudioTimeStamp *inTimeStamp, UInt32 inBusNumber, UInt32 inNumberFrames, AudioBufferList *ioData) { AudioBuffer buffer; buffer.mNumberChannels = 1; buffer.mDataByteSize = inNumberFrames * 2; buffer.mData = NULL; AudioBufferList bufferList; bufferList.mNumberBuffers = 1; bufferList.mBuffers[0] = buffer; OSStatus status; status = AudioUnitRender(audioUnit, ioActionFlags, inTimeStamp, inBusNumber, inNumberFrames, &bufferList); int16_t *q = (int16_t *)(&bufferList)->mBuffers[0].mData; // inNumberFrames, is 512 on a mac ,and 1024 on a device </code></pre> <p>(speaker output callback is the same by the way=512 bits).</p> <p>A part of the setting of the audio unit :</p> <pre><code>AudioStreamBasicDescription audioFormat; audioFormat.mSampleRate = 44100.00;//44100.00; audioFormat.mFormatID = kAudioFormatLinearPCM; audioFormat.mFormatFlags = kAudioFormatFlagIsSignedInteger | kAudioFormatFlagIsPacked; audioFormat.mFramesPerPacket = 1; audioFormat.mChannelsPerFrame = 1; audioFormat.mBitsPerChannel = 16; audioFormat.mBytesPerPacket = 2; audioFormat.mBytesPerFrame = 2; </code></pre> <p>Well i found here that someone say you have to set on the mac (retina is mine) the sample rate in the midi tool , i check it out but its 44100 in there . the chanels are 24 bit, i was trying with 16 bits but no good result . still 512 bits buffer size on my mac. I have a mac retina display 2012.</p>

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