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2014/10/15 ¤U¤È 10:13:38

iphone Programming Glossary: samplerate

Source for a good, simple, soft modem library

http://stackoverflow.com/questions/10693590/source-for-a-good-simple-soft-modem-library

in i r complexAdd r e out k r #define FILTER_LENGTH 64 typedef struct tTx enum stSendingOnes stSendingData State uint SampleRate uint OnesFreq uint ZeroesFreq uint BitRate uint32 SampleCnt uint BitSampleCnt uint Data uint DataLeft double Phase double.. uint DataLeft double Phase double PhaseIncrement uint pTxGetDataCallBack struct tTx uint8 tTx void TxInit tTx pTx uint SampleRate uint pTxGetDataCallBack tTx uint8 memset pTx 0 sizeof pTx pTx State stSendingOnes pTx SampleRate SampleRate pTx OnesFreq.. TxInit tTx pTx uint SampleRate uint pTxGetDataCallBack tTx uint8 memset pTx 0 sizeof pTx pTx State stSendingOnes pTx SampleRate SampleRate pTx OnesFreq 1300 pTx ZeroesFreq 2100 pTx BitRate 1200 pTx pTxGetDataCallBack pTxGetDataCallBack pTx SampleCnt..

How to record sound produced by mixer unit output (iOS Core Audio & Audio Graph)

http://stackoverflow.com/questions/7118429/how-to-record-sound-produced-by-mixer-unit-output-ios-core-audio-audio-graph

@ AudioUnitSetProperty EnableIO withStatus result return Then create a stream format I O stream format iOStreamFormat.mSampleRate 44100.0 iOStreamFormat.mFormatID kAudioFormatLinearPCM iOStreamFormat.mFormatFlags kAudioFormatFlagIsSignedInteger kAudioFormatFlagIsPacked.. iOStreamFormat if noErr result self printErrorMessage @ AudioUnitSetProperty StreamFormat withStatus result return SampleRate I O result AudioUnitSetProperty iOUnit kAudioUnitProperty_SampleRate kAudioUnitScope_Input 0 Output graphSampleRate.. StreamFormat withStatus result return SampleRate I O result AudioUnitSetProperty iOUnit kAudioUnitProperty_SampleRate kAudioUnitScope_Input 0 Output graphSampleRate sizeof graphSampleRate if noErr result self printErrorMessage @ AudioUnitSetProperty..

Source for a good, simple, soft modem library

http://stackoverflow.com/questions/10693590/source-for-a-good-simple-soft-modem-library

EXIT_SUCCESS Exit if fAudio NULL fclose fAudio if fData NULL fclose fData return err int main int argc char argv uint sampleRate double noiseLevel if argc 2 stricmp argv 1 help stricmp argv 1 help stricmp argv 1 stricmp argv 1 Usage printf Usage n.. s rx sample rate PCM input file data output file n argv 0 argv 0 return 0 if stricmp argv 1 tx argc 6 sscanf argv 2 u sampleRate 1 sscanf argv 3 lf noiseLevel 1 return testTx sampleRate noiseLevel argv 4 argv 5 else if stricmp argv 1 rx argc 5 sscanf.. 0 argv 0 return 0 if stricmp argv 1 tx argc 6 sscanf argv 2 u sampleRate 1 sscanf argv 3 lf noiseLevel 1 return testTx sampleRate noiseLevel argv 4 argv 5 else if stricmp argv 1 rx argc 5 sscanf argv 2 u sampleRate 1 return testRx sampleRate argv 3..

Drawing waveform with AVAssetReader

http://stackoverflow.com/questions/5032775/drawing-waveform-with-avassetreader

alloc initWithTrack songTrack outputSettings outputSettingsDict reader addOutput output output release UInt32 sampleRate channelCount NSArray formatDesc songTrack.formatDescriptions for unsigned int i 0 i formatDesc count i CMAudioFormatDescriptionRef.. i const AudioStreamBasicDescription fmtDesc CMAudioFormatDescriptionGetStreamBasicDescription item if fmtDesc sampleRate fmtDesc mSampleRate channelCount fmtDesc mChannelsPerFrame NSLog @ channels u bytes packet u sampleRate f fmtDesc mChannelsPerFrame.. if fmtDesc sampleRate fmtDesc mSampleRate channelCount fmtDesc mChannelsPerFrame NSLog @ channels u bytes packet u sampleRate f fmtDesc mChannelsPerFrame fmtDesc mBytesPerPacket fmtDesc mSampleRate UInt32 bytesPerSample 2 channelCount SInt16 normalizeMax..

FFT on iPhone to ignore background noise and find lower pitches

http://stackoverflow.com/questions/7181630/fft-on-iphone-to-ignore-background-noise-and-find-lower-pitches

sizeof SInt16 Update the UI with our newly acquired frequency value. THIS listener frequencyChangedWithValue bin THIS sampleRate bufferCapacity To start with I believe I need to apply a LOW PASS FILTER ... but I'm not an FFT expert and not sure exactly..

AudioQueue how to find out playback length of queued data

http://stackoverflow.com/questions/7375309/audioqueue-how-to-find-out-playback-length-of-queued-data

Foundation.h #import AudioToolbox AudioToolbox.h @interface MusicChunker NSObject AudioFileID audioFile int _sampleRate int _totalFrames UInt64 _framesPerPacket UInt64 _totalPackets UInt64 fileDataSize AudioFilePacketTableInfo _packetInfo int.. _fileHandle NSFileHandle fileHandleForReadingFromURL url error nil retain _fileLength _fileHandle seekToEndOfFile _sampleRate _fileDataFormat.mSampleRate _totalReadBytes 0 AudioFramePacketTranslation tran .mFrame 0 .mPacket packetCount 1 .mFrameOffsetInPacket.. NSData getNextDataChunk int seconds NSLog @ d total packets _totalPackets if _packetOffset _totalPackets return nil sampleRate seconds number of wanted frames int framesWanted _sampleRate seconds NSData header nil int wantedPackets framesWanted _framesPerPacket..

ExtAudioFileWrite to m4a/aac failing on dual-core devices (ipad 2, iphone 4s)

http://stackoverflow.com/questions/8719865/extaudiofilewrite-to-m4a-aac-failing-on-dual-core-devices-ipad-2-iphone-4s

and no error code. Here is the code in question The data formats AudioStreamBasicDescription AUCanonicalASBD Float64 sampleRate UInt32 channel AudioStreamBasicDescription audioFormat audioFormat.mSampleRate sampleRate audioFormat.mFormatID kAudioFormatLinearPCM.. AUCanonicalASBD Float64 sampleRate UInt32 channel AudioStreamBasicDescription audioFormat audioFormat.mSampleRate sampleRate audioFormat.mFormatID kAudioFormatLinearPCM audioFormat.mFormatFlags kAudioFormatFlagsAudioUnitCanonical audioFormat.mChannelsPerFrame..