pa_process.h

一个开源的sip源代码

*/
typedef struct {
    unsigned long framesPerUserBuffer;
    unsigned long framesPerHostBuffer;

    PaUtilHostBufferSizeMode hostBufferSizeMode;
    int useNonAdaptingProcess;
    unsigned long framesPerTempBuffer;

    unsigned int inputChannelCount;
    unsigned int bytesPerHostInputSample;
    unsigned int bytesPerUserInputSample;
    int userInputIsInterleaved;
    PaUtilConverter *inputConverter;
    PaUtilZeroer *inputZeroer;
    
    unsigned int outputChannelCount;
    unsigned int bytesPerHostOutputSample;
    unsigned int bytesPerUserOutputSample;
    int userOutputIsInterleaved;
    PaUtilConverter *outputConverter;
    PaUtilZeroer *outputZeroer;

    unsigned long initialFramesInTempInputBuffer;
    unsigned long initialFramesInTempOutputBuffer;

    void *tempInputBuffer;          /**< used for slips, block adaption, and conversion. */
    void **tempInputBufferPtrs;     /**< storage for non-interleaved buffer pointers, NULL for interleaved user input */
    unsigned long framesInTempInputBuffer; /**< frames remaining in input buffer from previous adaption iteration */

    void *tempOutputBuffer;         /**< used for slips, block adaption, and conversion. */
    void **tempOutputBufferPtrs;    /**< storage for non-interleaved buffer pointers, NULL for interleaved user output */
    unsigned long framesInTempOutputBuffer; /**< frames remaining in input buffer from previous adaption iteration */

    PaStreamCallbackTimeInfo *timeInfo;

    PaStreamCallbackFlags callbackStatusFlags;

    unsigned long hostInputFrameCount[2];
    PaUtilChannelDescriptor *hostInputChannels[2]; /**< pointers to arrays of channel descriptors.
                                                        pointers are NULL for half-duplex output processing.
                                                        hostInputChannels[i].data is NULL when the caller
                                                        calls PaUtil_SetNoInput()
                                                        */
    unsigned long hostOutputFrameCount[2];
    PaUtilChannelDescriptor *hostOutputChannels[2]; /**< pointers to arrays of channel descriptors.
                                                         pointers are NULL for half-duplex input processing.
                                                         hostOutputChannels[i].data is NULL when the caller
                                                         calls PaUtil_SetNoOutput()
                                                         */

    PaUtilTriangularDitherGenerator ditherGenerator;

    double samplePeriod;

    PaStreamCallback *streamCallback;
    void *userData;
} PaUtilBufferProcessor;


/** @name Initialization, termination, resetting and info */
/*@{*/

/** Initialize a buffer processor's representation stored in a
 PaUtilBufferProcessor structure. Be sure to call
 PaUtil_TerminateBufferProcessor after finishing with a buffer processor.

 @param bufferProcessor The buffer processor structure to initialize.

 @param inputChannelCount The number of input channels as passed to
 Pa_OpenStream or 0 for an output-only stream.

 @param userInputSampleFormat Format of user input samples, as passed to
 Pa_OpenStream. This parameter is ignored for ouput-only streams.
 
 @param hostInputSampleFormat Format of host input samples. This parameter is
 ignored for output-only streams. See note about host buffer interleave below.

 @param outputChannelCount The number of output channels as passed to
 Pa_OpenStream or 0 for an input-only stream.

 @param userOutputSampleFormat Format of user output samples, as passed to
 Pa_OpenStream. This parameter is ignored for input-only streams.
 
 @param hostOutputSampleFormat Format of host output samples. This parameter is
 ignored for input-only streams. See note about host buffer interleave below.

 @param sampleRate Sample rate of the stream. The more accurate this is the
 better - it is used for updating time stamps when adapting buffers.
 
 @param streamFlags Stream flags as passed to Pa_OpenStream, this parameter is
 used for selecting special sample conversion options such as clipping and
 dithering.
 
 @param framesPerUserBuffer Number of frames per user buffer, as requested
 by the framesPerBuffer parameter to Pa_OpenStream. This parameter may be
 zero to indicate that the user will accept any (and varying) buffer sizes.

 @param framesPerHostBuffer Specifies the number of frames per host buffer
 for the fixed buffer size mode, and the maximum number of frames
 per host buffer for the bounded host buffer size mode. It is ignored for
 the other modes.

 @param hostBufferSizeMode A mode flag indicating the size variability of
 host buffers that will be passed to the buffer processor. See
 PaUtilHostBufferSizeMode for further details.
 
 @param streamCallback The user stream callback passed to Pa_OpenStream.

 @param userData The user data field passed to Pa_OpenStream.
    
 @note The interleave flag is ignored for host buffer formats. Host
 interleave is determined by the use of different SetInput and SetOutput
 functions.

 @return An error code indicating whether the initialization was successful.
 If the error code is not PaNoError, the buffer processor was not initialized
 and should not be used.
 
 @see Pa_OpenStream, PaUtilHostBufferSizeMode, PaUtil_TerminateBufferProcessor
*/
PaError PaUtil_InitializeBufferProcessor( PaUtilBufferProcessor* bufferProcessor,
            int inputChannelCount, PaSampleFormat userInputSampleFormat,
            PaSampleFormat hostInputSampleFormat,
            int outputChannelCount, PaSampleFormat userOutputSampleFormat,
            PaSampleFormat hostOutputSampleFormat,
            double sampleRate,
            PaStreamFlags streamFlags,
            unsigned long framesPerUserBuffer, /* 0 indicates don't care */
            unsigned long framesPerHostBuffer,
            PaUtilHostBufferSizeMode hostBufferSizeMode,
            PaStreamCallback *streamCallback, void *userData );


/** Terminate a buffer processor's representation. Deallocates any temporary
 buffers allocated by PaUtil_InitializeBufferProcessor.
 
 @param bufferProcessor The buffer processor structure to terminate.

 @see PaUtil_InitializeBufferProcessor.
*/
void PaUtil_TerminateBufferProcessor( PaUtilBufferProcessor* bufferProcessor );


/** Clear any internally buffered data. If you call
 PaUtil_InitializeBufferProcessor in your OpenStream routine, make sure you
 call PaUtil_ResetBufferProcessor in your StartStream call.

 @param bufferProcessor The buffer processor to reset.
*/
void PaUtil_ResetBufferProcessor( PaUtilBufferProcessor* bufferProcessor );


/** Retrieve the input latency of a buffer processor.

 @param bufferProcessor The buffer processor examine.

 @return The input latency introduced by the buffer processor, in frames.

 @see PaUtil_GetBufferProcessorOutputLatency
*/
unsigned long PaUtil_GetBufferProcessorInputLatency( PaUtilBufferProcessor* bufferProcessor );

/** Retrieve the output latency of a buffer processor.

 @param bufferProcessor The buffer processor examine.

 @return The output latency introduced by the buffer processor, in frames.

 @see PaUtil_GetBufferProcessorInputLatency
*/
unsigned long PaUtil_GetBufferProcessorOutputLatency( PaUtilBufferProcessor* bufferProcessor );

/*@}*/


/** @name Host buffer pointer configuration

 Functions to set host input and output buffers, used by both callback streams
 and blocking read/write streams.
*/
/*@{*/ 


/** Set the number of frames in the input host buffer(s) specified by the
 PaUtil_Set*InputChannel functions.

 @param bufferProcessor The buffer processor.

 @param frameCount The number of host input frames. A 0 frameCount indicates to
 use the framesPerHostBuffer value passed to PaUtil_InitializeBufferProcessor.

 @see PaUtil_SetNoInput, PaUtil_SetInputChannel,
 PaUtil_SetInterleavedInputChannels, PaUtil_SetNonInterleavedInputChannel
*/
void PaUtil_SetInputFrameCount( PaUtilBufferProcessor* bufferProcessor,
        unsigned long frameCount );

        
/** Indicate that no input is avalable. This function should be used when
 priming the output of a full-duplex stream opened with the
 paPrimeOutputBuffersUsingStreamCallback flag. Note that it is not necessary
 to call this or any othe PaUtil_Set*Input* functions for ouput-only streams.

 @param bufferProcessor The buffer processor.
*/
void PaUtil_SetNoInput( PaUtilBufferProcessor* bufferProcessor );


/** Provide the buffer processor with a pointer to a host input channel.

 @param bufferProcessor The buffer processor.
 @param channel The channel number.
 @param data The buffer.
 @param stride The stride from one sample to the next, in samples. For
 interleaved host buffers, the stride will usually be the same as the number of
 channels in the buffer.
*/
void PaUtil_SetInputChannel( PaUtilBufferProcessor* bufferProcessor,
        unsigned int channel, void *data, unsigned int stride );


/** Provide the buffer processor with a pointer to an number of interleaved
 host input channels.

 @param bufferProcessor The buffer processor.
 @param firstChannel The first channel number.
 @param data The buffer.
 @param channelCount The number of interleaved channels in the buffer. If
 channelCount is zero, the number of channels specified to
 PaUtil_InitializeBufferProcessor will be used.
*/
void PaUtil_SetInterleavedInputChannels( PaUtilBufferProcessor* bufferProcessor,
        unsigned int firstChannel, void *data, unsigned int channelCount );


/** Provide the buffer processor with a pointer to one non-interleaved host
 output channel.

 @param bufferProcessor The buffer processor.
 @param channel The channel number.
 @param data The buffer.
*/
void PaUtil_SetNonInterleavedInputChannel( PaUtilBufferProcessor* bufferProcessor,
        unsigned int channel, void *data );


/** Use for the second buffer half when the input buffer is split in two halves.
 @see PaUtil_SetInputFrameCount
*/
void PaUtil_Set2ndInputFrameCount( PaUtilBufferProcessor* bufferProcessor,