PortAudio  2.0
Data Fields
PaStreamParameters Struct Reference

#include <portaudio.h>

Data Fields

PaDeviceIndex device
 
int channelCount
 
PaSampleFormat sampleFormat
 
PaTime suggestedLatency
 
void * hostApiSpecificStreamInfo
 

Detailed Description

Parameters for one direction (input or output) of a stream.

Field Documentation

int PaStreamParameters::channelCount

The number of channels of sound to be delivered to the stream callback or accessed by Pa_ReadStream() or Pa_WriteStream(). It can range from 1 to the value of maxInputChannels in the PaDeviceInfo record for the device specified by the device parameter.

Referenced by main(), Sine::open(), Pa_IsFormatSupported(), Pa_OpenDefaultStream(), Pa_OpenStream(), PlaySine(), test(), TestOnce(), and TestStopMode().

PaDeviceIndex PaStreamParameters::device

A valid device index in the range 0 to (Pa_GetDeviceCount()-1) specifying the device to be used or the special constant paUseHostApiSpecificDeviceSpecification which indicates that the actual device(s) to use are specified in hostApiSpecificStreamInfo. This field must not be set to paNoDevice.

Referenced by main(), Sine::open(), Pa_IsFormatSupported(), Pa_OpenDefaultStream(), Pa_OpenStream(), PlaySine(), test(), TestOnce(), and TestStopMode().

void* PaStreamParameters::hostApiSpecificStreamInfo

An optional pointer to a host api specific data structure containing additional information for device setup and/or stream processing. hostApiSpecificStreamInfo is never required for correct operation, if not used it should be set to NULL.

Referenced by main(), Sine::open(), Pa_IsFormatSupported(), Pa_OpenDefaultStream(), Pa_OpenStream(), PlaySine(), test(), TestOnce(), and TestStopMode().

PaSampleFormat PaStreamParameters::sampleFormat

The sample format of the buffer provided to the stream callback, a_ReadStream() or Pa_WriteStream(). It may be any of the formats described by the PaSampleFormat enumeration.

Referenced by main(), Sine::open(), Pa_IsFormatSupported(), Pa_OpenDefaultStream(), Pa_OpenStream(), PlaySine(), test(), TestOnce(), and TestStopMode().

PaTime PaStreamParameters::suggestedLatency

The desired latency in seconds. Where practical, implementations should configure their latency based on these parameters, otherwise they may choose the closest viable latency instead. Unless the suggested latency is greater than the absolute upper limit for the device implementations should round the suggestedLatency up to the next practical value - ie to provide an equal or higher latency than suggestedLatency wherever possible. Actual latency values for an open stream may be retrieved using the inputLatency and outputLatency fields of the PaStreamInfo structure returned by Pa_GetStreamInfo().

See Also
default*Latency in PaDeviceInfo, *Latency in PaStreamInfo

Referenced by computeRingBufferSize(), main(), Sine::open(), Pa_IsFormatSupported(), Pa_OpenDefaultStream(), Pa_OpenStream(), paqaCheckLatency(), PlaySine(), test(), TestOnce(), and TestStopMode().


The documentation for this struct was generated from the following file: