From 9c0e19a3be2288db79e2502e5fa450c3e20a668d Mon Sep 17 00:00:00 2001 From: Guenter Geiger Date: Fri, 9 May 2003 16:04:00 +0000 Subject: This commit was generated by cvs2svn to compensate for changes in r610, which included commits to RCS files with non-trunk default branches. svn path=/trunk/; revision=611 --- pd/portaudio/docs/pa_tut_devs.html | 65 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) create mode 100644 pd/portaudio/docs/pa_tut_devs.html (limited to 'pd/portaudio/docs/pa_tut_devs.html') diff --git a/pd/portaudio/docs/pa_tut_devs.html b/pd/portaudio/docs/pa_tut_devs.html new file mode 100644 index 00000000..1756992c --- /dev/null +++ b/pd/portaudio/docs/pa_tut_devs.html @@ -0,0 +1,65 @@ + + + + + + + + + PortAudio Tutorial + + +  +
+ + + +
+
+

+PortAudio Tutorial

+
+ +

+Querying for Available Devices

+ +
There are often several different audio devices available in +a computer with different capabilities. They can differ in the sample rates +supported, bit widths, etc. PortAudio provides a simple way to query for +the available devices, and then pass the selected device to Pa_OpenStream(). +For an example, see the file "pa_tests/pa_devs.c". +

To determine the number of devices: +

+
numDevices = Pa_CountDevices();
+
+You can then query each device in turn by calling Pa_GetDeviceInfo() with +an index. +
+
for( i=0; i<numDevices; i++ ) {
+     pdi = Pa_GetDeviceInfo( i );
+
+It will return a pointer to a PaDeviceInfo structure which is +defined as: +
+
typedef struct{
+    int structVersion; 
+    const char *name;
+    int maxInputChannels;
+    int maxOutputChannels;
+/* Number of discrete rates, or -1 if range supported. */
+    int numSampleRates;
+/* Array of supported sample rates, or {min,max} if range supported. */
+    const double *sampleRates;
+    PaSampleFormat nativeSampleFormat;
+}PaDeviceInfo;
+
+If the device supports a continuous range of sample rates, then numSampleRates +will equal -1, and the sampleRates array will have two values, the minimum  +and maximum rate. +

The device information is allocated by Pa_Initialize() and freed by +Pa_Terminate() so you do not have to free() the structure returned by Pa_GetDeviceInfo().

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