{5} Assigned, Active Tickets by Owner (Full Description) (9 matches)

From: meyer@mesw.de Subject: Re: [Portaudio] Sample Rate and FrameCount? Date: November 28, 2006 1:08:17 PM EST To: Axel.Roebel@ircam.fr Cc: portaudio@techweb.rfa.org, bjorn@xowave.com

We use paFramesPerBufferUnspecified, but set a higher output latency (because default output latency will lead to bad pops at least on ALSA/v19 -- this has been reported by a number of people already.) The API will then calculate a reliable buffer size for you automatically. No problems with this strategy so far.

Markus

PortAudio currently does not support OS X 10.3. The dependence on 10.4 is due to Memory barriers which are more reliable in 10.4 than they are in 10.3. It might be possible to use weak linking to support 10.3, albeit without memory barriers, but the situation is not clear. Other options have been discussed on the mailing list.

At the moment, core audio asks the device for a buffer size that is the same as the buffer size requested by the user. This makes sense and works well as long as SR conversion is not taking place. In the presence of SR conversion, a sample frame on the device no longer corresponds to a user sample frame. It would be good if this could be adapted in a better way, if possible, as it would reduce the chances of dropouts, and possibly reduce the CPU usage a bit.

Refer to mailing list discussion on PortMixer? and exposing devices for a full understanding of the changes:

diff -wruN orig/audacity/lib-src/portaudio-v19/include/portaudio.h audacity/lib-src/portaudio-v19/include/portaudio.h
--- orig/audacity/lib-src/portaudio-v19/include/portaudio.h	2006-09-04 14:05:58.000000000 -0500
+++ audacity/lib-src/portaudio-v19/include/portaudio.h	2006-09-04 05:30:19.000000000 -0500
@@ -1105,6 +1105,15 @@
 signed long Pa_GetStreamWriteAvailable( PaStream* stream );
 
 
+/** Retrieve the host type handling an open stream.
+
+ @return Returns a non-negative value representing the host API type
+ handling an open stream or, a PaErrorCode (which are always negative)
+ if PortAudio is not initialized or an error is encountered.
+*/
+PaHostApiTypeId Pa_GetStreamHostApiType( PaStream* stream );
+
+
 /* Miscellaneous utilities */
 
 
diff -wruN orig/audacity/lib-src/portaudio-v19/src/common/pa_front.c audacity/lib-src/portaudio-v19/src/common/pa_front.c
--- orig/audacity/lib-src/portaudio-v19/src/common/pa_front.c	2006-09-04 14:05:59.000000000 -0500
+++ audacity/lib-src/portaudio-v19/src/common/pa_front.c	2006-09-04 05:30:19.000000000 -0500
@@ -1327,8 +1327,10 @@
                                   hostApiInputParametersPtr, hostApiOutputParametersPtr,
                                   sampleRate, framesPerBuffer, streamFlags, streamCallback, userData );
 
-    if( result == paNoError )
+    if( result == paNoError ) {
         AddOpenStream( *stream );
+        PA_STREAM_REP(*stream)->hostApiType = hostApi->info.type;
+    }
 
 
 #ifdef PA_LOG_API_CALLS
@@ -1915,6 +1917,33 @@
 }
 
 
+PaHostApiTypeId Pa_GetStreamHostApiType( PaStream* stream )
+{
+    PaError error = PaUtil_ValidateStreamPointer( stream );
+    PaHostApiTypeId result;
+
+#ifdef PA_LOG_API_CALLS
+    PaUtil_DebugPrint("Pa_GetStreamHostApiType called:\n" );
+    PaUtil_DebugPrint("\tPaStream* stream: 0x%p\n", stream );
+#endif
+
+    if( error == paNoError )
+    {
+        result = PA_STREAM_REP(stream)->hostApiType;
+    }
+    else
+    {
+        result = (PaHostApiTypeId) error;
+    }
+
+#ifdef PA_LOG_API_CALLS
+    PaUtil_DebugPrint("Pa_GetStreamHostApiType returned:\n" );
+    PaUtil_DebugPrint("\tPaError: %d ( %s )\n\n", result, Pa_GetErrorText( result ) );
+#endif
+
+    return result;
+}
+
 PaError Pa_GetSampleSize( PaSampleFormat format )
 {
     int result;
diff -wruN orig/audacity/lib-src/portaudio-v19/src/common/pa_stream.c audacity/lib-src/portaudio-v19/src/common/pa_stream.c
--- orig/audacity/lib-src/portaudio-v19/src/common/pa_stream.c	2006-09-04 14:05:59.000000000 -0500
+++ audacity/lib-src/portaudio-v19/src/common/pa_stream.c	2006-09-04 05:30:19.000000000 -0500
@@ -93,6 +93,8 @@
     streamRepresentation->streamInfo.inputLatency = 0.;
     streamRepresentation->streamInfo.outputLatency = 0.;
     streamRepresentation->streamInfo.sampleRate = 0.;
+
+    streamRepresentation->hostApiType = 0;
 }
 
 
diff -wruN orig/audacity/lib-src/portaudio-v19/src/common/pa_stream.h audacity/lib-src/portaudio-v19/src/common/pa_stream.h
--- orig/audacity/lib-src/portaudio-v19/src/common/pa_stream.h	2006-09-04 14:05:59.000000000 -0500
+++ audacity/lib-src/portaudio-v19/src/common/pa_stream.h	2006-09-04 05:30:19.000000000 -0500
@@ -152,6 +152,7 @@
     PaStreamFinishedCallback *streamFinishedCallback;
     void *userData;
     PaStreamInfo streamInfo;
+    PaHostApiTypeId hostApiType;
 } PaUtilStreamRepresentation;
 
 

This file needs to be reviewed to see whether all of its contents are current. Possibly some contents are already in the tutorial or elsewhere.