From: rossb <rossb@0f58301d-fd10-0410-b4af-bbb618454e57>
Date: Thu, 20 Oct 2011 09:40:12 +0000 (+0000)
Subject: CoreAudio: if user specifies framesPerBuffer make sure host buffer is an integer... 
X-Git-Tag: pa_stable_v19_20111121_r1788~16
X-Git-Url: https://andrewgundersen.net/repos?a=commitdiff_plain;h=f519653f7e029c5336675cde3c62f63fb13e5d41;p=portaudio

CoreAudio: if user specifies framesPerBuffer make sure host buffer is an integer multiple of user buffer
---

diff --git a/src/hostapi/coreaudio/pa_mac_core.c b/src/hostapi/coreaudio/pa_mac_core.c
index bab668c..b182dac 100644
--- a/src/hostapi/coreaudio/pa_mac_core.c
+++ b/src/hostapi/coreaudio/pa_mac_core.c
@@ -1579,7 +1579,7 @@ static UInt32 CalculateOptimalBufferSize( PaMacAUHAL *auhalHostApi,
                                   double sampleRate,
                                   UInt32 requestedFramesPerBuffer )
 {
-    UInt32 suggested = 0;  
+    UInt32 resultBufferSizeFrames = 0;  
     // Use maximum of suggested input and output latencies.
     if( inputParameters )
     {
@@ -1588,28 +1588,25 @@ static UInt32 CalculateOptimalBufferSize( PaMacAUHAL *auhalHostApi,
         SInt32 variableLatencyFrames = suggestedLatencyFrames - fixedInputLatency;
         // Prevent negative latency.
         variableLatencyFrames = MAX( variableLatencyFrames, 0 );       
-        suggested = MAX( suggested, (UInt32) variableLatencyFrames );
+        resultBufferSizeFrames = MAX( resultBufferSizeFrames, (UInt32) variableLatencyFrames );
     }
     if( outputParameters )
     {        
         UInt32 suggestedLatencyFrames = outputParameters->suggestedLatency * sampleRate;
         SInt32 variableLatencyFrames = suggestedLatencyFrames - fixedOutputLatency;
         variableLatencyFrames = MAX( variableLatencyFrames, 0 );
-        suggested = MAX( suggested, (UInt32) variableLatencyFrames );
+        resultBufferSizeFrames = MAX( resultBufferSizeFrames, (UInt32) variableLatencyFrames );
     }
     
-    VDBUG( ("Block Size unspecified. Based on Latency, the user wants a Block Size near: %ld.\n",
-            suggested ) );
-    
     if( requestedFramesPerBuffer != paFramesPerBufferUnspecified )
     {
-        if( suggested > (requestedFramesPerBuffer + 1) )
-        {
-            // If the user asks for higher latency than the requested buffer size would provide
-            // then put multiple user buffers in one host buffer.
-            UInt32 userBuffersPerHostBuffer = (suggested + (requestedFramesPerBuffer - 1)) / requestedFramesPerBuffer;
-            suggested = userBuffersPerHostBuffer * requestedFramesPerBuffer;
-        }
+        // make host buffer the next highest integer multiple of user frames per buffer
+        UInt32 n = (resultBufferSizeFrames + requestedFramesPerBuffer - 1) / requestedFramesPerBuffer;
+        resultBufferSizeFrames = n * requestedFramesPerBuffer;
+
+    }else{
+    	VDBUG( ("Block Size unspecified. Based on Latency, the user wants a Block Size near: %ld.\n",
+            resultBufferSizeFrames ) );
     }
     
     // Clip to the capabilities of the device.
@@ -1617,16 +1614,16 @@ static UInt32 CalculateOptimalBufferSize( PaMacAUHAL *auhalHostApi,
     {
         ClipToDeviceBufferSize( auhalHostApi->devIds[inputParameters->device],
                                true, // In the old code isInput was false!
-                               suggested, &suggested );
+                               resultBufferSizeFrames, &resultBufferSizeFrames );
     }
     if( outputParameters )
     {
         ClipToDeviceBufferSize( auhalHostApi->devIds[outputParameters->device],
-                               false, suggested, &suggested );
+                               false, resultBufferSizeFrames, &resultBufferSizeFrames );
     }
-    VDBUG(("After querying hardware, setting block size to %ld.\n", suggested));
+    VDBUG(("After querying hardware, setting block size to %ld.\n", resultBufferSizeFrames));
 
-    return suggested;
+    return resultBufferSizeFrames;
 }
 
 /* =================================================================================================== */