#120 seems finally fixed with this

src/EMUUSBAudio/EMUUSBAudioEngine.cpp

@@ -922,6 +922,7 @@ IOReturn EMUUSBAudioEngine::GetDefaultSettings(IOUSBInterface1  *streamInterface
         } else {
             info = &mOutput;
         }
+        info -> sampleRate = sampleRate.whole;
 		info->interfaceNumber = ourInterfaceNumber;
 		info->streamDirection = direction;
 		info->streamInterface = streamInterface;
@@ -1192,7 +1193,9 @@ bool EMUUSBAudioEngine::initHardware (IOService *provider) {
 
 	CalculateSamplesPerFrame (sampleRate.whole, &averageFrameSamples, &additionalSampleFrameFreq);
 	// this calcs (frame size, etc.) could probably be simplified, but I'm leaving them this way for now (AC)
+    usbInputStream.sampleRate = sampleRate.whole;
 	usbInputStream.multFactor = usbInputStream.numChannels * (mChannelWidth / 8);
+    mOutput.sampleRate = sampleRate.whole;
 	mOutput.multFactor = mOutput.numChannels * (mChannelWidth / 8);
 	usbInputStream.maxFrameSize = (averageFrameSamples + 1) * usbInputStream.multFactor;
 	mOutput.maxFrameSize = (averageFrameSamples + 1) * mOutput.multFactor;
@@ -1517,6 +1520,7 @@ IOReturn EMUUSBAudioEngine::performFormatChangeInternal (IOAudioStream *audioStr
         //}
         usbInputStream.alternateSettingID = newAlternateSettingID;
         mChannelWidth = newFormat->fBitWidth;
+        usbInputStream.sampleRate = sampleRate.whole;
         usbInputStream.multFactor = usbInputStream.numChannels * (mChannelWidth / 8);
         debugIOLogC("alternateFrameSize is %d", alternateFrameSize);
         if (usbInputStream.maxFrameSize != alternateFrameSize) {
@@ -1556,6 +1560,7 @@ IOReturn EMUUSBAudioEngine::performFormatChangeInternal (IOAudioStream *audioStr
         //}
         mOutput.alternateSettingID = newAlternateSettingID;
         mChannelWidth = newFormat->fBitWidth;
+        mOutput.sampleRate = sampleRate.whole;
         mOutput.multFactor = mOutput.numChannels * (mChannelWidth / 8);
         debugIOLogC("alternateFrameSize is %d", alternateFrameSize);
         if (mOutput.maxFrameSize != alternateFrameSize) {
@@ -1742,7 +1747,9 @@ IOReturn EMUUSBAudioEngine::startUSBStream() {
                     usbInputStream.multFactor,newInputMultFactor,mOutput.multFactor,newOutputMultFactor);
         usbInputStream.maxFrameSize = altFrameSampleSize * newInputMultFactor;
         mOutput.maxFrameSize = altFrameSampleSize * newOutputMultFactor;
+        usbInputStream.sampleRate = sampleRate.whole;
         usbInputStream.multFactor = newInputMultFactor;
+        mOutput.sampleRate = sampleRate.whole;
         mOutput.multFactor = newOutputMultFactor;
         debugIOLogC("pre initBuffers");
         beginConfigurationChange();

src/EMUUSBAudio/EMUUSBInputStream.cpp

@@ -129,10 +129,13 @@ IOReturn       EMUUSBInputStream::gatherFromReadList() {
 
         if (mDropStartingFrames <= 0)
         {
-
+            UInt64 wrapTimeNs;
+            absolutetime_to_nanoseconds(pFrames[frameIndex].getTime(),&wrapTimeNs);
             // FIXME. We should not call from inside locked area.
-            usbRing-> push(source, size , pFrames[frameIndex].getTime() );
-            frameSizeQueue-> push(size , pFrames[frameIndex].getTime());
+            // -0.5/1ms: we need start instead of end of frame. Frame size depends on
+            // usb microinterval but we don't (yet) have access to that here.
+            usbRing-> push(source, size ,wrapTimeNs- (sampleRate>96000? 500000: 1000000), 1000000000l/(sampleRate * multFactor) );
+            frameSizeQueue-> push(size , wrapTimeNs);
 
             // if (frameIndex == 1) {
             //   debugIOLogC("latency %d",usbRing->available());

src/EMUUSBAudio/EMUUSBLogging.h

@@ -24,7 +24,7 @@
 #define DEBUGZEROTIME			TRUE
 #define DEBUGLOADING			TRUE
 #define DEBUGTIMESTAMPS			TRUE
-//#define DEBUGLOGGING          TRUE
+#define DEBUGLOGGING          TRUE
 
 
 //#include <IOKit/usb/IOUSBLog.h>

src/EMUUSBAudio/EMUUSBOutputStream.cpp

@@ -214,7 +214,7 @@ IOReturn EMUUSBOutputStream::PrepareWriteFrameList (UInt32 listNr) {
 
         if (frameSizeQueue->pop(&thisFrameSize) != kIOReturnSuccess) {
             debugIOLog("frameSizeQueue empty, guessing some queue size. May need fix..");
-            thisFrameSize = stockSamplesInFrame  * multFactor ;
+            thisFrameSize = (stockSamplesInFrame+1)  * multFactor ;
         }
 
         if (thisFrameSize >= numBytesToBufferEnd) {

src/EMUUSBAudio/LowPassFilter.h

@@ -22,8 +22,8 @@
 // to avoid the deviations grow above 1ms, yet as slow as possible
 // to maximize the stability of the estimation.
 #define K 1     // spring constant for filter
-#define M 10000 // mass for the filter
-#define DA 200  // 2 Sqrt[M K] for critical damping.
+#define M 1000 // mass for the filter
+#define DA 63  // 2 Sqrt[M K] for critical damping.
 
 
 //  where is math.h ?

src/EMUUSBAudio/RingBufferDefault.h

@@ -71,7 +71,7 @@ class RingBufferDefault: public RingBufferT<TYPE> {
     }
 
 
-    IOReturn push(TYPE object, AbsoluteTime time) override{
+    IOReturn push(TYPE object, UInt64 time) override{
         if (!buffer) {
             return kIOReturnNotReady;
         }
@@ -86,7 +86,7 @@ class RingBufferDefault: public RingBufferT<TYPE> {
         return kIOReturnSuccess;
 	}
 
-    IOReturn push(TYPE *objects, UInt32 num, AbsoluteTime time) override{
+    IOReturn push(TYPE *objects, UInt32 num, UInt64 time, UInt32 time_per_obj) override{
         if (!buffer) {
             return kIOReturnNotReady;
         }
@@ -97,7 +97,7 @@ class RingBufferDefault: public RingBufferT<TYPE> {
         }
         for ( UInt32 n = 0; n<num; n++) {
             buffer[writehead++] = objects[n];
-            if (writehead == size) { writehead = 0; notifyWrap(time); }
+            if (writehead == size) { writehead = 0; notifyWrap(time + n * time_per_obj); }
         }
         return kIOReturnSuccess;
     }

src/EMUUSBAudio/RingBufferT.h

@@ -36,17 +36,18 @@ template<typename T> class RingBufferT {
      eg a timestamp from a USB frame.
      @return kIOReturnSuccess if ok, possibly  kIOReturnOverrun */
 
-	virtual IOReturn push( T object, AbsoluteTime time) = 0;
+	virtual IOReturn push( T object, UInt64 time) = 0;
 
     /*! puts num objects in the ring. prints error and continues if overflow. 
      @param objects array[num] of num objects to push
      @param num the number of objects in the array
-     @param time the time stamp associated with the objects.
+     @param time the time stamp associated with the first object, in system time ns.
      This is typically the lowest level timestamp you can get our hands on,
      eg a timestamp from a USB frame.
+     @param time_per_obj the time per object of type T (ns)
      @return kIOReturnSuccess if ok, possibly  kIOReturnOverrun */
 
-    virtual IOReturn push(T *objects, UInt32 num, AbsoluteTime time) = 0 ;
+    virtual IOReturn push(T *objects, UInt32 num, UInt64 time, UInt32 time_per_obj) = 0 ;
 
     /* Get one object from the ring. 
      @param pointer to mem block to contain the object
@@ -71,10 +72,9 @@ template<typename T> class RingBufferT {
 
     /*! called when the write head wraps back to 0. Overwrite to get notification. 
      @param time the time associated with the push of the object that caused the wrap.
-    
      */
 
-    virtual void notifyWrap(AbsoluteTime time) = 0 ;
+    virtual void notifyWrap(UInt64 time) = 0 ;
 
     /*! set the current read head position. CoreAudio may start reading at weird positions.
      returns kIOReturnUnderrun if the head was repositioned (by lack of better return possibility). */

src/EMUUSBAudio/StreamInfo.h

@@ -126,7 +126,10 @@ struct StreamInfo {
     /*! The point where the next raw USB byte can be written in bufferPtr. Always in [0, bufferSize> */
     UInt32		bufferOffset;
 
-    /*! =numChannels * #bytes per sample for this stream =  frame size.
+    /*! the current sample rate (sampleframes per second) */
+    UInt32 sampleRate;
+
+    /*! sampleframe size in bytes =numChannels * #bytes per sample for this stream.
      this will be 6 for stereo 24 bit audio. */
     UInt32		multFactor;
 

v11/EMUUSBAudio.kext/Contents/Info.plist

@@ -3,7 +3,7 @@
 <plist version="1.0">
 <dict>
 	<key>BuildMachineOSBuild</key>
-	<string>16B2555</string>
+	<string>17G8030</string>
 	<key>CFBundleDevelopmentRegion</key>
 	<string>English</string>
 	<key>CFBundleDisplayName</key>
@@ -31,17 +31,17 @@
 	<key>DTCompiler</key>
 	<string>com.apple.compilers.llvm.clang.1_0</string>
 	<key>DTPlatformBuild</key>
-	<string>7A1001</string>
+	<string>7D175</string>
 	<key>DTPlatformVersion</key>
 	<string>GM</string>
 	<key>DTSDKBuild</key>
-	<string>15A278</string>
+	<string>15E60</string>
 	<key>DTSDKName</key>
 	<string>macosx10.11</string>
 	<key>DTXcode</key>
-	<string>0701</string>
+	<string>0730</string>
 	<key>DTXcodeBuild</key>
-	<string>7A1001</string>
+	<string>7D175</string>
 	<key>IOKitPersonalities</key>
 	<dict>
 		<key>EMUSBAudioTrackerPre</key>