--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/README.txt	Fri Oct 30 22:45:25 2009 +0100
@@ -0,0 +1,4 @@
+README
+
+audiodelay	measures delay between audio output and record using RtAudio
+

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/audiodelay/Makefile	Fri Oct 30 22:45:25 2009 +0100
@@ -0,0 +1,18 @@
+PROGRAMS = audiodelay
+RM = rm -f
+
+CC       = g++
+DEFS     =   -DHAVE_GETTIMEOFDAY -D__LINUX_ALSA__
+CFLAGS   = -O2 -Wall
+LIBRARY  = -lpthread -lasound -lrtaudio
+
+all: $(PROGRAMS)
+
+audiodelay: audiodelay.cpp 
+	$(CC) $(CFLAGS) $(DEFS) -o audiodelay audiodelay.cpp $(LIBRARY)
+
+clean: 
+	-$(RM) *.o $(PROGRAMS) *~ 
+
+strip: 
+	strip $(PROGRAMS)

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/audiodelay/audiodelay.cpp	Fri Oct 30 22:45:25 2009 +0100
@@ -0,0 +1,131 @@
+/******************************************/
+/*
+  audiodelay.cpp
+  by Peter Meerwald, pmeerw@pmeerw.net, 2009.
+
+  This program tests the delay between audio output and input.
+*/
+/******************************************/
+
+#include "RtAudio.h"
+#include <stdlib.h>
+#include <stdio.h>
+#include <math.h>
+#include <string.h>
+#include <sys/time.h>
+#include <time.h>
+
+const char *progname = "audiodelay";
+
+typedef signed short  AUDIOSAMPLE_TYPE;
+#define FORMAT RTAUDIO_SINT16
+
+static volatile unsigned int nmeasurements = 0;
+static float accum_measurements = 0.0f;
+
+static int inout(void *out_buf, void *in_buf, unsigned int nbuf_frames,
+           double stream_time, RtAudioStreamStatus status, void *data) {
+  if (status) 
+    printf("%s: stream over/underflow detected\n", progname);
+
+  static unsigned int count_inout = 0;
+  static struct timeval tv_start;
+  static struct timeval tv_stop;
+
+  AUDIOSAMPLE_TYPE *pout = (AUDIOSAMPLE_TYPE *)out_buf, *pin = (AUDIOSAMPLE_TYPE *)in_buf;
+
+  memset(out_buf, 0, nbuf_frames*sizeof(AUDIOSAMPLE_TYPE) * 2);
+  if ((count_inout % (512*128/nbuf_frames)) == 0) {
+      for (unsigned int i = nbuf_frames/2-4; i < nbuf_frames/2+4; i++) {
+        pout[2*i] = 32000;
+        pout[2*i+1] = 32000;
+      }
+    
+      gettimeofday(&tv_start, 0);
+  }
+
+  if (1) {
+    for (unsigned int i = 0; i < nbuf_frames; i++) {
+      if (pin[2*i] > 15000 || pin[2*i+1] > 15000) {
+
+        gettimeofday(&tv_stop, 0);
+      
+        unsigned int msec = (tv_stop.tv_sec - tv_start.tv_sec) * 1000;
+        if (tv_stop.tv_usec < tv_start.tv_usec)
+          msec -= (tv_start.tv_usec - tv_stop.tv_usec) / 1000;
+        else 
+          msec += (tv_stop.tv_usec - tv_start.tv_usec) / 1000;
+
+        accum_measurements += msec;
+        nmeasurements++;
+        printf("%s: measured delay %u ms, offset %u, average %.2f\n", progname, msec, i, accum_measurements / nmeasurements);
+            
+        break;
+      }
+    }
+  }
+
+  count_inout++;
+
+  return 0;
+}
+
+int main(int argc, char *argv[]) {
+  unsigned int channels = 2, sample_rate = 44100, buf_bytes, odevice = 0, idevice = 0, ioffset = 0, ooffset = 0;
+
+  RtAudio adac;
+  if (adac.getDeviceCount() < 1) {
+    std::cout << "\nNo audio devices found!\n";
+    exit(EXIT_FAILURE);
+  }
+
+  // Let RtAudio print messages to stderr.
+  adac.showWarnings(true);
+
+  // Set the same number of channels for both input and output.
+  unsigned int buf_frames = 128;
+  RtAudio::StreamParameters iparams, oparams;
+  iparams.deviceId = idevice;
+  iparams.nChannels = channels;
+  iparams.firstChannel = ioffset;
+  oparams.deviceId = odevice;
+  oparams.nChannels = channels;
+  oparams.firstChannel = ooffset;
+
+  RtAudio::StreamOptions options;
+  options.flags = 0; // RTAUDIO_MINIMIZE_LATENCY, RTAUDIO_HOG_DEVICE, RTAUDIO_SCHEDULE_REALTIME
+  options.numberOfBuffers = 2;
+  options.priority = 0; // for RTAUDIO_SCHEDULE_REALTIME
+
+  try {
+    adac.openStream(&oparams, &iparams, FORMAT, sample_rate, &buf_frames, &inout, (void *)&buf_bytes, &options);
+  }
+  catch (RtError& e) {
+    printf("%s: %s\n", progname, e.getMessage().c_str());
+    exit(EXIT_FAILURE);
+  }
+
+  buf_bytes = buf_frames * channels * sizeof(AUDIOSAMPLE_TYPE);
+
+  try {
+    adac.startStream();
+
+    printf("%s: stream latency %ld frames, %d sample rate\n", progname, adac.getStreamLatency(), adac.getStreamSampleRate());
+
+    printf("%s: running ... press <enter> to quit (%d buffer frames)\n", progname, buf_frames);
+    getchar();
+
+    // Stop the stream.
+    adac.stopStream();
+  }
+  catch (RtError& e) {
+    printf("%s: %s\n", progname, e.getMessage().c_str());
+    goto cleanup;
+  }
+
+cleanup:
+  if (adac.isStreamOpen()) 
+    adac.closeStream();
+
+  return 0;
+}