aaudio: improve accuracy of timestamps
Account for latency added by the AAudio service.
Fix input timestamps.
Bug: 37080396
Test: test_timestamps.cpp input_monitor.cpp
Change-Id: I1053cd21af722bb9b9371df4e5731bf4a0a57b0b
diff --git a/media/libaaudio/examples/utils/AAudioExampleUtils.h b/media/libaaudio/examples/utils/AAudioExampleUtils.h
index 66de25f..6cbcc58 100644
--- a/media/libaaudio/examples/utils/AAudioExampleUtils.h
+++ b/media/libaaudio/examples/utils/AAudioExampleUtils.h
@@ -25,7 +25,7 @@
#define NANOS_PER_MILLISECOND (NANOS_PER_MICROSECOND * 1000)
#define NANOS_PER_SECOND (NANOS_PER_MILLISECOND * 1000)
-static const char *getSharingModeText(aaudio_sharing_mode_t mode) {
+const char *getSharingModeText(aaudio_sharing_mode_t mode) {
const char *modeText = "unknown";
switch (mode) {
case AAUDIO_SHARING_MODE_EXCLUSIVE:
@@ -49,7 +49,7 @@
return (time.tv_sec * NANOS_PER_SECOND) + time.tv_nsec;
}
-void displayPeakLevel(float peakLevel) {
+static void displayPeakLevel(float peakLevel) {
printf("%5.3f ", peakLevel);
const int maxStars = 50; // arbitrary, fits on one line
int numStars = (int) (peakLevel * maxStars);
@@ -59,4 +59,24 @@
printf("\n");
}
+/**
+ * @param position1 position of hardware frame
+ * @param nanoseconds1
+ * @param position2 position of client read/write
+ * @param nanoseconds2
+ * @param sampleRate
+ * @return latency in milliseconds
+ */
+static double calculateLatencyMillis(int64_t position1, int64_t nanoseconds1,
+ int64_t position2, int64_t nanoseconds2,
+ int64_t sampleRate) {
+ int64_t deltaFrames = position2 - position1;
+ int64_t deltaTime =
+ (NANOS_PER_SECOND * deltaFrames / sampleRate);
+ int64_t timeCurrentFramePlayed = nanoseconds1 + deltaTime;
+ int64_t latencyNanos = timeCurrentFramePlayed - nanoseconds2;
+ double latencyMillis = latencyNanos / 1000000.0;
+ return latencyMillis;
+}
+
#endif // AAUDIO_EXAMPLE_UTILS_H