aaudio: account for hardware jitter in clock model
This will allow AAudio to track the DSP better when
the DSP has variable timing, such as when resampling.
Keep track of the maximum lateness.
Do not assume it is only one burst.
Account for the lateness on the input streams
so we don't try to read the data before the DSP
has written it.
Bug: 123643363
Test: record through iRig UA using Oboe Tester
Test: see bug for details
Change-Id: I49eb852c6d0324e8a26ee912da5108021ec113fe
diff --git a/media/libaaudio/src/client/IsochronousClockModel.h b/media/libaaudio/src/client/IsochronousClockModel.h
index 46ca48e..582bf4e 100644
--- a/media/libaaudio/src/client/IsochronousClockModel.h
+++ b/media/libaaudio/src/client/IsochronousClockModel.h
@@ -18,6 +18,7 @@
#define ANDROID_AAUDIO_ISOCHRONOUS_CLOCK_MODEL_H
#include <stdint.h>
+#include "utility/AudioClock.h"
namespace aaudio {
@@ -79,6 +80,15 @@
int64_t convertPositionToTime(int64_t framePosition) const;
/**
+ * Calculate the latest estimated time that the stream will be at that position.
+ * The more jittery the clock is then the later this will be.
+ *
+ * @param framePosition
+ * @return time in nanoseconds
+ */
+ int64_t convertPositionToLatestTime(int64_t framePosition) const;
+
+ /**
* Calculate an estimated position where the stream will be at the specified time.
*
* @param nanoTime time of interest
@@ -87,6 +97,18 @@
int64_t convertTimeToPosition(int64_t nanoTime) const;
/**
+ * Calculate the corresponding estimated position based on the specified time being
+ * the latest possible time.
+ *
+ * For the same nanoTime, this may return an earlier position than
+ * convertTimeToPosition().
+ *
+ * @param nanoTime
+ * @return position in frames
+ */
+ int64_t convertLatestTimeToPosition(int64_t nanoTime) const;
+
+ /**
* @param framesDelta difference in frames
* @return duration in nanoseconds
*/
@@ -101,6 +123,9 @@
void dump() const;
private:
+
+ int32_t getLateTimeOffsetNanos() const;
+
enum clock_model_state_t {
STATE_STOPPED,
STATE_STARTING,
@@ -108,13 +133,23 @@
STATE_RUNNING
};
+ // Amount of time to drift forward when we get a late timestamp.
+ // This value was calculated to allow tracking of a clock with 50 ppm error.
+ static constexpr int32_t kDriftNanos = 10 * 1000;
+ // TODO review value of kExtraLatenessNanos
+ static constexpr int32_t kExtraLatenessNanos = 100 * 1000;
+
int64_t mMarkerFramePosition;
int64_t mMarkerNanoTime;
int32_t mSampleRate;
int32_t mFramesPerBurst;
- int32_t mMaxLatenessInNanos;
+ int32_t mBurstPeriodNanos;
+ // Includes mBurstPeriodNanos because we sample randomly over time.
+ int32_t mMaxMeasuredLatenessNanos;
clock_model_state_t mState;
+ int32_t mTimestampCount = 0;
+
void update();
};