commit b7d8c5aa7a9c182e695e456c4aea8f8f6c550850
author jiabin <jiabin@google.com> Wed Aug 26 17:24:52 2020 -0700
committer Jiabin Huang <jiabin@google.com> Wed Sep 23 21:45:29 2020 +0000
tree 8d602524e90bf46e4cbe1e33a71fa472e7998c34
parent 8dbd241e279e1a637502e38af32ef6ead483768f

Add getExternalPosition in MMapStreamInterface.

GetExternalPosition will return a recent count of the number of
audio frames presented/received to/from an external observer. Using
the new API can return a precise timestamp to client, which can
help on A/V sync.

Test: atest AAudioTests
Bug: 158609200
Change-Id: If74e1d859a2bb2b4dba6af0e4e9164f05d19d962

services/oboeservice/AAudioServiceEndpointMMAP.cpp

diff --git a/services/oboeservice/AAudioServiceEndpointMMAP.cpp b/services/oboeservice/AAudioServiceEndpointMMAP.cpp
index 04c6453..5bccfd5 100644
--- a/services/oboeservice/AAudioServiceEndpointMMAP.cpp
+++ b/services/oboeservice/AAudioServiceEndpointMMAP.cpp
@@ -378,3 +378,18 @@
     parcelable.mDownDataQueueParcelable.setCapacityInFrames(getBufferCapacity());
     return AAUDIO_OK;
 }
+
+aaudio_result_t AAudioServiceEndpointMMAP::getExternalPosition(uint64_t *positionFrames,
+                                                               int64_t *timeNanos)
+{
+    if (!mExternalPositionSupported) {
+        return AAUDIO_ERROR_INVALID_STATE;
+    }
+    status_t status = mMmapStream->getExternalPosition(positionFrames, timeNanos);
+    if (status == INVALID_OPERATION) {
+        // getExternalPosition is not supported. Set mExternalPositionSupported as false
+        // so that the call will not go to the HAL next time.
+        mExternalPositionSupported = false;
+    }
+    return AAudioConvert_androidToAAudioResult(status);
+}

services/oboeservice/AAudioServiceEndpointMMAP.h

diff --git a/services/oboeservice/AAudioServiceEndpointMMAP.h b/services/oboeservice/AAudioServiceEndpointMMAP.h
index b6003b6..a2a0922 100644
--- a/services/oboeservice/AAudioServiceEndpointMMAP.h
+++ b/services/oboeservice/AAudioServiceEndpointMMAP.h
@@ -85,6 +85,8 @@
         return mHardwareTimeOffsetNanos;
     }
 
+    aaudio_result_t getExternalPosition(uint64_t *positionFrames, int64_t *timeNanos);
+
 private:
     MonotonicCounter                          mFramesTransferred;
 
@@ -101,6 +103,8 @@
 
     int64_t                                   mHardwareTimeOffsetNanos = 0; // TODO get from HAL
 
+    bool                                      mExternalPositionSupported = true;
+
 };
 
 } /* namespace aaudio */

services/oboeservice/AAudioServiceStreamMMAP.cpp

diff --git a/services/oboeservice/AAudioServiceStreamMMAP.cpp b/services/oboeservice/AAudioServiceStreamMMAP.cpp
index 54d7d06..a4c064e 100644
--- a/services/oboeservice/AAudioServiceStreamMMAP.cpp
+++ b/services/oboeservice/AAudioServiceStreamMMAP.cpp
@@ -162,7 +162,8 @@
     return result;
 }
 
-// Get timestamp that was written by getFreeRunningPosition()
+// Get timestamp from presentation position.
+// If fails, get time stamp that was written by getFreeRunningPosition()
 aaudio_result_t AAudioServiceStreamMMAP::getHardwareTimestamp(int64_t *positionFrames,
                                                                 int64_t *timeNanos) {
 
@@ -174,8 +175,11 @@
     sp<AAudioServiceEndpointMMAP> serviceEndpointMMAP =
             static_cast<AAudioServiceEndpointMMAP *>(endpoint.get());
 
-    // TODO Get presentation timestamp from the HAL
-    if (mAtomicStreamTimestamp.isValid()) {
+    uint64_t position;
+    if (serviceEndpointMMAP->getExternalPosition(&position, timeNanos) == AAUDIO_OK) {
+        *positionFrames = (int64_t) position;
+        return AAUDIO_OK;
+    } else if (mAtomicStreamTimestamp.isValid()) {
         Timestamp timestamp = mAtomicStreamTimestamp.read();
         *positionFrames = timestamp.getPosition();
         *timeNanos = timestamp.getNanoseconds() + serviceEndpointMMAP->getHardwareTimeOffsetNanos();