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/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();