From 99d1f78c9b16b5668e78c353373e0e7f4592cab9 Mon Sep 17 00:00:00 2001
From: Wei Jia <wjia@google.com>
Date: Thu, 23 Apr 2015 14:06:42 -0700
Subject: MediaSync: allow users to query play time for pending audio frames.

Bug: 19666434
Change-Id: I5cfd3e1a9b4f56aaa6482facd55a22ed1e7ed3e6
---
 include/media/stagefright/MediaSync.h |  3 +++
 media/libstagefright/MediaSync.cpp    | 36 +++++++++++++++++++++++++++++++++++
 2 files changed, 39 insertions(+)

diff --git a/include/media/stagefright/MediaSync.h b/include/media/stagefright/MediaSync.h
index 8bb8c7f..8ad74a4 100644
--- a/include/media/stagefright/MediaSync.h
+++ b/include/media/stagefright/MediaSync.h
@@ -113,6 +113,9 @@ public:
     // MediaClock::getMediaTime() and MediaClock::getRealTimeFor().
     sp<const MediaClock> getMediaClock();
 
+    // Get the play time for pending audio frames in audio sink.
+    status_t getPlayTimeForPendingAudioFrames(int64_t *outTimeUs);
+
 protected:
     virtual void onMessageReceived(const sp<AMessage> &msg);
 
diff --git a/media/libstagefright/MediaSync.cpp b/media/libstagefright/MediaSync.cpp
index 9c37a3d..8030a36 100644
--- a/media/libstagefright/MediaSync.cpp
+++ b/media/libstagefright/MediaSync.cpp
@@ -179,6 +179,42 @@ sp<const MediaClock> MediaSync::getMediaClock() {
     return mMediaClock;
 }
 
+status_t MediaSync::getPlayTimeForPendingAudioFrames(int64_t *outTimeUs) {
+    Mutex::Autolock lock(mMutex);
+    // User should check the playback rate if it doesn't want to receive a
+    // huge number for play time.
+    if (mPlaybackRate == 0.0f) {
+        *outTimeUs = INT64_MAX;
+        return OK;
+    }
+
+    uint32_t numFramesPlayed = 0;
+    if (mAudioTrack != NULL) {
+        status_t res = mAudioTrack->getPosition(&numFramesPlayed);
+        if (res != OK) {
+            return res;
+        }
+    }
+
+    int64_t numPendingFrames = mNumFramesWritten - numFramesPlayed;
+    if (numPendingFrames < 0) {
+        numPendingFrames = 0;
+        ALOGW("getPlayTimeForPendingAudioFrames: pending frame count is negative.");
+    }
+    double timeUs = numPendingFrames * 1000000.0
+            / (mNativeSampleRateInHz * (double)mPlaybackRate);
+    if (timeUs > (double)INT64_MAX) {
+        // Overflow.
+        *outTimeUs = INT64_MAX;
+        ALOGW("getPlayTimeForPendingAudioFrames: play time for pending audio frames "
+              "is too high, possibly due to super low playback rate(%f)", mPlaybackRate);
+    } else {
+        *outTimeUs = (int64_t)timeUs;
+    }
+
+    return OK;
+}
+
 status_t MediaSync::updateQueuedAudioData(
         size_t sizeInBytes, int64_t presentationTimeUs) {
     if (sizeInBytes == 0) {
-- 
cgit v1.1