Cannot Rewind WVM in MediaCodec Mode

The solution previously checked in as 2e0e3 is re-introduced here. However,
the MediaCodec-compatible heuristic is not used unless WVM is in Crypto Plugin
(i.e. Media Codec) mode.

To repeat from last time: The problem here is that WVM cannot independently
seek the audio and video read heads, but the API assumes it can. WVM does the
right thing for AwesomePlayer-based playback (essentially ignoring audio
seeks) but the wrong thing for MediaCodec-based playback. For MediaCodec
mode, we should respect the first seek we get for a given destination and
ignore the second.

In this part, the new heuristic is reintroduced, but the old heuristic is
maintained for use in non-Crypto Plugin mode.

Bug: 6793514
Change-Id: I7ced2bf20af117a57eec27490b0920d906a8a684

proprietary/wvm/WVMMediaSource.cpp

@@ -24,6 +24,7 @@ static void _cb(int code)
 }
 
 status_t WVMMediaSource::sLastError = NO_ERROR;
+int64_t WVMMediaSource::sLastSeekTimeUs = -1;
 
 WVMMediaSource::WVMMediaSource(WVSession *session, WVEsSelector esSelector,
                                const sp<MetaData> &metaData, bool isLive,
@@ -36,6 +37,7 @@ WVMMediaSource::WVMMediaSource(WVSession *session, WVEsSelector esSelector,
       mNewSegment(false),
       mCryptoInitialized(false),
       mStripADTS(false),
+      mCryptoPluginMode(cryptoPluginMode),
       mGroup(NULL),
       mKeyTime(0),
       mDts(0),
@@ -243,15 +245,25 @@ status_t WVMMediaSource::read(MediaBuffer **buffer, const ReadOptions *options)
             // prior to the specified time.
             seekNextSync = true;
         } else {
-            // Let video stream control seek
-            if (mESSelector == WV_EsSelector_Video) {
+            // If we are not in Crypto Plugin Mode, let the video stream
+            // control the seek.
+            // If we are in Crypto Plugin Mode, obey the first seek we get to a
+            // given point, then ignore the subsequent one.
+            if ((!mCryptoPluginMode && mESSelector == WV_EsSelector_Video) ||
+                (mCryptoPluginMode && seekTimeUs != sLastSeekTimeUs)) {
                 float scaleUsed;
                 std::string when = usecToNPT(seekTimeUs) + std::string("-");
+
                 WVStatus result = WV_Play(mSession, 1.0, &scaleUsed, when );
+
                 if (result != WV_Status_OK) {
                     ALOGE("WV_Play returned status %d in WVMMediaSource::read\n", result);
                     return ERROR_IO;
                 }
+
+                sLastSeekTimeUs = seekTimeUs;
+            } else if (mCryptoPluginMode) {
+                sLastSeekTimeUs = -1;
             }
         }
     }

proprietary/wvm/include/WVMMediaSource.h

@@ -26,7 +26,8 @@ class WVMFileSource;
 class WVMMediaSource : public MediaSource {
 public:
     WVMMediaSource(WVSession *session, WVEsSelector esSelector,
-                   const sp<MetaData> &metaData, bool isLive, bool cryptoPluginMode);
+                   const sp<MetaData> &metaData, bool isLive,
+                   bool cryptoPluginMode);
 
     void delegateFileSource(sp<WVMFileSource> fileSource);
     void delegateDataSource(sp<DataSource> dataSource);
@@ -76,6 +77,7 @@ protected:
 
 private:
     Mutex mLock;
+    static int64_t sLastSeekTimeUs;
 
     WVSession *mSession;
     WVEsSelector mESSelector;  // indicates audio vs. video
@@ -88,6 +90,7 @@ private:
     bool mNewSegment;
     bool mCryptoInitialized;
     bool mStripADTS;
+    bool mCryptoPluginMode;
 
     MediaBufferGroup *mGroup;