ATSParser now supports a mode in which PTS is considered to be absolute time

i.e. PTS 0 <=> media time 0

Change-Id: If10a0f98c129b95e8430dc419664b1def92e547e

2 files changed, 23 insertions, 10 deletions

diff --git a/media/libstagefright/mpeg2ts/ATSParser.cpp b/media/libstagefright/mpeg2ts/ATSParser.cpp
index 5bbc2b4..74a3b32 100644
--- a/media/libstagefright/mpeg2ts/ATSParser.cpp
+++ b/media/libstagefright/mpeg2ts/ATSParser.cpp
@@ -325,14 +325,16 @@ sp<MediaSource> ATSParser::Program::getSource(SourceType type) {
 }
 
 int64_t ATSParser::Program::convertPTSToTimestamp(uint64_t PTS) {
-    if (!mFirstPTSValid) {
-        mFirstPTSValid = true;
-        mFirstPTS = PTS;
-        PTS = 0;
-    } else if (PTS < mFirstPTS) {
-        PTS = 0;
-    } else {
-        PTS -= mFirstPTS;
+    if (!(mParser->mFlags & TS_TIMESTAMPS_ARE_ABSOLUTE)) {
+        if (!mFirstPTSValid) {
+            mFirstPTSValid = true;
+            mFirstPTS = PTS;
+            PTS = 0;
+        } else if (PTS < mFirstPTS) {
+            PTS = 0;
+        } else {
+            PTS -= mFirstPTS;
+        }
     }
 
     return (PTS * 100) / 9;
@@ -734,7 +736,8 @@ sp<MediaSource> ATSParser::Stream::getSource(SourceType type) {
 
 ////////////////////////////////////////////////////////////////////////////////
 
-ATSParser::ATSParser() {
+ATSParser::ATSParser(uint32_t flags)
+    : mFlags(flags) {
 }
 
 ATSParser::~ATSParser() {
diff --git a/media/libstagefright/mpeg2ts/ATSParser.h b/media/libstagefright/mpeg2ts/ATSParser.h
index 1e6451d..d12d998 100644
--- a/media/libstagefright/mpeg2ts/ATSParser.h
+++ b/media/libstagefright/mpeg2ts/ATSParser.h
@@ -38,7 +38,16 @@ struct ATSParser : public RefBase {
         DISCONTINUITY_FORMATCHANGE
     };
 
-    ATSParser();
+    enum Flags {
+        // The 90kHz clock (PTS/DTS) is absolute, i.e. PTS=0 corresponds to
+        // a media time of 0.
+        // If this flag is _not_ specified, the first PTS encountered in a
+        // program of this stream will be assumed to correspond to media time 0
+        // instead.
+        TS_TIMESTAMPS_ARE_ABSOLUTE = 1
+    };
+
+    ATSParser(uint32_t flags = 0);
 
     void feedTSPacket(const void *data, size_t size);
 
@@ -73,6 +82,7 @@ private:
     struct Program;
     struct Stream;
 
+    uint32_t mFlags;
     Vector<sp<Program> > mPrograms;
 
     void parseProgramAssociationTable(ABitReader *br);