nuplayer: fixes for subtitle pause/resume

- pause after the current block when select track
- ignore metadata timestamps as they're too sparse
- use smaller range when searching for next segment to prevent
  resumeUntil from downloading too much data

bug: 20500732
Change-Id: Ibda57a39ec86efd96a8dd0db95adeb92d076697a

2 files changed, 11 insertions, 3 deletions

diff --git a/media/libstagefright/httplive/LiveSession.cpp b/media/libstagefright/httplive/LiveSession.cpp
index d8c38e7..64a8532 100644
--- a/media/libstagefright/httplive/LiveSession.cpp
+++ b/media/libstagefright/httplive/LiveSession.cpp
@@ -1503,11 +1503,10 @@ void LiveSession::changeConfiguration(
             ALOGV("discarding fetcher-%d", fetcher->getFetcherID());
             fetcher->stopAsync();
         } else {
-            float threshold = -1.0f; // always finish fetching by default
+            float threshold = 0.0f; // default to pause after current block (47Kbytes)
             bool disconnect = false;
             if (timeUs >= 0ll) {
                 // seeking, no need to finish fetching
-                threshold = 0.0f;
                 disconnect = true;
             } else if (delayRemoval) {
                 // adapting, abort if remaining of current segment is over threshold
diff --git a/media/libstagefright/httplive/PlaylistFetcher.cpp b/media/libstagefright/httplive/PlaylistFetcher.cpp
index 53087b6..5a0deec 100644
--- a/media/libstagefright/httplive/PlaylistFetcher.cpp
+++ b/media/libstagefright/httplive/PlaylistFetcher.cpp
@@ -1424,11 +1424,17 @@ bool PlaylistFetcher::adjustSeqNumberWithAnchorTime(int64_t anchorTimeUs) {
 
     int64_t minDiffUs, maxDiffUs;
     if (mSeekMode == LiveSession::kSeekModeNextSample) {
+        // if the previous fetcher paused in the middle of a segment, we
+        // want to start at a segment that overlaps the last sample
         minDiffUs = -mPlaylist->getTargetDuration();
         maxDiffUs = 0ll;
     } else {
+        // if the previous fetcher paused at the end of a segment, ideally
+        // we want to start at the segment that's roughly aligned with its
+        // next segment, but if the two variants are not well aligned we
+        // adjust the diff to within (-T/2, T/2)
         minDiffUs = -mPlaylist->getTargetDuration() / 2;
-        maxDiffUs = mPlaylist->getTargetDuration();
+        maxDiffUs = mPlaylist->getTargetDuration() / 2;
     }
 
     int32_t oldSeqNumber = mSeqNumber;
@@ -1611,6 +1617,9 @@ status_t PlaylistFetcher::extractAndQueueAccessUnitsFromTs(const sp<ABuffer> &bu
                 ALOGE("MPEG2 Transport streams do not contain subtitles.");
                 return ERROR_MALFORMED;
             }
+            if (stream == LiveSession::STREAMTYPE_METADATA) {
+                continue;
+            }
             ATSParser::SourceType type =LiveSession::getSourceTypeForStream(stream);
             sp<AnotherPacketSource> source =
                 static_cast<AnotherPacketSource *>(