mkvparser: support seek for generic tracks (subtitles)

To support seek in generic tracks with subtitles the audio track
implementation of seek is made generic and inherited by audio track.

Change-Id: Ic88d2e859d077a1054b2af7d7680cfddfba8a589

mkvparser.cpp

@@ -5878,12 +5878,87 @@ bool Track::VetEntry(const BlockEntry* pBlockEntry) const
 }
 
 long Track::Seek(
-    long long /* time_ns */ ,
+    long long time_ns,
     const BlockEntry*& pResult) const
 {
-    // TODO(matthewjheaney): need to implement this?
+    const long status = GetFirst(pResult);
-    pResult = NULL;
+
-    return -1;  // generic error
+    if (status < 0)  //buffer underflow, etc
+        return status;
+
+    assert(pResult);
+
+    if (pResult->EOS())
+        return 0;
+
+    const Cluster* pCluster = pResult->GetCluster();
+    assert(pCluster);
+    assert(pCluster->GetIndex() >= 0);
+
+    if (time_ns <= pResult->GetBlock()->GetTime(pCluster))
+        return 0;
+
+    Cluster** const clusters = m_pSegment->m_clusters;
+    assert(clusters);
+
+    const long count = m_pSegment->GetCount();  //loaded only, not preloaded
+    assert(count > 0);
+
+    Cluster** const i = clusters + pCluster->GetIndex();
+    assert(i);
+    assert(*i == pCluster);
+    assert(pCluster->GetTime() <= time_ns);
+
+    Cluster** const j = clusters + count;
+
+    Cluster** lo = i;
+    Cluster** hi = j;
+
+    while (lo < hi)
+    {
+        //INVARIANT:
+        //[i, lo) <= time_ns
+        //[lo, hi) ?
+        //[hi, j)  > time_ns
+
+        Cluster** const mid = lo + (hi - lo) / 2;
+        assert(mid < hi);
+
+        pCluster = *mid;
+        assert(pCluster);
+        assert(pCluster->GetIndex() >= 0);
+        assert(pCluster->GetIndex() == long(mid - m_pSegment->m_clusters));
+
+        const long long t = pCluster->GetTime();
+
+        if (t <= time_ns)
+            lo = mid + 1;
+        else
+            hi = mid;
+
+        assert(lo <= hi);
+    }
+
+    assert(lo == hi);
+    assert(lo > i);
+    assert(lo <= j);
+
+    while (lo > i)
+    {
+        pCluster = *--lo;
+        assert(pCluster);
+        assert(pCluster->GetTime() <= time_ns);
+
+        pResult = pCluster->GetEntry(this);
+
+        if ((pResult != 0) && !pResult->EOS())
+            return 0;
+
+        //landed on empty cluster (no entries)
+    }
+
+    pResult = GetEOS();  //weird
+    return 0;
 }
 
 const ContentEncoding*
@@ -6341,91 +6416,6 @@ long AudioTrack::Parse(
 }
 
 
-long AudioTrack::Seek(
-    long long time_ns,
-    const BlockEntry*& pResult) const
-{
-    const long status = GetFirst(pResult);
-
-    if (status < 0)  //buffer underflow, etc
-        return status;
-
-    assert(pResult);
-
-    if (pResult->EOS())
-        return 0;
-
-    const Cluster* pCluster = pResult->GetCluster();
-    assert(pCluster);
-    assert(pCluster->GetIndex() >= 0);
-
-    if (time_ns <= pResult->GetBlock()->GetTime(pCluster))
-        return 0;
-
-    Cluster** const clusters = m_pSegment->m_clusters;
-    assert(clusters);
-
-    const long count = m_pSegment->GetCount();  //loaded only, not preloaded
-    assert(count > 0);
-
-    Cluster** const i = clusters + pCluster->GetIndex();
-    assert(i);
-    assert(*i == pCluster);
-    assert(pCluster->GetTime() <= time_ns);
-
-    Cluster** const j = clusters + count;
-
-    Cluster** lo = i;
-    Cluster** hi = j;
-
-    while (lo < hi)
-    {
-        //INVARIANT:
-        //[i, lo) <= time_ns
-        //[lo, hi) ?
-        //[hi, j)  > time_ns
-
-        Cluster** const mid = lo + (hi - lo) / 2;
-        assert(mid < hi);
-
-        pCluster = *mid;
-        assert(pCluster);
-        assert(pCluster->GetIndex() >= 0);
-        assert(pCluster->GetIndex() == long(mid - m_pSegment->m_clusters));
-
-        const long long t = pCluster->GetTime();
-
-        if (t <= time_ns)
-            lo = mid + 1;
-        else
-            hi = mid;
-
-        assert(lo <= hi);
-    }
-
-    assert(lo == hi);
-    assert(lo > i);
-    assert(lo <= j);
-
-    while (lo > i)
-    {
-        pCluster = *--lo;
-        assert(pCluster);
-        assert(pCluster->GetTime() <= time_ns);
-
-        pResult = pCluster->GetEntry(this);
-
-        if ((pResult != 0) && !pResult->EOS())
-            return 0;
-
-        //landed on empty cluster (no entries)
-    }
-
-    pResult = GetEOS();  //weird
-    return 0;
-}
-
-
 double AudioTrack::GetSamplingRate() const
 {
     return m_rate;
@@ -6835,7 +6825,7 @@ long Tracks::ParseTrackEntry(
     }
     else
     {
-        // neither video nor audio - probably metadata
+        // neither video nor audio - probably metadata or subtitles
 
         if (a.start >= 0)
             return E_FILE_FORMAT_INVALID;

mkvparser.hpp

@@ -333,7 +333,12 @@ public:
         long long element_size,
         Track*&);
 
-    enum Type { kVideo = 1, kAudio = 2 };
+    enum Type {
+        kVideo = 1,
+        kAudio = 2,
+        kSubtitle = 0x11,
+        kMetadata = 0x21
+     };
 
     Segment* const m_pSegment;
     const long long m_element_start;
@@ -472,7 +477,6 @@ public:
     double GetSamplingRate() const;
     long long GetChannels() const;
     long long GetBitDepth() const;
-    long Seek(long long time_ns, const BlockEntry*&) const;
 
 private:
     double m_rate;
@@ -948,8 +952,8 @@ private:
 class Segment
 {
     friend class Cues;
+    friend class Track;
     friend class VideoTrack;
-    friend class AudioTrack;
 
     Segment(const Segment&);
     Segment& operator=(const Segment&);