Bluray: Improved chapter handling.

libbluray adds an extra chapter marker for the end of the title - so
ignore this for our own purposes - and use the libbluray functionality
for determining the current chapter. This aligns our presentation with
the disc menu structure.

I still intend to convert the chapter seeks to use the libbluray methods
but this requires a little more work.

N.B. Position information can go wrong with 'series/season' discs.
libbluray presents us with a 'super' title that is an amalgamation of
all of the episodes on a disc. Once you've navigated beyond the first
actual title, however, all positioning is relative to the current title.

Author: Mark Kendall

mythtv/libs/libmythtv/bdringbuffer.cpp

@@ -432,7 +432,14 @@ long long BDRingBuffer::GetReadPosition(void) const
 uint32_t BDRingBuffer::GetNumChapters(void)
 {
     if (m_currentTitleInfo)
-        return m_currentTitleInfo->chapter_count;
+        return m_currentTitleInfo->chapter_count - 1;
+    return 0;
+}
+
+uint32_t BDRingBuffer::GetCurrentChapter(void)
+{
+    if (bdnav)
+        return bd_get_current_chapter(bdnav);
     return 0;
 }
 
@@ -516,7 +523,7 @@ bool BDRingBuffer::UpdateTitleInfo(uint32_t index)
     m_currentTitleAngleCount = m_currentTitleInfo->angle_count;
     m_currentAngle = 0;
     m_titlesize = bd_get_title_size(bdnav);
-    uint32_t chapter_count = m_currentTitleInfo->chapter_count;
+    uint32_t chapter_count = GetNumChapters();
     VERBOSE(VB_IMPORTANT, LOC + QString("Selected title/playlist: index %1. "
                                         "Duration: %2 (%3 mins) "
                                         "Number of Chapters: %4 Number of Angles: %5 "

mythtv/libs/libmythtv/bdringbuffer.h

@@ -75,6 +75,7 @@ class MPUBLIC BDRingBuffer : public RingBuffer
     virtual long long GetReadPosition(void) const; // RingBuffer
     uint64_t GetTotalReadPosition(void);
     uint32_t GetNumChapters(void);
+    uint32_t GetCurrentChapter(void);
     uint64_t GetNumAngles(void) { return m_currentTitleAngleCount; }
     uint64_t GetChapterStartTime(uint32_t chapter);
     uint64_t GetChapterStartFrame(uint32_t chapter);

mythtv/libs/libmythtv/mythbdplayer.cpp

@@ -95,32 +95,16 @@ void MythBDPlayer::EventStart(void)
 
 int MythBDPlayer::GetNumChapters(void)
 {
-    int num = 0;
     if (player_ctx->buffer->BD() && player_ctx->buffer->BD()->IsOpen())
-        num = player_ctx->buffer->BD()->GetNumChapters();
-    if (num > 1)
-        return num;
-    return 0;
+        return player_ctx->buffer->BD()->GetNumChapters();
+    return -1;
 }
 
 int MythBDPlayer::GetCurrentChapter(void)
 {
-    uint total = GetNumChapters();
-    if (!total)
-        return 0;
-
-    for (int i = (total - 1); i > -1 ; i--)
-    {
-        uint64_t frame = player_ctx->buffer->BD()->GetChapterStartFrame(i);
-        if (framesPlayed >= frame)
-        {
-            VERBOSE(VB_PLAYBACK, LOC +
-                    QString("GetCurrentChapter(selected chapter %1 framenum %2)")
-                            .arg(i + 1).arg(frame));
-            return i + 1;
-        }
-    }
-    return 0;
+    if (player_ctx->buffer->BD() && player_ctx->buffer->BD()->IsOpen())
+        return player_ctx->buffer->BD()->GetCurrentChapter() + 1;
+    return -1;
 }
 
 int64_t MythBDPlayer::GetChapter(int chapter)