Fixed detecting frame borders in MPEG-2 streams that have "bottom fields" or varying GOP structures

3 files changed, 34 insertions, 6 deletions

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index e2182fc7..ab1a3d98 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -620,6 +620,8 @@ Helmut Auer <vdr@helmutauer.de>
  command line option to be left empty to use the default values if only ENC shall be set
  for reporting an inconsistent behavior between opening the Recordings menu manually
  via the main menu and by pressing the Recordings key
+ for helping to debug a problem with frame detection in MPEG-2 streams that have "bottom fields"
+ or varying GOP structures
 
 Jeremy Hall <jhall@UU.NET>
  for fixing an incomplete initialization of the filter parameters in eit.c
@@ -3247,3 +3249,7 @@ Mariusz Bialonczyk <manio@skyboo.net>
 Eike Sauer <EikeSauer@t-online.de>
  for reporting a problem with channels that need more than 5 TS packets for detecting
  frame borders
+
+Christian Paulick <cpaulick@xeatre.tv>
+ for reporting a problem with frame detection in MPEG-2 streams that have "bottom fields"
+ or varying GOP structures
diff --git a/HISTORY b/HISTORY
index ba441d45..a42ff081 100644
--- a/HISTORY
+++ b/HISTORY
@@ -8132,7 +8132,7 @@ Video Disk Recorder Revision History
   and also to use the correct directory with --edit (the latter reported by Marko
   Mäkelä).
 
-2014-01-16: Version 2.1.4
+2014-01-17: Version 2.1.4
 
 - Updated 'sources.conf' (thanks to Antti Hartikainen).
 - cFont::CreateFont() now returns a dummy font in case there are no fonts installed.
@@ -8152,3 +8152,5 @@ Video Disk Recorder Revision History
   initial channel when VDR is started. This is necessary in case CI adapters are
   used that are not physically connected to a dedicated device. The respective checks
   in cDvbDevice have been removed to avoid redundancy.
+- Fixed detecting frame borders in MPEG-2 streams that have "bottom fields" or varying
+  GOP structures (reported by Christian Paulick, with help from Helmut Auer).
diff --git a/remux.c b/remux.c
index 587d7e5c..fd726017 100644
--- a/remux.c
+++ b/remux.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: remux.c 2.75 2013/03/03 10:37:58 kls Exp $
+ * $Id: remux.c 3.1 2014/01/18 11:27:30 kls Exp $
  */
 
 #include "remux.h"
@@ -1004,6 +1004,7 @@ protected:
   bool debug;
   bool newFrame;
   bool independentFrame;
+  int iFrameTemporalReferenceOffset;
 public:
   cFrameParser(void);
   virtual ~cFrameParser() {};
@@ -1017,6 +1018,7 @@ public:
   void SetDebug(bool Debug) { debug = Debug; }
   bool NewFrame(void) { return newFrame; }
   bool IndependentFrame(void) { return independentFrame; }
+  int IFrameTemporalReferenceOffset(void) { return iFrameTemporalReferenceOffset; }
   };
 
 cFrameParser::cFrameParser(void)
@@ -1024,6 +1026,7 @@ cFrameParser::cFrameParser(void)
   debug = true;
   newFrame = false;
   independentFrame = false;
+  iFrameTemporalReferenceOffset = 0;
 }
 
 // --- cAudioParser ----------------------------------------------------------
@@ -1056,6 +1059,7 @@ class cMpeg2Parser : public cFrameParser {
 private:
   uint32_t scanner;
   bool seenIndependentFrame;
+  int lastIFrameTemporalReference;
 public:
   cMpeg2Parser(void);
   virtual int Parse(const uchar *Data, int Length, int Pid);
@@ -1065,6 +1069,7 @@ cMpeg2Parser::cMpeg2Parser(void)
 {
   scanner = EMPTY_SCANNER;
   seenIndependentFrame = false;
+  lastIFrameTemporalReference = -1; // invalid
 }
 
 int cMpeg2Parser::Parse(const uchar *Data, int Length, int Pid)
@@ -1089,10 +1094,25 @@ int cMpeg2Parser::Parse(const uchar *Data, int Length, int Pid)
             scanner = OldScanner;
             return tsPayload.Used() - TS_SIZE;
             }
+         uchar b1 = tsPayload.GetByte();
+         uchar b2 = tsPayload.GetByte();
+         int TemporalReference = (b1 << 2 ) + ((b2 & 0xC0) >> 6);
+         uchar FrameType = (b2 >> 3) & 0x07;
+         if (tsPayload.Find(0x000001B5)) { // Extension start code
+            if (((tsPayload.GetByte() & 0xF0) >> 4) == 0x08) { // Picture coding extension
+               tsPayload.GetByte();
+               uchar PictureStructure = tsPayload.GetByte() & 0x03;
+               if (PictureStructure == 0x02) // bottom field
+                  break;
+               }
+            }
          newFrame = true;
-         tsPayload.GetByte();
-         uchar FrameType = (tsPayload.GetByte() >> 3) & 0x07;
          independentFrame = FrameType == 1; // I-Frame
+         if (independentFrame) {
+            if (lastIFrameTemporalReference >= 0)
+               iFrameTemporalReferenceOffset = TemporalReference - lastIFrameTemporalReference;
+            lastIFrameTemporalReference = TemporalReference;
+            }
          if (debug) {
             seenIndependentFrame |= independentFrame;
             if (seenIndependentFrame) {
@@ -1457,7 +1477,7 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
                        for (int i = 0; i < numPtsValues; i++)
                            ptsValues[i] = ptsValues[i + 1] - ptsValues[i];
                        qsort(ptsValues, numPtsValues, sizeof(uint32_t), CmpUint32);
-                       uint32_t Delta = ptsValues[0] / framesPerPayloadUnit;
+                       uint32_t Delta = ptsValues[0] / (framesPerPayloadUnit +  parser->IFrameTemporalReferenceOffset());
                        // determine frame info:
                        if (isVideo) {
                           if (abs(Delta - 3600) <= 1)
@@ -1475,7 +1495,7 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
                           }
                        else // audio
                           framesPerSecond = double(PTSTICKS) / Delta; // PTS of audio frames is always increasing
-                       dbgframes("\nDelta = %d  FPS = %5.2f  FPPU = %d NF = %d\n", Delta, framesPerSecond, framesPerPayloadUnit, numPtsValues + 1);
+                       dbgframes("\nDelta = %d  FPS = %5.2f  FPPU = %d NF = %d TRO = %d\n", Delta, framesPerSecond, framesPerPayloadUnit, numPtsValues + 1, parser->IFrameTemporalReferenceOffset());
                        synced = true;
                        parser->SetDebug(false);
                        }