Improved clearing the MTD buffer and syncing on TS packets

device.c

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: device.c 4.9 2017/03/23 14:19:59 kls Exp $
+ * $Id: device.c 4.10 2017/03/26 11:35:38 kls Exp $
  */
 
 #include "device.h"
@@ -1570,13 +1570,8 @@ int cDevice::PlayTs(const uchar *Data, int Length, bool VideoOnly)
      }
   else {
      while (Length >= TS_SIZE) {
-           if (Data[0] != TS_SYNC_BYTE) {
+           if (int Skipped = TS_SYNC(Data, Length))
-              int Skipped = 1;
-              while (Skipped < Length && (Data[Skipped] != TS_SYNC_BYTE || Length - Skipped > TS_SIZE && Data[Skipped + TS_SIZE] != TS_SYNC_BYTE))
-                    Skipped++;
-              esyslog("ERROR: skipped %d bytes to sync on start of TS packet", Skipped);
               return Played + Skipped;
-              }
            int Pid = TsPid(Data);
            if (TsHasPayload(Data)) { // silently ignore TS packets w/o payload
               int PayloadOffset = TsPayloadOffset(Data);

mtd.c

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: mtd.c 1.5 2017/03/25 14:09:31 kls Exp $
+ * $Id: mtd.c 1.6 2017/03/26 13:01:32 kls Exp $
  */
 
 #include "mtd.h"
@@ -229,7 +229,6 @@ cMtdCamSlot::cMtdCamSlot(cCamSlot *MasterSlot, int Index)
   mtdBuffer = new cRingBufferLinear(MTD_BUFFER_SIZE, TS_SIZE, true, "MTD buffer");
   mtdMapper = new cMtdMapper(Index + 1, MasterSlot->SlotNumber());
   delivered = false;
-  clearBuffer = false;
   ciAdapter = MasterSlot->ciAdapter; // we don't pass the CI adapter in the constructor, to prevent this one from being inserted into CamSlots
 }
 
@@ -279,8 +278,10 @@ void cMtdCamSlot::StopDecrypting(void)
   cCamSlot::StopDecrypting();
   if (!MasterSlot()->IsDecrypting())
      MasterSlot()->StopDecrypting();
+  cMutexLock MutexLock(&mutex);
   mtdMapper->Clear();
-  clearBuffer = true;
+  mtdBuffer->Clear();
+  delivered = false;
 }
 
 uchar *cMtdCamSlot::Decrypt(uchar *Data, int &Count)
@@ -297,18 +298,19 @@ uchar *cMtdCamSlot::Decrypt(uchar *Data, int &Count)
   else
      Count = 0;
   // Drop delivered data from previous call:
+  cMutexLock MutexLock(&mutex);
   if (delivered) {
      mtdBuffer->Del(TS_SIZE);
      delivered = false;
      }
-  if (clearBuffer) {
-     mtdBuffer->Clear();
-     clearBuffer = false;
-     }
   // Receive data from buffer:
   int c = 0;
   uchar *d = mtdBuffer->Get(c);
   if (d) {
+     if (int Skipped = TS_SYNC(d, c)) {
+        mtdBuffer->Del(Skipped);
+        return NULL;
+        }
      if (c >= TS_SIZE) {
         TsSetPid(d, mtdMapper->UniqToRealPid(TsPid(d)));
         delivered = true;
@@ -321,6 +323,13 @@ uchar *cMtdCamSlot::Decrypt(uchar *Data, int &Count)
 
 int cMtdCamSlot::PutData(const uchar *Data, int Count)
 {
+  cMutexLock MutexLock(&mutex);
+  int Free = mtdBuffer->Free();
+  Free -= Free % TS_SIZE;
+  if (Free < TS_SIZE)
+     return 0;
+  if (Free < Count)
+     Count = Free;
   return mtdBuffer->Put(Data, Count);
 }
 

mtd.h

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: mtd.h 1.4 2017/03/23 12:48:22 kls Exp $
+ * $Id: mtd.h 1.5 2017/03/25 14:47:03 kls Exp $
  */
 
 #ifndef __MTD_H
@@ -151,10 +151,10 @@ void MtdMapPid(uchar *p, cMtdMapper *MtdMapper);
 
 class cMtdCamSlot : public cCamSlot {
 private:
+  cMutex mutex;
   cMtdMapper *mtdMapper;
   cRingBufferLinear *mtdBuffer;
   bool delivered;
-  bool clearBuffer;
 protected:
   virtual const int *GetCaSystemIds(void);
   virtual void SendCaPmt(uint8_t CmdId);

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 4.4 2017/01/09 15:05:05 kls Exp $
+ * $Id: remux.c 4.5 2017/03/26 13:07:01 kls Exp $
  */
 
 #include "remux.h"
@@ -144,6 +144,19 @@ void TsSetPcr(uchar *p, int64_t Pcr)
      }
 }
 
+int TsSync(const uchar *Data, int Length, const char *File, const char *Function, int Line)
+{
+  int Skipped = 0;
+  while (Length > 0 && (*Data != TS_SYNC_BYTE || Length > TS_SIZE && Data[TS_SIZE] != TS_SYNC_BYTE)) {
+        Data++;
+        Length--;
+        Skipped++;
+        }
+  if (Skipped && File && Function && Line)
+     esyslog("ERROR: skipped %d bytes to sync on start of TS packet at %s/%s(%d)", Skipped, File, Function, Line);
+  return Skipped;
+}
+
 int64_t TsGetPts(const uchar *p, int l)
 {
   // Find the first packet with a PTS and use it:
@@ -1557,13 +1570,8 @@ int cFrameDetector::Analyze(const uchar *Data, int Length)
   newFrame = independentFrame = false;
   while (Length >= MIN_TS_PACKETS_FOR_FRAME_DETECTOR * TS_SIZE) { // makes sure we are looking at enough data, in case the frame type is not stored in the first TS packet
         // Sync on TS packet borders:
-        if (Data[0] != TS_SYNC_BYTE) {
+        if (int Skipped = TS_SYNC(Data, Length))
-           int Skipped = 1;
-           while (Skipped < Length && (Data[Skipped] != TS_SYNC_BYTE || Length - Skipped > TS_SIZE && Data[Skipped + TS_SIZE] != TS_SYNC_BYTE))
-                 Skipped++;
-           esyslog("ERROR: skipped %d bytes to sync on start of TS packet", Skipped);
            return Processed + Skipped;
-           }
         // Handle one TS packet:
         int Handled = TS_SIZE;
         if (TsHasPayload(Data) && !TsIsScrambled(Data)) {

remux.h

@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: remux.h 4.2 2017/02/27 16:11:57 kls Exp $
+ * $Id: remux.h 4.3 2017/03/26 13:06:37 kls Exp $
  */
 
 #ifndef __REMUX_H
@@ -144,6 +144,15 @@ inline int64_t TsGetPcr(const uchar *p)
 void TsHidePayload(uchar *p);
 void TsSetPcr(uchar *p, int64_t Pcr);
 
+// Helper macro and function to quickly check whether Data points to the beginning
+// of a TS packet. The return value is the number of bytes that need to be skipped
+// to synchronize on the next TS packet (zero if already sync'd). TsSync() can be
+// called directly, the macro just performs the initial check inline and adds some
+// debug information for logging.
+
+#define TS_SYNC(Data, Length) (*Data == TS_SYNC_BYTE ? 0 : TsSync(Data, Length, __FILE__, __FUNCTION__, __LINE__))
+int TsSync(const uchar *Data, int Length, const char *File = NULL, const char *Function = NULL, int Line = 0);
+
 // The following functions all take a pointer to a sequence of complete TS packets.
 
 int64_t TsGetPts(const uchar *p, int l);