vdr/remux.c

/*
 * remux.c: A streaming MPEG2 remultiplexer
 *
 * See the main source file 'vdr.c' for copyright information and
 * how to reach the author.
 *
 * The parts of this code that implement cTS2PES have been taken from
 * the Linux DVB driver's 'tuxplayer' example and were rewritten to suit
 * VDR's needs.
 *
 * The cRepacker family's code was originally written by Reinhard Nissl <rnissl@gmx.de>,
 * and adapted to the VDR coding style by Klaus.Schmidinger@cadsoft.de.
 *
 * $Id: remux.c 1.58 2007/02/24 16:36:10 kls Exp $
 */

#include "remux.h"
#include <stdlib.h>
#include "channels.h"
#include "shutdown.h"
#include "tools.h"

ePesHeader AnalyzePesHeader(const uchar *Data, int Count, int &PesPayloadOffset, bool *ContinuationHeader)
{
  if (Count < 7)
     return phNeedMoreData; // too short

  if ((Data[6] & 0xC0) == 0x80) { // MPEG 2
     if (Count < 9)
        return phNeedMoreData; // too short

     PesPayloadOffset = 6 + 3 + Data[8];
     if (Count < PesPayloadOffset)
        return phNeedMoreData; // too short

     if (ContinuationHeader)
        *ContinuationHeader = ((Data[6] == 0x80) && !Data[7] && !Data[8]);

     return phMPEG2; // MPEG 2
     }

  // check for MPEG 1 ...
  PesPayloadOffset = 6;

  // skip up to 16 stuffing bytes
  for (int i = 0; i < 16; i++) {
      if (Data[PesPayloadOffset] != 0xFF)
         break;

      if (Count <= ++PesPayloadOffset)
         return phNeedMoreData; // too short
      }

  // skip STD_buffer_scale/size
  if ((Data[PesPayloadOffset] & 0xC0) == 0x40) {
     PesPayloadOffset += 2;

     if (Count <= PesPayloadOffset)
        return phNeedMoreData; // too short
     }

  if (ContinuationHeader)
     *ContinuationHeader = false;

  if ((Data[PesPayloadOffset] & 0xF0) == 0x20) {
     // skip PTS only
     PesPayloadOffset += 5;
     }
  else if ((Data[PesPayloadOffset] & 0xF0) == 0x30) {
     // skip PTS and DTS
     PesPayloadOffset += 10;
     }
  else if (Data[PesPayloadOffset] == 0x0F) {
     // continuation header
     PesPayloadOffset++;

     if (ContinuationHeader)
        *ContinuationHeader = true;
     }
  else
     return phInvalid; // unknown

  if (Count < PesPayloadOffset)
     return phNeedMoreData; // too short

  return phMPEG1; // MPEG 1
}

// --- cRepacker -------------------------------------------------------------

#define MIN_LOG_INTERVAL 10 // min. # of seconds between two consecutive log messages of a cRepacker
#define LOG(a...) (LogAllowed() && (esyslog(a), true))

class cRepacker {
protected:
  bool initiallySyncing;
  int maxPacketSize;
  uint8_t subStreamId;
  time_t lastLog;
  int suppressedLogMessages;
  bool LogAllowed(void);
  void DroppedData(const char *Reason, int Count) { LOG("%s (dropped %d bytes)", Reason, Count); }
public:
  static int Put(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count, int CapacityNeeded);
  cRepacker(void);
  virtual ~cRepacker() {}
  virtual void Reset(void) { initiallySyncing = true; }
  virtual void Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count) = 0;
  virtual int BreakAt(const uchar *Data, int Count) = 0;
  virtual int QuerySnoopSize(void) { return 0; }
  void SetMaxPacketSize(int MaxPacketSize) { maxPacketSize = MaxPacketSize; }
  void SetSubStreamId(uint8_t SubStreamId) { subStreamId = SubStreamId; }
  };

cRepacker::cRepacker(void)
{
  initiallySyncing = true;
  maxPacketSize = 6 + 65535;
  subStreamId = 0;
  suppressedLogMessages = 0;;
  lastLog = 0;
}

bool cRepacker::LogAllowed(void)
{
  bool Allowed = time(NULL) - lastLog >= MIN_LOG_INTERVAL;
  lastLog = time(NULL);
  if (Allowed) {
     if (suppressedLogMessages) {
        esyslog("%d cRepacker messages suppressed", suppressedLogMessages);
        suppressedLogMessages = 0;
        }
     }
  else
     suppressedLogMessages++;
  return Allowed;
}

int cRepacker::Put(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count, int CapacityNeeded)
{
  if (CapacityNeeded >= Count && ResultBuffer->Free() < CapacityNeeded) {
     esyslog("ERROR: possible result buffer overflow, dropped %d out of %d byte", CapacityNeeded, CapacityNeeded);
     return 0;
     }
  int n = ResultBuffer->Put(Data, Count);
  if (n != Count)
     esyslog("ERROR: result buffer overflow, dropped %d out of %d byte", Count - n, Count);
  return n;
}

// --- cCommonRepacker -------------------------------------------------------

class cCommonRepacker : public cRepacker {
protected:
  int skippedBytes;
  int packetTodo;
  uchar fragmentData[6 + 65535 + 3];
  int fragmentLen;
  uchar pesHeader[6 + 3 + 255 + 3];
  int pesHeaderLen;
  uchar pesHeaderBackup[6 + 3 + 255];
  int pesHeaderBackupLen;
  uint32_t scanner;
  uint32_t localScanner;
  int localStart;
  bool PushOutPacket(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count);
  virtual int QuerySnoopSize() { return 4; }
  virtual void Reset(void);
  };

void cCommonRepacker::Reset(void)
{
  cRepacker::Reset();
  skippedBytes = 0;
  packetTodo = 0;
  fragmentLen = 0;
  pesHeaderLen = 0;
  pesHeaderBackupLen = 0;
  localStart = -1;
}

bool cCommonRepacker::PushOutPacket(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count)
{
  // enter packet length into PES header ...
  if (fragmentLen > 0) { // ... which is contained in the fragment buffer
     // determine PES packet payload
     int PacketLen = fragmentLen + Count - 6;
     fragmentData[ 4 ] = PacketLen >> 8;
     fragmentData[ 5 ] = PacketLen & 0xFF;
     // just skip packets with no payload
     int PesPayloadOffset = 0;
     if (AnalyzePesHeader(fragmentData, fragmentLen, PesPayloadOffset) <= phInvalid)
        LOG("cCommonRepacker: invalid PES packet encountered in fragment buffer!");
     else if (6 + PacketLen <= PesPayloadOffset) {
        fragmentLen = 0;
        return true; // skip empty packet
        }
     // amount of data to put into result buffer: a negative Count value means
     // to strip off any partially contained start code.
     int Bite = fragmentLen + (Count >= 0 ? 0 : Count);
     // put data into result buffer
     int n = Put(ResultBuffer, fragmentData, Bite, 6 + PacketLen);
     fragmentLen = 0;
     if (n != Bite)
        return false;
     }
  else if (pesHeaderLen > 0) { // ... which is contained in the PES header buffer
     int PacketLen = pesHeaderLen + Count - 6;
     pesHeader[ 4 ] = PacketLen >> 8;
     pesHeader[ 5 ] = PacketLen & 0xFF;
     // just skip packets with no payload
     int PesPayloadOffset = 0;
     if (AnalyzePesHeader(pesHeader, pesHeaderLen, PesPayloadOffset) <= phInvalid)
        LOG("cCommonRepacker: invalid PES packet encountered in header buffer!");
     else if (6 + PacketLen <= PesPayloadOffset) {
        pesHeaderLen = 0;
        return true; // skip empty packet
        }
     // amount of data to put into result buffer: a negative Count value means
     // to strip off any partially contained start code.
     int Bite = pesHeaderLen + (Count >= 0 ? 0 : Count);
     // put data into result buffer
     int n = Put(ResultBuffer, pesHeader, Bite, 6 + PacketLen);
     pesHeaderLen = 0;
     if (n != Bite)
        return false;
     }
  // append further payload
  if (Count > 0) {
     // amount of data to put into result buffer
     int Bite = Count;
     // put data into result buffer
     int n = Put(ResultBuffer, Data, Bite, Bite);
     if (n != Bite)
        return false;
     }
  // we did it ;-)
  return true;
}

// --- cVideoRepacker --------------------------------------------------------

class cVideoRepacker : public cCommonRepacker {
private:
  enum eState {
    syncing,
    findPicture,
    scanPicture
    };
  int state;
  void HandleStartCode(const uchar *const Data, cRingBufferLinear *const ResultBuffer, const uchar *&Payload, const uchar StreamID, const ePesHeader MpegLevel);
  inline bool ScanDataForStartCodeSlow(const uchar *const Data);
  inline bool ScanDataForStartCodeFast(const uchar *&Data, const uchar *Limit);
  inline bool ScanDataForStartCode(const uchar *&Data, int &Done, int &Todo);
  inline void AdjustCounters(const int Delta, int &Done, int &Todo);
  inline bool ScanForEndOfPictureSlow(const uchar *&Data);
  inline bool ScanForEndOfPictureFast(const uchar *&Data, const uchar *Limit);
  inline bool ScanForEndOfPicture(const uchar *&Data, const uchar *Limit);
public:
  cVideoRepacker(void);
  virtual void Reset(void);
  virtual void Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count);
  virtual int BreakAt(const uchar *Data, int Count);
  };

cVideoRepacker::cVideoRepacker(void)
{
  Reset();
}

void cVideoRepacker::Reset(void)
{
  cCommonRepacker::Reset();
  scanner = 0xFFFFFFFF;
  state = syncing;
}

void cVideoRepacker::HandleStartCode(const uchar *const Data, cRingBufferLinear *const ResultBuffer, const uchar *&Payload, const uchar StreamID, const ePesHeader MpegLevel)
{
  // synchronisation is detected some bytes after frame start.
  const int SkippedBytesLimit = 4;

  // which kind of start code have we got?
  switch (*Data) {
    case 0xB9 ... 0xFF: // system start codes
         LOG("cVideoRepacker: found system start code: stream seems to be scrambled or not demultiplexed");
         break;
    case 0xB0 ... 0xB1: // reserved start codes
    case 0xB6:
         LOG("cVideoRepacker: found reserved start code: stream seems to be scrambled");
         break;
    case 0xB4: // sequence error code
         LOG("cVideoRepacker: found sequence error code: stream seems to be damaged");
    case 0xB2: // user data start code
    case 0xB5: // extension start code
         break;
    case 0xB7: // sequence end code
    case 0xB3: // sequence header code
    case 0xB8: // group start code
    case 0x00: // picture start code
         if (state == scanPicture) {
            // the above start codes indicate that the current picture is done. So
            // push out the packet to start a new packet for the next picuture. If
            // the byte count get's negative then the current buffer ends in a
            // partitial start code that must be stripped off, as it shall be put
            // in the next packet.
            PushOutPacket(ResultBuffer, Payload, Data - 3 - Payload);
            // go on with syncing to the next picture
            state = syncing;
            }
         if (state == syncing) {
            if (initiallySyncing) // omit report for the typical initial case
               initiallySyncing = false;
            else if (skippedBytes > SkippedBytesLimit) // report that syncing dropped some bytes
               LOG("cVideoRepacker: skipped %d bytes to sync on next picture", skippedBytes - SkippedBytesLimit);
            skippedBytes = 0;
            // if there is a PES header available, then use it ...
            if (pesHeaderBackupLen > 0) {
               // ISO 13818-1 says:
               // In the case of video, if a PTS is present in a PES packet header
               // it shall refer to the access unit containing the first picture start
               // code that commences in this PES packet. A picture start code commences
               // in PES packet if the first byte of the picture start code is present
               // in the PES packet.
               memcpy(pesHeader, pesHeaderBackup, pesHeaderBackupLen);
               pesHeaderLen = pesHeaderBackupLen;
               pesHeaderBackupLen = 0;
               }
            else {
               // ... otherwise create a continuation PES header
               pesHeaderLen = 0;
               pesHeader[pesHeaderLen++] = 0x00;
               pesHeader[pesHeaderLen++] = 0x00;
               pesHeader[pesHeaderLen++] = 0x01;
               pesHeader[pesHeaderLen++] = StreamID; // video stream ID
               pesHeader[pesHeaderLen++] = 0x00; // length still unknown
               pesHeader[pesHeaderLen++] = 0x00; // length still unknown

               if (MpegLevel == phMPEG2) {
                  pesHeader[pesHeaderLen++] = 0x80;
                  pesHeader[pesHeaderLen++] = 0x00;
                  pesHeader[pesHeaderLen++] = 0x00;
                  }
               else
                  pesHeader[pesHeaderLen++] = 0x0F;
               }
            // append the first three bytes of the start code
            pesHeader[pesHeaderLen++] = 0x00;
            pesHeader[pesHeaderLen++] = 0x00;
            pesHeader[pesHeaderLen++] = 0x01;
            // the next packet's payload will begin with the fourth byte of
            // the start code (= the actual code)
            Payload = Data;
            // as there is no length information available, assume the
            // maximum we can hold in one PES packet
            packetTodo = maxPacketSize - pesHeaderLen;
            // go on with finding the picture data
            state++;
            }
         break;
    case 0x01 ... 0xAF: // slice start codes
         if (state == findPicture) {
            // go on with scanning the picture data
            state++;
            }
         break;
    }
}

bool cVideoRepacker::ScanDataForStartCodeSlow(const uchar *const Data)
{
  scanner <<= 8;
  bool FoundStartCode = (scanner == 0x00000100);
  scanner |= *Data;
  return FoundStartCode;
}

bool cVideoRepacker::ScanDataForStartCodeFast(const uchar *&Data, const uchar *Limit)
{
  Limit--;

  while (Data < Limit && (Data = (const uchar *)memchr(Data, 0x01, Limit - Data))) {
        if (Data[-2] || Data[-1])
           Data += 3;
        else {
           scanner = 0x00000100 | *++Data;
           return true;
           }
        }

  Data = Limit;
  uint32_t *Scanner = (uint32_t *)(Data - 3);
  scanner = ntohl(*Scanner);
  return false;
}

bool cVideoRepacker::ScanDataForStartCode(const uchar *&Data, int &Done, int &Todo)
{
  const uchar *const DataOrig = Data;
  const int MinDataSize = 4;

  if (Todo < MinDataSize || (state != syncing && packetTodo < MinDataSize))
     return ScanDataForStartCodeSlow(Data);

  int Limit = Todo;
  if (state != syncing && Limit > packetTodo)
     Limit = packetTodo;

  if (ScanDataForStartCodeSlow(Data))
     return true;

  if (ScanDataForStartCodeSlow(++Data)) {
     AdjustCounters(1, Done, Todo);
     return true;
     }
  ++Data;

  bool FoundStartCode = ScanDataForStartCodeFast(Data, DataOrig + Limit);
  AdjustCounters(Data - DataOrig, Done, Todo);
  return FoundStartCode;
}

void cVideoRepacker::AdjustCounters(const int Delta, int &Done, int &Todo)
{
  Done += Delta;
  Todo -= Delta;

  if (state <= syncing)
     skippedBytes += Delta;
  else
     packetTodo -= Delta;
}

void cVideoRepacker::Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count)
{
  // synchronisation is detected some bytes after frame start.
  const int SkippedBytesLimit = 4;

  // reset local scanner
  localStart = -1;

  int pesPayloadOffset = 0;
  bool continuationHeader = false;
  ePesHeader mpegLevel = AnalyzePesHeader(Data, Count, pesPayloadOffset, &continuationHeader);
  if (mpegLevel <= phInvalid) {
     DroppedData("cVideoRepacker: no valid PES packet header found", Count);
     return;
     }
  if (!continuationHeader) {
    // backup PES header
    pesHeaderBackupLen = pesPayloadOffset;
    memcpy(pesHeaderBackup, Data, pesHeaderBackupLen);
    }

  // skip PES header
  int done = pesPayloadOffset;
  int todo = Count - done;
  const uchar *data = Data + done;
  // remember start of the data
  const uchar *payload = data;

  while (todo > 0) {
        // collect number of skipped bytes while syncing
        if (state <= syncing)
           skippedBytes++;
        // did we reach a start code?
        if (ScanDataForStartCode(data, done, todo))
           HandleStartCode(data, ResultBuffer, payload, Data[3], mpegLevel);
        // move on
        data++;
        done++;
        todo--;
        // do we have to start a new packet as there is no more space left?
        if (state != syncing && --packetTodo <= 0) {
           // we connot start a new packet here if the current might end in a start
           // code and this start code shall possibly be put in the next packet. So
           // overfill the current packet until we can safely detect that we won't
           // break a start code into pieces:
           //
           // A) the last four bytes were a start code.
           // B) the current byte introduces a start code.
           // C) the last three bytes begin a start code.
           //
           // Todo : Data                          : Rule : Result
           // -----:-------------------------------:------:-------
           //      : XX 00 00 00 01 YY|YY YY YY YY :      :
           //    0 :                ^^|            : A    : push
           // -----:-------------------------------:------:-------
           //      : XX XX 00 00 00 01|YY YY YY YY :      :
           //    0 :                ^^|            : B    : wait
           //   -1 :                  |^^          : A    : push
           // -----:-------------------------------:------:-------
           //      : XX XX XX 00 00 00|01 YY YY YY :      :
           //    0 :                ^^|            : C    : wait
           //   -1 :                  |^^          : B    : wait
           //   -2 :                  |   ^^       : A    : push
           // -----:-------------------------------:------:-------
           //      : XX XX XX XX 00 00|00 01 YY YY :      :
           //    0 :                ^^|            : C    : wait
           //   -1 :                  |^^          : C    : wait
           //   -2 :                  |   ^^       : B    : wait
           //   -3 :                  |      ^^    : A    : push
           // -----:-------------------------------:------:-------
           //      : XX XX XX XX XX 00|00 00 01 YY :      :
           //    0 :                ^^|            : C    : wait
           //   -1 :                  |^^          : C    : wait
           //   -2 :                  |   ^^       :      : push
           // -----:-------------------------------:------:-------
           bool A = ((scanner & 0xFFFFFF00) == 0x00000100);
           bool B = ((scanner &   0xFFFFFF) ==   0x000001);
           bool C = ((scanner &       0xFF) ==       0x00) && (packetTodo >= -1);
           if (A || (!B && !C)) {
              // actually we cannot push out an overfull packet. So we'll have to
              // adjust the byte count and payload start as necessary. If the byte
              // count get's negative we'll have to append the excess from fragment's
              // tail to the next PES header.
              int bite = data + packetTodo - payload;
              const uchar *excessData = fragmentData + fragmentLen + bite;
              // a negative byte count means to drop some bytes from the current
              // fragment's tail, to not exceed the maximum packet size.
              PushOutPacket(ResultBuffer, payload, bite);
              // create a continuation PES header
              pesHeaderLen = 0;
              pesHeader[pesHeaderLen++] = 0x00;
              pesHeader[pesHeaderLen++] = 0x00;
              pesHeader[pesHeaderLen++] = 0x01;
              pesHeader[pesHeaderLen++] = Data[3]; // video stream ID
              pesHeader[pesHeaderLen++] = 0x00; // length still unknown
              pesHeader[pesHeaderLen++] = 0x00; // length still unknown

              if (mpegLevel == phMPEG2) {
                 pesHeader[pesHeaderLen++] = 0x80;
                 pesHeader[pesHeaderLen++] = 0x00;
                 pesHeader[pesHeaderLen++] = 0x00;
                 }
              else
                 pesHeader[pesHeaderLen++] = 0x0F;

              // copy any excess data
              while (bite++ < 0) {
                    // append the excess data here
                    pesHeader[pesHeaderLen++] = *excessData++;
                    packetTodo++;
                    }
              // the next packet's payload will begin here
              payload = data + packetTodo;
              // as there is no length information available, assume the
              // maximum we can hold in one PES packet
              packetTodo += maxPacketSize - pesHeaderLen;
              }
           }
        }
  // the packet is done. Now store any remaining data into fragment buffer
  // if we are no longer syncing.
  if (state != syncing) {
     // append the PES header ...
     int bite = pesHeaderLen;
     pesHeaderLen = 0;
     if (bite > 0) {
        memcpy(fragmentData + fragmentLen, pesHeader, bite);
        fragmentLen += bite;
        }
     // append payload. It may contain part of a start code at it's end,
     // which will be removed when the next packet gets processed.
     bite = data - payload;
     if (bite > 0) {
        memcpy(fragmentData + fragmentLen, payload, bite);
        fragmentLen += bite;
        }
     }
  // report that syncing dropped some bytes
  if (skippedBytes > SkippedBytesLimit) {
     if (!initiallySyncing) // omit report for the typical initial case
        LOG("cVideoRepacker: skipped %d bytes while syncing on next picture", skippedBytes - SkippedBytesLimit);
     skippedBytes = SkippedBytesLimit;
     }
}

bool cVideoRepacker::ScanForEndOfPictureSlow(const uchar *&Data)
{
  localScanner <<= 8;
  localScanner |= *Data++;
  // check start codes which follow picture data
  switch (localScanner) {
    case 0x00000100: // picture start code
    case 0x000001B8: // group start code
    case 0x000001B3: // sequence header code
    case 0x000001B7: // sequence end code
         return true;
    }
  return false;
}

bool cVideoRepacker::ScanForEndOfPictureFast(const uchar *&Data, const uchar *Limit)
{
  Limit--;

  while (Data < Limit && (Data = (const uchar *)memchr(Data, 0x01, Limit - Data))) {
        if (Data[-2] || Data[-1])
           Data += 3;
        else {
           localScanner = 0x00000100 | *++Data;
           // check start codes which follow picture data
           switch (localScanner) {
             case 0x00000100: // picture start code
             case 0x000001B8: // group start code
             case 0x000001B3: // sequence header code
             case 0x000001B7: // sequence end code
                  Data++;
                  return true;
             default:
                  Data += 3;
             }
           }
        }

  Data = Limit + 1;
  uint32_t *LocalScanner = (uint32_t *)(Data - 4);
  localScanner = ntohl(*LocalScanner);
  return false;
}

bool cVideoRepacker::ScanForEndOfPicture(const uchar *&Data, const uchar *Limit)
{
  const uchar *const DataOrig = Data;
  const int MinDataSize = 4;
  bool FoundEndOfPicture;

  if (Limit - Data <= MinDataSize) {
     FoundEndOfPicture = false;
     while (Data < Limit) {
           if (ScanForEndOfPictureSlow(Data)) {
              FoundEndOfPicture = true;
              break;
              }
           }
     }
  else {
     FoundEndOfPicture = true;
     if (!ScanForEndOfPictureSlow(Data)) {
        if (!ScanForEndOfPictureSlow(Data)) {
           if (!ScanForEndOfPictureFast(Data, Limit))
              FoundEndOfPicture = false;
           }
        }
     }

  localStart += (Data - DataOrig);
  return FoundEndOfPicture;
}

int cVideoRepacker::BreakAt(const uchar *Data, int Count)
{
  if (initiallySyncing)
     return -1; // fill the packet buffer completely until we have synced once

  int PesPayloadOffset = 0;

  if (AnalyzePesHeader(Data, Count, PesPayloadOffset) <= phInvalid)
     return -1; // not enough data for test

  // just detect end of picture
  if (state == scanPicture) {
     // setup local scanner
     if (localStart < 0) {
        localScanner = scanner;
        localStart = 0;
        }
     // start where we've stopped at the last run
     const uchar *data = Data + PesPayloadOffset + localStart;
     const uchar *limit = Data + Count;
     // scan data
     if (ScanForEndOfPicture(data, limit))
        return data - Data;
     }
  // just fill up packet and append next start code
  return PesPayloadOffset + packetTodo + 4;
}

// --- cAudioRepacker --------------------------------------------------------

class cAudioRepacker : public cCommonRepacker {
private:
  static int bitRates[2][3][16];
  enum eState {
    syncing,
    scanFrame
    };
  int state;
  int frameTodo;
  int frameSize;
  int cid;
  static bool IsValidAudioHeader(uint32_t Header, bool Mpeg2, int *FrameSize = NULL);
public:
  cAudioRepacker(int Cid);
  virtual void Reset(void);
  virtual void Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count);
  virtual int BreakAt(const uchar *Data, int Count);
  };

int cAudioRepacker::bitRates[2][3][16] = { // all values are specified as kbits/s
  {
    { 0,  32,  64,  96, 128, 160, 192, 224, 256, 288, 320, 352, 384, 416, 448, -1 }, // MPEG 1, Layer I
    { 0,  32,  48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, 384, -1 }, // MPEG 1, Layer II
    { 0,  32,  40,  48,  56,  64,  80,  96, 112, 128, 160, 192, 224, 256, 320, -1 }  // MPEG 1, Layer III
  },
  {
    { 0,  32,  48,  56,  64,  80,  96, 112, 128, 144, 160, 176, 192, 224, 256, -1 }, // MPEG 2, Layer I
    { 0,   8,  16,  24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160, -1 }, // MPEG 2, Layer II/III
    { 0,   8,  16,  24,  32,  40,  48,  56,  64,  80,  96, 112, 128, 144, 160, -1 }  // MPEG 2, Layer II/III
  }
  };

cAudioRepacker::cAudioRepacker(int Cid)
{
  cid = Cid;
  Reset();
}

void cAudioRepacker::Reset(void)
{
  cCommonRepacker::Reset();
  scanner = 0;
  state = syncing;
  frameTodo = 0;
  frameSize = 0;
}

bool cAudioRepacker::IsValidAudioHeader(uint32_t Header, bool Mpeg2, int *FrameSize)
{
  int syncword           = (Header & 0xFFF00000) >> 20;
  int id                 = (Header & 0x00080000) >> 19;
  int layer              = (Header & 0x00060000) >> 17;
//int protection_bit     = (Header & 0x00010000) >> 16;
  int bitrate_index      = (Header & 0x0000F000) >> 12;
  int sampling_frequency = (Header & 0x00000C00) >> 10;
  int padding_bit        = (Header & 0x00000200) >>  9;
//int private_bit        = (Header & 0x00000100) >>  8;
//int mode               = (Header & 0x000000C0) >>  6;
//int mode_extension     = (Header & 0x00000030) >>  4;
//int copyright          = (Header & 0x00000008) >>  3;
//int orignal_copy       = (Header & 0x00000004) >>  2;
  int emphasis           = (Header & 0x00000003);

  if (syncword != 0xFFF)
     return false;

  if (id == 0 && !Mpeg2) // reserved in MPEG 1
     return false;

  if (layer == 0) // reserved
     return false;

  if (bitrate_index == 0xF) // forbidden
     return false;

  if (sampling_frequency == 3) // reserved
     return false;

  if (emphasis == 2) // reserved
     return false;

  if (FrameSize) {
     if (bitrate_index == 0)
        *FrameSize = 0;
     else {
        static int samplingFrequencies[2][4] = { // all values are specified in Hz
          { 44100, 48000, 32000, -1 }, // MPEG 1
          { 22050, 24000, 16000, -1 }  // MPEG 2
          };

        static int slots_per_frame[2][3] = {
          { 12, 144, 144 }, // MPEG 1, Layer I, II, III
          { 12, 144,  72 }  // MPEG 2, Layer I, II, III
          };

        int mpegIndex = 1 - id;
        int layerIndex = 3 - layer;

        // Layer I (i. e., layerIndex == 0) has a larger slot size
        int slotSize = (layerIndex == 0) ? 4 : 1; // bytes

        int br = 1000 * bitRates[mpegIndex][layerIndex][bitrate_index]; // bits/s
        int sf = samplingFrequencies[mpegIndex][sampling_frequency];

        int N = slots_per_frame[mpegIndex][layerIndex] * br / sf; // slots

        *FrameSize = (N + padding_bit) * slotSize; // bytes
        }
     }

  return true;
}

void cAudioRepacker::Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count)
{
  // synchronisation is detected some bytes after frame start.
  const int SkippedBytesLimit = 4;

  // reset local scanner
  localStart = -1;

  int pesPayloadOffset = 0;
  bool continuationHeader = false;
  ePesHeader mpegLevel = AnalyzePesHeader(Data, Count, pesPayloadOffset, &continuationHeader);
  if (mpegLevel <= phInvalid) {
     DroppedData("cAudioRepacker: no valid PES packet header found", Count);
     return;
     }
  if (!continuationHeader) {
     // backup PES header
     pesHeaderBackupLen = pesPayloadOffset;
     memcpy(pesHeaderBackup, Data, pesHeaderBackupLen);
     }

  // skip PES header
  int done = pesPayloadOffset;
  int todo = Count - done;
  const uchar *data = Data + done;
  // remember start of the data
  const uchar *payload = data;

  while (todo > 0) {
        // collect number of skipped bytes while syncing
        if (state <= syncing)
           skippedBytes++;
        // did we reach an audio frame header?
        scanner <<= 8;
        scanner |= *data;
        if ((scanner & 0xFFF00000) == 0xFFF00000) {
           if (frameTodo <= 0 && (frameSize == 0 || skippedBytes >= 4) && IsValidAudioHeader(scanner, mpegLevel == phMPEG2, &frameSize)) {
              if (state == scanFrame) {
                 // As a new audio frame starts here, the previous one is done. So push
                 // out the packet to start a new packet for the next audio frame. If
                 // the byte count gets negative then the current buffer ends in a
                 // partitial audio frame header that must be stripped off, as it shall
                 // be put in the next packet.
                 PushOutPacket(ResultBuffer, payload, data - 3 - payload);
                 // go on with syncing to the next audio frame
                 state = syncing;
                 }
              if (state == syncing) {
                 if (initiallySyncing) // omit report for the typical initial case
                    initiallySyncing = false;
                 else if (skippedBytes > SkippedBytesLimit) // report that syncing dropped some bytes
                    LOG("cAudioRepacker(0x%02X): skipped %d bytes to sync on next audio frame", cid, skippedBytes - SkippedBytesLimit);
                 skippedBytes = 0;
                 // if there is a PES header available, then use it ...
                 if (pesHeaderBackupLen > 0) {
                    // ISO 13818-1 says:
                    // In the case of audio, if a PTS is present in a PES packet header
                    // it shall refer to the access unit commencing in the PES packet. An
                    // audio access unit commences in a PES packet if the first byte of
                    // the audio access unit is present in the PES packet.
                    memcpy(pesHeader, pesHeaderBackup, pesHeaderBackupLen);
                    pesHeaderLen = pesHeaderBackupLen;
                    pesHeaderBackupLen = 0;
                    }
                 else {
                    // ... otherwise create a continuation PES header
                    pesHeaderLen = 0;
                    pesHeader[pesHeaderLen++] = 0x00;
                    pesHeader[pesHeaderLen++] = 0x00;
                    pesHeader[pesHeaderLen++] = 0x01;
                    pesHeader[pesHeaderLen++] = Data[3]; // audio stream ID
                    pesHeader[pesHeaderLen++] = 0x00; // length still unknown
                    pesHeader[pesHeaderLen++] = 0x00; // length still unknown

                    if (mpegLevel == phMPEG2) {
                       pesHeader[pesHeaderLen++] = 0x80;
                       pesHeader[pesHeaderLen++] = 0x00;
                       pesHeader[pesHeaderLen++] = 0x00;
                       }
                    else
                       pesHeader[pesHeaderLen++] = 0x0F;
                    }
                 // append the first three bytes of the audio frame header
                 pesHeader[pesHeaderLen++] = 0xFF;
                 pesHeader[pesHeaderLen++] = (scanner >> 16) & 0xFF;
                 pesHeader[pesHeaderLen++] = (scanner >>  8) & 0xFF;
                 // the next packet's payload will begin with the fourth byte of
                 // the audio frame header (= the actual byte)
                 payload = data;
                 // maximum we can hold in one PES packet
                 packetTodo = maxPacketSize - pesHeaderLen;
                 // expected remainder of audio frame: so far we have read 3 bytes from the frame header
                 frameTodo = frameSize - 3;
                 // go on with collecting the frame's data
                 state++;
                 }
              }
           }
        data++;
        done++;
        todo--;
        // do we have to start a new packet as the current is done?
        if (frameTodo > 0) {
           if (--frameTodo == 0) {
              // the current audio frame is is done now. So push out the packet to
              // start a new packet for the next audio frame.
              PushOutPacket(ResultBuffer, payload, data - payload);
              // go on with syncing to the next audio frame
              state = syncing;
              }
           }
        // do we have to start a new packet as there is no more space left?
        if (state != syncing && --packetTodo <= 0) {
           // We connot start a new packet here if the current might end in an audio
           // frame header and this header shall possibly be put in the next packet. So
           // overfill the current packet until we can safely detect that we won't
           // break an audio frame header into pieces:
           //
           // A) the last four bytes were an audio frame header.
           // B) the last three bytes introduce an audio frame header.
           // C) the last two bytes introduce an audio frame header.
           // D) the last byte introduces an audio frame header.
           //
           // Todo : Data                          : Rule : Result
           // -----:-------------------------------:------:-------
           //      : XX XX FF Fz zz zz|YY YY YY YY :      :
           //    0 :                ^^|            : A    : push
           // -----:-------------------------------:------:-------
           //      : XX XX XX FF Fz zz|zz YY YY YY :      :
           //    0 :                ^^|            : B    : wait
           //   -1 :                  |^^          : A    : push
           // -----:-------------------------------:------:-------
           //      : XX XX XX XX FF Fz|zz zz YY YY :      :
           //    0 :                ^^|            : C    : wait
           //   -1 :                  |^^          : B    : wait
           //   -2 :                  |   ^^       : A    : push
           // -----:-------------------------------:------:-------
           //      : XX XX XX XX XX FF|Fz zz zz YY :      :
           //    0 :                ^^|            : D    : wait
           //   -1 :                  |^^          : C    : wait
           //   -2 :                  |   ^^       : B    : wait
           //   -3 :                  |      ^^    : A    : push
           // -----:-------------------------------:------:-------
           bool A = ((scanner & 0xFFF00000) == 0xFFF00000);
           bool B = ((scanner &   0xFFF000) ==   0xFFF000);
           bool C = ((scanner &     0xFFF0) ==     0xFFF0);
           bool D = ((scanner &       0xFF) ==       0xFF);
           if (A || (!B && !C && !D)) {
              // Actually we cannot push out an overfull packet. So we'll have to
              // adjust the byte count and payload start as necessary. If the byte
              // count gets negative we'll have to append the excess from fragment's
              // tail to the next PES header.
              int bite = data + packetTodo - payload;
              const uchar *excessData = fragmentData + fragmentLen + bite;
              // A negative byte count means to drop some bytes from the current
              // fragment's tail, to not exceed the maximum packet size.
              PushOutPacket(ResultBuffer, payload, bite);
              // create a continuation PES header
              pesHeaderLen = 0;
              pesHeader[pesHeaderLen++] = 0x00;
              pesHeader[pesHeaderLen++] = 0x00;
              pesHeader[pesHeaderLen++] = 0x01;
              pesHeader[pesHeaderLen++] = Data[3]; // audio stream ID
              pesHeader[pesHeaderLen++] = 0x00; // length still unknown
              pesHeader[pesHeaderLen++] = 0x00; // length still unknown

              if (mpegLevel == phMPEG2) {
                 pesHeader[pesHeaderLen++] = 0x80;
                 pesHeader[pesHeaderLen++] = 0x00;
                 pesHeader[pesHeaderLen++] = 0x00;
                 }
              else
                 pesHeader[pesHeaderLen++] = 0x0F;

              // copy any excess data
              while (bite++ < 0) {
                    // append the excess data here
                    pesHeader[pesHeaderLen++] = *excessData++;
                    packetTodo++;
                    }
              // the next packet's payload will begin here
              payload = data + packetTodo;
              // as there is no length information available, assume the
              // maximum we can hold in one PES packet
              packetTodo += maxPacketSize - pesHeaderLen;
              }
           }
        }
  // The packet is done. Now store any remaining data into fragment buffer
  // if we are no longer syncing.
  if (state != syncing) {
     // append the PES header ...
     int bite = pesHeaderLen;
     pesHeaderLen = 0;
     if (bite > 0) {
        memcpy(fragmentData + fragmentLen, pesHeader, bite);
        fragmentLen += bite;
        }
     // append payload. It may contain part of an audio frame header at it's
     // end, which will be removed when the next packet gets processed.
     bite = data - payload;
     if (bite > 0) {
        memcpy(fragmentData + fragmentLen, payload, bite);
        fragmentLen += bite;
        }
     }
  // report that syncing dropped some bytes
  if (skippedBytes > SkippedBytesLimit) {
     if (!initiallySyncing) // omit report for the typical initial case
        LOG("cAudioRepacker(0x%02X): skipped %d bytes while syncing on next audio frame", cid, skippedBytes - SkippedBytesLimit);
     skippedBytes = SkippedBytesLimit;
     }
}

int cAudioRepacker::BreakAt(const uchar *Data, int Count)
{
  if (initiallySyncing)
     return -1; // fill the packet buffer completely until we have synced once

  int PesPayloadOffset = 0;

  ePesHeader MpegLevel = AnalyzePesHeader(Data, Count, PesPayloadOffset);
  if (MpegLevel <= phInvalid)
     return -1; // not enough data for test

  // determine amount of data to fill up packet and to append next audio frame header
  int packetRemainder = PesPayloadOffset + packetTodo + 4;

  // just detect end of an audio frame
  if (state == scanFrame) {
     // when remaining audio frame size is known, then omit scanning
     if (frameTodo > 0) {
        // determine amount of data to fill up audio frame and to append next audio frame header
        int remaining = PesPayloadOffset + frameTodo + 4;
        if (remaining < packetRemainder)
           return remaining;
        return packetRemainder;
        }
     // setup local scanner
     if (localStart < 0) {
        localScanner = scanner;
        localStart = 0;
        }
     // start where we've stopped at the last run
     const uchar *data = Data + PesPayloadOffset + localStart;
     const uchar *limit = Data + Count;
     // scan data
     while (data < limit) {
           localStart++;
           localScanner <<= 8;
           localScanner |= *data++;
           // check whether the next audio frame follows
           if (((localScanner & 0xFFF00000) == 0xFFF00000) && IsValidAudioHeader(localScanner, MpegLevel == phMPEG2))
              return data - Data;
           }
     }
  // just fill up packet and append next audio frame header
  return packetRemainder;
}

// --- cDolbyRepacker --------------------------------------------------------

class cDolbyRepacker : public cRepacker {
private:
  static int frameSizes[];
  uchar fragmentData[6 + 65535];
  int fragmentLen;
  int fragmentTodo;
  uchar pesHeader[6 + 3 + 255 + 4 + 4];
  int pesHeaderLen;
  uchar pesHeaderBackup[6 + 3 + 255];
  int pesHeaderBackupLen;
  uchar chk1;
  uchar chk2;
  int ac3todo;
  enum eState {
    find_0b,
    find_77,
    store_chk1,
    store_chk2,
    get_length,
    output_packet
    };
  int state;
  int skippedBytes;
  void ResetPesHeader(bool ContinuationFrame = false);
  void AppendSubStreamID(bool ContinuationFrame = false);
  bool FinishRemainder(cRingBufferLinear *ResultBuffer, const uchar *const Data, const int Todo, int &Bite);
  bool StartNewPacket(cRingBufferLinear *ResultBuffer, const uchar *const Data, const int Todo, int &Bite);
public:
  cDolbyRepacker(void);
  virtual void Reset(void);
  virtual void Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count);
  virtual int BreakAt(const uchar *Data, int Count);
  };

// frameSizes are in words, i. e. multiply them by 2 to get bytes
int cDolbyRepacker::frameSizes[] = {
  // fs = 48 kHz
    64,   64,   80,   80,   96,   96,  112,  112,  128,  128,  160,  160,  192,  192,  224,  224,
   256,  256,  320,  320,  384,  384,  448,  448,  512,  512,  640,  640,  768,  768,  896,  896,
  1024, 1024, 1152, 1152, 1280, 1280,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
  // fs = 44.1 kHz
    69,   70,   87,   88,  104,  105,  121,  122,  139,  140,  174,  175,  208,  209,  243,  244,
   278,  279,  348,  349,  417,  418,  487,  488,  557,  558,  696,  697,  835,  836,  975,  976,
  1114, 1115, 1253, 1254, 1393, 1394,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
  // fs = 32 kHz
    96,   96,  120,  120,  144,  144,  168,  168,  192,  192,  240,  240,  288,  288,  336,  336,
   384,  384,  480,  480,  576,  576,  672,  672,  768,  768,  960,  960, 1152, 1152, 1344, 1344,
  1536, 1536, 1728, 1728, 1920, 1920,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
  //
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
     0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,    0,
  };

cDolbyRepacker::cDolbyRepacker(void)
{
  pesHeader[0] = 0x00;
  pesHeader[1] = 0x00;
  pesHeader[2] = 0x01;
  pesHeader[3] = 0xBD;
  pesHeader[4] = 0x00;
  pesHeader[5] = 0x00;
  Reset();
}

void cDolbyRepacker::AppendSubStreamID(bool ContinuationFrame)
{
  if (subStreamId) {
     pesHeader[pesHeaderLen++] = subStreamId;
     // number of ac3 frames "starting" in this packet (1 by design).
     pesHeader[pesHeaderLen++] = 0x01;
     // offset to start of first ac3 frame (0 means "no ac3 frame starting"
     // so 1 (by design) addresses the first byte after the next two bytes).
     pesHeader[pesHeaderLen++] = 0x00;
     pesHeader[pesHeaderLen++] = (ContinuationFrame ? 0x00 : 0x01);
     }
}

void cDolbyRepacker::ResetPesHeader(bool ContinuationFrame)
{
  pesHeader[6] = 0x80;
  pesHeader[7] = 0x00;
  pesHeader[8] = 0x00;
  pesHeaderLen = 9;
  AppendSubStreamID(ContinuationFrame);
}

void cDolbyRepacker::Reset(void)
{
  cRepacker::Reset();
  ResetPesHeader();
  state = find_0b;
  ac3todo = 0;
  chk1 = 0;
  chk2 = 0;
  fragmentLen = 0;
  fragmentTodo = 0;
  pesHeaderBackupLen = 0;
  skippedBytes = 0;
}

bool cDolbyRepacker::FinishRemainder(cRingBufferLinear *ResultBuffer, const uchar *const Data, const int Todo, int &Bite)
{
  bool success = true;
  // enough data available to put PES packet into buffer?
  if (fragmentTodo <= Todo) {
     // output a previous fragment first
     if (fragmentLen > 0) {
        Bite = fragmentLen;
        int n = Put(ResultBuffer, fragmentData, Bite, fragmentLen + fragmentTodo);
        if (Bite != n)
           success = false;
        fragmentLen = 0;
        }
     Bite = fragmentTodo;
     if (success) {
        int n = Put(ResultBuffer, Data, Bite, Bite);
        if (Bite != n)
           success = false;
        }
     fragmentTodo = 0;
     // ac3 frame completely processed?
     if (Bite >= ac3todo)
        state = find_0b; // go on with finding start of next packet
     }
  else {
     // copy the fragment into separate buffer for later processing
     Bite = Todo;
     memcpy(fragmentData + fragmentLen, Data, Bite);
     fragmentLen += Bite;
     fragmentTodo -= Bite;
     }
  return success;
}

bool cDolbyRepacker::StartNewPacket(cRingBufferLinear *ResultBuffer, const uchar *const Data, const int Todo, int &Bite)
{
  bool success = true;
  int packetLen = pesHeaderLen + ac3todo;
  // limit packet to maximum size
  if (packetLen > maxPacketSize)
     packetLen = maxPacketSize;
  pesHeader[4] = (packetLen - 6) >> 8;
  pesHeader[5] = (packetLen - 6) & 0xFF;
  Bite = pesHeaderLen;
  // enough data available to put PES packet into buffer?
  if (packetLen - pesHeaderLen <= Todo) {
     int n = Put(ResultBuffer, pesHeader, Bite, packetLen);
     if (Bite != n)
        success = false;
     Bite = packetLen - pesHeaderLen;
     if (success) {
        n = Put(ResultBuffer, Data, Bite, Bite);
        if (Bite != n)
           success = false;
        }
     // ac3 frame completely processed?
     if (Bite >= ac3todo)
        state = find_0b; // go on with finding start of next packet
     }
  else {
     fragmentTodo = packetLen;
     // copy the pesheader into separate buffer for later processing
     memcpy(fragmentData + fragmentLen, pesHeader, Bite);
     fragmentLen += Bite;
     fragmentTodo -= Bite;
     // copy the fragment into separate buffer for later processing
     Bite = Todo;
     memcpy(fragmentData + fragmentLen, Data, Bite);
     fragmentLen += Bite;
     fragmentTodo -= Bite;
     }
  return success;
}

void cDolbyRepacker::Repack(cRingBufferLinear *ResultBuffer, const uchar *Data, int Count)
{
  // synchronisation is detected some bytes after frame start.
  const int SkippedBytesLimit = 4;

  // check for MPEG 2
  if ((Data[6] & 0xC0) != 0x80) {
     DroppedData("cDolbyRepacker: MPEG 2 PES header expected", Count);
     return;
     }

  // backup PES header
  if (Data[6] != 0x80 || Data[7] != 0x00 || Data[8] != 0x00) {
     pesHeaderBackupLen = 6 + 3 + Data[8];
     memcpy(pesHeaderBackup, Data, pesHeaderBackupLen);
     }

  // skip PES header
  int done = 6 + 3 + Data[8];
  int todo = Count - done;
  const uchar *data = Data + done;

  // look for 0x0B 0x77 <chk1> <chk2> <frameSize>
  while (todo > 0) {
        switch (state) {
          case find_0b:
               if (*data == 0x0B) {
                  state++;
                  // copy header information once for later use
                  if (pesHeaderBackupLen > 0) {
                     pesHeaderLen = pesHeaderBackupLen;
                     pesHeaderBackupLen = 0;
                     memcpy(pesHeader, pesHeaderBackup, pesHeaderLen);
                     AppendSubStreamID();
                     }
                  }
               data++;
               done++;
               todo--;
               skippedBytes++; // collect number of skipped bytes while syncing
               continue;
          case find_77:
               if (*data != 0x77) {
                  state = find_0b;
                  continue;
                  }
               data++;
               done++;
               todo--;
               skippedBytes++; // collect number of skipped bytes while syncing
               state++;
               continue;
          case store_chk1:
               chk1 = *data++;
               done++;
               todo--;
               skippedBytes++; // collect number of skipped bytes while syncing
               state++;
               continue;
          case store_chk2:
               chk2 = *data++;
               done++;
               todo--;
               skippedBytes++; // collect number of skipped bytes while syncing
               state++;
               continue;
          case get_length:
               ac3todo = 2 * frameSizes[*data];
               // frameSizeCode was invalid => restart searching
               if (ac3todo <= 0) {
                  // reset PES header instead of using a wrong one
                  ResetPesHeader();
                  if (chk1 == 0x0B) {
                     if (chk2 == 0x77) {
                        state = store_chk1;
                        continue;
                        }
                     if (chk2 == 0x0B) {
                        state = find_77;
                        continue;
                        }
                     state = find_0b;
                     continue;
                     }
                  if (chk2 == 0x0B) {
                     state = find_77;
                     continue;
                     }
                  state = find_0b;
                  continue;
                  }
               if (initiallySyncing) // omit report for the typical initial case
                  initiallySyncing = false;
               else if (skippedBytes > SkippedBytesLimit) // report that syncing dropped some bytes
                  LOG("cDolbyRepacker: skipped %d bytes to sync on next AC3 frame", skippedBytes - SkippedBytesLimit);
               skippedBytes = 0;
               // append read data to header for common output processing
               pesHeader[pesHeaderLen++] = 0x0B;
               pesHeader[pesHeaderLen++] = 0x77;
               pesHeader[pesHeaderLen++] = chk1;
               pesHeader[pesHeaderLen++] = chk2;
               ac3todo -= 4;
               state++;
               // fall through to output
          case output_packet: {
               int bite = 0;
               // finish remainder of ac3 frame?
               if (fragmentTodo > 0)
                  FinishRemainder(ResultBuffer, data, todo, bite);
               else {
                  // start a new packet
                  StartNewPacket(ResultBuffer, data, todo, bite);
                  // prepare for next (continuation) packet
                  ResetPesHeader(state == output_packet);
                  }
               data += bite;
               done += bite;
               todo -= bite;
               ac3todo -= bite;
               }
          }
        }
  // report that syncing dropped some bytes
  if (skippedBytes > SkippedBytesLimit) {
     if (!initiallySyncing) // omit report for the typical initial case
        LOG("cDolbyRepacker: skipped %d bytes while syncing on next AC3 frame", skippedBytes - 4);
     skippedBytes = SkippedBytesLimit;
     }
}

int cDolbyRepacker::BreakAt(const uchar *Data, int Count)
{
  if (initiallySyncing)
     return -1; // fill the packet buffer completely until we have synced once
  // enough data for test?
  if (Count < 6 + 3)
     return -1;
  // check for MPEG 2
  if ((Data[6] & 0xC0) != 0x80)
     return -1;
  int headerLen = Data[8] + 6 + 3;
  // break after fragment tail?
  if (ac3todo > 0)
     return headerLen + ac3todo;
  // enough data for test?
  if (Count < headerLen + 5)
     return -1;
  const uchar *data = Data + headerLen;
  // break after ac3 frame?
  if (data[0] == 0x0B && data[1] == 0x77 && frameSizes[data[4]] > 0)
     return headerLen + 2 * frameSizes[data[4]];
  return -1;
}

// --- cTS2PES ---------------------------------------------------------------

#include <netinet/in.h>

//XXX TODO: these should really be available in some driver header file!
#define PROG_STREAM_MAP  0xBC
#ifndef PRIVATE_STREAM1
#define PRIVATE_STREAM1  0xBD
#endif
#define PADDING_STREAM   0xBE
#ifndef PRIVATE_STREAM2
#define PRIVATE_STREAM2  0xBF
#endif
#define AUDIO_STREAM_S   0xC0
#define AUDIO_STREAM_E   0xDF
#define VIDEO_STREAM_S   0xE0
#define VIDEO_STREAM_E   0xEF
#define ECM_STREAM       0xF0
#define EMM_STREAM       0xF1
#define DSM_CC_STREAM    0xF2
#define ISO13522_STREAM  0xF3
#define PROG_STREAM_DIR  0xFF

//pts_dts flags
#define PTS_ONLY         0x80

#define TS_SIZE        188
#define PID_MASK_HI    0x1F
#define CONT_CNT_MASK  0x0F

// Flags:
#define PAY_LOAD       0x10
#define ADAPT_FIELD    0x20
#define PAY_START      0x40
#define TS_ERROR       0x80

#define MAX_PLENGTH  0xFFFF          // the maximum PES packet length (theoretically)
#define MMAX_PLENGTH (64*MAX_PLENGTH) // some stations send PES packets that are extremely large, e.g. DVB-T in Finland or HDTV 1920x1080

#define IPACKS 2048

// Start codes:
#define SC_SEQUENCE 0xB3  // "sequence header code"
#define SC_GROUP    0xB8  // "group start code"
#define SC_PICTURE  0x00  // "picture start code"

#define MAXNONUSEFULDATA (10*1024*1024)
#define MAXNUMUPTERRORS  10

class cTS2PES {
private:
  int pid;
  int size;
  int found;
  int count;
  uint8_t *buf;
  uint8_t cid;
  uint8_t rewriteCid;
  uint8_t subStreamId;
  int plength;
  uint8_t plen[2];
  uint8_t flag1;
  uint8_t flag2;
  uint8_t hlength;
  int mpeg;
  uint8_t check;
  int mpeg1_required;
  int mpeg1_stuffing;
  bool done;
  cRingBufferLinear *resultBuffer;
  int tsErrors;
  int ccErrors;
  int ccCounter;
  cRepacker *repacker;
  static uint8_t headr[];
  void store(uint8_t *Data, int Count);
  void reset_ipack(void);
  void send_ipack(void);
  void write_ipack(const uint8_t *Data, int Count);
  void instant_repack(const uint8_t *Buf, int Count);
public:
  cTS2PES(int Pid, cRingBufferLinear *ResultBuffer, int Size, uint8_t RewriteCid = 0x00, uint8_t SubStreamId = 0x00, cRepacker *Repacker = NULL);
  ~cTS2PES();
  int Pid(void) { return pid; }
  void ts_to_pes(const uint8_t *Buf); // don't need count (=188)
  void Clear(void);
  };

uint8_t cTS2PES::headr[] = { 0x00, 0x00, 0x01 };

cTS2PES::cTS2PES(int Pid, cRingBufferLinear *ResultBuffer, int Size, uint8_t RewriteCid, uint8_t SubStreamId, cRepacker *Repacker)
{
  pid = Pid;
  resultBuffer = ResultBuffer;
  size = Size;
  rewriteCid = RewriteCid;
  subStreamId = SubStreamId;
  repacker = Repacker;
  if (repacker) {
     repacker->SetMaxPacketSize(size);
     repacker->SetSubStreamId(subStreamId);
     size += repacker->QuerySnoopSize();
     }

  tsErrors = 0;
  ccErrors = 0;
  ccCounter = -1;

  if (!(buf = MALLOC(uint8_t, size)))
     esyslog("Not enough memory for ts_transform");

  reset_ipack();
}

cTS2PES::~cTS2PES()
{
  if (tsErrors || ccErrors)
     dsyslog("cTS2PES got %d TS errors, %d TS continuity errors", tsErrors, ccErrors);
  free(buf);
  delete repacker;
}

void cTS2PES::Clear(void)
{
  reset_ipack();
  if (repacker)
     repacker->Reset();
}

void cTS2PES::store(uint8_t *Data, int Count)
{
  if (repacker)
     repacker->Repack(resultBuffer, Data, Count);
  else
     cRepacker::Put(resultBuffer, Data, Count, Count);
}

void cTS2PES::reset_ipack(void)
{
  found = 0;
  cid = 0;
  plength = 0;
  flag1 = 0;
  flag2 = 0;
  hlength = 0;
  mpeg = 0;
  check = 0;
  mpeg1_required = 0;
  mpeg1_stuffing = 0;
  done = false;
  count = 0;
}

void cTS2PES::send_ipack(void)
{
  if (count <= ((mpeg == 2) ? 9 : 7)) // skip empty packets
     return;
  buf[3] = rewriteCid ? rewriteCid : cid;
  buf[4] = (uint8_t)(((count - 6) & 0xFF00) >> 8);
  buf[5] = (uint8_t)((count - 6) & 0x00FF);
  store(buf, count);

  switch (mpeg) {
    case 2:
            buf[6] = 0x80;
            buf[7] = 0x00;
            buf[8] = 0x00;
            count = 9;
            break;
    case 1:
            buf[6] = 0x0F;
            count = 7;
            break;
    }
}

void cTS2PES::write_ipack(const uint8_t *Data, int Count)
{
  if (count < 6) {
     memcpy(buf, headr, 3);
     count = 6;
     }

  // determine amount of data to process
  int bite = Count;
  if (count + bite > size)
     bite = size - count;
  if (repacker) {
     int breakAt = repacker->BreakAt(buf, count);
     // avoid memcpy of data after break location
     if (0 <= breakAt && breakAt < count + bite) {
        bite = breakAt - count;
        if (bite < 0) // should never happen
           bite = 0;
        }
     }

  memcpy(buf + count, Data, bite);
  count += bite;

  if (repacker) {
     // determine break location
     int breakAt = repacker->BreakAt(buf, count);
     if (breakAt > size) // won't fit into packet?
        breakAt = -1;
     if (breakAt > count) // not enough data?
        breakAt = -1;
     // push out data before break location
     if (breakAt > 0) {
        // adjust bite if above memcpy was to large
        bite -= count - breakAt;
        count = breakAt;
        send_ipack();
        // recurse for data after break location
        if (Count - bite > 0)
           write_ipack(Data + bite, Count - bite);
        }
     }

  // push out data when buffer is full
  if (count >= size) {
     send_ipack();
     // recurse for remaining data
     if (Count - bite > 0)
        write_ipack(Data + bite, Count - bite);
     }
}

void cTS2PES::instant_repack(const uint8_t *Buf, int Count)
{
  int c = 0;

  while (c < Count && (mpeg == 0 || (mpeg == 1 && found < mpeg1_required) || (mpeg == 2 && found < 9)) && (found < 5 || !done)) {
        switch (found ) {
          case 0:
          case 1:
                  if (Buf[c] == 0x00)
                     found++;
                  else
                     found = 0;
                  c++;
                  break;
          case 2:
                  if (Buf[c] == 0x01)
                     found++;
                  else if (Buf[c] != 0)
                     found = 0;
                  c++;
                  break;
          case 3:
                  cid = 0;
                  switch (Buf[c]) {
                    case PROG_STREAM_MAP:
                    case PRIVATE_STREAM2:
                    case PROG_STREAM_DIR:
                    case ECM_STREAM     :
                    case EMM_STREAM     :
                    case PADDING_STREAM :
                    case DSM_CC_STREAM  :
                    case ISO13522_STREAM:
                         done = true;
                    case PRIVATE_STREAM1:
                    case VIDEO_STREAM_S ... VIDEO_STREAM_E:
                    case AUDIO_STREAM_S ... AUDIO_STREAM_E:
                         found++;
                         cid = Buf[c++];
                         break;
                    default:
                         found = 0;
                         break;
                    }
                  break;
          case 4:
                  if (Count - c > 1) {
                     unsigned short *pl = (unsigned short *)(Buf + c);
                     plength = ntohs(*pl);
                     c += 2;
                     found += 2;
                     mpeg1_stuffing = 0;
                     }
                  else {
                     plen[0] = Buf[c];
                     found++;
                     return;
                     }
                  break;
          case 5: {
                    plen[1] = Buf[c++];
                    unsigned short *pl = (unsigned short *)plen;
                    plength = ntohs(*pl);
                    found++;
                    mpeg1_stuffing = 0;
                  }
                  break;
          case 6:
                  if (!done) {
                     flag1 = Buf[c++];
                     found++;
                     if (mpeg1_stuffing == 0) { // first stuffing iteration: determine MPEG level
                        if ((flag1 & 0xC0) == 0x80)
                           mpeg = 2;
                        else {
                           mpeg = 1;
                           mpeg1_required = 7;
                           }
                        }
                     if (mpeg == 1) {
                        if (flag1 == 0xFF) { // MPEG1 stuffing
                           if (++mpeg1_stuffing > 16)
                              found = 0; // invalid MPEG1 header
                           else { // ignore stuffing
                              found--;
                              if (plength > 0)
                                 plength--;
                              }
                           }
                        else if ((flag1 & 0xC0) == 0x40) // STD_buffer_scale/size
                           mpeg1_required += 2;
                        else if (flag1 != 0x0F && (flag1 & 0xF0) != 0x20 && (flag1 & 0xF0) != 0x30)
                           found = 0; // invalid MPEG1 header
                        else {
                           flag2 = 0;
                           hlength = 0;
                           }
                        }
                     }
                  break;
          case 7:
                  if (!done && (mpeg == 2 || mpeg1_required > 7)) {
                     flag2 = Buf[c++];
                     found++;
                     }
                  break;
          case 8:
                  if (!done && (mpeg == 2 || mpeg1_required > 7)) {
                     hlength = Buf[c++];
                     found++;
                     if (mpeg == 1 && hlength != 0x0F && (hlength & 0xF0) != 0x20 && (hlength & 0xF0) != 0x30)
                        found = 0; // invalid MPEG1 header
                     }
                  break;
          default:
                  break;
          }
        }

  if (!plength)
     plength = MMAX_PLENGTH - 6;

  if (done || ((mpeg == 2 && found >= 9) || (mpeg == 1 && found >= mpeg1_required))) {
     switch (cid) {
       case AUDIO_STREAM_S ... AUDIO_STREAM_E:
       case VIDEO_STREAM_S ... VIDEO_STREAM_E:
       case PRIVATE_STREAM1:

            if (mpeg == 2 && found == 9) {
               write_ipack(&flag1, 1);
               write_ipack(&flag2, 1);
               write_ipack(&hlength, 1);
               }

            if (mpeg == 1 && found == mpeg1_required) {
               write_ipack(&flag1, 1);
               if (mpeg1_required > 7) {
                  write_ipack(&flag2, 1);
                  write_ipack(&hlength, 1);
                  }
               }

            if (mpeg == 2 && (flag2 & PTS_ONLY) && found < 14) {
               while (c < Count && found < 14) {
                     write_ipack(Buf + c, 1);
                     c++;
                     found++;
                     }
               if (c == Count)
                  return;
               }

            while (c < Count && found < plength + 6) {
                  int l = Count - c;
                  if (l + found > plength + 6)
                     l = plength + 6 - found;
                  write_ipack(Buf + c, l);
                  found += l;
                  c += l;
                  }

            break;
       }

     if (done) {
        if (found + Count - c < plength + 6) {
           found += Count - c;
           c = Count;
           }
        else {
           c += plength + 6 - found;
           found = plength + 6;
           }
        }

     if (plength && found == plength + 6) {
        if (plength == MMAX_PLENGTH - 6)
           esyslog("ERROR: PES packet length overflow in remuxer (stream corruption)");
        send_ipack();
        reset_ipack();
        if (c < Count)
           instant_repack(Buf + c, Count - c);
        }
     }
  return;
}

void cTS2PES::ts_to_pes(const uint8_t *Buf) // don't need count (=188)
{
  if (!Buf)
     return;

  if (Buf[1] & TS_ERROR)
     tsErrors++;

  if (!(Buf[3] & (ADAPT_FIELD | PAY_LOAD)))
     return; // discard TS packet with adaption_field_control set to '00'.

  if ((Buf[3] & PAY_LOAD) && ((Buf[3] ^ ccCounter) & CONT_CNT_MASK)) {
     // This should check duplicates and packets which do not increase the counter.
     // But as the errors usually come in bursts this should be enough to
     // show you there is something wrong with signal quality.
     if (ccCounter != -1 && ((Buf[3] ^ (ccCounter + 1)) & CONT_CNT_MASK)) {
        ccErrors++;
        // Enable this if you are having problems with signal quality.
        // These are the errors I used to get with Nova-T when antenna
        // was not positioned correcly (not transport errors). //tvr
        //dsyslog("TS continuity error (%d)", ccCounter);
        }
     ccCounter = Buf[3] & CONT_CNT_MASK;
     }

  if (Buf[1] & PAY_START) {
     if (found > 6) {
        if (plength != MMAX_PLENGTH - 6 && plength != found - 6)
           dsyslog("PES packet shortened to %d bytes (expected: %d bytes)", found, plength + 6);
        plength = found - 6;
        send_ipack();
        reset_ipack();
        }
     found = 0;
     }

  uint8_t off = 0;

  if (Buf[3] & ADAPT_FIELD) {  // adaptation field?
     off = Buf[4] + 1;
     if (off + 4 > 187)
        return;
     }

  if (Buf[3] & PAY_LOAD)
     instant_repack(Buf + 4 + off, TS_SIZE - 4 - off);
}

// --- cRemux ----------------------------------------------------------------

#define RESULTBUFFERSIZE KILOBYTE(256)

cRemux::cRemux(int VPid, const int *APids, const int *DPids, const int *SPids, bool ExitOnFailure)
{
  exitOnFailure = ExitOnFailure;
  isRadio = VPid == 0 || VPid == 1 || VPid == 0x1FFF;
  numUPTerrors = 0;
  synced = false;
  skipped = 0;
  numTracks = 0;
  resultSkipped = 0;
  resultBuffer = new cRingBufferLinear(RESULTBUFFERSIZE, IPACKS, false, "Result");
  resultBuffer->SetTimeouts(0, 100);
  if (VPid)
#define TEST_cVideoRepacker
#ifdef TEST_cVideoRepacker
     ts2pes[numTracks++] = new cTS2PES(VPid, resultBuffer, IPACKS, 0xE0, 0x00, new cVideoRepacker);
#else
     ts2pes[numTracks++] = new cTS2PES(VPid, resultBuffer, IPACKS, 0xE0);
#endif
  if (APids) {
     int n = 0;
     while (*APids && numTracks < MAXTRACKS && n < MAXAPIDS) {
#define TEST_cAudioRepacker
#ifdef TEST_cAudioRepacker
           ts2pes[numTracks++] = new cTS2PES(*APids++, resultBuffer, IPACKS, 0xC0 + n, 0x00, new cAudioRepacker(0xC0 + n));
           n++;
#else
           ts2pes[numTracks++] = new cTS2PES(*APids++, resultBuffer, IPACKS, 0xC0 + n++);
#endif
           }
     }
  if (DPids) {
     int n = 0;
     while (*DPids && numTracks < MAXTRACKS && n < MAXDPIDS)
           ts2pes[numTracks++] = new cTS2PES(*DPids++, resultBuffer, IPACKS, 0x00, 0x80 + n++, new cDolbyRepacker);
     }
  /* future...
  if (SPids) {
     int n = 0;
     while (*SPids && numTracks < MAXTRACKS && n < MAXSPIDS)
           ts2pes[numTracks++] = new cTS2PES(*SPids++, resultBuffer, IPACKS, 0x00, 0x28 + n++);
     }
  */
}

cRemux::~cRemux()
{
  for (int t = 0; t < numTracks; t++)
      delete ts2pes[t];
  delete resultBuffer;
}

int cRemux::GetPid(const uchar *Data)
{
  return (((uint16_t)Data[0] & PID_MASK_HI) << 8) | (Data[1] & 0xFF);
}

int cRemux::GetPacketLength(const uchar *Data, int Count, int Offset)
{
  // Returns the length of the packet starting at Offset, or -1 if Count is
  // too small to contain the entire packet.
  int Length = (Offset + 5 < Count) ? (Data[Offset + 4] << 8) + Data[Offset + 5] + 6 : -1;
  if (Length > 0 && Offset + Length <= Count)
     return Length;
  return -1;
}

int cRemux::ScanVideoPacket(const uchar *Data, int Count, int Offset, uchar &PictureType)
{
  // Scans the video packet starting at Offset and returns its length.
  // If the return value is -1 the packet was not completely in the buffer.
  int Length = GetPacketLength(Data, Count, Offset);
  if (Length > 0) {
     int PesPayloadOffset = 0;
     if (AnalyzePesHeader(Data + Offset, Length, PesPayloadOffset) >= phMPEG1) {
        const uchar *p = Data + Offset + PesPayloadOffset + 2;
        const uchar *pLimit = Data + Offset + Length - 3;
#ifdef TEST_cVideoRepacker
        // cVideoRepacker ensures that a new PES packet is started for a new sequence,
        // group or picture which allows us to easily skip scanning through a huge
        // amount of video data.
        if (p < pLimit) {
           if (p[-2] || p[-1] || p[0] != 0x01)
              pLimit = 0; // skip scanning: packet doesn't start with 0x000001
           else {
              switch (p[1]) {
                case SC_SEQUENCE:
                case SC_GROUP:
                case SC_PICTURE:
                     break;
                default: // skip scanning: packet doesn't start a new sequence, group or picture
                     pLimit = 0;
                }
              }
           }
#endif
        while (p < pLimit && (p = (const uchar *)memchr(p, 0x01, pLimit - p))) {
              if (!p[-2] && !p[-1]) { // found 0x000001
                 switch (p[1]) {
                   case SC_PICTURE: PictureType = (p[3] >> 3) & 0x07;
                                    return Length;
                   }
                 p += 4; // continue scanning after 0x01ssxxyy
                 }
              else
                 p += 3; // continue scanning after 0x01xxyy
              }
        }
     PictureType = NO_PICTURE;
     return Length;
     }
  return -1;
}

#define TS_SYNC_BYTE 0x47

int cRemux::Put(const uchar *Data, int Count)
{
  int used = 0;

  // Make sure we are looking at a TS packet:

  while (Count > TS_SIZE) {
        if (Data[0] == TS_SYNC_BYTE && Data[TS_SIZE] == TS_SYNC_BYTE)
           break;
        Data++;
        Count--;
        used++;
        }
  if (used)
     esyslog("ERROR: skipped %d byte to sync on TS packet", used);

  // Convert incoming TS data into multiplexed PES:

  for (int i = 0; i < Count; i += TS_SIZE) {
      if (Count - i < TS_SIZE)
         break;
      if (Data[i] != TS_SYNC_BYTE)
         break;
      if (resultBuffer->Free() < 2 * IPACKS)
         break; // A cTS2PES might write one full packet and also a small rest
      int pid = GetPid(Data + i + 1);
      if (Data[i + 3] & 0x10) { // got payload
         for (int t = 0; t < numTracks; t++) {
             if (ts2pes[t]->Pid() == pid) {
                ts2pes[t]->ts_to_pes(Data + i);
                break;
                }
             }
         }
      used += TS_SIZE;
      }

  // Check if we're getting anywhere here:
  if (!synced && skipped >= 0) {
     if (skipped > MAXNONUSEFULDATA) {
        esyslog("ERROR: no useful data seen within %d byte of video stream", skipped);
        skipped = -1;
        if (exitOnFailure)
           ShutdownHandler.RequestEmergencyExit();
        }
     else
        skipped += used;
     }

  return used;
}

uchar *cRemux::Get(int &Count, uchar *PictureType)
{
  // Remove any previously skipped data from the result buffer:

  if (resultSkipped > 0) {
     resultBuffer->Del(resultSkipped);
     resultSkipped = 0;
     }

#if 0
  // Test recording without determining the real frame borders:
  if (PictureType)
     *PictureType = I_FRAME;
  return resultBuffer->Get(Count);
#endif

  // Check for frame borders:

  if (PictureType)
     *PictureType = NO_PICTURE;

  Count = 0;
  uchar *resultData = NULL;
  int resultCount = 0;
  uchar *data = resultBuffer->Get(resultCount);
  if (data) {
     for (int i = 0; i < resultCount - 3; i++) {
         if (data[i] == 0 && data[i + 1] == 0 && data[i + 2] == 1) {
            int l = 0;
            uchar StreamType = data[i + 3];
            if (VIDEO_STREAM_S <= StreamType && StreamType <= VIDEO_STREAM_E) {
               uchar pt = NO_PICTURE;
               l = ScanVideoPacket(data, resultCount, i, pt);
               if (l < 0)
                  return resultData;
               if (pt != NO_PICTURE) {
                  if (pt < I_FRAME || B_FRAME < pt) {
                     esyslog("ERROR: unknown picture type '%d'", pt);
                     if (++numUPTerrors > MAXNUMUPTERRORS && exitOnFailure)
                        ShutdownHandler.RequestEmergencyExit();
                     }
                  else if (!synced) {
                     if (pt == I_FRAME) {
                        if (PictureType)
                           *PictureType = pt;
                        resultSkipped = i; // will drop everything before this position
                        SetBrokenLink(data + i, l);
                        synced = true;
                        }
                     }
                  else if (Count)
                     return resultData;
                  else if (PictureType)
                     *PictureType = pt;
                  }
               }
            else { //if (AUDIO_STREAM_S <= StreamType && StreamType <= AUDIO_STREAM_E || StreamType == PRIVATE_STREAM1) {
               l = GetPacketLength(data, resultCount, i);
               if (l < 0)
                  return resultData;
               if (isRadio) {
                  if (!synced) {
                     if (PictureType)
                        *PictureType = I_FRAME;
                     resultSkipped = i; // will drop everything before this position
                     synced = true;
                     }
                  else if (Count)
                     return resultData;
                  else if (PictureType)
                     *PictureType = I_FRAME;
                  }
               }
            if (synced) {
               if (!Count)
                  resultData = data + i;
               Count += l;
               }
            else
               resultSkipped = i + l;
            if (l > 0)
               i += l - 1; // the loop increments, too
            }
         }
     }
  return resultData;
}

void cRemux::Del(int Count)
{
  resultBuffer->Del(Count);
}

void cRemux::Clear(void)
{
  for (int t = 0; t < numTracks; t++)
      ts2pes[t]->Clear();
  resultBuffer->Clear();
  synced = false;
  skipped = 0;
  resultSkipped = 0;
}

void cRemux::SetBrokenLink(uchar *Data, int Length)
{
  int PesPayloadOffset = 0;
  if (AnalyzePesHeader(Data, Length, PesPayloadOffset) >= phMPEG1 && (Data[3] & 0xF0) == VIDEO_STREAM_S) {
     for (int i = PesPayloadOffset; i < Length - 7; i++) {
         if (Data[i] == 0 && Data[i + 1] == 0 && Data[i + 2] == 1 && Data[i + 3] == 0xB8) {
            if (!(Data[i + 7] & 0x40)) // set flag only if GOP is not closed
               Data[i + 7] |= 0x20;
            return;
            }
         }
     dsyslog("SetBrokenLink: no GOP header found in video packet");
     }
  else
     dsyslog("SetBrokenLink: no video packet in frame");
}