vdr-plugin-streamdev/remux/tsremux.c

#include "remux/tsremux.h"

#define SC_PICTURE  0x00  // "picture header"
#define PID_MASK_HI 0x1F

void cTSRemux::SetBrokenLink(uchar *Data, int Length)
{
  if (Length > 9 && Data[0] == 0 && Data[1] == 0 && Data[2] == 1 && (Data[3] & 0xF0) == VIDEO_STREAM_S) {
     for (int i = Data[8] + 9; i < Length - 7; i++) { // +9 to skip video packet header
         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");
}

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

int cTSRemux::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 cTSRemux::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) {
     if (Length >= 8) {
        int i = Offset + 8; // the minimum length of the video packet header
        i += Data[i] + 1;   // possible additional header bytes
        for (; i < Offset + Length - 5; i++) {
            if (Data[i] == 0 && Data[i + 1] == 0 && Data[i + 2] == 1) {
               switch (Data[i + 3]) {
                 case SC_PICTURE: PictureType = (Data[i + 5] >> 3) & 0x07;
                                  return Length;
                 }
               }
            }
        }
     PictureType = NO_PICTURE;
     return Length;
     }
  return -1;
}