gstreamer/gst/mpeg1sys/systems.c

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <string.h>

#include "main.h"

static void
buffer_timecode (timecode, marker, buffer)
     guint64 timecode;
     unsigned char marker;
     unsigned char **buffer;

{
  unsigned char temp;

  temp = (marker << 4) | ((timecode >> 29) & 0x38) |
      ((timecode >> 29) & 0x6) | 1;
  *((*buffer)++) = temp;
  temp = (timecode & 0x3fc00000) >> 22;
  *((*buffer)++) = temp;
  temp = ((timecode & 0x003f8000) >> 14) | 1;
  *((*buffer)++) = temp;
  temp = (timecode & 0x7f80) >> 7;
  *((*buffer)++) = temp;
  temp = ((timecode & 0x007f) << 1) | 1;
  *((*buffer)++) = temp;
}

/*************************************************************************
	creates a complete sector.
	Also copies Pack and Sys_Header informations into the
	sector buffer, then reads a packet full of data from
	the input stream into the sector buffer.
*************************************************************************/


void
create_sector (sector, pack, sys_header,
    packet_size, inputbuffer, type,
    buffer_scale, buffer_size, buffers, PTS, DTS, timestamps, which_streams)

     Sector_struc *sector;
     Pack_struc *pack;
     Sys_header_struc *sys_header;
     unsigned int packet_size;
     unsigned char *inputbuffer;

     unsigned char type;
     unsigned char buffer_scale;
     unsigned int buffer_size;
     unsigned char buffers;
     guint64 PTS;
     guint64 DTS;
     unsigned char timestamps;
     unsigned int which_streams;

{
  int i, j, tmp;
  unsigned char *index;
  unsigned char *size_offset;

  /* printf("creating sector\n"); */

  index = sector->buf;
  sector->length_of_sector = 0;

/* Should we copy Pack Header information ? */

  if (pack != NULL) {
    i = sizeof (pack->buf);
    memcpy (index, pack->buf, i);
    index += i;
    sector->length_of_sector += i;
  }

/* Should we copy System Header information ? */

  if (sys_header != NULL) {
    i = sizeof (sys_header->buf);

    /* only one stream? 3 bytes less in sys header */
    if (which_streams != STREAMS_BOTH)
      i -= 3;

    memcpy (index, sys_header->buf, i);
    index += i;
    sector->length_of_sector += i;
  }

  /* write constant packet header data */

  *(index++) = (unsigned char) (PACKET_START) >> 16;
  *(index++) = (unsigned char) (PACKET_START & 0x00ffff) >> 8;
  *(index++) = (unsigned char) (PACKET_START & 0x0000ff);
  *(index++) = type;

  /* we remember this offset in case we will have to shrink this packet */

  size_offset = index;
  *(index++) = (unsigned char) ((packet_size - PACKET_HEADER_SIZE) >> 8);
  *(index++) = (unsigned char) ((packet_size - PACKET_HEADER_SIZE) & 0xff);

  *(index++) = STUFFING_BYTE;
  *(index++) = STUFFING_BYTE;
  *(index++) = STUFFING_BYTE;

  i = 0;

  if (!buffers)
    i += 2;
  if (timestamps == TIMESTAMPS_NO)
    i += 9;
  else if (timestamps == TIMESTAMPS_PTS)
    i += 5;

  /* printf("%i stuffing %d\n", i, timestamps); */

  for (j = 0; j < i; j++)
    *(index++) = STUFFING_BYTE;

  /* should we write buffer info ? */

  if (buffers) {
    *(index++) = (unsigned char) (0x40 |
        (buffer_scale << 5) | (buffer_size >> 8));
    *(index++) = (unsigned char) (buffer_size & 0xff);
  }

  /* should we write PTS, PTS & DTS or nothing at all ? */

  switch (timestamps) {
    case TIMESTAMPS_NO:
      *(index++) = MARKER_NO_TIMESTAMPS;
      break;
    case TIMESTAMPS_PTS:
      buffer_timecode (PTS, MARKER_JUST_PTS, &index);
      sector->TS = PTS;
      break;
    case TIMESTAMPS_PTS_DTS:
      buffer_timecode (PTS, MARKER_PTS, &index);
      buffer_timecode (DTS, MARKER_DTS, &index);
      sector->TS = DTS;
      break;
  }

/* read in packet data */

  i = (packet_size - PACKET_HEADER_SIZE - AFTER_PACKET_LENGTH);

  if (type == PADDING_STR) {
    for (j = 0; j < i; j++)
      *(index++) = (unsigned char) STUFFING_BYTE;
    tmp = i;
  } else {
    /*tmp = fread (index, sizeof (unsigned char), i, inputstream); */
    memcpy (index, inputbuffer, i);
    tmp = i;
    index += tmp;

    /* if we did not get enough data bytes, shorten the Packet length */

    if (tmp != i) {
      packet_size -= (i - tmp);
      *(size_offset++) =
          (unsigned char) ((packet_size - PACKET_HEADER_SIZE) >> 8);
      *(size_offset++) =
          (unsigned char) ((packet_size - PACKET_HEADER_SIZE) & 0xff);

/* zero byte stuffing in the last Packet of a stream */
/* we don't need this any more, since we shortenend the packet */
/* 	    for (j=tmp; j<i; j++) */
/* 		*(index++)=(unsigned char) ZERO_STUFFING_BYTE; */
    }
  }


  /* write other struct data */

  sector->length_of_sector += packet_size;
  sector->length_of_packet_data = tmp;

}

/*************************************************************************
	writes specifical pack header information into a buffer
	later this will be copied from the sector routine into
	the sector buffer
*************************************************************************/

void
create_pack (pack, SCR, mux_rate)

     Pack_struc *pack;
     unsigned int mux_rate;
     guint64 SCR;

{
  unsigned char *index;

  index = pack->buf;

  *(index++) = (unsigned char) ((PACK_START) >> 24);
  *(index++) = (unsigned char) ((PACK_START & 0x00ff0000) >> 16);
  *(index++) = (unsigned char) ((PACK_START & 0x0000ff00) >> 8);
  *(index++) = (unsigned char) (PACK_START & 0x000000ff);
  buffer_timecode (SCR, MARKER_SCR, &index);
  *(index++) = (unsigned char) (0x80 | (mux_rate >> 15));
  *(index++) = (unsigned char) (0xff & (mux_rate >> 7));
  *(index++) = (unsigned char) (0x01 | ((mux_rate & 0x7f) << 1));
  pack->SCR = SCR;
}


/*************************************************************************
	writes specifical system header information into a buffer
	later this will be copied from the sector routine into
	the sector buffer
*************************************************************************/

void
create_sys_header (sys_header, rate_bound, audio_bound,
    fixed, CSPS, audio_lock, video_lock,
    video_bound,
    stream1, buffer1_scale, buffer1_size,
    stream2, buffer2_scale, buffer2_size, which_streams)

     Sys_header_struc *sys_header;
     unsigned int rate_bound;
     unsigned char audio_bound;
     unsigned char fixed;
     unsigned char CSPS;
     unsigned char audio_lock;
     unsigned char video_lock;
     unsigned char video_bound;

     unsigned char stream1;
     unsigned char buffer1_scale;
     unsigned int buffer1_size;
     unsigned char stream2;
     unsigned char buffer2_scale;
     unsigned int buffer2_size;
     unsigned int which_streams;

{
  unsigned char *index;

  index = sys_header->buf;

  /* if we are not using both streams, we should clear some
     options here */

  if (!(which_streams & STREAMS_AUDIO))
    audio_bound = 0;
  if (!(which_streams & STREAMS_VIDEO))
    video_bound = 0;

  *(index++) = (unsigned char) ((SYS_HEADER_START) >> 24);
  *(index++) = (unsigned char) ((SYS_HEADER_START & 0x00ff0000) >> 16);
  *(index++) = (unsigned char) ((SYS_HEADER_START & 0x0000ff00) >> 8);
  *(index++) = (unsigned char) (SYS_HEADER_START & 0x000000ff);

  if (which_streams == STREAMS_BOTH) {
    *(index++) = (unsigned char) (SYS_HEADER_LENGTH >> 8);
    *(index++) = (unsigned char) (SYS_HEADER_LENGTH & 0xff);
  } else {
    *(index++) = (unsigned char) ((SYS_HEADER_LENGTH - 3) >> 8);
    *(index++) = (unsigned char) ((SYS_HEADER_LENGTH - 3) & 0xff);
  }

  *(index++) = (unsigned char) (0x80 | (rate_bound >> 15));
  *(index++) = (unsigned char) (0xff & (rate_bound >> 7));
  *(index++) = (unsigned char) (0x01 | ((rate_bound & 0x7f) << 1));
  *(index++) = (unsigned char) ((audio_bound << 2) | (fixed << 1) | CSPS);
  *(index++) = (unsigned char) ((audio_lock << 7) |
      (video_lock << 6) | 0x20 | video_bound);

  *(index++) = (unsigned char) RESERVED_BYTE;

  if (which_streams & STREAMS_AUDIO) {
    *(index++) = stream1;
    *(index++) = (unsigned char) (0xc0 |
        (buffer1_scale << 5) | (buffer1_size >> 8));
    *(index++) = (unsigned char) (buffer1_size & 0xff);
  }

  if (which_streams & STREAMS_VIDEO) {
    *(index++) = stream2;
    *(index++) = (unsigned char) (0xc0 |
        (buffer2_scale << 5) | (buffer2_size >> 8));
    *(index++) = (unsigned char) (buffer2_size & 0xff);
  }

}