gstreamer/gst/mpeg1sys/systems.c

#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);
	bcopy (pack->buf, index, 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;

		bcopy (sys_header->buf, index, 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);
    }

}