mpv/libmpdemux/parse_es.c

//=================== MPEG-ES VIDEO PARSER =========================

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>

#include "config.h"
#include "mp_msg.h"
#include "help_mp.h"

#include "stream/stream.h"
#include "demuxer.h"
#include "parse_es.h"

//static unsigned char videobuffer[MAX_VIDEO_PACKET_SIZE];
unsigned char* videobuffer=NULL;
int videobuf_len=0;
int next_nal = -1;
///! legacy variable, 4 if stream is synced, 0 if not
int videobuf_code_len=0;

#define MAX_SYNCLEN (10 * 1024 * 1024)
// sync video stream, and returns next packet code
int sync_video_packet(demux_stream_t *ds){
  if (!videobuf_code_len) {
  int skipped=0;
    if (!demux_pattern_3(ds, NULL, MAX_SYNCLEN, &skipped, 0x100)) {
      if (skipped == MAX_SYNCLEN)
      mp_msg(MSGT_DEMUXER, MSGL_ERR, "parse_es: could not sync video stream!\n");
      goto eof_out;
    }
    next_nal = demux_getc(ds);
    if (next_nal < 0)
      goto eof_out;
    videobuf_code_len = 4;
  if(skipped) mp_dbg(MSGT_PARSEES,MSGL_DBG2,"videobuf: %d bytes skipped  (next: 0x1%02X)\n",skipped,next_nal);
  }
  return 0x100|next_nal;

eof_out:
  next_nal = -1;
  videobuf_code_len = 0;
  return 0;
}

// return: packet length
int read_video_packet(demux_stream_t *ds){
int packet_start;
  int res, read;
  
  if (VIDEOBUFFER_SIZE - videobuf_len < 5)
    return 0;
  // SYNC STREAM
//  if(!sync_video_packet(ds)) return 0; // cannot sync (EOF)

  // COPY STARTCODE:
  packet_start=videobuf_len;
  videobuffer[videobuf_len+0]=0;
  videobuffer[videobuf_len+1]=0;
  videobuffer[videobuf_len+2]=1;
  videobuffer[videobuf_len+3]=next_nal;
  videobuf_len+=4;
  
  // READ PACKET:
  res = demux_pattern_3(ds, &videobuffer[videobuf_len],
          VIDEOBUFFER_SIZE - videobuf_len, &read, 0x100);
  videobuf_len += read;
  if (!res)
    goto eof_out;
 
  videobuf_len-=3;

  mp_dbg(MSGT_PARSEES,MSGL_DBG2,"videobuf: packet 0x1%02X  len=%d  (total=%d)\n",videobuffer[packet_start+3],videobuf_len-packet_start,videobuf_len);

  // Save next packet code:
  next_nal = demux_getc(ds);
  if (next_nal < 0)
    goto eof_out;
  videobuf_code_len=4;

  return videobuf_len-packet_start;

eof_out:
  next_nal = -1;
  videobuf_code_len = 0;
  return videobuf_len - packet_start;
}

// return: next packet code
int skip_video_packet(demux_stream_t *ds){

  // SYNC STREAM
//  if(!sync_video_packet(ds)) return 0; // cannot sync (EOF)
  
  videobuf_code_len=0; // force resync
  
  // SYNC AGAIN:
  return sync_video_packet(ds);
}