demux_mpg.c

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//  MPG/VOB file parser for DEMUXER v2.5  by A'rpi/ESP-team

#include <mplaylib.h>
#include <mplaylib.h>
#include <mplaylib.h>
#include <math.h>

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

#include "stream/stream.h"
#include "demuxer.h"
#include "parse_es.h"
#include "stheader.h"
#include "mp3_hdr.h"

//#define MAX_PS_PACKETSIZE 2048
#define MAX_PS_PACKETSIZE (224*1024)

#define UNKNOWN         0
#define VIDEO_MPEG1     0x10000001
#define VIDEO_MPEG2     0x10000002
#define VIDEO_MPEG4     0x10000004
#define VIDEO_H264      0x10000005
#define AUDIO_MP2       0x50
#define AUDIO_A52       0x2000
#define AUDIO_LPCM_BE   0x10001
#define AUDIO_AAC       mmioFOURCC('M', 'P', '4', 'A')

typedef struct mpg_demuxer {
  float last_pts;
  float first_pts;              // first pts found in stream
  float first_to_final_pts_len; // difference between final pts and first pts
  int has_valid_timestamps;     // !=0 iff time stamps look linear
                                // (not necessarily starting with 0)
  unsigned int es_map[0x40];	//es map of stream types (associated to the pes id) from 0xb0 to 0xef
  int num_a_streams;
  int a_stream_ids[MAX_A_STREAMS];
} mpg_demuxer_t;

extern char* dvdsub_lang;
static int mpeg_pts_error=0;
off_t ps_probe = 0;

static int parse_psm(demuxer_t *demux, int len) {
  unsigned char c, id, type;
  unsigned int plen, prog_len, es_map_len;
  mpg_demuxer_t *priv = (mpg_demuxer_t *) demux->priv;
  
  mp_dbg(MSGT_DEMUX,MSGL_V, "PARSE_PSM, len=%d\n", len);
  if(! len || len > 1018)
    return 0;
  
  c = stream_read_char(demux->stream);
  if(! (c & 0x80)) {
    stream_skip(demux->stream, len - 1);  //not yet valid, discard
    return 0;
  }
  stream_skip(demux->stream, 1);
  prog_len = stream_read_word(demux->stream);		//length of program descriptors
  stream_skip(demux->stream, prog_len);			//.. that we ignore
  es_map_len = stream_read_word(demux->stream);		//length of elementary streams map
  es_map_len = FFMIN(es_map_len, len - prog_len - 8);	//sanity check
  while(es_map_len > 0) {
    type = stream_read_char(demux->stream);
    id = stream_read_char(demux->stream);
    if(id >= 0xB0 && id <= 0xEF && priv) {
      int idoffset = id - 0xB0;
      switch(type) {
        case 0x1:
          priv->es_map[idoffset] = VIDEO_MPEG1;
          break;
        case 0x2:
          priv->es_map[idoffset] = VIDEO_MPEG2;
          break;
        case 0x3:
        case 0x4:
          priv->es_map[idoffset] = AUDIO_MP2;
          break;
        case 0x0f:
        case 0x11:
          priv->es_map[idoffset] = AUDIO_AAC;
          break;
        case 0x10:
          priv->es_map[idoffset] = VIDEO_MPEG4;
          break;
        case 0x1b:
          priv->es_map[idoffset] = VIDEO_H264;
          break;
        case 0x81:
          priv->es_map[idoffset] = AUDIO_A52;
          break;
      }
      mp_dbg(MSGT_DEMUX,MSGL_V, "PSM ES, id=0x%x, type=%x, stype: %x\n", id, type, priv->es_map[idoffset]);
    }
    plen = stream_read_word(demux->stream);		//length of elementary stream descriptors
    plen = FFMIN(plen, es_map_len);			//sanity check
    stream_skip(demux->stream, plen);			//skip descriptors for now
    es_map_len -= 4 + plen;
  }
  stream_skip(demux->stream, 4);			//skip crc32
  return 1;
}

// 500000 is a wild guess
#define TIMESTAMP_PROBE_LEN 500000

//MAX_PTS_DIFF_FOR_CONSECUTIVE denotes the maximum difference
//between two pts to consider them consecutive
//1.0 is a wild guess
#define MAX_PTS_DIFF_FOR_CONSECUTIVE 1.0

//returns the first pts found within TIME_STAMP_PROBE_LEN bytes after stream_pos in demuxer's stream.
//if no pts is found or an error occurs, -1.0 is returned.
//Packs are freed.
static float read_first_mpeg_pts_at_position(demuxer_t* demuxer, off_t stream_pos)
{
  stream_t *s = demuxer->stream;
  mpg_demuxer_t *mpg_d = demuxer->priv;
  float pts = -1.0; //the pts to return;
  float found_pts1; //the most recently found pts
  float found_pts2; //the pts found before found_pts1
  float found_pts3; //the pts found before found_pts2
  int found = 0;

  if(!mpg_d || stream_pos < 0)
    return pts;

  found_pts3 = found_pts2 = found_pts1 = mpg_d->last_pts;
  stream_seek(s, stream_pos);

  //We look for pts.
  //However, we do not stop at the first found one, as timestamps may reset
  //Therefore, we seek until we found three consecutive
  //pts within MAX_PTS_DIFF_FOR_CONSECUTIVE.

  while(found<3 && !s->eof
   && (fabsf(found_pts2-found_pts1) < MAX_PTS_DIFF_FOR_CONSECUTIVE)
   && (fabsf(found_pts3-found_pts2) < MAX_PTS_DIFF_FOR_CONSECUTIVE)
   && (stream_tell(s) < stream_pos + TIMESTAMP_PROBE_LEN)
   && ds_fill_buffer(demuxer->video))
  {
    if(mpg_d->last_pts != found_pts1)
    {
      if(!found)
        found_pts3 = found_pts2 = found_pts1 = mpg_d->last_pts; //the most recently found pts
      else
      {
        found_pts3 = found_pts2;
        found_pts2 = found_pts1;
        found_pts1 = mpg_d->last_pts;
      }
      found++;
    }
  }

  if(found == 3) pts = found_pts3;

  //clean up from searching of first pts;
  ds_free_packs(demuxer->audio);
  ds_free_packs(demuxer->video);
  ds_free_packs(demuxer->sub);

  return pts;
}

/// Open an mpg physical stream
static demuxer_t* demux_mpg_open(demuxer_t* demuxer) {
  stream_t *s = demuxer->stream;
  mpg_demuxer_t* mpg_d;

  if (!ds_fill_buffer(demuxer->video)) return 0;
  mpg_d = calloc(1,sizeof(mpg_demuxer_t));
  if(mpg_d)
  {
    demuxer->priv = mpg_d;
    mpg_d->last_pts = -1.0;
    mpg_d->first_pts = -1.0;

    //if seeking is allowed set has_valid_timestamps if appropriate
    if(demuxer->seekable
       && (demuxer->stream->type == STREAMTYPE_FILE
           || demuxer->stream->type == STREAMTYPE_VCD)
       && demuxer->movi_start != demuxer-> movi_end
    )
    {
      //We seek to the beginning of the stream, to somewhere in the
      //middle, and to the end of the stream, while remembering the pts
      //at each of the three positions. With these pts, we check whether
      //or not the pts are "linear enough" to justify seeking by the pts
      //of the stream

      //The position where the stream is now
      off_t pos = stream_tell(s);
      float first_pts = read_first_mpeg_pts_at_position(demuxer, demuxer->movi_start);
      if(first_pts != -1.0)
      {
        float middle_pts = read_first_mpeg_pts_at_position(demuxer, (demuxer->movi_end + demuxer->movi_start)/2);
        if(middle_pts != -1.0)
        {
          float final_pts = read_first_mpeg_pts_at_position(demuxer, demuxer->movi_end - TIMESTAMP_PROBE_LEN);
          if(final_pts != -1.0)
          {
            // found proper first, middle, and final pts.
            float proportion = (middle_pts-first_pts==0) ? -1 : (final_pts-middle_pts)/(middle_pts-first_pts);
            // if they are linear enough set has_valid_timestamps
            if((0.5 < proportion) && (proportion < 2))
            {
              mpg_d->first_pts = first_pts;
              mpg_d->first_to_final_pts_len = final_pts - first_pts;
              mpg_d->has_valid_timestamps = 1;
            }
          }
        }
      }

      //Cleaning up from seeking in stream
      demuxer->stream->eof=0;
      demuxer->video->eof=0;
      demuxer->audio->eof=0;

      stream_seek(s,pos);
      ds_fill_buffer(demuxer->video);
    } // if ( demuxer->seekable )
  } // if ( mpg_d )
  return demuxer;
}

static void demux_close_mpg(demuxer_t* demuxer) {
  mpg_demuxer_t* mpg_d = demuxer->priv;
  if (mpg_d) free(mpg_d);
}


static unsigned long long read_mpeg_timestamp(stream_t *s,int c){
  unsigned int d,e;
  unsigned long long pts;
  d=stream_read_word(s);
  e=stream_read_word(s);
  if( ((c&1)!=1) || ((d&1)!=1) || ((e&1)!=1) ){
    ++mpeg_pts_error;
    return 0; // invalid pts
  }
  pts=(((uint64_t)((c>>1)&7))<<30)|((d>>1)<<15)|(e>>1);
  mp_dbg(MSGT_DEMUX,MSGL_DBG3," pts {%"PRIu64"}",pts);
  return pts;
}

static void new_audio_stream(demuxer_t *demux, int aid){
  if(!demux->a_streams[aid]){
    mpg_demuxer_t *mpg_d=(mpg_demuxer_t*)demux->priv;
    sh_audio_t* sh_a;
    new_sh_audio(demux,aid);
    sh_a = (sh_audio_t*)demux->a_streams[aid];
    switch(aid & 0xE0){  // 1110 0000 b  (high 3 bit: type  low 5: id)
      case 0x00: sh_a->format=0x50;break; // mpeg
      case 0xA0: sh_a->format=0x10001;break;  // dvd pcm
      case 0x80: if((aid & 0xF8) == 0x88) sh_a->format=0x2001;//dts
                  else sh_a->format=0x2000;break; // ac3
    }
    //evo files
    if((aid & 0xC0) == 0xC0) sh_a->format=0x2000;
    else if(aid >= 0x98 && aid <= 0x9f) sh_a->format=0x2001;
    if (mpg_d) mpg_d->a_stream_ids[mpg_d->num_a_streams++] = aid;
  }
  if(demux->audio->id==-1) demux->audio->id=aid;
}

static int demux_mpg_read_packet(demuxer_t *demux,int id){
  int d;
  int len;
  int set_pts=0; // !=0 iff pts has been set to a proper value
  unsigned char c=0;
  unsigned long long pts=0;
  unsigned long long dts=0;
  int l;
  int pes_ext2_subid=-1;
  double stream_pts = MP_NOPTS_VALUE;
  demux_stream_t *ds=NULL;
  demux_packet_t* dp;
  mpg_demuxer_t *priv = (mpg_demuxer_t *) demux->priv;

  mp_dbg(MSGT_DEMUX,MSGL_DBG3,"demux_read_packet: %X\n",id);

//  if(id==0x1F0){
//    demux->synced=0; // force resync after 0x1F0
//    return -1;
//}

//  if(id==0x1BA) packet_start_pos=stream_tell(demux->stream);
  if((id<0x1BC || id>=0x1F0) && id != 0x1FD) return -1;
  if(id==0x1BE) return -1; // padding stream
  if(id==0x1BF) return -1; // private2

  len=stream_read_word(demux->stream);
  mp_dbg(MSGT_DEMUX,MSGL_DBG3,"PACKET len=%d",len);
//  if(len==62480){ demux->synced=0;return -1;} /* :) */
  if(len==0 || len>MAX_PS_PACKETSIZE){
    mp_dbg(MSGT_DEMUX,MSGL_DBG2,"Invalid PS packet len: %d\n",len);
    return -2;  // invalid packet !!!!!!
  }

  mpeg_pts_error=0;

  if(id==0x1BC) {
    parse_psm(demux, len);
    return 0;
  }

  while(len>0){   // Skip stuFFing bytes
    c=stream_read_char(demux->stream);
    --len;
    if(c!=0xFF)break;
  }
  if((c>>6)==1){  // Read (skip) STD scale & size value
//    printf("  STD_scale=%d",(c>>5)&1);
    d=((c&0x1F)<<8)|stream_read_char(demux->stream);
    len-=2;
//    printf("  STD_size=%d",d);
    c=stream_read_char(demux->stream);
  }
  // Read System-1 stream timestamps:
  if((c>>4)==2){
    pts=read_mpeg_timestamp(demux->stream,c);
    set_pts=1;
    len-=4;
  } else
  if((c>>4)==3){
    pts=read_mpeg_timestamp(demux->stream,c);
    c=stream_read_char(demux->stream);
    if((c>>4)!=1) pts=0; //printf("{ERROR4}");
    else set_pts = 1;
    dts=read_mpeg_timestamp(demux->stream,c);
    len-=4+1+4;
  } else
  if((c>>6)==2){
    int pts_flags;
    int hdrlen;
    int parse_ext2;
    // System-2 (.VOB) stream:
    c=stream_read_char(demux->stream);
    pts_flags=c>>6;
    parse_ext2 = (id == 0x1FD) && ((c & 0x3F) == 1);
    c=stream_read_char(demux->stream);
    hdrlen=c;
    len-=2;
    mp_dbg(MSGT_DEMUX,MSGL_DBG3,"  hdrlen=%d  (len=%d)",hdrlen,len);
    if(hdrlen>len){ mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: invalid header length  \n"); return -1;}
    if(pts_flags==2 && hdrlen>=5){
      c=stream_read_char(demux->stream);
      pts=read_mpeg_timestamp(demux->stream,c);
      set_pts=1;
      len-=5;hdrlen-=5;
    } else
    if(pts_flags==3 && hdrlen>=10){
      c=stream_read_char(demux->stream);
      pts=read_mpeg_timestamp(demux->stream,c);
      set_pts=1;
      c=stream_read_char(demux->stream);
      dts=read_mpeg_timestamp(demux->stream,c);
      len-=10;hdrlen-=10;
    }
    len-=hdrlen;
    if(parse_ext2 && hdrlen>=3) {
      c=stream_read_char(demux->stream);
      hdrlen--;

      if((c & 0x0F) != 0x0F) {
        mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: pes_extension_flag2 not set, discarding pes packet\n");
        return -1;
      }
      if(c & 0x80) { //pes_private_data_flag
        if(hdrlen<16) {
          mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: not enough pes_private_data bytes: %d < 16, discarding pes packet\n", hdrlen);
          return -1;
        }
        stream_skip(demux->stream, 16);
        hdrlen-=16;
      }
      if(c & 0x40) { //pack_header_field_flag
        int l = stream_read_char(demux->stream);
        if(l < 0) //couldn't read from the stream?
          return -1;
        hdrlen--;
        if(l < 0 || hdrlen < l) {
          mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: not enough pack_header bytes: hdrlen: %d < skip: %d, discarding pes packet\n",
                                   hdrlen, l);
          return -1;
        }
        stream_skip(demux->stream, l);
        hdrlen-=l;
      }
      if(c & 0x20) { //program_packet_sequence_counter_flag
        if(hdrlen < 2) {
          mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: not enough program_packet bytes: hdrlen: %d, discarding pes packet\n", hdrlen);
          return -1;
        }
        stream_skip(demux->stream, 2);
        hdrlen-=2;
      }
      if(c & 0x10) {
        //STD
        stream_skip(demux->stream, 2);
        hdrlen-=2;
      }
      c=stream_read_char(demux->stream); //pes_extension2 flag
      hdrlen--;
      if(c!=0x81)  { mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: unknown pes_extension2 format, len is > 1  \n"); return -1;}