path: root/libmpdemux/demux_mpg.c

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

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

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

#include "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(hdrlen>0) {
      if(!parse_ext2)
        stream_skip(demux->stream,hdrlen); // skip header bytes
      else if(hdrlen>=3) {
        c=stream_read_char(demux->stream);
        hdrlen--;
        if(c != 0x1F && c!= 0x0F) { mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: invalid pes_extension field  \n"); return -1;}
        if(c == 0x1F) {
          //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;}
        c=stream_read_char(demux->stream); //pes_extension2 payload === substream id
        if(c<0x55 || c>0x5F)   { mp_msg(MSGT_DEMUX,MSGL_V,"demux_mpg: unknown vc1 substream_id: 0x%x  \n", c); return -1;}
        pes_ext2_subid=c;
      }
    }
    
    if(id==0x1FD && pes_ext2_subid!=-1) {
      //==== EVO VC1 STREAMS ===//
      if(!demux->v_streams[pes_ext2_subid]) new_sh_video(demux,pes_ext2_subid);
      if(demux->video->id==-1) demux->video->id=pes_ext2_subid;
      if(demux->video->id==pes_ext2_subid){
        ds=demux->video;
        if(!ds->sh) ds->sh=demux->v_streams[pes_ext2_subid];
        if(priv && ds->sh) {
          sh_video_t *sh = (sh_video_t *)ds->sh;
          sh->format = mmioFOURCC('W', 'V', 'C', '1');
        }
      }
    }
    //============== DVD Audio sub-stream ======================
    if(id==0x1BD){
      int aid, rawa52 = 0;
      off_t tmppos;
      unsigned int tmp;

      tmppos = stream_tell(demux->stream);
      tmp = stream_read_word(demux->stream);
      stream_seek(demux->stream, tmppos);
      /// vdr stores A52 without the 4 header bytes, so we have to check this condition first
      if(tmp == 0x0B77) {
        aid = 128;
        rawa52 = 1;
      }
      else {
        aid=stream_read_char(demux->stream);--len;
        if(len<3) return -1; // invalid audio packet
      }
      
      // AID:
      // 0x20..0x3F  subtitle
      // 0x80..0x9F  AC3 audio
      // 0xA0..0xBF  PCM audio
      
      if((aid & 0xE0) == 0x20){
        // subtitle:
        aid&=0x1F;

        if(!demux->s_streams[aid]){
            mp_msg(MSGT_DEMUX,MSGL_V,"==> Found subtitle: %d\n",aid);
            new_sh_sub(demux, aid);
        }

        if(demux->sub->id > -1)
          demux->sub->id &= 0x1F;
        if(!dvdsub_lang && demux->sub->id == -1)
          demux->sub->id = aid;
        if(demux->sub->id==aid){
            ds=demux->sub;
        }
          
      } else if((aid & 0xC0) == 0x80 || (aid & 0xE0) == 0x00 || (aid & 0xC0) == 0xC0) {

//        aid=128+(aid&0x7F);
        // aid=0x80..0xBF
        new_audio_stream(demux, aid);
      if(demux->audio->id==aid){
        int type;
        ds=demux->audio;
        if(!ds->sh) ds->sh=demux->a_streams[aid];
        // READ Packet: Skip additional audio header data:
        if(!rawa52) {
        c=stream_read_char(demux->stream);//num of frames
        type=stream_read_char(demux->stream);//startpos hi
        type=(type<<8)|stream_read_char(demux->stream);//startpos lo
//        printf("\r[%02X][%04X]",c,type);
        len-=3;
        }
        if((aid&0xE0)==0xA0 && len>=3){
	  unsigned char* hdr;
	  // save audio header as codecdata!
	  if(!((sh_audio_t*)(ds->sh))->codecdata_len){
	      ((sh_audio_t*)(ds->sh))->codecdata=malloc(3);
	      ((sh_audio_t*)(ds->sh))->codecdata_len=3;
	  }
	  hdr=((sh_audio_t*)(ds->sh))->codecdata;
          // read LPCM header:
	  // emphasis[1], mute[1], rvd[1], frame number[5]:
          hdr[0]=stream_read_char(demux->stream);
//          printf(" [%01X:%02d]",c>>5,c&31);
	  // quantization[2],freq[2],rvd[1],channels[3]
          hdr[1]=stream_read_char(demux->stream);
//          printf("[%01X:%01X] ",c>>4,c&15);
	  // dynamic range control (0x80=off):
          hdr[2]=stream_read_char(demux->stream);
//          printf("[%02X] ",c);
          len-=3;
          if(len<=0) mp_msg(MSGT_DEMUX,MSGL_V,"End of packet while searching for PCM header\n");
        }
//        printf("  \n");
      } //  if(demux->audio->id==aid)

      } else mp_msg(MSGT_DEMUX,MSGL_V,"Unknown 0x1BD substream: 0x%02X  \n",aid);

    } //if(id==0x1BD)

  } else {
    if(c!=0x0f){
      mp_msg(MSGT_DEMUX,MSGL_V,"  {ERROR5,c=%d}  \n",c);
      return -1;  // invalid packet !!!!!!
    }
  }
  if(mpeg_pts_error) mp_msg(MSGT_DEMUX,MSGL_V,"  {PTS_err:%d}  \n",mpeg_pts_error);
  mp_dbg(MSGT_DEMUX,MSGL_DBG3," => len=%d\n",len);

//  if(len<=0 || len>MAX_PS_PACKETSIZE) return -1;  // Invalid packet size
  if(len<=0 || len>MAX_PS_PACKETSIZE){
    mp_dbg(MSGT_DEMUX,MSGL_DBG2,"Invalid PS data len: %d\n",len);
    return -1;  // invalid packet !!!!!!
  }
  
  if(id>=0x1C0 && id<=0x1DF){
    // mpeg audio
    int aid=id-0x1C0;
    new_audio_stream(demux, aid);
    if(demux->audio->id==aid){
      ds=demux->audio;
      if(!ds->sh) ds->sh=demux->a_streams[aid];
      if(priv && ds->sh) {
        sh_audio_t *sh = (sh_audio_t *)ds->sh;
        if(priv->es_map[id - 0x1B0])
          sh->format = priv->es_map[id - 0x1B0];
          mp_dbg(MSGT_DEMUX,MSGL_DBG2,"ASSIGNED TO STREAM %d CODEC %x\n", id, priv->es_map[id - 0x1B0]);
      }
    }
  } else
  if(id>=0x1E0 && id<=0x1EF){
    // mpeg video
    int aid=id-0x1E0;
    if(!demux->v_streams[aid]) new_sh_video(demux,aid);
    if(demux->video->id==-1) demux->video->id=aid;
    if(demux->video->id==aid){
      ds=demux->video;
      if(!ds->sh) ds->sh=demux->v_streams[aid];
      if(priv && ds->sh) {
        sh_video_t *sh = (sh_video_t *)ds->sh;
        if(priv->es_map[id - 0x1B0]) {
          sh->format = priv->es_map[id - 0x1B0];
          mp_dbg(MSGT_DEMUX,MSGL_DBG2,"ASSIGNED TO STREAM %d CODEC %x\n", id, priv->es_map[id - 0x1B0]);
        }
      }
    }
  }

  if(ds){
    mp_dbg(MSGT_DEMUX,MSGL_DBG2,"DEMUX_MPG: Read %d data bytes from packet %04X\n",len,id);
//    printf("packet start = 0x%X  \n",stream_tell(demux->stream)-packet_start_pos);

    dp=new_demux_packet(len);
    if(!dp) {
      mp_dbg(MSGT_DEMUX,MSGL_ERR,"DEMUX_MPG ERROR: couldn't create demux_packet(%d bytes)\n",len);
      stream_skip(demux->stream,len);
      return 0;
    }
    l = stream_read(demux->stream,dp->buffer,len);
    if(l<len)
      resize_demux_packet(dp, l);
    len = l;
    dp->pts=pts/90000.0f;
    dp->pos=demux->filepos;
    /*
      workaround:
      set dp->stream_pts only when feeding the video stream, or strangely interleaved files
      (such as SWIII) will show strange alternations in the stream time, wildly going
      back and forth
    */
    if(ds == demux->video && stream_control(demux->stream, STREAM_CTRL_GET_CURRENT_TIME,(void *)&stream_pts)!=STREAM_UNSUPORTED)
      dp->stream_pts = stream_pts;
    ds_add_packet(ds,dp);
    if (demux->priv && set_pts) ((mpg_demuxer_t*)demux->priv)->last_pts = pts/90000.0f;
//    if(ds==demux->sub) parse_dvdsub(ds->last->buffer,ds->last->len);
    return 1;
  }