demux_audio.c

自己移植的linux下的流媒体播放器原代码,支持mms协议,支持ftp和http协议.

        l -= w->cbSize;
      }
     }
    }

    if(verbose>0) print_wave_header(w);
    if(l)
      stream_skip(s,l);
    do
    {
      chunk_type = stream_read_fourcc(demuxer->stream);
      chunk_size = stream_read_dword_le(demuxer->stream);
      if (chunk_type != mmioFOURCC('d', 'a', 't', 'a'))
        stream_skip(demuxer->stream, chunk_size);
    } while (chunk_type != mmioFOURCC('d', 'a', 't', 'a'));
    demuxer->movi_start = stream_tell(s);
    demuxer->movi_end = s->end_pos;
//    printf("wav: %X .. %X\n",(int)demuxer->movi_start,(int)demuxer->movi_end);
    // Check if it contains dts audio
    if((w->wFormatTag == 0x01) && (w->nChannels == 2) && (w->nSamplesPerSec == 44100)) {
	unsigned char buf[16384]; // vlc uses 16384*4 (4 dts frames)
	unsigned int i;
	stream_read(s, buf, sizeof(buf));
	for (i = 0; i < sizeof(buf); i += 2) {
	    // DTS, 14 bit, LE
	    if((buf[i] == 0xff) && (buf[i+1] == 0x1f) && (buf[i+2] == 0x00) &&
	       (buf[i+3] == 0xe8) && ((buf[i+4] & 0xfe) == 0xf0) && (buf[i+5] == 0x07)) {
		sh_audio->format = 0x2001;
		mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, LE\n");
		break;
	    }
	    // DTS, 14 bit, BE
	    if((buf[i] == 0x1f) && (buf[i+1] == 0xff) && (buf[i+2] == 0xe8) &&
	       (buf[i+3] == 0x00) && (buf[i+4] == 0x07) && ((buf[i+5] & 0xfe) == 0xf0)) {
		sh_audio->format = 0x2001;
		mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 14 bit, BE\n");
		break;
	    }
	    // DTS, 16 bit, BE
	    if((buf[i] == 0x7f) && (buf[i+1] == 0xfe) && (buf[i+2] == 0x80) &&
	       (buf[i+3] == 0x01)) {
		sh_audio->format = 0x2001;
		mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, BE\n");
		break;
	    }
	    // DTS, 16 bit, LE
	    if((buf[i] == 0xfe) && (buf[i+1] == 0x7f) && (buf[i+2] == 0x01) &&
	       (buf[i+3] == 0x80)) {
		sh_audio->format = 0x2001;
		mp_msg(MSGT_DEMUX,MSGL_V,"[demux_audio] DTS audio in wav, 16 bit, LE\n");
		break;
	    }
	}
	if (sh_audio->format == 0x2001)
	    mp_msg(MSGT_DEMUX,MSGL_DBG2,"[demux_audio] DTS sync offset = %u\n", i);

    }
    stream_seek(s,demuxer->movi_start);
  } break;
  case fLaC:
	    sh_audio->format = mmioFOURCC('f', 'L', 'a', 'C');
	    demuxer->movi_start = stream_tell(s);
	    demuxer->movi_end = s->end_pos;
	    break;
  }

  priv = (da_priv_t*)malloc(sizeof(da_priv_t));
  priv->frmt = frmt;
  priv->last_pts = -1;
  demuxer->priv = priv;
  demuxer->audio->id = 0;
  demuxer->audio->sh = sh_audio;
  sh_audio->ds = demuxer->audio;
  sh_audio->samplerate = sh_audio->audio.dwRate;

  if(stream_tell(s) != demuxer->movi_start)
  {
    mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking from 0x%X to start pos 0x%X\n",
            (int)stream_tell(s), (int)demuxer->movi_start);
    stream_seek(s,demuxer->movi_start);
    if (stream_tell(s) != demuxer->movi_start) {
      mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking failed, now at 0x%X!\n",
              (int)stream_tell(s));
      if (next_frame_pos) {
        mp_msg(MSGT_DEMUX, MSGL_V, "demux_audio: seeking to 0x%X instead\n",
                (int)next_frame_pos);
        stream_seek(s, next_frame_pos);
      }
    }
  }

  mp_msg(MSGT_DEMUX,MSGL_V,"demux_audio: audio data 0x%X - 0x%X  \n",(int)demuxer->movi_start,(int)demuxer->movi_end);

  return 1;
}


int demux_audio_fill_buffer(demux_stream_t *ds) {
  int l;
  demux_packet_t* dp;
  sh_audio_t* sh_audio;
  demuxer_t* demux;
  da_priv_t* priv;
  stream_t* s;
#ifdef MP_DEBUG
  assert(ds != NULL);
  assert(ds->sh != NULL);
  assert(ds->demuxer != NULL);
#endif
  sh_audio = ds->sh;
  demux = ds->demuxer;
  priv = demux->priv;
  s = demux->stream;

  if(s->eof || (demux->movi_end && stream_tell(s) >= demux->movi_end) )
    return 0;

  switch(priv->frmt) {
  case MP3 :
    while(1) {
      uint8_t hdr[4];
      stream_read(s,hdr,4);
      if (s->eof || (demux->movi_end && stream_tell(s) >= demux->movi_end))
        return 0;
      l = mp_decode_mp3_header(hdr);
      if(l < 0) {
	stream_skip(s,-3);
      } else {
	dp = new_demux_packet(l);
	memcpy(dp->buffer,hdr,4);
	stream_read(s,dp->buffer + 4,l-4);
	priv->last_pts = priv->last_pts < 0 ? 0 : priv->last_pts + 1152/(float)sh_audio->samplerate; // FIXME: 1152->576 if MPEG-2
	break;
      }
    } break;
  case WAV : {
    l = sh_audio->wf->nAvgBytesPerSec;
    dp = new_demux_packet(l);
    l = stream_read(s,dp->buffer,l);
    priv->last_pts = priv->last_pts < 0 ? 0 : priv->last_pts + l/(float)sh_audio->i_bps;
    break;
  }
  case fLaC: {
    l = 65535;
    dp = new_demux_packet(l);
    l = stream_read(s,dp->buffer,l);
    priv->last_pts = priv->last_pts < 0 ? 0 : priv->last_pts + l/(float)sh_audio->i_bps;
    break;
  }
  default:
    printf("Audio demuxer : unknown format %d\n",priv->frmt);
    return 0;
  }

  resize_demux_packet(dp, l);
  ds->pts = priv->last_pts - (ds_tell_pts(demux->audio) -
              sh_audio->a_in_buffer_len)/(float)sh_audio->i_bps;
  ds_add_packet(ds, dp);
  return 1;
}

static void high_res_mp3_seek(demuxer_t *demuxer,float time) {
  uint8_t hdr[4];
  int len,nf;
  da_priv_t* priv = demuxer->priv;
  sh_audio_t* sh = (sh_audio_t*)demuxer->audio->sh;

  nf = time*sh->samplerate/1152;
  while(nf > 0) {
    stream_read(demuxer->stream,hdr,4);
    len = mp_decode_mp3_header(hdr);
    if(len < 0) {
      stream_skip(demuxer->stream,-3);
      continue;
    }
    stream_skip(demuxer->stream,len-4);
    priv->last_pts += 1152/(float)sh->samplerate;
    nf--;
  }
}

void demux_audio_seek(demuxer_t *demuxer,float rel_seek_secs,int flags){
  sh_audio_t* sh_audio;
  stream_t* s;
  int base,pos;
  float len;
  da_priv_t* priv;

  if(!(sh_audio = demuxer->audio->sh))
    return;
  s = demuxer->stream;
  priv = demuxer->priv;

  if(priv->frmt == MP3 && hr_mp3_seek && !(flags & 2)) {
    len = (flags & 1) ? rel_seek_secs - priv->last_pts : rel_seek_secs;
    if(len < 0) {
      stream_seek(s,demuxer->movi_start);
      len = priv->last_pts + len;
      priv->last_pts = 0;
    }
    if(len > 0)
      high_res_mp3_seek(demuxer,len);
    sh_audio->delay = priv->last_pts -  (ds_tell_pts(demuxer->audio)-sh_audio->a_in_buffer_len)/(float)sh_audio->i_bps;
    resync_audio_stream(sh_audio);
    return;
  }

  base = flags&1 ? demuxer->movi_start : stream_tell(s);
  if(flags&2)
    pos = base + ((demuxer->movi_end - demuxer->movi_start)*rel_seek_secs);
  else
    pos = base + (rel_seek_secs*sh_audio->i_bps);

  if(demuxer->movi_end && pos >= demuxer->movi_end) {
     pos = demuxer->movi_end;
    //sh_audio->delay = (stream_tell(s) - demuxer->movi_start)/(float)sh_audio->i_bps;
    //return;
  } else if(pos < demuxer->movi_start)
    pos = demuxer->movi_start;

  priv->last_pts = (pos-demuxer->movi_start)/(float)sh_audio->i_bps;
  sh_audio->delay = priv->last_pts - (ds_tell_pts(demuxer->audio)-sh_audio->a_in_buffer_len)/(float)sh_audio->i_bps;
  
  switch(priv->frmt) {
  case WAV:
    pos -= (pos % (sh_audio->channels * sh_audio->samplesize) );
    // We need to decrease the pts by one step to make it the "last one"
    priv->last_pts -= sh_audio->wf->nAvgBytesPerSec/(float)sh_audio->i_bps;
    break;
  }

  stream_seek(s,pos);

  resync_audio_stream(sh_audio);

}

void demux_close_audio(demuxer_t* demuxer) {
  da_priv_t* priv = demuxer->priv;

  if(!priv)
    return;
  free(priv);
}

int demux_audio_control(demuxer_t *demuxer,int cmd, void *arg){
    sh_audio_t *sh_audio=demuxer->audio->sh;
    int audio_length = demuxer->movi_end / sh_audio->i_bps;
    da_priv_t* priv = demuxer->priv;
	    
    switch(cmd) {
	case DEMUXER_CTRL_GET_TIME_LENGTH:
	    if (audio_length<=0) return DEMUXER_CTRL_DONTKNOW;
	    *((unsigned long *)arg)=(unsigned long)audio_length;
	    return DEMUXER_CTRL_GUESS;

	case DEMUXER_CTRL_GET_PERCENT_POS:
	    if (audio_length<=0) 
    		return DEMUXER_CTRL_DONTKNOW;
    	    *((int *)arg)=(int)( (priv->last_pts*100)  / audio_length);
	    return DEMUXER_CTRL_OK;

	default:
	    return DEMUXER_CTRL_NOTIMPL;
    }
}