avilib.c

mediastreamer2是开源的网络传输媒体流的库

   return 0;
}

int AVI_write_frame(avi_t *AVI, char *data, long bytes, int keyframe)
{
  unsigned long pos;
  
  if(AVI->mode==AVI_MODE_READ) { AVI_errno = AVI_ERR_NOT_PERM; return -1; }
  
  pos = AVI->pos;

  if(avi_write_data(AVI,data,bytes,0,keyframe)) return -1;
   
  AVI->last_pos = pos;
  AVI->last_len = bytes;
  AVI->video_frames++;
  return 0;
}

int AVI_dup_frame(avi_t *AVI)
{
   if(AVI->mode==AVI_MODE_READ) { AVI_errno = AVI_ERR_NOT_PERM; return -1; }

   if(AVI->last_pos==0) return 0; /* No previous real frame */
   if(avi_add_index_entry(AVI,(unsigned char *)"00db",0x10,AVI->last_pos,AVI->last_len)) return -1;
   AVI->video_frames++;
   AVI->must_use_index = 1;
   return 0;
}

int AVI_write_audio(avi_t *AVI, char *data, long bytes)
{
   if(AVI->mode==AVI_MODE_READ) { AVI_errno = AVI_ERR_NOT_PERM; return -1; }

   if( avi_write_data(AVI,data,bytes,1,0) ) return -1;
   AVI->track[AVI->aptr].audio_bytes += bytes;
   return 0;
}


int AVI_append_audio(avi_t *AVI, char *data, long bytes)
{

  long i, length, pos;
  unsigned char c[4];

  if(AVI->mode==AVI_MODE_READ) { AVI_errno = AVI_ERR_NOT_PERM; return -1; }
  
  // update last index entry:
  
  --AVI->n_idx;
  length = str2ulong(AVI->idx[AVI->n_idx]+12);
  pos    = str2ulong(AVI->idx[AVI->n_idx]+8);

  //update;
  long2str(AVI->idx[AVI->n_idx]+12,length+bytes);   

  ++AVI->n_idx;

  AVI->track[AVI->aptr].audio_bytes += bytes;

  //update chunk header
  lseek(AVI->fdes, pos+4, SEEK_SET);
  long2str(c, length+bytes);     
  avi_write(AVI->fdes,(char *) c, 4);

  lseek(AVI->fdes, pos+8+length, SEEK_SET);

  i=PAD_EVEN(length + bytes);

  bytes = i - length;
  avi_write(AVI->fdes, data, bytes);
  AVI->pos = pos + 8 + i;

  return 0;
}


long AVI_bytes_remain(avi_t *AVI)
{
   if(AVI->mode==AVI_MODE_READ) return 0;

   return ( AVI_MAX_LEN - (AVI->pos + 8 + 16*AVI->n_idx));
}

long AVI_bytes_written(avi_t *AVI)
{
   if(AVI->mode==AVI_MODE_READ) return 0;

   return (AVI->pos + 8 + 16*AVI->n_idx);
}

int AVI_set_audio_track(avi_t *AVI, int track)
{
  
  if(track < 0 || track + 1 > AVI->anum) return(-1);

  //this info is not written to file anyway
  AVI->aptr=track;
  return 0;
}

int AVI_get_audio_track(avi_t *AVI)
{
    return(AVI->aptr);
}


/*******************************************************************
 *                                                                 *
 *    Utilities for reading video and audio from an AVI File       *
 *                                                                 *
 *******************************************************************/

int AVI_close(avi_t *AVI)
{
   int ret;

   /* If the file was open for writing, the header and index still have
      to be written */

   if(AVI->mode == AVI_MODE_WRITE)
      ret = avi_close_output_file(AVI);
   else
      ret = 0;

   /* Even if there happened an error, we first clean up */

   close(AVI->fdes);
   if(AVI->idx) free(AVI->idx);
   if(AVI->video_index) free(AVI->video_index);
   //FIXME
   //if(AVI->audio_index) free(AVI->audio_index);
   free(AVI);

   return ret;
}


#define ERR_EXIT(x) \
{ \
   AVI_close(AVI); \
   AVI_errno = x; \
   return 0; \
}

avi_t *AVI_open_input_file(char *filename, int getIndex)
{
  avi_t *AVI=NULL;
  
  /* Create avi_t structure */
  
  AVI = (avi_t *) malloc(sizeof(avi_t));
  if(AVI==NULL)
    {
      AVI_errno = AVI_ERR_NO_MEM;
      return 0;
    }
  memset((void *)AVI,0,sizeof(avi_t));
  
  AVI->mode = AVI_MODE_READ; /* open for reading */
  
  /* Open the file */
  
  AVI->fdes = open(filename,O_RDONLY|O_BINARY);
  if(AVI->fdes < 0)
    {
      AVI_errno = AVI_ERR_OPEN;
      free(AVI);
      return 0;
    }
  
  avi_parse_input_file(AVI, getIndex);

  AVI->aptr=0; //reset  

  return AVI;
}

avi_t *AVI_open_fd(int fd, int getIndex)
{
  avi_t *AVI=NULL;
  
  /* Create avi_t structure */
  
  AVI = (avi_t *) malloc(sizeof(avi_t));
  if(AVI==NULL)
    {
      AVI_errno = AVI_ERR_NO_MEM;
      return 0;
    }
  memset((void *)AVI,0,sizeof(avi_t));
  
  AVI->mode = AVI_MODE_READ; /* open for reading */
  
  // file alread open
  AVI->fdes = fd;
  
  avi_parse_input_file(AVI, getIndex);

  AVI->aptr=0; //reset
  
  return AVI;
}

int avi_parse_input_file(avi_t *AVI, int getIndex)
{
  long i, n, rate, scale, idx_type;
  unsigned char *hdrl_data;
  long header_offset=0, hdrl_len=0;
  long nvi, nai[AVI_MAX_TRACKS], ioff;
  long tot[AVI_MAX_TRACKS];
  int j;
  int lasttag = 0;
  int vids_strh_seen = 0;
  int vids_strf_seen = 0;
  int auds_strh_seen = 0;
  //  int auds_strf_seen = 0;
  int num_stream = 0;
  char data[256];
  
  /* Read first 12 bytes and check that this is an AVI file */

   if( avi_read(AVI->fdes,data,12) != 12 ) ERR_EXIT(AVI_ERR_READ)

   if( strncasecmp(data  ,"RIFF",4) !=0 ||
       strncasecmp(data+8,"AVI ",4) !=0 ) ERR_EXIT(AVI_ERR_NO_AVI)

   /* Go through the AVI file and extract the header list,
      the start position of the 'movi' list and an optionally
      present idx1 tag */

   hdrl_data = 0;

   while(1)
   {
      if( avi_read(AVI->fdes,data,8) != 8 ) break; /* We assume it's EOF */

      n = str2ulong((unsigned char *) data+4);
      n = PAD_EVEN(n);

      if(strncasecmp(data,"LIST",4) == 0)
      {
         if( avi_read(AVI->fdes,data,4) != 4 ) ERR_EXIT(AVI_ERR_READ)
         n -= 4;
         if(strncasecmp(data,"hdrl",4) == 0)
         {
            hdrl_len = n;
            hdrl_data = (unsigned char *) malloc(n);
            if(hdrl_data==0) ERR_EXIT(AVI_ERR_NO_MEM);
				 
	    // offset of header
	    
	    header_offset = lseek(AVI->fdes,0,SEEK_CUR);
				 
            if( avi_read(AVI->fdes,(char *)hdrl_data,n) != n ) ERR_EXIT(AVI_ERR_READ)
         }
         else if(strncasecmp(data,"movi",4) == 0)
         {
            AVI->movi_start = lseek(AVI->fdes,0,SEEK_CUR);
            lseek(AVI->fdes,n,SEEK_CUR);
         }
         else
            lseek(AVI->fdes,n,SEEK_CUR);
      }
      else if(strncasecmp(data,"idx1",4) == 0)
      {
         /* n must be a multiple of 16, but the reading does not
            break if this is not the case */

         AVI->n_idx = AVI->max_idx = n/16;
         AVI->idx = (unsigned  char((*)[16]) ) malloc(n);
         if(AVI->idx==0) ERR_EXIT(AVI_ERR_NO_MEM)
         if(avi_read(AVI->fdes, (char *) AVI->idx, n) != n ) ERR_EXIT(AVI_ERR_READ)
      }
      else
         lseek(AVI->fdes,n,SEEK_CUR);
   }

   if(!hdrl_data      ) ERR_EXIT(AVI_ERR_NO_HDRL)
   if(!AVI->movi_start) ERR_EXIT(AVI_ERR_NO_MOVI)

   /* Interpret the header list */

   for(i=0;i<hdrl_len;)
   {
      /* List tags are completly ignored */

      if(strncasecmp((char *) hdrl_data+i, "LIST",4)==0) { i+= 12; continue; }

      n = str2ulong(hdrl_data+i+4);
      n = PAD_EVEN(n);

      /* Interpret the tag and its args */

      if(strncasecmp((char *)hdrl_data+i,"strh",4)==0)
      {
         i += 8;
         if(strncasecmp((char *)hdrl_data+i,"vids",4) == 0 && !vids_strh_seen)
         {
            memcpy(AVI->compressor,hdrl_data+i+4,4);
            AVI->compressor[4] = 0;

	    // ThOe
	    AVI->v_codech_off = header_offset + i+4;

            scale = str2ulong((unsigned char *)hdrl_data+i+20);
            rate  = str2ulong(hdrl_data+i+24);
            if(scale!=0) AVI->fps = (double)rate/(double)scale;
            AVI->video_frames = str2ulong(hdrl_data+i+32);
            AVI->video_strn = num_stream;
	    AVI->max_len = 0;
            vids_strh_seen = 1;
            lasttag = 1; /* vids */
         }
         else if (strncasecmp ((char *) hdrl_data+i,"auds",4) ==0 && ! auds_strh_seen)
         {

	   //inc audio tracks
	   AVI->aptr=AVI->anum;
	   ++AVI->anum;
	   
	   if(AVI->anum > AVI_MAX_TRACKS) {
	     fprintf(stderr, "error - only %d audio tracks supported\n", AVI_MAX_TRACKS);
	     return(-1);
	   }
	   
	   AVI->track[AVI->aptr].audio_bytes = str2ulong(hdrl_data+i+32)*avi_sampsize(AVI, 0);
	   AVI->track[AVI->aptr].audio_strn = num_stream;
	   //	   auds_strh_seen = 1;
	   lasttag = 2; /* auds */
	   
	   // ThOe
	   AVI->track[AVI->aptr].a_codech_off = header_offset + i;
	   
         }
         else
            lasttag = 0;
         num_stream++;
      }
      else if(strncasecmp((char *) hdrl_data+i,"strf",4)==0)
      {
         i += 8;
         if(lasttag == 1)
         {
            AVI->width  = str2ulong(hdrl_data+i+4);
            AVI->height = str2ulong(hdrl_data+i+8);
            vids_strf_seen = 1;
	    //ThOe
	    AVI->v_codecf_off = header_offset + i+16;

	    memcpy(AVI->compressor2, hdrl_data+i+16, 4);
            AVI->compressor2[4] = 0;

         }
         else if(lasttag == 2)
         {
            AVI->track[AVI->aptr].a_fmt   = str2ushort(hdrl_data+i  );

	    //ThOe
	    AVI->track[AVI->aptr].a_codecf_off = header_offset + i;
	    
            AVI->track[AVI->aptr].a_chans = str2ushort(hdrl_data+i+2);
            AVI->track[AVI->aptr].a_rate  = str2ulong (hdrl_data+i+4);
	    //ThOe: read mp3bitrate
	    AVI->track[AVI->aptr].mp3rate = 8*str2ulong(hdrl_data+i+8)/1000;
	    //:ThOe
            AVI->track[AVI->aptr].a_bits  = str2ushort(hdrl_data+i+14);
	    //            auds_strf_seen = 1;
         }
         lasttag = 0;
      }
      else
      {
         i += 8;
         lasttag = 0;
      }

      i += n;
   }

   free(hdrl_data);

   if(!vids_strh_seen || !vids_strf_seen) ERR_EXIT(AVI_ERR_NO_VIDS)

   AVI->video_tag[0] = AVI->video_strn/10 + '0';
   AVI->video_tag[1] = AVI->video_strn%10 + '0';
   AVI->video_tag[2] = 'd';
   AVI->video_tag[3] = 'b';

   /* Audio tag is set to "99wb" if no audio present */
   if(!AVI->track[0].a_chans) AVI->track[0].audio_strn = 99;

   for(j=0; j<AVI->anum; ++j) {
     AVI->track[j].audio_tag[0] = (j+1)/10 + '0';
     AVI->track[j].audio_tag[1] = (j+1)%10 + '0';
     AVI->track[j].audio_tag[2] = 'w';
     AVI->track[j].audio_tag[3] = 'b';
   }

   lseek(AVI->fdes,AVI->movi_start,SEEK_SET);

   /* get index if wanted */

   if(!getIndex) return(0);

   /* if the file has an idx1, check if this is relative
      to the start of the file or to the start of the movi list */

   idx_type = 0;

   if(AVI->idx)
   {
      long pos, len;

      /* Search the first videoframe in the idx1 and look where
         it is in the file */

      for(i=0;i<AVI->n_idx;i++)
         if( strncasecmp((char *) AVI->idx[i],(char *) AVI->video_tag,3)==0 ) break;
      if(i>=AVI->n_idx) ERR_EXIT(AVI_ERR_NO_VIDS)

      pos = str2ulong(AVI->idx[i]+ 8);
      len = str2ulong(AVI->idx[i]+12);

      lseek(AVI->fdes,pos,SEEK_SET);
      if(avi_read(AVI->fdes,data,8)!=8) ERR_EXIT(AVI_ERR_READ)
      if( strncasecmp((char *)data,(char *)AVI->idx[i],4)==0 && 
      str2ulong((unsigned char *)data+4)==len )
      {
         idx_type = 1; /* Index from start of file */
      }
      else
      {
         lseek(AVI->fdes,pos+AVI->movi_start-4,SEEK_SET);
         if(avi_read(AVI->fdes,data,8)!=8) ERR_EXIT(AVI_ERR_READ)
         if( strncasecmp((char *)data,(char *)AVI->idx[i],4)==0 && str2ulong((unsigned char *)data+4)==len )
         {
            idx_type = 2; /* Index from start of movi list */
         }
      }
      /* idx_type remains 0 if neither of the two tests above succeeds */
   }

   if(idx_type == 0)
   {
      /* we must search through the file to get the index */

      lseek(AVI->fdes, AVI->movi_start, SEEK_SET);

      AVI->n_idx = 0;

      while(1)
      {
         if( avi_read(AVI->fdes,data,8) != 8 ) break;
         n = str2ulong((unsigned char *)data+4);

         /* The movi list may contain sub-lists, ignore them */

         if(strncasecmp(data,"LIST",4)==0)