wave.c

AAC音频解码算法程序

#include <stdio.h>
#include <windows.h>
#include "wave.h"
#include "error.h"

struct
{
   byte riffheader[4];
   byte WAVElen[4];
   struct
   {
      byte fmtheader[8];
      byte fmtlen[4];
      struct
      {
         byte FormatTag[2];
         byte Channels[2];
         byte SamplesPerSec[4];
         byte AvgBytesPerSec[4];
         byte BlockAlign[2];
         byte BitsPerSample[2]; /* format specific for PCM */
      } fmt;
      struct
      {
         byte dataheader[4];
         byte datalen[4];
         /* from here you insert your PCM data */
      } data;
   } WAVE;
} RIFF = 
{  { 'R','I','F','F' } , { sizeof(RIFF.WAVE),0,0,0 } , 
   {  { 'W','A','V','E','f','m','t',' ' } , { sizeof(RIFF.WAVE.fmt),0,0,0} ,
      { {1,0} , {0,0},{0,0,0,0},{0,0,0,0},{0,0},{0,0} } ,
      { { 'd','a','t','a' }  , {0,0,0,0} }
   }
};

long total_byte=0;

static void long2littleendian(long inval,byte *outval,int b)
{
  int i;
  for(i=0;i<b;i++) {
    outval[i] = (inval>>(i*8)) & 0xff;
  } 
}

/* always big endian */
static void long2bigendian(long inval,byte *outval,int b)
{
  int i;
  for(i=0;i<b;i++) {
    outval[i] = (inval>>((b-i-1)*8)) & 0xff;
  }
}

static int testEndian(void) 
{
  long i,a=0,b=0,c=0;
  int ret = 0;

  for(i=0;i<sizeof(long);i++) {
    ((byte *)&a)[i] = i;
    b<<=8;
    b |= i;
    c |= i << (i*8);
  }
  if(a == b)
      ret = 1;
  else if(a != c) {
      fprintf(stderr,"Strange endianess?? %08lx %08lx %08lx\n",a,b,c);
      exit(1);
  }
  return ret;
}

FILE* wave_open(char *wavfilename,WAVE_INFO *wave_info)
{
   int bps;
   FILE *wavefile;
   int flipendian = 0;

   /* standard MS PCM, and its format specific is BitsPerSample */
    long2littleendian(1,RIFF.WAVE.fmt.FormatTag,sizeof(RIFF.WAVE.fmt.FormatTag));
	long2littleendian(bps=16,RIFF.WAVE.fmt.BitsPerSample,sizeof(RIFF.WAVE.fmt.BitsPerSample));
  /* if(wave_info->format == AUDIO_FORMAT_SIGNED_16) {
      flipendian = testEndian();
   }
   else if(wave_info->format == AUDIO_FORMAT_UNSIGNED_8)
      long2littleendian(bps=8,RIFF.WAVE.fmt.BitsPerSample,sizeof(RIFF.WAVE.fmt.BitsPerSample));
   else
   {
      fprintf(stderr,"Format not supported.");
      return -1;
   }*/
   if(wave_info->samplerate < 0) wave_info->samplerate = 44100;

   long2littleendian(wave_info->channels,RIFF.WAVE.fmt.Channels,sizeof(RIFF.WAVE.fmt.Channels));
    long2littleendian(wave_info->samplerate,RIFF.WAVE.fmt.SamplesPerSec,sizeof(RIFF.WAVE.fmt.SamplesPerSec));
   long2littleendian((int)(wave_info->channels * wave_info->samplerate * bps)>>3,
         RIFF.WAVE.fmt.AvgBytesPerSec,sizeof(RIFF.WAVE.fmt.AvgBytesPerSec));
   long2littleendian((int)(wave_info->channels * bps)>>3,
         RIFF.WAVE.fmt.BlockAlign,sizeof(RIFF.WAVE.fmt.BlockAlign));

   if( (wavefile  = fopen(wavfilename, "wb" )) == NULL ) ERROROUT("The file 'data' was not opened\n");
   long2littleendian(0,RIFF.WAVE.data.datalen,sizeof(RIFF.WAVE.data.datalen));
   long2littleendian(sizeof(RIFF.WAVE),RIFF.WAVElen,sizeof(RIFF.WAVElen));
   fwrite(&RIFF, sizeof(RIFF),1,wavefile);
   return wavefile;
}

void wave_write(FILE *wavefile,short * buf,int len,WAVE_INFO wave_info)
{
   int temp;
 //  if(!wavefile) return 0;
   temp = fwrite(buf, sizeof(short), len, wavefile);
   if(temp <= 0) total_byte+=0;
   total_byte+=temp;
//   printf("temp %d",  temp);
//   printf("total_bytes %d\n",total_byte );

}

int wave_close(FILE *wavefile,WAVE_INFO wave_info)
{
   if(!wavefile) return 0;
   if(fseek(wavefile, 0L, SEEK_SET) >= 0) {
     long2littleendian(total_byte*2,RIFF.WAVE.data.datalen,sizeof(RIFF.WAVE.data.datalen));
     long2littleendian(total_byte*2+sizeof(RIFF.WAVE),RIFF.WAVElen,sizeof(RIFF.WAVElen));
     fwrite(&RIFF, sizeof(RIFF),1,wavefile);
//	 printf("bytes %d", total_byte);
//	 printf("Samplerate %d", (int)RIFF.WAVE.fmt.SamplesPerSec);

   }
   else {
     fprintf(stderr,"Warning can't rewind WAV file. File-format isn't fully conform now.\n");
   }
	fclose(wavefile);
    return 0;
}