common.c

MPEG 2的音频编码软件。喜欢多媒体的开发人员可以看看。

void WriteScale(bit_alloc, scfsi, scalar, fr_ps, s)
unsigned int bit_alloc[2][SBLIMIT], scfsi[2][SBLIMIT], scalar[2][3][SBLIMIT];
frame_params *fr_ps;
FILE *s;
{
int stereo  = fr_ps->stereo;
int sblimit = fr_ps->sblimit;
int lay     = fr_ps->header->lay;
int i,j,k;

        if(lay == 2) {
            fprintf(s, "SFSI ");
            for (i=0;i<sblimit;i++) for (k=0;k<stereo;k++)
                if (bit_alloc[k][i])  fprintf(s,"%d",scfsi[k][i]);
            fprintf(s, "\nSCFs ");
            for (k=0;k<stereo;k++) {
                for (i=0;i<sblimit;i++)
                    if (bit_alloc[k][i])
                        switch (scfsi[k][i]) {
                          case 0: for (j=0;j<3;j++)
                                  fprintf(s,"%2d%c",scalar[k][j][i],
                                          (j==2)?';':'-');
                                  break;
                          case 1:
                          case 3: fprintf(s,"%2d-",scalar[k][0][i]);
                                  fprintf(s,"%2d;",scalar[k][2][i]);
                                  break;
                          case 2: fprintf(s,"%2d;",scalar[k][0][i]);
                        }
                fprintf(s, "\n");
            }
        }
        else{   /* lay == 1 */
            fprintf(s, "SCFs ");
            for (i=0;i<sblimit;i++) for (k=0;k<stereo;k++)
                if (bit_alloc[k][i])  fprintf(s,"%2d;",scalar[k][0][i]);
            fprintf(s, "\n");
        }
}

void WriteSamples(ch, sample, bit_alloc, fr_ps, s)
int ch;
unsigned int FAR sample[SBLIMIT];
unsigned int bit_alloc[SBLIMIT];
frame_params *fr_ps;
FILE *s;
{
int i;
int stereo = fr_ps->stereo;
int sblimit = fr_ps->sblimit;

        fprintf(s, "SMPL ");
        for (i=0;i<sblimit;i++)
                if ( bit_alloc[i] != 0)
                    fprintf(s, "%d:", sample[i]);
        if(ch==(stereo-1) )     fprintf(s, "\n");
        else                    fprintf(s, "\t");
}

int NumericQ(s) /* see if a string lookd like a numeric argument */
char *s;
{
char    c;

    while( (c = *s++)!='\0' && isspace((int)c)) /* strip leading ws */
        ;
    if( c == '+' || c == '-' )
        c = *s++;               /* perhaps skip leading + or - */
    return isdigit((int)c);
}

int BitrateIndex(ver,layr, bRate)   /* convert bitrate in kbps to index */
int     layr,ver;           /* 1 or 2 */
int     bRate;          /* legal rates from 32 to 448 */
{
int     index = 0;
int     found = 0;

    while(!found && index<15)   {
        if(bitrate[ver][layr-1][index] == bRate)
            found = 1;
        else
            ++index;
    }
    if(found)
        return(index);
    else {
        fprintf(stderr, "BitrateIndex: %d (layer %d) is not a legal bitrate\n",
                bRate, layr);
        return(-1);     /* Error! */
    }
}

int SmpFrqIndex(sRate, version)  /* convert samp frq in Hz to index */
long sRate;             /* legal rates 16000, 22050, 24000, 32000, 44100, 48000 */
int  *version;
{
    if (sRate == 44100L) {
        *version = MPEG_AUDIO_ID; return(0);
    }
    else if (sRate == 48000L) {
        *version = MPEG_AUDIO_ID; return(1);
    }
    else if (sRate == 32000L) {
        *version = MPEG_AUDIO_ID; return(2);
    }
    else if (sRate == 24000L) {
        *version = MPEG_PHASE2_LSF; return(1);
    }
    else if (sRate == 22050L) {
        *version = MPEG_PHASE2_LSF; return(0);
    }
    else if (sRate == 16000L) {
        *version = MPEG_PHASE2_LSF; return(2);
    }
    else {
        fprintf(stderr, "SmpFrqIndex: %ld is not a legal sample rate\n", sRate);
        return(-1);      /* Error! */
    }
}


/*******************************************************************************
*
*  Allocate number of bytes of memory equal to "block".
*
*******************************************************************************/

void  FAR *mem_alloc(block, item)
unsigned long   block;
char            *item;
{

    void    *ptr;

#ifdef  MACINTOSH
    ptr = NewPtr(block);
#endif

#ifdef MSC60
    /*ptr = (void FAR *) _fmalloc((unsigned int)block);*/ /* far memory, 92-07-08 sr */
    ptr = (void FAR *) malloc((unsigned int)block); /* far memory, 93-08-24 ss */
#endif

#if ! defined (MACINTOSH) && ! defined (MSC60)
    ptr = (void FAR *) malloc(block);
#endif

    if (ptr != NULL){
#ifdef  MSC60
        _fmemset(ptr, 0, (unsigned int)block); /* far memory, 92-07-08 sr */
#else
        memset(ptr, 0, block);
#endif
    }
    else{
        printf("Unable to allocate %s\n", item);
        exit(0);
    }
    return(ptr);
}


/****************************************************************************
*
*  Free memory pointed to by "*ptr_addr".
*
*****************************************************************************/

void    mem_free(ptr_addr)
void    **ptr_addr;
{

    if (*ptr_addr != NULL){
#ifdef  MACINTOSH
        DisposPtr(*ptr_addr);
#else
        free(*ptr_addr);
#endif
        *ptr_addr = NULL;
    }

}

/*******************************************************************************
*
*  Check block of memory all equal to a single byte, else return FALSE
*
*******************************************************************************/

int memcheck(array, test, num)
char *array;
int test;       /* but only tested as a char (bottom 8 bits) */
int num;
{
 int i=0;

   while (array[i] == test && i<num) i++;
   if (i==num) return TRUE;
   else return FALSE;
}


/*****************************************************************************
*
*  Routines to determine byte order and swap bytes
*
*****************************************************************************/
enum byte_order NativeByteOrder = order_unknown;

enum byte_order DetermineByteOrder()
{
    char s[ sizeof(long) + 1 ];
    union
    {
        long longval;
        char charval[ sizeof(long) ];
    } probe;
    probe.longval = 0x41424344L;  /* ABCD in ASCII */
    strncpy( s, probe.charval, sizeof(long) );
    s[ sizeof(long) ] = '\0';
    /* fprintf( stderr, "byte order is %s\n", s ); */
    if ( strcmp(s, "ABCD") == 0 )
        return order_bigEndian;
    else
        if ( strcmp(s, "DCBA") == 0 )
            return order_littleEndian;
        else
            return order_unknown;
}

void SwapBytesInWords( short *loc, int words )
{
    int i;
    short thisval;
    char *dst, *src;
    src = (char *) &thisval;
    for ( i = 0; i < words; i++ )
    {
        thisval = *loc;
        dst = (char *) loc++;
        dst[0] = src[1];
        dst[1] = src[0];
    }
}

/*****************************************************************************
 *
 *  Read Audio Interchange File Format (AIFF) headers.
 *
 *****************************************************************************/

int aiff_read_headers( FILE *file_ptr, IFF_AIFF *aiff_ptr )
{
    int i, chunkSize, subSize, sound_position;
    
    if ( fseek(file_ptr, 0, SEEK_SET) != 0 )
        return -1;
    
    if ( Read32BitsHighLow(file_ptr) != IFF_ID_FORM )
        return -1;
    
    chunkSize = Read32BitsHighLow( file_ptr );
    
    if ( Read32BitsHighLow(file_ptr) != IFF_ID_AIFF )
        return -1;
    
    sound_position = 0;
    while ( chunkSize > 0 )
    {
        chunkSize -= 4;
        switch ( Read32BitsHighLow(file_ptr) )
	{
            
          case IFF_ID_COMM:
            chunkSize -= subSize = Read32BitsHighLow( file_ptr );
            aiff_ptr->numChannels = Read16BitsHighLow( file_ptr );
            subSize -= 2;
            aiff_ptr->numSampleFrames = Read32BitsHighLow( file_ptr );
            subSize -= 4;
            aiff_ptr->sampleSize = Read16BitsHighLow( file_ptr );
            subSize -= 2;
            aiff_ptr->sampleRate  = ReadIeeeExtendedHighLow( file_ptr );
            subSize -= 10;
            while ( subSize > 0 )
	    {
                getc( file_ptr );
                subSize -= 1;
	    }
            break;
            
          case IFF_ID_SSND:
            chunkSize -= subSize = Read32BitsHighLow( file_ptr );
            aiff_ptr->blkAlgn.offset = Read32BitsHighLow( file_ptr );
            subSize -= 4;
            aiff_ptr->blkAlgn.blockSize = Read32BitsHighLow( file_ptr );
            subSize -= 4;
            sound_position = ftell( file_ptr ) + aiff_ptr->blkAlgn.offset;
            if ( fseek(file_ptr, (long) subSize, SEEK_CUR) != 0 )
                return -1;
            aiff_ptr->sampleType = IFF_ID_SSND;
            break;
            
          default:
            chunkSize -= subSize = Read32BitsHighLow( file_ptr );
            while ( subSize > 0 )
	    {
                getc( file_ptr );
                subSize -= 1;
	    }
            break;
	}
    }
    return sound_position;
}

/*****************************************************************************
 *
 *  Seek past some Audio Interchange File Format (AIFF) headers to sound data.
 *
 *****************************************************************************/

int aiff_seek_to_sound_data( FILE *file_ptr )
{
	if ( fseek(file_ptr, AIFF_FORM_HEADER_SIZE + AIFF_SSND_HEADER_SIZE, SEEK_SET) != 0 )
        return(-1);
    return(0);
}

/*******************************************************************************
 *
 *  Write Audio Interchange File Format (AIFF) headers.
 *
 *******************************************************************************/

int aiff_write_headers( FILE *file_ptr, IFF_AIFF *aiff_ptr )
{
    int chunkSize;
    int sampleBytes = (aiff_ptr->sampleSize / 8) + (aiff_ptr->sampleSize % 8 ? 1 : 0);
    
    if ( fseek(file_ptr, 0L, SEEK_SET) != 0 )
        return -1;
    
    /* write FORM chunk */
    chunkSize = 8 + 18 + 8 + aiff_ptr->numChannels * aiff_ptr->numSampleFrames * sampleBytes;
    Write32BitsHighLow( file_ptr, IFF_ID_FORM );
    Write32BitsHighLow( file_ptr, chunkSize );
    Write32BitsHighLow( file_ptr, IFF_ID_AIFF );
    /* write COMM chunk */
    Write32BitsHighLow( file_ptr, IFF_ID_COMM );
    Write32BitsHighLow( file_ptr, 18 ); /* chunk size */
    Write16BitsHighLow( file_ptr, aiff_ptr->numChannels );
    Write32BitsHighLow( file_ptr, aiff_ptr->numSampleFrames );
    Write16BitsHighLow( file_ptr, aiff_ptr->sampleSize );
    WriteIeeeExtendedHighLow( file_ptr, aiff_ptr->sampleRate );
    /* write SSND chunk header */
    chunkSize = 8 + aiff_ptr->numChannels * aiff_ptr->numSampleFrames * sampleBytes;
    Write32BitsHighLow( file_ptr, IFF_ID_SSND );
    Write32BitsHighLow( file_ptr, chunkSize );
    Write32BitsHighLow( file_ptr, 0 ); /* offset */
    Write32BitsHighLow( file_ptr, 0 ); /* block size */
    return 0;
}