abx.c

音频编码

{
    if ( strlen (name) < strlen (ext) )
        return 0;
    name += strlen (name) - strlen (ext);
    return strcasecmp (name, ext)  ?  0  :  1;
}


typedef struct {
    const char* const  extention;
    const char* const  command;
} decoder_t;


#define REDIR     " 2> /dev/null"
#define STDOUT    "/dev/fd/1"
#define PATH      PATH_OF_EXTERNAL_TOOLS_FOR_UNCOMPRESSING

const decoder_t  decoder [] = {
    { ".mp1"    , PATH"mpg123 -w - %s"                         REDIR },  // MPEG Layer I         : www.iis.fhg.de, www.mpeg.org
    { ".mp2"    , PATH"mpg123 -w - %s"                         REDIR },  // MPEG Layer II        : www.iis.fhg.de, www.uq.net.au/~zzmcheng, www.mpeg.org
    { ".mp3"    , PATH"mpg123 -w - %s"                         REDIR },  // MPEG Layer III       : www.iis.fhg.de, www.mp3dev.org/mp3, www.mpeg.org
    { ".mp3pro" , PATH"mpg123 -w - %s"                         REDIR },  // MPEG Layer III       : www.iis.fhg.de, www.mp3dev.org/mp3, www.mpeg.org
    { ".mpt"    , PATH"mpg123 -w - %s"                         REDIR },  // MPEG Layer III       : www.iis.fhg.de, www.mp3dev.org/mp3, www.mpeg.org
    { ".mpp"    , PATH"mppdec %s -"                            REDIR },  // MPEGplus             : www.stud.uni-hannover.de/user/73884
    { ".mpc"    , PATH"mppdec %s -"                            REDIR },  // MPEGplus             : www.stud.uni-hannover.de/user/73884
    { ".mp+"    , PATH"mppdec %s -"                            REDIR },  // MPEGplus             : www.stud.uni-hannover.de/user/73884
    { ".aac"    , PATH"faad -t.wav -w %s"                      REDIR },  // Advanced Audio Coding: psytel.hypermart.net, www.aac-tech.com, sourceforge.net/projects/faac, www.aac-audio.com, www.mpeg.org
    { "aac.lqt" , PATH"faad -t.wav -w %s"                      REDIR },  // Advanced Audio Coding: psytel.hypermart.net, www.aac-tech.com, sourceforge.net/projects/faac, www.aac-audio.com, www.mpeg.org
    { ".ac3"    , PATH"ac3dec %s"                              REDIR },  // Dolby AC3            : www.att.com
    { "ac3.lqt" , PATH"ac3dec %s"                              REDIR },  // Dolby AC3            : www.att.com
    { ".ogg"    , PATH"ogg123 -d wav -o file:"STDOUT" %s"      REDIR },  // Ogg Vorbis           : www.xiph.org/ogg/vorbis/index.html
    { ".pac"    , PATH"lpac -x %s "STDOUT                      REDIR },  // Lossless predictive Audio Compression: www-ft.ee.tu-berlin.de/~liebchen/lpac.html ([e-mail])
    { ".shn"    , PATH"shorten -x < %s"                        REDIR },  // Shorten              : shnutils.freeshell.org, www.softsound.com/Shorten.html ([e-mail], [e-mail])
    { ".wav.gz" , "gzip  -d < %s | sox -twav - -twav -sw -"    REDIR },  // gziped WAV
    { ".wav.sz" , PATH"szip  -d < %s | sox -twav - -twav -sw -"REDIR },  // sziped WAV
    { ".wav.sz2", PATH"szip2 -d < %s | sox -twav - -twav -sw -"REDIR },  // sziped WAV
    { ".raw"    , "sox -r44100 -sw -c2 -traw %s -twav -sw -"   REDIR },  // raw files are treated as CD like audio
    { ".cdr"    , "sox -r44100 -sw -c2 -traw %s -twav -sw -"   REDIR },  // CD-DA files are treated as CD like audio, no preemphasis info available
    { ".rm"     , "echo %s '???'"                              REDIR },  // Real Audio           : www.real.com
    { ".epc"    , "echo %s '???'"                              REDIR },  // ePAC                 : www.audioveda.com, www.lucent.com/ldr
    { ".mov"    , "echo %s '???'"                              REDIR },  // QDesign Music 2      : www.qdesign.com
    { ".vqf"    , "echo %s '???'"                              REDIR },  // TwinVQ               : www.yamaha-xg.com/english/xg/SoundVQ, www.vqf.com, sound.splab.ecl.ntt.co.jp/twinvq-e
    { ".wma"    , "echo %s '???'"                              REDIR },  // Microsoft Media Audio: www.windowsmedia.com, www.microsoft.com/windows/windowsmedia
    { ".flac"   , PATH"flac -c -d %s"                          REDIR },  // Free Lossless Audio Coder: flac.sourceforge.net/
    { ".fla"    , PATH"flac -c -d %s"                          REDIR },  // Free Lossless Audio Coder: flac.sourceforge.net/
    { ".ape"    , "( "PATH"MAC %s _._.wav -d > /dev/null; cat _._.wav; rm _._.wav )"  REDIR },  // Monkey's Audio Codec : www.monkeysaudio.com ([e-mail])
    { ".rka"    , "( "PATH"rkau %s _._.wav   > /dev/null; cat _._.wav; rm _._.wav )"  REDIR },  // RK Audio:              
    { ".rkau"   , "( "PATH"rkau %s _._.wav   > /dev/null; cat _._.wav; rm _._.wav )"  REDIR },  // RK Audio:              
    { ".mod"    , "xmp -b16 -c -f44100 --stereo -o- %s | sox -r44100 -sw -c2 -traw - -twav -sw -"
                                                               REDIR },  // Amiga's Music on Disk:
    { ""        , "sox %s -twav -sw -"                         REDIR },  // Rest, may be sox can handle it
};

#undef REDIR
#undef STDOUT
#undef PATH


int  readwave ( stereo_t* buff, size_t maxlen, const char* name, size_t* len )
{
    char*           command = malloc (2*strlen(name) + 512);
    char*           name_q  = malloc (2*strlen(name) + 128);
    unsigned short  header [22];
    FILE*           fp;
    size_t          i;
    size_t          j;

    // The *nice* shell quoting
    i = j = 0;
    if ( name[i] == '-' )
        name_q[j++] = '.',
        name_q[j++] = '/';
        
    while (name[i]) {
        if ( !isalnum (name[i]) && name[i]!='-' && name[i]!='_' && name[i]!='.' )
            name_q[j++] = '\\';
        name_q[j++] = name[i++];
    }
    name_q[j] = '\0';

    fprintf (stderr, "Reading %s", name );
    for ( i = 0; i < sizeof(decoder)/sizeof(*decoder); i++ )
        if ( has_ext (name, decoder[i].extention) ) {
            sprintf ( command, decoder[i].command, name_q );
            break;
        }

    free (name_q);
    if ( (fp = popen (command, "r")) == NULL ) {
        fprintf (stderr, "Can't exec:\n%s\n", command );
        exit (1);
    }
    free (command);
    
    fprintf (stderr, " ..." );
    fread ( header, sizeof(*header), sizeof(header)/sizeof(*header), fp );
    switch ( header[11] ) {
        case 2:
            *len = fread ( buff, sizeof(stereo_t), maxlen, fp );
            break;
        case 1:
            *len = fread ( buff, sizeof(sample_t), maxlen, fp );
            for ( i = *len; i-- > 0; )
                buff[i][0] = buff[i][1] = ((sample_t*)buff) [i];
            break;
        case 0:
            fprintf (stderr, "\b\b\b\b, Standard Open Source Bug detected, try murksaround ..." );
            *len = fread ( buff, sizeof(stereo_t), maxlen, fp );
            header[11] =     2;
            header[12] = 65534;  /* use that of the other channel */
            break;
        default:
            fprintf (stderr, "Only 1 or 2 channels are supported, not %u\n", header[11] );
            pclose (fp);
            return -1;
    }
    pclose ( fp ); 
    fprintf (stderr, "\n" );
    return header[12] ? header[12] : 65534;
}


double  cross_analyze ( const stereo_t* p1, const stereo_t *p2, size_t len )
{
    float   P1 [MAX] [2];
    float   P2 [MAX] [2];
    int     i;
    int     maxindex;
    double  sum1;
    double  sum2;
    double  max;
    double  y1;
    double  y2;
    double  y3;
    double  yo;
    double  xo;
    double  tmp;
    double  tmp1;
    double  tmp2;
    int     ret = 0;
    int     cnt = 5;

    // Calculating effective voltage
    sum1 = sum2 = 0.;
    for ( i = 0; i < len; i++ ) {
        sum1 += (double)p1[i][0] * p1[i][0];
        sum2 += (double)p2[i][0] * p2[i][0];
    }
    sum1 = sqrt ( sum1/len );
    sum2 = sqrt ( sum2/len );

    // Searching beginning of signal (not stable for pathological signals)
    for ( i = 0; i < len; i++ )
        if ( abs (p1[i][0]) >= sum1  &&  abs (p2[i][0]) >= sum2 )
            break;
    p1  += i;
    p2  += i;
    len -= i;

    if ( len <= MAX )
        return 0;

    // Filling arrays for FFT
    do {
        sum1 = sum2 = 0.;
        for ( i = 0; i < MAX; i++ ) {
#ifdef USEDIFF
            tmp1  = p1 [i][0] - p1 [i+1][0];
            tmp2  = p2 [i+ret][0] - p2 [i+ret+1][0];
#else
            tmp1  = p1 [i][0];
            tmp2  = p2 [i+ret][0];
#endif
            sum1 += tmp1*tmp1;
            sum2 += tmp2*tmp2;
            P1 [i][0] = tmp1;
            P2 [i][0] = tmp2;
            P1 [i][1] = 0.;
            P2 [i][1] = 0.;
        }

        fft (P1, MAX);
        fft (P2, MAX);

        for ( i = 0; i < MAX; i++ ) {
            double  a0 = P1 [i][0];
            double  a1 = P1 [i][1];
            double  b0 = P2 [(MAX-i)&(MAX-1)][0];
            double  b1 = P2 [(MAX-i)&(MAX-1)][1];
            P1 [i][0] = a0*b0 - a1*b1;
            P1 [i][1] = a0*b1 + a1*b0;
        }

        fft (P1, MAX);

        max = P1 [maxindex = 0][0];
        for ( i = 1; i < MAX; i++ )
            if ( P1[i][0] > max )
                max = P1 [maxindex = i][0];

        y2 = P1 [ maxindex           ][0];
        y1 = P1 [(maxindex-1)&(MAX-1)][0] - y2;
        y3 = P1 [(maxindex+1)&(MAX-1)][0] - y2;

        xo = 0.5 * (y1-y3) / (y1+y3);
        yo = 0.5 * ( (y1+y3)*xo + (y3-y1) ) * xo;

        if (maxindex > MAX/2 )
            maxindex -= MAX;

        ret += maxindex;
        tmp = 100./MAX/sqrt(sum1*sum2);
        if (verbose)
            printf ( "[%5d]%8.4f  [%5d]%8.4f  [%5d]%8.4f  [%10.4f]%8.4f\n",
                     ret- 1, (y1+y2)*tmp,
                     ret   ,     y2 *tmp,
                     ret+ 1, (y3+y2)*tmp,
                     ret+xo, (yo+y2)*tmp );

    } while ( maxindex  &&  cnt-- );

    return ret + xo;
}


short  to_short ( int x )
{
    return x == (short)x  ?  (short)x  :  (short) ((x >> 31) ^ 0x7FFF);
}


void  DC_cancel ( stereo_t* p, size_t len )
{
    double  sum1 = 0;
    double  sum2 = 0;
    size_t  i;
    int     diff1;
    int     diff2;
    
    for (i = 0; i < len; i++ ) {
        sum1 += p[i][0];
        sum2 += p[i][1];
    }
    if ( fabs(sum1) < len  &&  fabs(sum2) < len )
        return;
        
    diff1 = round ( sum1 / len );
    diff2 = round ( sum2 / len );
    if (verbose)
        fprintf (stderr, "Removing DC (left=%d, right=%d)\n", diff1, diff2 );
    
    for (i = 0; i < len; i++ ) {
        p[i][0] = to_short ( p[i][0] - diff1);
        p[i][1] = to_short ( p[i][1] - diff2);
    }
}

void  multiply ( char c, stereo_t* p, size_t len, double fact )
{
    size_t  i;
    
    if ( fact == 1. )
        return;
    if (verbose)
        fprintf (stderr, "Multiplying %c by %7.5f\n", c, fact );
    
    for (i = 0; i < len; i++ ) {
        p[i][0] = to_short ( p[i][0] * fact );
        p[i][1] = to_short ( p[i][1] * fact );
    }
}


int  maximum ( stereo_t* p, size_t len )
{
    int     max = 0;
    size_t  i;
    
    for (i = 0; i < len; i++ ) {
        if (abs(p[i][0]) > max) max = abs(p[i][0]);
        if (abs(p[i][1]) > max) max = abs(p[i][1]);
    }
    return max;
}


void  usage ( void )
{
    fprintf ( stderr, 
        "usage:  abx [-v] File_A File_B\n"
        "\n"
        "File_A and File_B loaded and played. File_A should be the better/reference\n"
        "file, File_B the other. You can press the following keys:\n"
        "\n"
        "  a/A:    Listen to File A\n"
        "  b/B:    Listen to File B\n"
        "  x/X:    Listen to the randomly selected File X, which is A or B\n"
        "  Ctrl-A: You vote for X=A\n"
        "  Ctrl-B: You vote for X=B\n"
        "  m:      Alternating playing A and B. Fast switching\n"
        "  M:      Alternating playing A and B. Slow switching\n"
        "  d/D/Ctrl-D/Alt-d/Alt-D:\n"
        "          Listen to the difference A-B (+0 dB...+40 dB)\n"
        "  o/p:    Chunk select\n"
        "  hjkl:   Chunk fine adjust (hj: start, kl: stop)\n"
        "  Space:  Chunk deselect\n"
        "  0...9:  Listen to B, but difference A-B is amplified by 0-9 dB\n"
        "  Q:      Quit the program\n"
        "\n"
    );
}


int  main ( int argc, char** argv )
{
    stereo_t*  _A = calloc ( sizeof(stereo_t), MAX_LEN );
    stereo_t*  _B = calloc ( sizeof(stereo_t), MAX_LEN );
    stereo_t*  A  = _A;
    stereo_t*  B  = _B;
    size_t     len_A;
    size_t     len_B;
    size_t     len;
    int        max_A;
    int        max_B;
    int        max;
    long       freq1;
    long       freq2;
    int        shift;
    double     fshift;
    double     ampl;
    int        ampl_X;
    korr_t     k;
    
    if (argc > 1  &&  0 == strcmp (argv[1], "-v") ) {
        verbose = 1;
        argc--;
        argv++;
    }

    switch ( argc ) {
    case 0:
    case 1:
    case 2:
    default:
        usage ();
        return 1;
    case 3:
        usage();
        break;
    }

    freq1 = readwave ( A, MAX_LEN, argv[1], &len_A );
    DC_cancel ( A, len_A );
    freq2 = readwave ( B, MAX_LEN, argv[2], &len_B );
    DC_cancel ( B, len_B );
    
    if      ( freq1 == 65534  &&  freq2 != 65534 )
        freq1 = freq2;
    else if ( freq2 == 65534  &&  freq1 != 65534 )
        freq2 = freq1;
    else if ( freq1 == 65534  &&  freq2 == 65534 )
        freq1 = freq2 = 44100;

    if ( freq1 != freq2 ) {
        fprintf ( stderr, "Different sample frequencies currently not supported\n");
        fprintf ( stderr, "A: %ld, B: %ld\n", freq1, freq2 );
        return 2;
    }

    len    = len_A < len_B  ?  len_A  :  len_B;
    fshift = cross_analyze ( A, B, len );
    shift  = floor ( fshift + 0.5 );

    if ( verbose ) {
        fprintf ( stderr, "Delay Ch1 is %.4f samples\n", fshift );
	fprintf ( stderr, "Delay Ch2 is %.4f samples\n", 
	          cross_analyze ( (stereo_t*)(((sample_t*)A)+1), (stereo_t*)(((sample_t*)B)+1), len ) );
    }

    if (shift > 0) {
        if (verbose) 
            fprintf ( stderr, "Delaying A by %d samples\n", +shift);
        B     += shift;
        len_B -= shift;
    }
    if (shift < 0) {
        if (verbose)
            fprintf ( stderr, "Delaying B by %d samples\n", -shift);
        A     -= shift;
        len_A += shift;
    }

    len    = len_A < len_B  ?  len_A  :  len_B;
    memset ( &k, 0, sizeof(k) );    
    analyze_stereo ( A, B, len, &k );
    ampl  = report (&k);
    max_A = maximum ( A, len ); 
    max_B = maximum ( B, len ); 
    
    if ( ampl <= 0.98855 ) { /* < -0.05 dB */
        max    = max_A*ampl < max_B  ?  max_B  :  max_A*ampl;
        ampl_X = (int)(29203 / max);
        if ( ampl_X < 2 ) ampl_X = 1;
        multiply ( 'A', A, len, ampl*ampl_X );
        multiply ( 'B', B, len,      ampl_X );
    } else if ( ampl >= 1.01158 ) { /* > +0.05 dB */
        max    = max_A < max_B/ampl  ?  max_B/ampl  :  max_A;
        ampl_X = (int)(29203 / max);
        if ( ampl_X < 2 ) ampl_X = 1;
        multiply ( 'A', A, len,         ampl_X );
        multiply ( 'B', B, len, 1./ampl*ampl_X );
    } else {
        max    = max_A < max_B ? max_B : max_A;
        ampl_X = (int)(29203 / max);
        if ( ampl_X < 2 ) ampl_X = 1;
        multiply ( 'A', A, len, ampl_X );
        multiply ( 'B', B, len, ampl_X );
    }

    set ();
    Set_Realtime ();
    testing ( A, B, len, freq1 );
    reset ();

    free (_A);
    free (_B);
    return 0;
}

/* end of abx.c */