mad.h

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/*
 * mad - MPEG audio decoder
 * Copyright (C) 2000-2001 Robert Leslie
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 * If you would like to negotiate alternate licensing terms, you may do
 * so by contacting the author: Robert Leslie <rob@mars.org>
 */

# define SIZEOF_INT 4
# define SIZEOF_LONG 4
# define SIZEOF_LONG_LONG 8

/* Id: version.h,v 1.16 2001/04/05 04:57:11 rob Exp */

# ifndef LIBMAD_VERSION_H
# define LIBMAD_VERSION_H

# define MAD_VERSION_MAJOR      0
# define MAD_VERSION_MINOR      13
# define MAD_VERSION_PATCH      0
# define MAD_VERSION_EXTRA      " (beta)"

# define MAD_VERSION_STRINGIZE(str)     #str
# define MAD_VERSION_STRING(num)        MAD_VERSION_STRINGIZE(num)

# define MAD_VERSION            MAD_VERSION_STRING(MAD_VERSION_MAJOR) "."  \
                                MAD_VERSION_STRING(MAD_VERSION_MINOR) "."  \
                                MAD_VERSION_STRING(MAD_VERSION_PATCH)  \
                                MAD_VERSION_EXTRA

# define MAD_PUBLISHYEAR        "2000-2001"
# define MAD_AUTHOR             "Robert Leslie"
# define MAD_EMAIL              "rob@mars.org"

extern char const mad_version[];
extern char const mad_copyright[];
extern char const mad_author[];
extern char const mad_build[];

# endif

/* Id: fixed.h,v 1.23 2001/04/05 04:57:11 rob Exp */

# ifndef LIBMAD_FIXED_H
# define LIBMAD_FIXED_H

# if SIZEOF_INT >= 4
typedef   signed int mad_fixed_t;

typedef   signed int mad_fixed64hi_t;
typedef unsigned int mad_fixed64lo_t;
# else
typedef   signed long mad_fixed_t;

typedef   signed long mad_fixed64hi_t;
typedef unsigned long mad_fixed64lo_t;
# endif

/*
 * Fixed-point format: 0xABBBBBBB
 * A == whole part      (sign + 3 bits)
 * B == fractional part (28 bits)
 *
 * Values are signed two's complement, so the effective range is:
 * 0x80000000 to 0x7fffffff
 *       -8.0 to +7.9999999962747097015380859375
 *
 * The smallest representable value is:
 * 0x00000001 == 0.0000000037252902984619140625 (i.e. about 3.725e-9)
 *
 * 28 bits of fractional accuracy represent about
 * 8.6 digits of decimal accuracy.
 *
 * Fixed-point numbers can be added or subtracted as normal
 * integers, but multiplication requires shifting the 64-bit result
 * from 56 fractional bits back to 28 (and rounding.)
 *
 * Changing the definition of MAD_F_FRACBITS is only partially
 * supported, and must be done with care.
 */

# define MAD_F_FRACBITS         28

# if MAD_F_FRACBITS == 28
#  define MAD_F(x)              ((mad_fixed_t) (x##L))
# else
#  if MAD_F_FRACBITS < 28
#   warning "MAD_F_FRACBITS < 28"
#   define MAD_F(x)             ((mad_fixed_t)  \
                                 (((x##L) +  \
                                   (1L << (28 - MAD_F_FRACBITS - 1))) >>  \
                                  (28 - MAD_F_FRACBITS)))
#  elif MAD_F_FRACBITS > 28
#   error "MAD_F_FRACBITS > 28 not currently supported"
#   define MAD_F(x)             ((mad_fixed_t)  \
                                 ((x##L) << (MAD_F_FRACBITS - 28)))
#  endif
# endif

# define MAD_F_MIN              ((mad_fixed_t) -0x80000000L)
# define MAD_F_MAX              ((mad_fixed_t) +0x7fffffffL)

# define MAD_F_ONE              MAD_F(0x10000000)

# define mad_f_tofixed(x)       ((mad_fixed_t)  \
                                 ((x) * (double) (1L << MAD_F_FRACBITS) + 0.5))
# define mad_f_todouble(x)      ((double)  \
                                 ((x) / (double) (1L << MAD_F_FRACBITS)))

# define mad_f_intpart(x)       ((x) >> MAD_F_FRACBITS)
# define mad_f_fracpart(x)      ((x) & ((1L << MAD_F_FRACBITS) - 1))
                                /* (x should be positive) */

# define mad_f_fromint(x)       ((x) << MAD_F_FRACBITS)

# define mad_f_add(x, y)        ((x) + (y))
# define mad_f_sub(x, y)        ((x) - (y))

# if defined(FPM_64BIT)

/*
 * This version should be the most accurate if 64-bit (long long) types are
 * supported by the compiler, although it may not be the most efficient.
 */
#  if defined(OPT_ACCURACY)
#   define mad_f_mul(x, y)  \
    ((mad_fixed_t)  \
     ((((signed long long) (x) * (y)) +  \
       (1L << (MAD_F_SCALEBITS - 1))) >> MAD_F_SCALEBITS))
#  else
#   define mad_f_mul(x, y)  \
    ((mad_fixed_t) (((signed long long) (x) * (y)) >> MAD_F_SCALEBITS))
#  endif

#  define MAD_F_SCALEBITS  MAD_F_FRACBITS

/* --- Intel --------------------------------------------------------------- */

# elif defined(FPM_INTEL)

/*
 * This Intel version is fast and accurate; the disposition of the least
 * significant bit depends on OPT_ACCURACY via mad_f_scale64().
 */
#  define MAD_F_MLX(hi, lo, x, y)  \
    asm ("imull %3"  \
         : "=a" (lo), "=d" (hi)  \
         : "%a" (x), "rm" (y)  \
         : "cc")

#  if defined(OPT_ACCURACY)
/*
 * This gives best accuracy but is not very fast.
 */
#   define MAD_F_MLA(hi, lo, x, y)  \
    ({ mad_fixed64hi_t __hi;  \
       mad_fixed64lo_t __lo;  \
       MAD_F_MLX(__hi, __lo, (x), (y));  \
       asm ("addl %2,%0\n\t"  \
            "adcl %3,%1"  \
            : "=rm" (lo), "=rm" (hi)  \
            : "r" (__lo), "r" (__hi), "0" (lo), "1" (hi)  \
            : "cc");  \
    })
#  endif  /* OPT_ACCURACY */

#  if defined(OPT_ACCURACY)
/*
 * Surprisingly, this is faster than SHRD followed by ADC.
 */
#   define mad_f_scale64(hi, lo)  \
    ({ mad_fixed64hi_t __hi_;  \
       mad_fixed64lo_t __lo_;  \
       mad_fixed_t __result;  \
       asm ("addl %4,%2\n\t"  \
            "adcl %5,%3"  \
            : "=rm" (__lo_), "=rm" (__hi_)  \
            : "0" (lo), "1" (hi),  \
              "ir" (1L << (MAD_F_SCALEBITS - 1)), "ir" (0)  \
            : "cc");  \
       asm ("shrdl %3,%2,%1"  \
            : "=rm" (__result)  \
            : "0" (__lo_), "r" (__hi_), "I" (MAD_F_SCALEBITS)  \
            : "cc");  \
       __result;  \
    })
#  else
#   define mad_f_scale64(hi, lo)  \
    ({ mad_fixed_t __result;  \
       asm ("shrdl %3,%2,%1"  \
            : "=rm" (__result)  \
            : "0" (lo), "r" (hi), "I" (MAD_F_SCALEBITS)  \
            : "cc");  \
       __result;  \
    })
#  endif  /* OPT_ACCURACY */

#  define MAD_F_SCALEBITS  MAD_F_FRACBITS

/* --- ARM ----------------------------------------------------------------- */

# elif defined(FPM_ARM)

/* 
 * This ARM V4 version is as accurate as FPM_64BIT but much faster. The
 * least significant bit is properly rounded at no CPU cycle cost!
 */
# if 1
/*
 * There's a bug somewhere, possibly in the compiler, that sometimes makes
 * this necessary instead of the default implementation via MAD_F_MLX and
 * mad_f_scale64. It may be related to the use (or lack) of
 * -finline-functions and/or -fstrength-reduce.
 *
 * This is also apparently faster than MAD_F_MLX/mad_f_scale64.
 */
#  define mad_f_mul(x, y)  \
    ({ mad_fixed64hi_t __hi;  \
       mad_fixed64lo_t __lo;  \
       mad_fixed_t __result;  \
       asm ("smull      %0, %1, %3, %4\n\t"  \
            "movs       %0, %0, lsr %5\n\t"  \
            "adc        %2, %0, %1, lsl %6"  \
            : "=&r" (__lo), "=&r" (__hi), "=r" (__result)  \
            : "%r" (x), "r" (y),  \
              "M" (MAD_F_SCALEBITS), "M" (32 - MAD_F_SCALEBITS)  \
            : "cc");  \
       __result;  \
    })
# endif

#  define MAD_F_MLX(hi, lo, x, y)  \
    asm ("smull %0, %1, %2, %3"  \
         : "=&r" (lo), "=&r" (hi)  \
         : "%r" (x), "r" (y))

#  define MAD_F_MLA(hi, lo, x, y)  \
    asm ("smlal %0, %1, %2, %3"  \
         : "+r" (lo), "+r" (hi)  \
         : "%r" (x), "r" (y))

#  define mad_f_scale64(hi, lo)  \
    ({ mad_fixed_t __result;  \
       asm ("movs       %0, %1, lsr %3\n\t"  \
            "adc        %0, %0, %2, lsl %4"  \
            : "=r" (__result)  \
            : "r" (lo), "r" (hi),  \
              "M" (MAD_F_SCALEBITS), "M" (32 - MAD_F_SCALEBITS)  \
            : "cc");  \
       __result;  \
    })

#  define MAD_F_SCALEBITS  MAD_F_FRACBITS

/* --- MIPS ---------------------------------------------------------------- */

# elif defined(FPM_MIPS)

/*
 * This MIPS version is fast and accurate; the disposition of the least
 * significant bit depends on OPT_ACCURACY via mad_f_scale64().
 */
#  define MAD_F_MLX(hi, lo, x, y)  \
    asm ("mult  %2,%3"  \
         : "=l" (lo), "=h" (hi)  \
         : "%r" (x), "r" (y))

# if defined(HAVE_MADD_ASM)
#  define MAD_F_MLA(hi, lo, x, y)  \
    asm ("madd  %2,%3"  \
         : "+l" (lo), "+h" (hi)  \
         : "%r" (x), "r" (y))
# elif defined(HAVE_MADD16_ASM)
/*
 * This loses significant accuracy due to the 16-bit integer limit in the
 * multiply/accumulate instruction.
 */
#  define MAD_F_ML0(hi, lo, x, y)  \
    asm ("mult  %2,%3"  \
         : "=l" (lo), "=h" (hi)  \
         : "%r" ((x) >> 12), "r" ((y) >> 16))
#  define MAD_F_MLA(hi, lo, x, y)  \
    asm ("madd16        %2,%3"  \
         : "+l" (lo), "+h" (hi)  \
         : "%r" ((x) >> 12), "r" ((y) >> 16))
#  define MAD_F_MLZ(hi, lo)  ((mad_fixed_t) (lo))
# endif

# if defined(OPT_SPEED)
#  define mad_f_scale64(hi, lo)  \
    ((mad_fixed_t) ((hi) << (32 - MAD_F_SCALEBITS)))
#  define MAD_F_SCALEBITS  MAD_F_FRACBITS
# endif

/* --- SPARC --------------------------------------------------------------- */

# elif defined(FPM_SPARC)

/*
 * This SPARC V8 version is fast and accurate; the disposition of the least
 * significant bit depends on OPT_ACCURACY via mad_f_scale64().
 */
#  define MAD_F_MLX(hi, lo, x, y)  \
    asm ("smul %2, %3, %0\n\t"  \
         "rd %%y, %1"  \
         : "=r" (lo), "=r" (hi)  \
         : "%r" (x), "rI" (y))

/* --- PowerPC ------------------------------------------------------------- */

# elif defined(FPM_PPC)

/*
 * This PowerPC version is tuned for the 4xx embedded processors. It is
 * effectively a tuned version of FPM_64BIT. It is a little faster and just
 * as accurate. The disposition of the least significant bit depends on
 * OPT_ACCURACY via mad_f_scale64().
 */
#  define MAD_F_MLX(hi, lo, x, y)  \
    asm ("mulhw %1, %2, %3\n\t"  \
         "mullw %0, %2, %3"  \
         : "=&r" (lo), "=&r" (hi)  \
         : "%r" (x), "r" (y))

#  define MAD_F_MLA(hi, lo, x, y)  \
    ({ mad_fixed64hi_t __hi;  \
       mad_fixed64lo_t __lo;  \
       MAD_F_MLX(__hi, __lo, (x), (y));  \
       asm ("addc %0, %2, %3\n\t"  \
            "adde %1, %4, %5"  \
            : "=r" (lo), "=r" (hi)  \
            : "%r" (__lo), "0" (lo), "%r" (__hi), "1" (hi));  \
    })

#  if defined(OPT_ACCURACY)
/*
 * This is accurate and ~2 - 2.5 times slower than the unrounded version.
 *
 * The __volatile__ improves the generated code by another 5% (fewer spills
 * to memory); eventually they should be removed.
 */
#   define mad_f_scale64(hi, lo)  \
    ({ mad_fixed_t __result;  \
       mad_fixed64hi_t __hi_;  \
       mad_fixed64lo_t __lo_;  \
       asm __volatile__ ("addc %0, %2, %4\n\t"  \
                         "addze %1, %3"  \
            : "=r" (__lo_), "=r" (__hi_)  \
            : "r" (lo), "r" (hi), "r" (1 << (MAD_F_SCALEBITS - 1)));  \
       asm __volatile__ ("rlwinm %0, %2,32-%3,0,%3-1\n\t"  \
                         "rlwimi %0, %1,32-%3,%3,31"  \
            : "=&r" (__result)  \
            : "r" (__lo_), "r" (__hi_), "I" (MAD_F_SCALEBITS));  \
            __result;  \
    })
#  else
#   define mad_f_scale64(hi, lo)  \
    ({ mad_fixed_t __result;  \
       asm ("rlwinm %0, %2,32-%3,0,%3-1\n\t"  \
            "rlwimi %0, %1,32-%3,%3,31"  \
            : "=r" (__result)  \
            : "r" (lo), "r" (hi), "I" (MAD_F_SCALEBITS));  \
            __result;  \
    })
#  endif  /* OPT_ACCURACY */

#  define MAD_F_SCALEBITS  MAD_F_FRACBITS

/* --- Default ------------------------------------------------------------- */

# elif defined(FPM_DEFAULT)

/*
 * This version is the most portable but it loses significant accuracy.
 * Furthermore, accuracy is biased against the second argument, so care
 * should be taken when ordering operands.
 *
 * The scale factors are constant as this is not used with SSO.
 *
 * Pre-rounding is required to stay within the limits of compliance.
 */
#  define mad_f_mul(x, y)       ((((x) + (1L << 11)) >> 12) *  \
                                 (((y) + (1L << 15)) >> 16))

/* ------------------------------------------------------------------------- */

# else
#  error "no FPM selected"
# endif

/* default implementations */

# if !defined(mad_f_mul)
#  define mad_f_mul(x, y)  \
    ({ mad_fixed64hi_t __hi;  \
       mad_fixed64lo_t __lo;  \
       MAD_F_MLX(__hi, __lo, (x), (y));  \
       mad_f_scale64(__hi, __lo);  \
    })
# endif

# if !defined(MAD_F_MLA)
#  define MAD_F_ML0(hi, lo, x, y)       ((lo)  = mad_f_mul((x), (y)))
#  define MAD_F_MLA(hi, lo, x, y)       ((lo) += mad_f_mul((x), (y)))
#  define MAD_F_MLZ(hi, lo)             ((void) (hi), (mad_fixed_t) (lo))
# endif

# if !defined(MAD_F_ML0)
#  define MAD_F_ML0(hi, lo, x, y)       MAD_F_MLX((hi), (lo), (x), (y))
# endif

# if !defined(MAD_F_MLZ)
#  define MAD_F_MLZ(hi, lo)             mad_f_scale64((hi), (lo))
# endif

# if !defined(mad_f_scale64)
#  if defined(OPT_ACCURACY)
#   define mad_f_scale64(hi, lo)  \
    ((((mad_fixed_t)  \
       (((hi) << (32 - (MAD_F_SCALEBITS - 1))) |  \
        ((lo) >> (MAD_F_SCALEBITS - 1)))) + 1) >> 1)
#  else
#   define mad_f_scale64(hi, lo)  \
    ((mad_fixed_t)  \
     (((hi) << (32 - MAD_F_SCALEBITS)) |  \
      ((lo) >> MAD_F_SCALEBITS)))
#  endif
#  define MAD_F_SCALEBITS  MAD_F_FRACBITS
# endif

/* miscellaneous C routines */

mad_fixed_t mad_f_abs(mad_fixed_t);

# endif

/* Id: bit.h,v 1.7 2001/04/05 04:57:11 rob Exp */

# ifndef LIBMAD_BIT_H
# define LIBMAD_BIT_H

struct mad_bitptr {
  unsigned char const *byte;
  unsigned short cache;
  unsigned short left;
};

void mad_bit_init(struct mad_bitptr *, unsigned char const *);

# define mad_bit_finish(bitptr)         /* nothing */

unsigned int mad_bit_length(struct mad_bitptr const *,
                            struct mad_bitptr const *);

# define mad_bit_bitsleft(bitptr)  ((bitptr)->left)
unsigned char const *mad_bit_nextbyte(struct mad_bitptr const *);

void mad_bit_skip(struct mad_bitptr *, unsigned int);
unsigned long mad_bit_read(struct mad_bitptr *, unsigned int);
void mad_bit_write(struct mad_bitptr *, unsigned int, unsigned long);

unsigned short mad_bit_crc(struct mad_bitptr, unsigned int, unsigned short);

# endif

/* Id: timer.h,v 1.10 2001/04/05 04:57:11 rob Exp */

# ifndef LIBMAD_TIMER_H
# define LIBMAD_TIMER_H

typedef struct {
  signed long seconds;          /* whole seconds */
  unsigned long fraction;       /* 1/MAD_TIMER_RESOLUTION seconds */
} mad_timer_t;

extern mad_timer_t const mad_timer_zero;

# define MAD_TIMER_RESOLUTION   352800000UL

enum mad_units {
  MAD_UNITS_HOURS        =    -2,
  MAD_UNITS_MINUTES      =    -1,
  MAD_UNITS_SECONDS      =     0,

  /* metric units */

  MAD_UNITS_DECISECONDS  =    10,
  MAD_UNITS_CENTISECONDS =   100,
  MAD_UNITS_MILLISECONDS =  1000,

  /* audio sample units */

  MAD_UNITS_8000_HZ      =  8000,
  MAD_UNITS_11025_HZ     = 11025,
  MAD_UNITS_12000_HZ     = 12000,

  MAD_UNITS_16000_HZ     = 16000,
  MAD_UNITS_22050_HZ     = 22050,
  MAD_UNITS_24000_HZ     = 24000,

  MAD_UNITS_32000_HZ     = 32000,
  MAD_UNITS_44100_HZ     = 44100,
  MAD_UNITS_48000_HZ     = 48000,

  /* video frame/field units */

  MAD_UNITS_24_FPS       =    24,
  MAD_UNITS_25_FPS       =    25,
  MAD_UNITS_30_FPS       =    30,
  MAD_UNITS_48_FPS       =    48,
  MAD_UNITS_50_FPS       =    50,
  MAD_UNITS_60_FPS       =    60,

  /* CD audio frames */

  MAD_UNITS_75_FPS       =    75,

  /* video drop-frame units */

  MAD_UNITS_23_976_FPS   =   -24,
  MAD_UNITS_24_975_FPS   =   -25,
  MAD_UNITS_29_97_FPS    =   -30,
  MAD_UNITS_47_952_FPS   =   -48,
  MAD_UNITS_49_95_FPS    =   -50,
  MAD_UNITS_59_94_FPS    =   -60
};

# define mad_timer_reset(timer) (*(timer) = mad_timer_zero)

int mad_timer_compare(mad_timer_t, mad_timer_t);

# define mad_timer_sign(timer)  mad_timer_compare((timer), mad_timer_zero)

void mad_timer_negate(mad_timer_t *);
mad_timer_t mad_timer_abs(mad_timer_t);

void mad_timer_set(mad_timer_t *, unsigned long, unsigned long, unsigned long);
void mad_timer_add(mad_timer_t *, mad_timer_t);
void mad_timer_multiply(mad_timer_t *, signed long);

signed long mad_timer_count(mad_timer_t, enum mad_units);
unsigned long mad_timer_fraction(mad_timer_t, unsigned long);
void mad_timer_string(mad_timer_t, char *, char const *,
                      enum mad_units, enum mad_units, unsigned long);

# endif

/* Id: stream.h,v 1.12 2001/04/10 05:18:21 rob Exp */

# ifndef LIBMAD_STREAM_H
# define LIBMAD_STREAM_H

# define MAD_BUFFER_GUARD       8
# define MAD_BUFFER_MDLEN       (511 + 2048 + MAD_BUFFER_GUARD)

enum mad_error {
  MAD_ERROR_BUFLEN         = 0x0001,    /* input buffer too small (or EOF) */
  MAD_ERROR_BUFPTR         = 0x0002,    /* invalid (null) buffer pointer */

  MAD_ERROR_NOMEM          = 0x0031,    /* not enough memory */

  MAD_ERROR_LOSTSYNC       = 0x0101,    /* lost synchronization */
  MAD_ERROR_BADLAYER       = 0x0102,    /* reserved header layer value */
  MAD_ERROR_BADBITRATE     = 0x0103,    /* forbidden bitrate value */
  MAD_ERROR_BADSAMPLERATE  = 0x0104,    /* reserved sample frequency value */
  MAD_ERROR_BADEMPHASIS    = 0x0105,    /* reserved emphasis value */

  MAD_ERROR_BADCRC         = 0x0201,    /* CRC check failed */
  MAD_ERROR_BADBITALLOC    = 0x0211,    /* forbidden bit allocation value */
  MAD_ERROR_BADSCALEFACTOR = 0x0221,    /* bad scalefactor index */
  MAD_ERROR_BADFRAMELEN    = 0x0231,    /* bad frame length */
  MAD_ERROR_BADBIGVALUES   = 0x0232,    /* bad big_values count */
  MAD_ERROR_BADBLOCKTYPE   = 0x0233,    /* reserved block_type */
  MAD_ERROR_BADSCFSI       = 0x0234,    /* bad scalefactor selection info */
  MAD_ERROR_BADDATAPTR     = 0x0235,    /* bad main_data_begin pointer */
  MAD_ERROR_BADPART3LEN    = 0x0236,    /* bad audio data length */
  MAD_ERROR_BADHUFFTABLE   = 0x0237,    /* bad Huffman table select */
  MAD_ERROR_BADHUFFDATA    = 0x0238,    /* Huffman data overrun */
  MAD_ERROR_BADSTEREO      = 0x0239     /* incompatible block_type for JS */
};

# define MAD_RECOVERABLE(error) ((error) & 0xff00)

struct mad_stream {
  unsigned char const *buffer;          /* input bitstream buffer */
  unsigned char const *bufend;          /* end of buffer */
  unsigned long skiplen;                /* bytes to skip before next frame */

  int sync;                             /* stream sync found */
  unsigned long freerate;               /* free bitrate (fixed) */

  unsigned char const *this_frame;      /* start of current frame */
  unsigned char const *next_frame;      /* start of next frame */
  struct mad_bitptr ptr;                /* current processing bit pointer */

  struct mad_bitptr anc_ptr;            /* ancillary bits pointer */
  unsigned int anc_bitlen;              /* number of ancillary bits */

  unsigned char (*main_data)[MAD_BUFFER_MDLEN];
                                        /* Layer III main_data() */
  unsigned int md_len;                  /* bytes in main_data */

  int options;                          /* decoding options (see below) */
  enum mad_error error;                 /* error code (see above) */
};

enum {
  MAD_OPTION_IGNORECRC      = 0x0001,   /* ignore CRC errors */
  MAD_OPTION_HALFSAMPLERATE = 0x0002,   /* generate PCM at 1/2 sample rate */
# if 0  /* not yet implemented */
  MAD_OPTION_LEFTCHANNEL    = 0x0010,   /* decode left channel only */
  MAD_OPTION_RIGHTCHANNEL   = 0x0020,   /* decode right channel only */
  MAD_OPTION_SINGLECHANNEL  = 0x0030,   /* combine channels */
# endif
};

void mad_stream_init(struct mad_stream *);
void mad_stream_finish(struct mad_stream *);

# define mad_stream_options(stream, opts)  ((stream)->options = (opts))

void mad_stream_buffer(struct mad_stream *,
                       unsigned char const *, unsigned long);
void mad_stream_skip(struct mad_stream *, unsigned long);

int mad_stream_sync(struct mad_stream *);

# endif

/* Id: frame.h,v 1.13 2001/04/05 04:57:11 rob Exp */

# ifndef LIBMAD_FRAME_H
# define LIBMAD_FRAME_H

enum mad_layer {
  MAD_LAYER_I   = 1,                    /* Layer I */
  MAD_LAYER_II  = 2,                    /* Layer II */
  MAD_LAYER_III = 3                     /* Layer III */
};

enum mad_mode {
  MAD_MODE_SINGLE_CHANNEL = 0,          /* single channel */
  MAD_MODE_DUAL_CHANNEL   = 1,          /* dual channel */
  MAD_MODE_JOINT_STEREO   = 2,          /* joint (MS/intensity) stereo */
  MAD_MODE_STEREO         = 3           /* normal LR stereo */
};

enum mad_emphasis {
  MAD_EMPHASIS_NONE       = 0,          /* no emphasis */
  MAD_EMPHASIS_50_15_US   = 1,          /* 50/15 microseconds emphasis */
  MAD_EMPHASIS_CCITT_J_17 = 3           /* CCITT J.17 emphasis */
};

struct mad_frame {
  struct mad_header {
    enum mad_layer layer;               /* audio layer (1, 2, or 3) */
    enum mad_mode mode;                 /* channel mode (see above) */
    int mode_extension;                 /* additional mode info */
    enum mad_emphasis emphasis;         /* de-emphasis to use (see above) */

    unsigned long bitrate;              /* stream bitrate (bps) */
    unsigned int samplerate;            /* sampling frequency (Hz) */

    unsigned short crc_check;           /* frame CRC accumulator */
    unsigned short crc_target;          /* final target CRC checksum */

    int flags;                          /* flags (see below) */
    int private_bits;                   /* private bits (see below) */

    mad_timer_t duration;               /* audio playing time of frame */
  } header;

  int options;                          /* decoding options (from stream) */

  mad_fixed_t sbsample[2][36][32];      /* synthesis subband filter samples */
  mad_fixed_t (*overlap)[2][32][18];    /* Layer III block overlap data */
};

# define MAD_NCHANNELS(header)          ((header)->mode ? 2 : 1)
# define MAD_NSBSAMPLES(header)  \
  ((header)->layer == MAD_LAYER_I ? 12 :  \
   (((header)->layer == MAD_LAYER_III &&  \
     ((header)->flags & MAD_FLAG_LSF_EXT)) ? 18 : 36))

enum {
  MAD_FLAG_NPRIVATE_III   = 0x0007,     /* number of Layer III private bits */
  MAD_FLAG_INCOMPLETE     = 0x0008,     /* header but not data is decoded */

  MAD_FLAG_PROTECTION     = 0x0010,     /* frame has CRC protection */
  MAD_FLAG_COPYRIGHT      = 0x0020,     /* frame is copyright */
  MAD_FLAG_ORIGINAL       = 0x0040,     /* frame is original (else copy) */
  MAD_FLAG_PADDING        = 0x0080,     /* frame has additional slot */

  MAD_FLAG_I_STEREO       = 0x0100,     /* uses intensity joint stereo */
  MAD_FLAG_MS_STEREO      = 0x0200,     /* uses middle/side joint stereo */
  MAD_FLAG_FREEFORMAT     = 0x0400,     /* uses free format bitrate */

  MAD_FLAG_LSF_EXT        = 0x1000,     /* lower sampling freq. extension */
  MAD_FLAG_MC_EXT         = 0x2000,     /* multichannel audio extension */
  MAD_FLAG_MPEG_2_5_EXT   = 0x4000      /* MPEG 2.5 (unofficial) extension */
};

enum {
  MAD_PRIVATE_HEADER      = 0x0100,     /* header private bit */
  MAD_PRIVATE_III         = 0x001f      /* Layer III private bits (up to 5) */
};

void mad_header_init(struct mad_header *);

# define mad_header_finish(header)  /* nothing */

int mad_header_decode(struct mad_header *, struct mad_stream *);

void mad_frame_init(struct mad_frame *);
void mad_frame_finish(struct mad_frame *);

int mad_frame_decode(struct mad_frame *, struct mad_stream *);

void mad_frame_mute(struct mad_frame *);

# endif

/* Id: synth.h,v 1.8 2001/04/05 04:57:11 rob Exp */

# ifndef LIBMAD_SYNTH_H
# define LIBMAD_SYNTH_H

struct mad_synth {
  mad_fixed_t filter[2][2][2][16][8];   /* polyphase filterbank outputs */
                                        /* [ch][eo][peo][s][v] */

  unsigned int phase;                   /* current processing phase */

  struct mad_pcm {
    unsigned int samplerate;            /* sampling frequency (Hz) */
    unsigned short channels;            /* number of channels */
    unsigned short length;              /* number of samples per channel */
    mad_fixed_t samples[2][1152];       /* PCM output samples */
  } pcm;
};

void mad_synth_init(struct mad_synth *);

# define mad_synth_finish(synth)  /* nothing */

void mad_synth_mute(struct mad_synth *);

void mad_synth_frame(struct mad_synth *, struct mad_frame const *);

# endif

/* Id: decoder.h,v 1.9 2001/04/05 04:57:11 rob Exp */

# ifndef LIBMAD_DECODER_H
# define LIBMAD_DECODER_H

enum mad_decoder_mode {
  MAD_DECODER_MODE_SYNC  = 0,
  MAD_DECODER_MODE_ASYNC
};

enum mad_flow {
  MAD_FLOW_CONTINUE = 0x0000,
  MAD_FLOW_STOP     = 0x0010,
  MAD_FLOW_BREAK    = 0x0011,
  MAD_FLOW_IGNORE   = 0x0020
};

struct mad_decoder {
  enum mad_decoder_mode mode;

  int options;

  struct {
    long pid;
    int in;
    int out;
  } async;

  struct {
    struct mad_stream stream;
    struct mad_frame frame;
    struct mad_synth synth;
  } *sync;

  void *cb_data;

  enum mad_flow (*input_func)(void *, struct mad_stream *);
  enum mad_flow (*header_func)(void *, struct mad_header const *);
  enum mad_flow (*filter_func)(void *, struct mad_frame *);
  enum mad_flow (*output_func)(void *,
                               struct mad_header const *, struct mad_pcm *);
  enum mad_flow (*error_func)(void *, struct mad_stream *, struct mad_frame *);
  enum mad_flow (*message_func)(void *, void *, unsigned int *);
};

void mad_decoder_init(struct mad_decoder *, void *,
                      enum mad_flow (*)(void *, struct mad_stream *),
                      enum mad_flow (*)(void *, struct mad_header const *),
                      enum mad_flow (*)(void *, struct mad_frame *),
                      enum mad_flow (*)(void *,
                                        struct mad_header const *,
                                        struct mad_pcm *),
                      enum mad_flow (*)(void *,
                                        struct mad_stream *,
                                        struct mad_frame *),
                      enum mad_flow (*)(void *, void *, unsigned int *));
int mad_decoder_finish(struct mad_decoder *);

# define mad_decoder_options(decoder, opts)  ((decoder)->options = (opts))

int mad_decoder_run(struct mad_decoder *, enum mad_decoder_mode);
int mad_decoder_message(struct mad_decoder *, void *, unsigned int *);

# endif

---