synth.c

VC++视频开发实例集锦(包括“远程视频监控”"语音识别系统"等13个经典例子)

  /* 18 */ lo[ 2][slot] = SHIFT(t135);

  t169 = (MUL(t132 - t133, costab16) * 2) - t134;

  t151 = (t169 * 2) - t135;

  /* 22 */ lo[ 6][slot] = SHIFT(t151);

  t170 = (((MUL(t148 - t149, costab16) * 2) - t150) * 2) - t151;

  /* 26 */ lo[10][slot] = SHIFT(t170);
  /* 30 */ lo[14][slot] =
	     SHIFT((((((MUL(t166 - t167, costab16) * 2) -
		       t168) * 2) - t169) * 2) - t170);

  t171 = MUL(t106 - t107, costab8);
  t172 = MUL(t108 - t109, costab24);
  t173 = t171 + t172;

  t138 = (t173 * 2) - t110;

  t123 = (t138 * 2) - t111;

  t139 = (MUL(t121 - t122, costab16) * 2) - t123;

  t117 = (t123 * 2) - t112;

  /* 15 */ hi[ 0][slot] = SHIFT(t117);

  t124 = (MUL(t115 - t116, costab16) * 2) - t117;

  /* 17 */ lo[ 1][slot] = SHIFT(t124);

  t131 = (t139 * 2) - t124;

  /* 19 */ lo[ 3][slot] = SHIFT(t131);

  t140 = (t164 * 2) - t131;

  /* 21 */ lo[ 5][slot] = SHIFT(t140);

  t174 = (MUL(t136 - t137, costab16) * 2) - t138;

  t155 = (t174 * 2) - t139;

  t147 = (t155 * 2) - t140;

  /* 23 */ lo[ 7][slot] = SHIFT(t147);

  t156 = (((MUL(t144 - t145, costab16) * 2) - t146) * 2) - t147;

  /* 25 */ lo[ 9][slot] = SHIFT(t156);

  t175 = (((MUL(t152 - t153, costab16) * 2) - t154) * 2) - t155;

  t165 = (t175 * 2) - t156;

  /* 27 */ lo[11][slot] = SHIFT(t165);

  t176 = (((((MUL(t161 - t162, costab16) * 2) -
	     t163) * 2) - t164) * 2) - t165;

  /* 29 */ lo[13][slot] = SHIFT(t176);
  /* 31 */ lo[15][slot] =
	     SHIFT((((((((MUL(t171 - t172, costab16) * 2) -
			 t173) * 2) - t174) * 2) - t175) * 2) - t176);

  /*
   * Totals:
   *  80 multiplies
   *  80 additions
   * 119 subtractions
   *  49 shifts (not counting SSO)
   */
}

# undef MUL
# undef SHIFT

/* third SSO shift and/or D[] optimization preshift */

# if defined(OPT_SSO)
#  if MAD_F_FRACBITS != 28
#   error "MAD_F_FRACBITS must be 28 to use OPT_SSO"
#  endif
#  define ML0(hi, lo, x, y)	((lo)  = (x) * (y))
#  define MLA(hi, lo, x, y)	((lo) += (x) * (y))
#  define MLN(hi, lo)		((lo)  = -(lo))
#  define MLZ(hi, lo)		((void) (hi), (mad_fixed_t) (lo))
#  define SHIFT(x)		((x) >> 2)
#  define PRESHIFT(x)		((MAD_F(x) + (1L << 13)) >> 14)
# else
#  define ML0(hi, lo, x, y)	MAD_F_ML0((hi), (lo), (x), (y))
#  define MLA(hi, lo, x, y)	MAD_F_MLA((hi), (lo), (x), (y))
#  define MLN(hi, lo)		MAD_F_MLN((hi), (lo))
#  define MLZ(hi, lo)		MAD_F_MLZ((hi), (lo))
#  define SHIFT(x)		(x)
#  if defined(MAD_F_SCALEBITS)
#   undef  MAD_F_SCALEBITS
#   define MAD_F_SCALEBITS	(MAD_F_FRACBITS - 12)
#   define PRESHIFT(x)		(MAD_F(x) >> 12)
#  else
#   define PRESHIFT(x)		MAD_F(x)
#  endif
# endif

static
mad_fixed_t const D[17][32] = {
# include "D.dat"
};

# if defined(ASO_SYNTH)
void synth_full(struct mad_synth *, struct mad_frame const *,
		unsigned int, unsigned int);
# else
/*
 * NAME:	synth->full()
 * DESCRIPTION:	perform full frequency PCM synthesis
 */
static
void synth_full(struct mad_synth *synth, struct mad_frame const *frame,
		unsigned int nch, unsigned int ns)
{
  unsigned int phase, ch, s, sb, pe, po;
  mad_fixed_t *pcm1, *pcm2, (*filter)[2][2][16][8];
  mad_fixed_t const (*sbsample)[36][32];
  register mad_fixed_t (*fe)[8], (*fx)[8], (*fo)[8];
  register mad_fixed_t const (*Dptr)[32], *ptr;
  register mad_fixed64hi_t hi;
  register mad_fixed64lo_t lo;

  for (ch = 0; ch < nch; ++ch) {
    sbsample = &frame->sbsample[ch];
    filter   = &synth->filter[ch];
    phase    = synth->phase;
    pcm1     = synth->pcm.samples[ch];

    for (s = 0; s < ns; ++s) {
      dct32((*sbsample)[s], phase >> 1,
	    (*filter)[0][phase & 1], (*filter)[1][phase & 1]);

      pe = phase & ~1;
      po = ((phase - 1) & 0xf) | 1;

      /* calculate 32 samples */

      fe = &(*filter)[0][ phase & 1][0];
      fx = &(*filter)[0][~phase & 1][0];
      fo = &(*filter)[1][~phase & 1][0];

      Dptr = &D[0];

      ptr = *Dptr + po;
      ML0(hi, lo, (*fx)[0], ptr[ 0]);
      MLA(hi, lo, (*fx)[1], ptr[14]);
      MLA(hi, lo, (*fx)[2], ptr[12]);
      MLA(hi, lo, (*fx)[3], ptr[10]);
      MLA(hi, lo, (*fx)[4], ptr[ 8]);
      MLA(hi, lo, (*fx)[5], ptr[ 6]);
      MLA(hi, lo, (*fx)[6], ptr[ 4]);
      MLA(hi, lo, (*fx)[7], ptr[ 2]);
      MLN(hi, lo);

      ptr = *Dptr + pe;
      MLA(hi, lo, (*fe)[0], ptr[ 0]);
      MLA(hi, lo, (*fe)[1], ptr[14]);
      MLA(hi, lo, (*fe)[2], ptr[12]);
      MLA(hi, lo, (*fe)[3], ptr[10]);
      MLA(hi, lo, (*fe)[4], ptr[ 8]);
      MLA(hi, lo, (*fe)[5], ptr[ 6]);
      MLA(hi, lo, (*fe)[6], ptr[ 4]);
      MLA(hi, lo, (*fe)[7], ptr[ 2]);

      *pcm1++ = SHIFT(MLZ(hi, lo));

      pcm2 = pcm1 + 30;

      for (sb = 1; sb < 16; ++sb) {
	++fe;
	++Dptr;

	/* D[32 - sb][i] == -D[sb][31 - i] */

	ptr = *Dptr + po;
	ML0(hi, lo, (*fo)[0], ptr[ 0]);
	MLA(hi, lo, (*fo)[1], ptr[14]);
	MLA(hi, lo, (*fo)[2], ptr[12]);
	MLA(hi, lo, (*fo)[3], ptr[10]);
	MLA(hi, lo, (*fo)[4], ptr[ 8]);
	MLA(hi, lo, (*fo)[5], ptr[ 6]);
	MLA(hi, lo, (*fo)[6], ptr[ 4]);
	MLA(hi, lo, (*fo)[7], ptr[ 2]);
	MLN(hi, lo);

	ptr = *Dptr + pe;
	MLA(hi, lo, (*fe)[7], ptr[ 2]);
	MLA(hi, lo, (*fe)[6], ptr[ 4]);
	MLA(hi, lo, (*fe)[5], ptr[ 6]);
	MLA(hi, lo, (*fe)[4], ptr[ 8]);
	MLA(hi, lo, (*fe)[3], ptr[10]);
	MLA(hi, lo, (*fe)[2], ptr[12]);
	MLA(hi, lo, (*fe)[1], ptr[14]);
	MLA(hi, lo, (*fe)[0], ptr[ 0]);

	*pcm1++ = SHIFT(MLZ(hi, lo));

	ptr = *Dptr - pe;
	ML0(hi, lo, (*fe)[0], ptr[31 - 16]);
	MLA(hi, lo, (*fe)[1], ptr[31 - 14]);
	MLA(hi, lo, (*fe)[2], ptr[31 - 12]);
	MLA(hi, lo, (*fe)[3], ptr[31 - 10]);
	MLA(hi, lo, (*fe)[4], ptr[31 -  8]);
	MLA(hi, lo, (*fe)[5], ptr[31 -  6]);
	MLA(hi, lo, (*fe)[6], ptr[31 -  4]);
	MLA(hi, lo, (*fe)[7], ptr[31 -  2]);

	ptr = *Dptr - po;
	MLA(hi, lo, (*fo)[7], ptr[31 -  2]);
	MLA(hi, lo, (*fo)[6], ptr[31 -  4]);
	MLA(hi, lo, (*fo)[5], ptr[31 -  6]);
	MLA(hi, lo, (*fo)[4], ptr[31 -  8]);
	MLA(hi, lo, (*fo)[3], ptr[31 - 10]);
	MLA(hi, lo, (*fo)[2], ptr[31 - 12]);
	MLA(hi, lo, (*fo)[1], ptr[31 - 14]);
	MLA(hi, lo, (*fo)[0], ptr[31 - 16]);

	*pcm2-- = SHIFT(MLZ(hi, lo));

	++fo;
      }

      ++Dptr;

      ptr = *Dptr + po;
      ML0(hi, lo, (*fo)[0], ptr[ 0]);
      MLA(hi, lo, (*fo)[1], ptr[14]);
      MLA(hi, lo, (*fo)[2], ptr[12]);
      MLA(hi, lo, (*fo)[3], ptr[10]);
      MLA(hi, lo, (*fo)[4], ptr[ 8]);
      MLA(hi, lo, (*fo)[5], ptr[ 6]);
      MLA(hi, lo, (*fo)[6], ptr[ 4]);
      MLA(hi, lo, (*fo)[7], ptr[ 2]);

      *pcm1 = SHIFT(-MLZ(hi, lo));
      pcm1 += 16;

      phase = (phase + 1) % 16;
    }
  }
}
# endif

/*
 * NAME:	synth->half()
 * DESCRIPTION:	perform half frequency PCM synthesis
 */
static
void synth_half(struct mad_synth *synth, struct mad_frame const *frame,
		unsigned int nch, unsigned int ns)
{
  unsigned int phase, ch, s, sb, pe, po;
  mad_fixed_t *pcm1, *pcm2, (*filter)[2][2][16][8];
  mad_fixed_t const (*sbsample)[36][32];
  register mad_fixed_t (*fe)[8], (*fx)[8], (*fo)[8];
  register mad_fixed_t const (*Dptr)[32], *ptr;
  register mad_fixed64hi_t hi;
  register mad_fixed64lo_t lo;

  for (ch = 0; ch < nch; ++ch) {
    sbsample = &frame->sbsample[ch];
    filter   = &synth->filter[ch];
    phase    = synth->phase;
    pcm1     = synth->pcm.samples[ch];

    for (s = 0; s < ns; ++s) {
      dct32((*sbsample)[s], phase >> 1,
	    (*filter)[0][phase & 1], (*filter)[1][phase & 1]);

      pe = phase & ~1;
      po = ((phase - 1) & 0xf) | 1;

      /* calculate 16 samples */

      fe = &(*filter)[0][ phase & 1][0];
      fx = &(*filter)[0][~phase & 1][0];
      fo = &(*filter)[1][~phase & 1][0];

      Dptr = &D[0];

      ptr = *Dptr + po;
      ML0(hi, lo, (*fx)[0], ptr[ 0]);
      MLA(hi, lo, (*fx)[1], ptr[14]);
      MLA(hi, lo, (*fx)[2], ptr[12]);
      MLA(hi, lo, (*fx)[3], ptr[10]);
      MLA(hi, lo, (*fx)[4], ptr[ 8]);
      MLA(hi, lo, (*fx)[5], ptr[ 6]);
      MLA(hi, lo, (*fx)[6], ptr[ 4]);
      MLA(hi, lo, (*fx)[7], ptr[ 2]);
      MLN(hi, lo);

      ptr = *Dptr + pe;
      MLA(hi, lo, (*fe)[0], ptr[ 0]);
      MLA(hi, lo, (*fe)[1], ptr[14]);
      MLA(hi, lo, (*fe)[2], ptr[12]);
      MLA(hi, lo, (*fe)[3], ptr[10]);
      MLA(hi, lo, (*fe)[4], ptr[ 8]);
      MLA(hi, lo, (*fe)[5], ptr[ 6]);
      MLA(hi, lo, (*fe)[6], ptr[ 4]);
      MLA(hi, lo, (*fe)[7], ptr[ 2]);

      *pcm1++ = SHIFT(MLZ(hi, lo));

      pcm2 = pcm1 + 14;

      for (sb = 1; sb < 16; ++sb) {
	++fe;
	++Dptr;

	/* D[32 - sb][i] == -D[sb][31 - i] */

	if (!(sb & 1)) {
	  ptr = *Dptr + po;
	  ML0(hi, lo, (*fo)[0], ptr[ 0]);
	  MLA(hi, lo, (*fo)[1], ptr[14]);
	  MLA(hi, lo, (*fo)[2], ptr[12]);
	  MLA(hi, lo, (*fo)[3], ptr[10]);
	  MLA(hi, lo, (*fo)[4], ptr[ 8]);
	  MLA(hi, lo, (*fo)[5], ptr[ 6]);
	  MLA(hi, lo, (*fo)[6], ptr[ 4]);
	  MLA(hi, lo, (*fo)[7], ptr[ 2]);
	  MLN(hi, lo);

	  ptr = *Dptr + pe;
	  MLA(hi, lo, (*fe)[7], ptr[ 2]);
	  MLA(hi, lo, (*fe)[6], ptr[ 4]);
	  MLA(hi, lo, (*fe)[5], ptr[ 6]);
	  MLA(hi, lo, (*fe)[4], ptr[ 8]);
	  MLA(hi, lo, (*fe)[3], ptr[10]);
	  MLA(hi, lo, (*fe)[2], ptr[12]);
	  MLA(hi, lo, (*fe)[1], ptr[14]);
	  MLA(hi, lo, (*fe)[0], ptr[ 0]);

	  *pcm1++ = SHIFT(MLZ(hi, lo));

	  ptr = *Dptr - po;
	  ML0(hi, lo, (*fo)[7], ptr[31 -  2]);
	  MLA(hi, lo, (*fo)[6], ptr[31 -  4]);
	  MLA(hi, lo, (*fo)[5], ptr[31 -  6]);
	  MLA(hi, lo, (*fo)[4], ptr[31 -  8]);
	  MLA(hi, lo, (*fo)[3], ptr[31 - 10]);
	  MLA(hi, lo, (*fo)[2], ptr[31 - 12]);
	  MLA(hi, lo, (*fo)[1], ptr[31 - 14]);
	  MLA(hi, lo, (*fo)[0], ptr[31 - 16]);

	  ptr = *Dptr - pe;
	  MLA(hi, lo, (*fe)[0], ptr[31 - 16]);
	  MLA(hi, lo, (*fe)[1], ptr[31 - 14]);
	  MLA(hi, lo, (*fe)[2], ptr[31 - 12]);
	  MLA(hi, lo, (*fe)[3], ptr[31 - 10]);
	  MLA(hi, lo, (*fe)[4], ptr[31 -  8]);
	  MLA(hi, lo, (*fe)[5], ptr[31 -  6]);
	  MLA(hi, lo, (*fe)[6], ptr[31 -  4]);
	  MLA(hi, lo, (*fe)[7], ptr[31 -  2]);

	  *pcm2-- = SHIFT(MLZ(hi, lo));
	}

	++fo;
      }

      ++Dptr;

      ptr = *Dptr + po;
      ML0(hi, lo, (*fo)[0], ptr[ 0]);
      MLA(hi, lo, (*fo)[1], ptr[14]);
      MLA(hi, lo, (*fo)[2], ptr[12]);
      MLA(hi, lo, (*fo)[3], ptr[10]);
      MLA(hi, lo, (*fo)[4], ptr[ 8]);
      MLA(hi, lo, (*fo)[5], ptr[ 6]);
      MLA(hi, lo, (*fo)[6], ptr[ 4]);
      MLA(hi, lo, (*fo)[7], ptr[ 2]);

      *pcm1 = SHIFT(-MLZ(hi, lo));
      pcm1 += 8;

      phase = (phase + 1) % 16;
    }
  }
}

/*
 * NAME:	synth->frame()
 * DESCRIPTION:	perform PCM synthesis of frame subband samples
 */
void mad_synth_frame(struct mad_synth *synth, struct mad_frame const *frame)
{
  unsigned int nch, ns;
  void (*synth_frame)(struct mad_synth *, struct mad_frame const *,
		      unsigned int, unsigned int);

  nch = MAD_NCHANNELS(&frame->header);
  ns  = MAD_NSBSAMPLES(&frame->header);

  synth->pcm.samplerate = frame->header.samplerate;
  synth->pcm.channels   = nch;
  synth->pcm.length     = 32 * ns;

  synth_frame = synth_full;

  if (frame->options & MAD_OPTION_HALFSAMPLERATE) {
    synth->pcm.samplerate /= 2;
    synth->pcm.length     /= 2;

    synth_frame = synth_half;
  }

  synth_frame(synth, frame, nch, ns);

  synth->phase = (synth->phase + ns) % 16;
}