audio/mp3: Move Requantize_Process_Long to Go

audio/mp3/l3.go

@@ -28,7 +28,10 @@ import (
 	"unsafe"
 )
 
-var powtab34 = make([]float64, 8207)
+var (
+	powtab34 = make([]float64, 8207)
+	pretab   = []float64{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 3, 3, 3, 2}
+)
 
 func init() {
 	for i := range powtab34 {
@@ -36,12 +39,34 @@ func init() {
 	}
 }
 
+func requantizeProcessLong(gr, ch, is_pos, sfb int) {
+	sf_mult := 0.5
+	if C.g_side_info.scalefac_scale[gr][ch] != 0 {
+		sf_mult = 1.0
+	}
+	tmp1 := 1.0
+	// https://github.com/technosaurus/PDMP3/issues/4
+	if sfb < 21 {
+		pf_x_pt := float64(C.g_side_info.preflag[gr][ch]) * pretab[sfb]
+		tmp1 = math.Pow(2.0, -(sf_mult * (float64(C.g_main_data.scalefac_l[gr][ch][sfb]) + pf_x_pt)))
+	}
+	tmp2 := math.Pow(2.0, 0.25*(float64(C.g_side_info.global_gain[gr][ch])-210))
+	tmp3 := 0.0
+	if C.g_main_data.is[gr][ch][is_pos] < 0.0 {
+		tmp3 = -powtab34[int(-C.g_main_data.is[gr][ch][is_pos])]
+	} else {
+		tmp3 = powtab34[int(C.g_main_data.is[gr][ch][is_pos])]
+	}
+	C.g_main_data.is[gr][ch][is_pos] = C.float(tmp1 * tmp2 * tmp3)
+}
+
 func requantizeProcessShort(gr, ch, is_pos, sfb, win int) {
 	sf_mult := 0.5
 	if C.g_side_info.scalefac_scale[gr][ch] != 0 {
 		sf_mult = 1.0
 	}
 	tmp1 := 1.0
+	// https://github.com/technosaurus/PDMP3/issues/4
 	if sfb < 12 {
 		tmp1 = math.Pow(2.0, -(sf_mult * float64(C.g_main_data.scalefac_s[gr][ch][sfb][win])))
 	}
@@ -94,8 +119,8 @@ func L3_Requantize(gr C.unsigned, ch C.unsigned) {
 				if i == next_sfb {
 					sfb++
 					next_sfb = sfBandIndicesSet[sfreq].l[sfb+1]
-				} /* end if */
+				}
-				C.Requantize_Process_Long(gr, ch, C.unsigned(i), C.unsigned(sfb))
+				requantizeProcessLong(int(gr), int(ch), i, sfb)
 			}
 			/* And next the remaining,non-zero,bands which uses short blocks */
 			sfb = 3
@@ -126,7 +151,7 @@ func L3_Requantize(gr C.unsigned, ch C.unsigned) {
 				sfBandIndicesSet[sfreq].s[sfb]
 			for i := 0; i < int(C.g_side_info.count1[gr][ch]); /* i++ done below! */ {
 				/* Check if we're into the next scalefac band */
-				if i == next_sfb { /* Yes */
+				if i == next_sfb {
 					sfb++
 					next_sfb = sfBandIndicesSet[sfreq].s[sfb+1] * 3
 					win_len = sfBandIndicesSet[sfreq].s[sfb+1] -
@@ -136,7 +161,7 @@ func L3_Requantize(gr C.unsigned, ch C.unsigned) {
 					for j := 0; j < win_len; j++ {
 						requantizeProcessShort(int(gr), int(ch), i, sfb, win)
 						i++
-					} /* end for(j... */
+					}
 				}
 			}
 		}
@@ -147,8 +172,8 @@ func L3_Requantize(gr C.unsigned, ch C.unsigned) {
 			if i == next_sfb {
 				sfb++
 				next_sfb = sfBandIndicesSet[sfreq].l[sfb+1]
-			} /* end if */
+			}
-			C.Requantize_Process_Long(gr, ch, C.unsigned(i), C.unsigned(sfb))
+			requantizeProcessLong(int(gr), int(ch), i, sfb)
 		}
 	}
 }

audio/mp3/pdmp3.c

@@ -60,17 +60,6 @@ static const unsigned g_mpeg1_bitrates[3 /* layer 1-3 */][15 /* header bitrate_i
 },
 g_sampling_frequency[3] = { 44100 * Hz,48000 * Hz,32000 * Hz };
 
-#ifdef POW34_ITERATE
-static const float powtab34[32] = {
-  0.000000f,1.000000f,2.519842f,4.326749f,6.349605f,8.549880f,10.902724f,
-  13.390519f,16.000001f,18.720756f,21.544349f,24.463783f,27.473145f,30.567354f,
-  33.741995f,36.993185f,40.317478f,43.711792f,47.173351f,50.699637f,54.288359f,
-  57.937415f,61.644873f,65.408949f,69.227988f,73.100453f,77.024908f,81.000011f,
-  85.024502f,89.097200f,93.216988f,97.382814f
-}
-#endif
-  ;
-
 unsigned synth_init = 1;
 
 /* Scale factor band indices
@@ -171,59 +160,6 @@ static void dmp_samples(t_mpeg1_main_data *md,int gr,int ch,int type){
 }
 #endif
 
-/**Description: calculates y=x^(4/3) when requantizing samples.
-* Parameters: TBD
-* Return value: TBD
-* Author: Krister Lagerström(krister@kmlager.com) **/
-static inline float Requantize_Pow_43(unsigned is_pos){
-#ifdef POW34_TABLE
-  static float powtab34[8207];
-  static int init = 0;
-  int i;
-
-  if(init == 0) {   /* First time initialization */
-    for(i = 0; i < 8207; i++)
-      powtab34[i] = pow((float) i,4.0 / 3.0);
-    init = 1;
-  }
-#ifdef DEBUG
-  if(is_pos > 8206) {
-    ERR("is_pos = %d larger than 8206!",is_pos);
-    is_pos = 8206;
-  }
-#endif /* DEBUG */
-  return(powtab34[is_pos]);  /* Done */
-#elif defined POW34_ITERATE
-  float a4,a2,x,x2,x3,x_next,is_f1,is_f2,is_f3;
-  unsigned i;
-//static unsigned init = 0;
-//static float powtab34[32];
-  static float coeff[3] = {-1.030797119e+02,6.319399834e+00,2.395095071e-03};
-//if(init == 0) { /* First time initialization */
-//  for(i = 0; i < 32; i++) powtab34[i] = pow((float) i,4.0 / 3.0);
-//  init = 1;
-//}
-  /* We use a table for 0<is_pos<32 since they are so common */
-  if(is_pos < 32) return(powtab34[is_pos]);
-  a2 = is_pos * is_pos;
-  a4 = a2 * a2;
-  is_f1 =(float) is_pos;
-  is_f2 = is_f1 * is_f1;
-  is_f3 = is_f1 * is_f2;
-  /*  x = coeff[0] + coeff[1]*is_f1 + coeff[2]*is_f2 + coeff[3]*is_f3; */
-  x = coeff[0] + coeff[1]*is_f1 + coeff[2]*is_f2;
-  for(i = 0; i < 3; i++) {
-    x2 = x*x;
-    x3 = x*x2;
-    x_next =(2*x3 + a4) /(3*x2);
-    x = x_next;
-  }
-  return(x);
-#else /* no optimization */
-return powf((float)is_pos,4.0f / 3.0f);
-#endif /* POW34_TABLE || POW34_ITERATE */
-}
-
 /**Description: decodes a layer 3 bitstream into audio samples.
 * Parameters: Outdata vector.
 * Return value: OK or ERROR if the frame contains errors.
@@ -484,29 +420,6 @@ void Read_Huffman(unsigned part_2_start,unsigned gr,unsigned ch){
   return;  /* Done */
 }
 
-/**Description: requantize sample in subband that uses long blocks.
-* Parameters: TBD
-* Return value: TBD
-* Author: Krister Lagerström(krister@kmlager.com) **/
-void Requantize_Process_Long(unsigned gr,unsigned ch,unsigned is_pos,unsigned sfb){
-  float res,tmp1,tmp2,tmp3,sf_mult,pf_x_pt;
-  static float pretab[21] = { 0,0,0,0,0,0,0,0,0,0,0,1,1,1,1,2,2,3,3,3,2 };
-
-  sf_mult = g_side_info.scalefac_scale[gr][ch] ? 1.0 : 0.5;
-  pf_x_pt = g_side_info.preflag[gr][ch] * pretab[sfb];
-  if (sfb >= 21) {
-    tmp1 = 1.0;
-  } else {
-    tmp1 = pow(2.0,-(sf_mult *(g_main_data.scalefac_l[gr][ch][sfb] + pf_x_pt)));
-  }
-  tmp2 = pow(2.0,0.25 *((int32_t) g_side_info.global_gain[gr][ch] - 210));
-  if(g_main_data.is[gr][ch][is_pos] < 0.0)
-    tmp3 = -Requantize_Pow_43(-g_main_data.is[gr][ch][is_pos]);
-  else tmp3 = Requantize_Pow_43(g_main_data.is[gr][ch][is_pos]);
-  res = g_main_data.is[gr][ch][is_pos] = tmp1 * tmp2 * tmp3;
-  return; /* Done */
-}
-
 /**Description: output audio data
 * Parameters: Pointers to the samples,the number of samples
 * Return value: None

audio/mp3/pdmp3.h

@@ -107,8 +107,6 @@ void L3_Hybrid_Synthesis(unsigned gr,unsigned ch);
 void L3_Frequency_Inversion(unsigned gr,unsigned ch);
 void L3_Subband_Synthesis(unsigned gr,unsigned ch, unsigned* outdata);
 
-void Requantize_Process_Long(unsigned gr,unsigned ch,unsigned is_pos,unsigned sfb);
-
 int Read_CRC(void);
 
 int Huffman_Decode(unsigned table_num, int32_t* x, int32_t*y, int32_t* v, int32_t* w);