git-svn-id: http://webrtc.googlecode.com/svn/trunk@4 4adac7df-926f-26a2-2b94-8c16560cd09d

modules/audio_coding/codecs/iSAC/main/source/transform.c

@@ -0,0 +1,165 @@
+/*
+ *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "settings.h"
+#include "fft.h"
+#include "codec.h"
+#include <math.h>
+
+static double costab1[FRAMESAMPLES_HALF];
+static double sintab1[FRAMESAMPLES_HALF];
+static double costab2[FRAMESAMPLES_QUARTER];
+static double sintab2[FRAMESAMPLES_QUARTER];
+
+#if defined(WEBRTC_LINUX)
+extern long int lrint(double x); /* Note! This declaration is missing in math.h, that is why it is declared as extern*/
+#define WebRtcIsac_lrint lrint
+#elif defined(WEBRTC_MAC)
+extern long int lrint(double x); /* Note! This declaration is missing in math.h, that is why it is declared as extern*/
+#define WebRtcIsac_lrint lrint
+#elif defined(X64)
+static __inline WebRtc_Word32 WebRtcIsac_lrint(double flt) {
+  WebRtc_Word32 intgr;
+  intgr = (WebRtc_Word32)floor(flt+.499999999999);
+  return intgr ;
+}
+#elif defined(WEBRTC_TARGET_PC)
+
+static __inline WebRtc_Word32 WebRtcIsac_lrint(double flt) {
+
+  WebRtc_Word32 intgr;
+
+  _asm
+  {
+    fld flt
+        fistp intgr
+ } ;
+
+  return intgr ;
+}
+#else// Do a slow but correct implementation of lrint
+
+static __inline WebRtc_Word32 WebRtcIsac_lrint(double flt) {
+  WebRtc_Word32 intgr;
+  intgr = (WebRtc_Word32)floor(flt+.499999999999);
+  return intgr ;
+}
+#endif
+
+void WebRtcIsac_InitTransform()
+{
+  int k;
+  double fact, phase;
+
+  fact = PI / (FRAMESAMPLES_HALF);
+  phase = 0.0;
+  for (k = 0; k < FRAMESAMPLES_HALF; k++) {
+    costab1[k] = cos(phase);
+    sintab1[k] = sin(phase);
+    phase += fact;
+  }
+
+  fact = PI * ((double) (FRAMESAMPLES_HALF - 1)) / ((double) FRAMESAMPLES_HALF);
+  phase = 0.5 * fact;
+  for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
+    costab2[k] = cos(phase);
+    sintab2[k] = sin(phase);
+    phase += fact;
+  }
+}
+
+
+void WebRtcIsac_Time2Spec(double *inre1,
+                         double *inre2,
+                         WebRtc_Word16 *outreQ7,
+                         WebRtc_Word16 *outimQ7,
+                         FFTstr *fftstr_obj)
+{
+
+  int k;
+  int dims[1];
+  double tmp1r, tmp1i, xr, xi, yr, yi, fact;
+  double tmpre[FRAMESAMPLES_HALF], tmpim[FRAMESAMPLES_HALF];
+
+
+  dims[0] = FRAMESAMPLES_HALF;
+
+
+  /* Multiply with complex exponentials and combine into one complex vector */
+  fact = 0.5 / sqrt(FRAMESAMPLES_HALF);
+  for (k = 0; k < FRAMESAMPLES_HALF; k++) {
+    tmp1r = costab1[k];
+    tmp1i = sintab1[k];
+    tmpre[k] = (inre1[k] * tmp1r + inre2[k] * tmp1i) * fact;
+    tmpim[k] = (inre2[k] * tmp1r - inre1[k] * tmp1i) * fact;
+  }
+
+
+  /* Get DFT */
+  WebRtcIsac_Fftns(1, dims, tmpre, tmpim, -1, 1.0, fftstr_obj);
+
+  /* Use symmetry to separate into two complex vectors and center frames in time around zero */
+  for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
+    xr = tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
+    yi = -tmpre[k] + tmpre[FRAMESAMPLES_HALF - 1 - k];
+    xi = tmpim[k] - tmpim[FRAMESAMPLES_HALF - 1 - k];
+    yr = tmpim[k] + tmpim[FRAMESAMPLES_HALF - 1 - k];
+
+    tmp1r = costab2[k];
+    tmp1i = sintab2[k];
+    outreQ7[k] = (WebRtc_Word16)WebRtcIsac_lrint((xr * tmp1r - xi * tmp1i) * 128.0);
+    outimQ7[k] = (WebRtc_Word16)WebRtcIsac_lrint((xr * tmp1i + xi * tmp1r) * 128.0);
+    outreQ7[FRAMESAMPLES_HALF - 1 - k] = (WebRtc_Word16)WebRtcIsac_lrint((-yr * tmp1i - yi * tmp1r) * 128.0);
+    outimQ7[FRAMESAMPLES_HALF - 1 - k] = (WebRtc_Word16)WebRtcIsac_lrint((-yr * tmp1r + yi * tmp1i) * 128.0);
+  }
+}
+
+
+void WebRtcIsac_Spec2time(double *inre, double *inim, double *outre1, double *outre2, FFTstr *fftstr_obj)
+{
+
+  int k;
+  double tmp1r, tmp1i, xr, xi, yr, yi, fact;
+
+  int dims;
+
+  dims = FRAMESAMPLES_HALF;
+
+  for (k = 0; k < FRAMESAMPLES_QUARTER; k++) {
+    /* Move zero in time to beginning of frames */
+    tmp1r = costab2[k];
+    tmp1i = sintab2[k];
+    xr = inre[k] * tmp1r + inim[k] * tmp1i;
+    xi = inim[k] * tmp1r - inre[k] * tmp1i;
+    yr = -inim[FRAMESAMPLES_HALF - 1 - k] * tmp1r - inre[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
+    yi = -inre[FRAMESAMPLES_HALF - 1 - k] * tmp1r + inim[FRAMESAMPLES_HALF - 1 - k] * tmp1i;
+
+    /* Combine into one vector,  z = x + j * y */
+    outre1[k] = xr - yi;
+    outre1[FRAMESAMPLES_HALF - 1 - k] = xr + yi;
+    outre2[k] = xi + yr;
+    outre2[FRAMESAMPLES_HALF - 1 - k] = -xi + yr;
+  }
+
+
+  /* Get IDFT */
+  WebRtcIsac_Fftns(1, &dims, outre1, outre2, 1, FRAMESAMPLES_HALF, fftstr_obj);
+
+
+  /* Demodulate and separate */
+  fact = sqrt(FRAMESAMPLES_HALF);
+  for (k = 0; k < FRAMESAMPLES_HALF; k++) {
+    tmp1r = costab1[k];
+    tmp1i = sintab1[k];
+    xr = (outre1[k] * tmp1r - outre2[k] * tmp1i) * fact;
+    outre2[k] = (outre2[k] * tmp1r + outre1[k] * tmp1i) * fact;
+    outre1[k] = xr;
+  }
+}