1 files changed, 133 insertions, 0 deletions
diff --git a/gst/siren/rmlt.c b/gst/siren/rmlt.c
new file mode 100644
index 00000000..229b9106
--- /dev/null
+++ b/gst/siren/rmlt.c
@@ -0,0 +1,133 @@
+/*
+ * Siren Encoder/Decoder library
+ *
+ *   @author: Youness Alaoui <kakaroto@kakaroto.homelinux.net>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+
+#include "siren7.h"
+
+
+static int rmlt_initialized = 0;
+static float rmlt_window_640[640];
+static float rmlt_window_320[320];
+
+#define PI_2     1.57079632679489661923
+
+void siren_rmlt_init() {
+  int i = 0;
+  float angle;
+
+  for (i = 0; i < 640; i++) {
+    angle = (float) (((i + 0.5) * PI_2) / 640);
+    rmlt_window_640[i] = (float) sin(angle);
+  }
+  for (i = 0; i < 320; i++) {
+    angle = (float) (((i + 0.5) * PI_2) / 320);
+    rmlt_window_320[i] = (float) sin(angle);
+  }
+
+  rmlt_initialized = 1;
+}
+
+int siren_rmlt_encode_samples(float *samples, float *old_samples, int dct_length, float *rmlt_coefs) {
+  int half_dct_length = dct_length / 2;
+  float *old_ptr = old_samples + half_dct_length;
+  float *coef_high = rmlt_coefs + half_dct_length;
+  float *coef_low = rmlt_coefs + half_dct_length;
+  float *samples_low = samples;
+  float *samples_high = samples + dct_length;
+  float *window_low = NULL;
+  float *window_high = NULL;
+  int i = 0;
+
+  if (rmlt_initialized == 0)
+    siren_rmlt_init();
+
+  if (dct_length == 320)
+    window_low = rmlt_window_320;
+  else if (dct_length == 640)
+    window_low = rmlt_window_640;
+  else
+    return 4;
+
+  window_high = window_low + dct_length;
+
+
+  for (i = 0; i < half_dct_length; i++) {
+    *--coef_low = *--old_ptr;
+    *coef_high++ = (*samples_low * *--window_high) - (*--samples_high * *window_low);
+    *old_ptr = (*samples_high * *window_high) + (*samples_low++ * *window_low++);
+  }
+  siren_dct4(rmlt_coefs, rmlt_coefs, dct_length);
+
+  return 0;
+}
+
+
+
+int siren_rmlt_decode_samples(float *coefs, float *old_coefs, int dct_length, float *samples)  {
+  int half_dct_length = dct_length / 2;
+  float *old_low = old_coefs;
+  float *old_high = old_coefs + half_dct_length;
+  float *samples_low = samples ;
+  float *samples_high = samples + dct_length;
+  float *samples_middle_low = samples + half_dct_length;
+  float *samples_middle_high = samples + half_dct_length;
+  float *window_low = NULL;
+  float *window_high = NULL;
+  float *window_middle_low = NULL;
+  float *window_middle_high = NULL;
+  float sample_low_val;
+  float sample_high_val;
+  float sample_middle_low_val;
+  float sample_middle_high_val;
+  int i = 0;
+
+  if (rmlt_initialized == 0)
+    siren_rmlt_init();
+
+  if (dct_length == 320)
+    window_low = rmlt_window_320;
+  else if (dct_length == 640)
+    window_low = rmlt_window_640;
+  else
+    return 4;
+
+
+  window_high = window_low + dct_length;
+  window_middle_low = window_low + half_dct_length;
+  window_middle_high = window_low + half_dct_length;
+
+  siren_dct4(coefs, samples, dct_length);
+
+  for (i = 0; i < half_dct_length; i+=2) {
+    sample_low_val = *samples_low;
+    sample_high_val = *--samples_high;
+    sample_middle_low_val = *--samples_middle_low;
+    sample_middle_high_val = *samples_middle_high;
+    *samples_low++ = (*old_low * *--window_high) + (sample_middle_low_val * *window_low);
+    *samples_high = (sample_middle_low_val * *window_high) - (*old_low * *window_low++);
+    *samples_middle_high++ = (sample_low_val * *window_middle_high) - (*--old_high * *--window_middle_low);
+    *samples_middle_low = (*old_high * *window_middle_high++) + (sample_low_val * *window_middle_low);
+    *old_low++ = sample_middle_high_val;
+    *old_high = sample_high_val;
+  }
+
+  return 0;
+}