1 files changed, 157 insertions, 0 deletions
diff --git a/audio/filter/af_extrastereo.c b/audio/filter/af_extrastereo.c
new file mode 100644
index 0000000000..0f7fe36861
--- /dev/null
+++ b/audio/filter/af_extrastereo.c
@@ -0,0 +1,157 @@
+/*
+ * Copyright (C) 2004 Alex Beregszaszi & Pierre Lombard
+ *
+ * This file is part of MPlayer.
+ *
+ * MPlayer 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.
+ *
+ * MPlayer 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 MPlayer; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include <inttypes.h>
+#include <math.h>
+#include <limits.h>
+
+#include "af.h"
+
+// Data for specific instances of this filter
+typedef struct af_extrastereo_s
+{
+    float mul;
+}af_extrastereo_t;
+
+static struct mp_audio* play_s16(struct af_instance* af, struct mp_audio* data);
+static struct mp_audio* play_float(struct af_instance* af, struct mp_audio* data);
+
+// Initialization and runtime control
+static int control(struct af_instance* af, int cmd, void* arg)
+{
+  af_extrastereo_t* s   = (af_extrastereo_t*)af->setup;
+
+  switch(cmd){
+  case AF_CONTROL_REINIT:{
+    // Sanity check
+    if(!arg) return AF_ERROR;
+
+    af->data->rate   = ((struct mp_audio*)arg)->rate;
+    af->data->nch    = 2;
+    if (((struct mp_audio*)arg)->format == AF_FORMAT_FLOAT_NE)
+    {
+	af->data->format = AF_FORMAT_FLOAT_NE;
+	af->data->bps = 4;
+	af->play = play_float;
+    }// else
+    {
+	af->data->format = AF_FORMAT_S16_NE;
+	af->data->bps = 2;
+	af->play = play_s16;
+    }
+
+    return af_test_output(af,(struct mp_audio*)arg);
+  }
+  case AF_CONTROL_COMMAND_LINE:{
+    float f;
+    sscanf((char*)arg,"%f", &f);
+    s->mul = f;
+    return AF_OK;
+  }
+  case AF_CONTROL_ES_MUL | AF_CONTROL_SET:
+    s->mul = *(float*)arg;
+    return AF_OK;
+  case AF_CONTROL_ES_MUL | AF_CONTROL_GET:
+    *(float*)arg = s->mul;
+    return AF_OK;
+  }
+  return AF_UNKNOWN;
+}
+
+// Deallocate memory
+static void uninit(struct af_instance* af)
+{
+    free(af->data);
+    free(af->setup);
+}
+
+// Filter data through filter
+static struct mp_audio* play_s16(struct af_instance* af, struct mp_audio* data)
+{
+  af_extrastereo_t *s = af->setup;
+  register int i = 0;
+  int16_t *a = (int16_t*)data->audio;	// Audio data
+  int len = data->len/2;		// Number of samples
+  int avg, l, r;
+
+  for (i = 0; i < len; i+=2)
+  {
+    avg = (a[i] + a[i + 1]) / 2;
+
+    l = avg + (int)(s->mul * (a[i] - avg));
+    r = avg + (int)(s->mul * (a[i + 1] - avg));
+
+    a[i] = clamp(l, SHRT_MIN, SHRT_MAX);
+    a[i + 1] = clamp(r, SHRT_MIN, SHRT_MAX);
+  }
+
+  return data;
+}
+
+static struct mp_audio* play_float(struct af_instance* af, struct mp_audio* data)
+{
+  af_extrastereo_t *s = af->setup;
+  register int i = 0;
+  float *a = (float*)data->audio;	// Audio data
+  int len = data->len/4;		// Number of samples
+  float avg, l, r;
+
+  for (i = 0; i < len; i+=2)
+  {
+    avg = (a[i] + a[i + 1]) / 2;
+
+    l = avg + (s->mul * (a[i] - avg));
+    r = avg + (s->mul * (a[i + 1] - avg));
+
+    a[i] = af_softclip(l);
+    a[i + 1] = af_softclip(r);
+  }
+
+  return data;
+}
+
+// Allocate memory and set function pointers
+static int af_open(struct af_instance* af){
+  af->control=control;
+  af->uninit=uninit;
+  af->play=play_s16;
+  af->mul=1;
+  af->data=calloc(1,sizeof(struct mp_audio));
+  af->setup=calloc(1,sizeof(af_extrastereo_t));
+  if(af->data == NULL || af->setup == NULL)
+    return AF_ERROR;
+
+  ((af_extrastereo_t*)af->setup)->mul = 2.5;
+  return AF_OK;
+}
+
+// Description of this filter
+struct af_info af_info_extrastereo = {
+    "Increase difference between audio channels",
+    "extrastereo",
+    "Alex Beregszaszi & Pierre Lombard",
+    "",
+    AF_FLAGS_NOT_REENTRANT,
+    af_open
+};