--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/gst_plugins_base/gst/audioconvert/gstchannelmix.c Thu Dec 17 08:53:32 2009 +0200
@@ -0,0 +1,636 @@
+/* GStreamer
+ * Copyright (C) 2004 Ronald Bultje <rbultje@ronald.bitfreak.net>
+ *
+ * gstchannelmix.c: setup of channel conversion matrices
+ *
+ * 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.
+ */
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <math.h>
+#include <string.h>
+#include <gst/audio/multichannel.h>
+
+#include "gstchannelmix.h"
+
+/*
+ * Channel matrix functions.
+ */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+void
+gst_channel_mix_unset_matrix (AudioConvertCtx * this)
+{
+ gint i;
+
+ /* don't access if nothing there */
+ if (!this->matrix)
+ return;
+
+ /* free */
+ for (i = 0; i < this->in.channels; i++)
+ g_free (this->matrix[i]);
+ g_free (this->matrix);
+
+ this->matrix = NULL;
+ g_free (this->tmp);
+ this->tmp = NULL;
+}
+
+/*
+ * Detect and fill in identical channels. E.g.
+ * forward the left/right front channels in a
+ * 5.1 to 2.0 conversion.
+ */
+
+static void
+gst_channel_mix_fill_identical (AudioConvertCtx * this)
+{
+ gint ci, co;
+
+ /* Apart from the compatible channel assignments, we can also have
+ * same channel assignments. This is much simpler, we simply copy
+ * the value from source to dest! */
+ for (co = 0; co < this->out.channels; co++) {
+ /* find a channel in input with same position */
+ for (ci = 0; ci < this->in.channels; ci++) {
+ if (this->in.pos[ci] == this->out.pos[co]) {
+ this->matrix[ci][co] = 1.0;
+ }
+ }
+ }
+}
+
+/*
+ * Detect and fill in compatible channels. E.g.
+ * forward left/right front to mono (or the other
+ * way around) when going from 2.0 to 1.0.
+ */
+
+static void
+gst_channel_mix_fill_compatible (AudioConvertCtx * this)
+{
+ /* Conversions from one-channel to compatible two-channel configs */
+ struct
+ {
+ GstAudioChannelPosition pos1[2];
+ GstAudioChannelPosition pos2[1];
+ } conv[] = {
+ /* front: mono <-> stereo */
+ { {
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT}, {
+ GST_AUDIO_CHANNEL_POSITION_FRONT_MONO}},
+ /* front center: 2 <-> 1 */
+ { {
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER}, {
+ GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER}},
+ /* rear: 2 <-> 1 */
+ { {
+ GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT}, {
+ GST_AUDIO_CHANNEL_POSITION_REAR_CENTER}}, { {
+ GST_AUDIO_CHANNEL_POSITION_INVALID}}
+ };
+ gint c;
+
+ /* conversions from compatible (but not the same) channel schemes. This
+ * goes two ways: if the sink has both pos1[0,1] and src has pos2[0] or
+ * if the src has both pos1[0,1] and sink has pos2[0], then we do the
+ * conversion. We hereby assume that the existance of pos1[0,1] and
+ * pos2[0] are mututally exclusive. There are no checks for that,
+ * unfortunately. This shouldn't lead to issues (like crashes or so),
+ * though. */
+ for (c = 0; conv[c].pos1[0] != GST_AUDIO_CHANNEL_POSITION_INVALID; c++) {
+ gint pos1_0 = -1, pos1_1 = -1, pos2_0 = -1, n;
+
+ /* Try to go from the given 2 channels to the given 1 channel */
+ for (n = 0; n < this->in.channels; n++) {
+ if (this->in.pos[n] == conv[c].pos1[0])
+ pos1_0 = n;
+ else if (this->in.pos[n] == conv[c].pos1[1])
+ pos1_1 = n;
+ }
+ for (n = 0; n < this->out.channels; n++) {
+ if (this->out.pos[n] == conv[c].pos2[0])
+ pos2_0 = n;
+ }
+
+ if (pos1_0 != -1 && pos1_1 != -1 && pos2_0 != -1) {
+ this->matrix[pos1_0][pos2_0] = 1.0;
+ this->matrix[pos1_1][pos2_0] = 1.0;
+ }
+
+ /* Try to go from the given 1 channel to the given 2 channels */
+ pos1_0 = -1;
+ pos1_1 = -1;
+ pos2_0 = -1;
+
+ for (n = 0; n < this->out.channels; n++) {
+ if (this->out.pos[n] == conv[c].pos1[0])
+ pos1_0 = n;
+ else if (this->out.pos[n] == conv[c].pos1[1])
+ pos1_1 = n;
+ }
+ for (n = 0; n < this->in.channels; n++) {
+ if (this->in.pos[n] == conv[c].pos2[0])
+ pos2_0 = n;
+ }
+
+ if (pos1_0 != -1 && pos1_1 != -1 && pos2_0 != -1) {
+ this->matrix[pos2_0][pos1_0] = 1.0;
+ this->matrix[pos2_0][pos1_1] = 1.0;
+ }
+ }
+}
+
+/*
+ * Detect and fill in channels not handled by the
+ * above two, e.g. center to left/right front in
+ * 5.1 to 2.0 (or the other way around).
+ *
+ * Unfortunately, limited to static conversions
+ * for now.
+ */
+
+static void
+gst_channel_mix_detect_pos (AudioConvertFmt * caps,
+ gint * f, gboolean * has_f,
+ gint * c, gboolean * has_c, gint * r, gboolean * has_r,
+ gint * s, gboolean * has_s, gint * b, gboolean * has_b)
+{
+ gint n;
+
+ for (n = 0; n < caps->channels; n++) {
+ switch (caps->pos[n]) {
+ case GST_AUDIO_CHANNEL_POSITION_FRONT_MONO:
+ case GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT:
+ case GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT:
+ *has_f = TRUE;
+ if (f[0] == -1)
+ f[0] = n;
+ else
+ f[1] = n;
+ break;
+ case GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER:
+ case GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER:
+ case GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER:
+ *has_c = TRUE;
+ if (c[0] == -1)
+ c[0] = n;
+ else
+ c[1] = n;
+ break;
+ case GST_AUDIO_CHANNEL_POSITION_REAR_CENTER:
+ case GST_AUDIO_CHANNEL_POSITION_REAR_LEFT:
+ case GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT:
+ *has_r = TRUE;
+ if (r[0] == -1)
+ r[0] = n;
+ else
+ r[1] = n;
+ break;
+ case GST_AUDIO_CHANNEL_POSITION_SIDE_LEFT:
+ case GST_AUDIO_CHANNEL_POSITION_SIDE_RIGHT:
+ *has_s = TRUE;
+ if (s[0] == -1)
+ s[0] = n;
+ else
+ s[1] = n;
+ break;
+ case GST_AUDIO_CHANNEL_POSITION_LFE:
+ *has_b = TRUE;
+ b[0] = n;
+ break;
+ default:
+ break;
+ }
+ }
+}
+
+static void
+gst_channel_mix_fill_one_other (gfloat ** matrix,
+ AudioConvertFmt * from_caps, gint * from_idx,
+ GstAudioChannelPosition from_pos_l,
+ GstAudioChannelPosition from_pos_r,
+ GstAudioChannelPosition from_pos_c,
+ AudioConvertFmt * to_caps, gint * to_idx,
+ GstAudioChannelPosition to_pos_l,
+ GstAudioChannelPosition to_pos_r,
+ GstAudioChannelPosition to_pos_c, gfloat ratio)
+{
+ gfloat in_r, out_r[2] = { 0.f, 0.f };
+
+ /*
+ * The idea is that we add up from the input (which means that if we
+ * have stereo input, we divide their sum by two) and put that in
+ * the matrix for their output ratio (given in $ratio).
+ * For left channels, we need to invert the signal sign (* -1).
+ */
+
+ if (from_caps->pos[from_idx[0]] == from_pos_c)
+ in_r = 1.0;
+ else
+ in_r = 0.5;
+
+ if (to_caps->pos[to_idx[0]] == to_pos_l)
+ out_r[0] = in_r * -ratio;
+ else
+ out_r[0] = in_r * ratio;
+
+ if (to_idx[1] != -1) {
+ if (to_caps->pos[to_idx[1]] == to_pos_l)
+ out_r[1] = in_r * -ratio;
+ else
+ out_r[1] = in_r * ratio;
+ }
+
+ matrix[from_idx[0]][to_idx[0]] = out_r[0];
+ if (to_idx[1] != -1)
+ matrix[from_idx[0]][to_idx[1]] = out_r[1];
+ if (from_idx[1] != -1) {
+ matrix[from_idx[1]][to_idx[0]] = out_r[0];
+ if (to_idx[1] != -1)
+ matrix[from_idx[1]][to_idx[1]] = out_r[1];
+ }
+}
+
+#define RATIO_FRONT_CENTER (1.0 / sqrt (2.0))
+#define RATIO_FRONT_REAR (1.0 / sqrt (2.0))
+#define RATIO_FRONT_BASS (1.0)
+#define RATIO_REAR_BASS (1.0 / sqrt (2.0))
+#define RATIO_CENTER_BASS (1.0 / sqrt (2.0))
+
+static void
+gst_channel_mix_fill_others (AudioConvertCtx * this)
+{
+ gboolean in_has_front = FALSE, out_has_front = FALSE,
+ in_has_center = FALSE, out_has_center = FALSE,
+ in_has_rear = FALSE, out_has_rear = FALSE,
+ in_has_side = FALSE, out_has_side = FALSE,
+ in_has_bass = FALSE, out_has_bass = FALSE;
+ gint in_f[2] = { -1, -1 }, out_f[2] = {
+ -1, -1}, in_c[2] = {
+ -1, -1}, out_c[2] = {
+ -1, -1}, in_r[2] = {
+ -1, -1}, out_r[2] = {
+ -1, -1}, in_s[2] = {
+ -1, -1}, out_s[2] = {
+ -1, -1}, in_b[2] = {
+ -1, -1}, out_b[2] = {
+ -1, -1};
+
+ /* First see where (if at all) the various channels from/to
+ * which we want to convert are located in our matrix/array. */
+ gst_channel_mix_detect_pos (&this->in,
+ in_f, &in_has_front,
+ in_c, &in_has_center, in_r, &in_has_rear,
+ in_s, &in_has_side, in_b, &in_has_bass);
+ gst_channel_mix_detect_pos (&this->out,
+ out_f, &out_has_front,
+ out_c, &out_has_center, out_r, &out_has_rear,
+ out_s, &out_has_side, out_b, &out_has_bass);
+
+ /* center/front */
+ if (!in_has_center && in_has_front && out_has_center) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_f,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_MONO,
+ &this->out, out_c,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER, RATIO_FRONT_CENTER);
+ } else if (in_has_center && !out_has_center && out_has_front) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_c,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER,
+ &this->out, out_f,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_MONO, RATIO_FRONT_CENTER);
+ }
+
+ /* rear/front */
+ if (!in_has_rear && in_has_front && out_has_rear) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_f,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_MONO,
+ &this->out, out_r,
+ GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_CENTER, RATIO_FRONT_REAR);
+ } else if (in_has_rear && !out_has_rear && out_has_front) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_r,
+ GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_CENTER,
+ &this->out, out_f,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_MONO, RATIO_FRONT_REAR);
+ }
+
+ /* bass/any */
+ if (in_has_bass && !out_has_bass) {
+ if (out_has_front) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_b,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_LFE,
+ &this->out, out_f,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_MONO, RATIO_FRONT_BASS);
+ }
+ if (out_has_center) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_b,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_LFE,
+ &this->out, out_c,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER, RATIO_CENTER_BASS);
+ }
+ if (out_has_rear) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_b,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_LFE,
+ &this->out, out_r,
+ GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_CENTER, RATIO_REAR_BASS);
+ }
+ } else if (!in_has_bass && out_has_bass) {
+ if (in_has_front) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_f,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_MONO,
+ &this->out, out_b,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_LFE, RATIO_FRONT_BASS);
+ }
+ if (in_has_center) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_c,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_LEFT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_RIGHT_OF_CENTER,
+ GST_AUDIO_CHANNEL_POSITION_FRONT_CENTER,
+ &this->out, out_b,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_LFE, RATIO_CENTER_BASS);
+ }
+ if (in_has_rear) {
+ gst_channel_mix_fill_one_other (this->matrix,
+ &this->in, in_r,
+ GST_AUDIO_CHANNEL_POSITION_REAR_LEFT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_RIGHT,
+ GST_AUDIO_CHANNEL_POSITION_REAR_CENTER,
+ &this->out, out_b,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_INVALID,
+ GST_AUDIO_CHANNEL_POSITION_LFE, RATIO_REAR_BASS);
+ }
+ }
+
+ /* FIXME: side */
+}
+
+/*
+ * Normalize output values.
+ */
+
+static void
+gst_channel_mix_fill_normalize (AudioConvertCtx * this)
+{
+ gfloat sum, top = 0;
+ gint i, j;
+
+ for (j = 0; j < this->out.channels; j++) {
+ /* calculate sum */
+ sum = 0.0;
+ for (i = 0; i < this->in.channels; i++) {
+ sum += fabs (this->matrix[i][j]);
+ }
+ if (sum > top) {
+ top = sum;
+ }
+ }
+
+ /* normalize to this */
+ for (j = 0; j < this->out.channels; j++) {
+ for (i = 0; i < this->in.channels; i++) {
+ this->matrix[i][j] /= top;
+ }
+ }
+}
+
+/*
+ * Automagically generate conversion matrix.
+ */
+
+static void
+gst_channel_mix_fill_matrix (AudioConvertCtx * this)
+{
+ gst_channel_mix_fill_identical (this);
+ gst_channel_mix_fill_compatible (this);
+ gst_channel_mix_fill_others (this);
+ gst_channel_mix_fill_normalize (this);
+}
+
+/* only call after this->out and this->in are filled in */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_channel_mix_setup_matrix (AudioConvertCtx * this)
+{
+ gint i, j;
+ GString *s;
+
+ /* don't lose memory */
+ gst_channel_mix_unset_matrix (this);
+
+ /* temp storage */
+ if (this->in.is_int || this->out.is_int) {
+ this->tmp = (gpointer) g_new (gint32, this->out.channels);
+ } else {
+ this->tmp = (gpointer) g_new (gdouble, this->out.channels);
+ }
+
+ /* allocate */
+ this->matrix = g_new0 (gfloat *, this->in.channels);
+ for (i = 0; i < this->in.channels; i++) {
+ this->matrix[i] = g_new (gfloat, this->out.channels);
+ for (j = 0; j < this->out.channels; j++)
+ this->matrix[i][j] = 0.;
+ }
+
+ /* setup the matrix' internal values */
+ gst_channel_mix_fill_matrix (this);
+
+ /* debug */
+ s = g_string_new ("Matrix for");
+ g_string_append_printf (s, " %d -> %d: ",
+ this->in.channels, this->out.channels);
+ g_string_append (s, "{");
+ for (i = 0; i < this->in.channels; i++) {
+ if (i != 0)
+ g_string_append (s, ",");
+ g_string_append (s, " {");
+ for (j = 0; j < this->out.channels; j++) {
+ if (j != 0)
+ g_string_append (s, ",");
+ g_string_append_printf (s, " %f", this->matrix[i][j]);
+ }
+ g_string_append (s, " }");
+ }
+ g_string_append (s, " }");
+ GST_DEBUG (s->str);
+ g_string_free (s, TRUE);
+}
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+gboolean
+gst_channel_mix_passthrough (AudioConvertCtx * this)
+{
+ gint i;
+
+ /* only NxN matrices can be identities */
+ if (this->in.channels != this->out.channels)
+ return FALSE;
+
+ /* this assumes a normalized matrix */
+ for (i = 0; i < this->in.channels; i++)
+ if (this->matrix[i][i] != 1.)
+ return FALSE;
+
+ return TRUE;
+}
+
+/* IMPORTANT: out_data == in_data is possible, make sure to not overwrite data
+ * you might need later on! */
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+void
+gst_channel_mix_mix_int (AudioConvertCtx * this,
+ gint32 * in_data, gint32 * out_data, gint samples)
+{
+ gint in, out, n;
+ gint64 res;
+ gboolean backwards;
+ gint inchannels, outchannels;
+ gint32 *tmp = (gint32 *) this->tmp;
+
+ g_return_if_fail (this->matrix != NULL);
+ g_return_if_fail (this->tmp != NULL);
+
+ inchannels = this->in.channels;
+ outchannels = this->out.channels;
+ backwards = outchannels > inchannels;
+
+ /* FIXME: use liboil here? */
+ for (n = (backwards ? samples - 1 : 0); n < samples && n >= 0;
+ backwards ? n-- : n++) {
+ for (out = 0; out < outchannels; out++) {
+ /* convert */
+ res = 0;
+ for (in = 0; in < inchannels; in++) {
+ res += in_data[n * inchannels + in] * this->matrix[in][out];
+ }
+
+ /* clip (shouldn't we use doubles instead as intermediate format?) */
+ if (res < G_MININT32)
+ res = G_MININT32;
+ else if (res > G_MAXINT32)
+ res = G_MAXINT32;
+ tmp[out] = res;
+ }
+ memcpy (&out_data[n * outchannels], this->tmp,
+ sizeof (gint32) * outchannels);
+ }
+}
+#ifdef __SYMBIAN32__
+EXPORT_C
+#endif
+
+
+void
+gst_channel_mix_mix_float (AudioConvertCtx * this,
+ gdouble * in_data, gdouble * out_data, gint samples)
+{
+ gint in, out, n;
+ gdouble res;
+ gboolean backwards;
+ gint inchannels, outchannels;
+ gdouble *tmp = (gdouble *) this->tmp;
+
+ g_return_if_fail (this->matrix != NULL);
+ g_return_if_fail (this->tmp != NULL);
+
+ inchannels = this->in.channels;
+ outchannels = this->out.channels;
+ backwards = outchannels > inchannels;
+
+ /* FIXME: use liboil here? */
+ for (n = (backwards ? samples - 1 : 0); n < samples && n >= 0;
+ backwards ? n-- : n++) {
+ for (out = 0; out < outchannels; out++) {
+ /* convert */
+ res = 0.0;
+ for (in = 0; in < inchannels; in++) {
+ res += in_data[n * inchannels + in] * this->matrix[in][out];
+ }
+
+ /* clip (shouldn't we use doubles instead as intermediate format?) */
+ if (res < -1.0)
+ res = -1.0;
+ else if (res > 1.0)
+ res = 1.0;
+ tmp[out] = res;
+ }
+ memcpy (&out_data[n * outchannels], this->tmp,
+ sizeof (gdouble) * outchannels);
+ }
+}