X-Git-Url: http://research.m1stereo.tv/gitweb?a=blobdiff_plain;f=src%2Fmodules%2Fcore%2Ffilter_mono.c;fp=src%2Fmodules%2Fcore%2Ffilter_mono.c;h=b11fd1f6dc6036705f2d3b888dfd24a7a1da2130;hb=63dc2f08b9ec162234aa8d6688bf56ec71349acb;hp=0000000000000000000000000000000000000000;hpb=7d16ff1b54da872cece55d06c72e2c45d5bec3e7;p=melted

diff --git a/src/modules/core/filter_mono.c b/src/modules/core/filter_mono.c
new file mode 100644
index 0000000..b11fd1f
--- /dev/null
+++ b/src/modules/core/filter_mono.c
@@ -0,0 +1,95 @@
+/*
+ * filter_mono.c -- mix all channels to a mono signal across n channels
+ * Copyright (C) 2003-2006 Ushodaya Enterprises Limited
+ * Author: Dan Dennedy <dan@dennedy.org>
+ *
+ * This program 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.
+ *
+ * This program 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 this program; if not, write to the Free Software Foundation,
+ * Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include "filter_mono.h"
+
+#include <framework/mlt_frame.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+/** Get the audio.
+*/
+
+static int filter_get_audio( mlt_frame frame, int16_t **buffer, mlt_audio_format *format, int *frequency, int *channels, int *samples )
+{
+	// Get the properties of the a frame
+	mlt_properties properties = MLT_FRAME_PROPERTIES( frame );
+	int channels_out = mlt_properties_get_int( properties, "mono.channels" );
+	int i, j, size;
+	int16_t *new_buffer;
+
+	// Get the producer's audio
+	mlt_frame_get_audio( frame, buffer, format, frequency, channels, samples );
+
+	size = *samples * channels_out * sizeof( int16_t );
+	new_buffer = mlt_pool_alloc( size );
+	mlt_properties_set_data( properties, "audio", new_buffer, size, ( mlt_destructor )mlt_pool_release, NULL );
+
+	// Mix
+	for ( i = 0; i < *samples; i++ )
+	{
+		int16_t mixdown = 0;
+		for ( j = 0; j < *channels; j++ )
+			mixdown += (*buffer)[ ( i * *channels ) + j ] / *channels;
+		for ( j = 0; j < channels_out; j++ )
+			new_buffer[ ( i * channels_out ) + j ] = mixdown;
+	}
+
+	// Apply results
+	*buffer = new_buffer;
+	*channels = channels_out;
+	
+	return 0;
+}
+
+/** Filter processing.
+*/
+
+static mlt_frame filter_process( mlt_filter this, mlt_frame frame )
+{
+	mlt_properties properties = MLT_FILTER_PROPERTIES( this );
+	mlt_properties frame_props = MLT_FRAME_PROPERTIES( frame );
+
+	// Propogate the parameters
+	mlt_properties_set_int( frame_props, "mono.channels", mlt_properties_get_int( properties, "channels" ) );
+
+	// Override the get_audio method
+	mlt_frame_push_audio( frame, filter_get_audio );
+
+	return frame;
+}
+
+/** Constructor for the filter.
+*/
+
+mlt_filter filter_mono_init( char *arg )
+{
+	mlt_filter this = mlt_filter_new( );
+	if ( this != NULL )
+	{
+		this->process = filter_process;
+		if ( arg != NULL )
+			mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "channels", atoi( arg ) );
+		else
+			mlt_properties_set_int( MLT_FILTER_PROPERTIES( this ), "channels", 2 );
+	}
+	return this;
+}