vector.c

/*
 *	Quadrature polar to vector conversion filter.
 *
 *	Copyright Jeroen Vreeken (pe1rxq@amsat.org), 2005
 *
 *	This software 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.
 */

#include "gstiq.h"
#include <string.h>
#include <math.h>

static GstElementDetails iqvector_details = GST_ELEMENT_DETAILS(
	"Quadrature Polar to Vector conversion",
	"Filter/Effect/Audio",
	"Converts a polar Quadrature signal to vector representation",
	"Jeroen Vreeken (pe1rxq@amsat.org)"
);

static GstStaticPadTemplate sink_template = GST_STATIC_PAD_TEMPLATE(
	"sink",
	GST_PAD_SINK,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS(
		"audio/x-polar-float, "
		"endianness = (int) BYTE_ORDER, "
		"depth = (int) 64, "
		"width = (int) 64, "
		"rate = (int) [ 1, MAX ], "
		"channels = (int) 1"
	)
);

static GstStaticPadTemplate src_template = GST_STATIC_PAD_TEMPLATE(
	"src",
	GST_PAD_SRC,
	GST_PAD_ALWAYS,
	GST_STATIC_CAPS(
		"audio/x-complex-float, "
		"endianness = (int) BYTE_ORDER, "
		"depth = (int) 64, "
		"width = (int) 64, "
		"rate = (int) [ 1, MAX ], "
		"channels = (int) 1"
	)
);

static GstElementClass *parent_class = NULL;

static GstFlowReturn gst_iqvector_chain(GstPad *pad, GstBuffer *buf)
{
	Gst_iqvector *vector;
	GstCaps *caps;
	GstBuffer *outbuf;
	gfloat *iqbufout, *iqbuf, ival, qval;
	int i;

	vector = GST_IQVECTOR(gst_pad_get_parent(pad));

	if (!gst_buffer_is_writable(buf)) {
		outbuf = gst_buffer_new_and_alloc(GST_BUFFER_SIZE(buf));
		GST_BUFFER_TIMESTAMP(outbuf) = GST_BUFFER_TIMESTAMP(buf);
		GST_BUFFER_OFFSET(outbuf) = GST_BUFFER_OFFSET(buf);
	} else
		outbuf = buf;
	iqbuf = (gfloat *)GST_BUFFER_DATA(buf);
	iqbufout = (gfloat *)GST_BUFFER_DATA(outbuf);
	for (i = 0; i < GST_BUFFER_SIZE(outbuf)/sizeof(gfloat); i += 2) {
		ival = iqbuf[i];
		qval = iqbuf[i+1];
		
		iqbufout[i+1] = cos(qval) * ival;
		iqbufout[i+0] = sin(qval) * ival;
	}
	if (buf != outbuf)
		gst_buffer_unref(buf);
	caps = gst_pad_get_caps(vector->srcpad);
	gst_buffer_set_caps(outbuf, caps);
	gst_caps_unref(caps);
	gst_pad_push(vector->srcpad, outbuf);
	gst_object_unref(vector);
	return GST_FLOW_OK;
}

static GstStateChangeReturn gst_iqvector_change_state(GstElement *element,
    GstStateChange transition)
{
	return parent_class->change_state(element, transition);
}

static gboolean gst_iqvector_setcaps(GstPad *pad, GstCaps *caps)
{
	Gst_iqvector *vector;
	GstCaps *newcaps;
	GstStructure *structure;
	GstPad *other;
	gint rate;

	vector = GST_IQVECTOR(gst_pad_get_parent(pad));
	other = pad == vector->srcpad ? vector->sinkpad : vector->srcpad;
	structure = gst_caps_get_structure(caps, 0);
	gst_structure_get_int(structure, "rate", &rate);
	newcaps = gst_pad_get_caps(other);
	newcaps = gst_caps_make_writable(newcaps);
	structure = gst_caps_get_structure(newcaps, 0);
	gst_structure_set(structure, "rate", G_TYPE_INT, rate, NULL);
	
	gst_pad_use_fixed_caps(other);
	gst_object_unref(vector);
	return gst_pad_set_caps(other, newcaps);
}

static void gst_iqvector_class_init(Gst_iqvector_class *klass)
{
	GObjectClass *gobject_class;
	GstElementClass *gstelement_class;

	gobject_class = (GObjectClass *) klass;
	gstelement_class = (GstElementClass *) klass;

	parent_class = g_type_class_ref(GST_TYPE_ELEMENT);

	gstelement_class->change_state = gst_iqvector_change_state;

	gst_element_class_set_details(gstelement_class, &iqvector_details);

	gst_element_class_add_pad_template(gstelement_class,
	    gst_static_pad_template_get(&sink_template));
	gst_element_class_add_pad_template(gstelement_class,
	    gst_static_pad_template_get(&src_template));
}

static void gst_iqvector_init(Gst_iqvector *vector)
{
	vector->sinkpad = gst_pad_new_from_template(
	    gst_static_pad_template_get (&sink_template), "sink");

	gst_pad_set_chain_function (vector->sinkpad, gst_iqvector_chain);
	gst_element_add_pad (GST_ELEMENT(vector), vector->sinkpad);

	vector->srcpad = gst_pad_new_from_template(
	    gst_static_pad_template_get(&src_template), "src");
	gst_element_add_pad(GST_ELEMENT(vector), vector->srcpad);

	gst_pad_set_setcaps_function(vector->srcpad, gst_iqvector_setcaps);
	gst_pad_set_setcaps_function(vector->sinkpad, gst_iqvector_setcaps);
}

GType gst_iqvector_get_type(void)
{
	static GType iqvector_type = 0;

	if (!iqvector_type) {
		static const GTypeInfo iqvector_info = {
			sizeof(Gst_iqvector_class),
			NULL,
			NULL,
			(GClassInitFunc)gst_iqvector_class_init,
			NULL,
			NULL,
			sizeof(Gst_iqvector),
			0,
			(GInstanceInitFunc)gst_iqvector_init,
		};
		iqvector_type = g_type_register_static(GST_TYPE_ELEMENT,
		    "GstIQVector", &iqvector_info, 0);
	}
	return iqvector_type;
}