gstsbcparse.c

实现bluez蓝牙profile需要的库

/*
 *
 *  BlueZ - Bluetooth protocol stack for Linux
 *
 *  Copyright (C) 2004-2007  Marcel Holtmann <[e-mail]>
 *
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Lesser General Public
 *  License as published by the Free Software Foundation; either
 *  version 2.1 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
 *  Lesser General Public License for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public
 *  License along with this library; if not, write to the Free Software
 *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <string.h>

#include "gstsbcparse.h"

GST_DEBUG_CATEGORY_STATIC(sbc_parse_debug);
#define GST_CAT_DEFAULT sbc_parse_debug

GST_BOILERPLATE(GstSbcParse, gst_sbc_parse, GstElement, GST_TYPE_ELEMENT);

static const GstElementDetails sbc_parse_details =
	GST_ELEMENT_DETAILS("Bluetooth SBC parser",
				"Codec/Parser/Audio",
				"Parse a SBC audio stream",
				"Marcel Holtmann <[e-mail]>");

static GstStaticPadTemplate sbc_parse_sink_factory =
	GST_STATIC_PAD_TEMPLATE("sink", GST_PAD_SINK, GST_PAD_ALWAYS,
		GST_STATIC_CAPS("audio/x-sbc"));

static GstStaticPadTemplate sbc_parse_src_factory =
	GST_STATIC_PAD_TEMPLATE("src", GST_PAD_SRC, GST_PAD_ALWAYS,
		GST_STATIC_CAPS("audio/x-sbc, "
				"rate = (int) { 16000, 32000, 44100, 48000 }, "
				"channels = (int) [ 1, 2 ], "
				"mode = (string) { mono, dual, stereo, joint }, "
				"blocks = (int) { 4, 8, 12, 16 }, "
				"subbands = (int) { 4, 8 }, "
				"allocation = (string) { snr, loudness }"));

static GstFlowReturn sbc_parse_chain(GstPad *pad, GstBuffer *buffer)
{
	GstSbcParse *parse = GST_SBC_PARSE(gst_pad_get_parent(pad));
	GstFlowReturn res = GST_FLOW_OK;
	guint size, offset = 0;
	guint8 *data;
	GstClockTime timestamp;

	timestamp = GST_BUFFER_TIMESTAMP(buffer);

	if (parse->buffer) {
		GstBuffer *temp = buffer;
		buffer = gst_buffer_span(parse->buffer, 0, buffer,
			GST_BUFFER_SIZE(parse->buffer) + GST_BUFFER_SIZE(buffer));
		gst_buffer_unref(temp);
		gst_buffer_unref(parse->buffer);
		parse->buffer = NULL;
	}

	data = GST_BUFFER_DATA(buffer);
	size = GST_BUFFER_SIZE(buffer);

	while (offset < size) {
		GstBuffer *output;
		GstPadTemplate *template;
		GstCaps *caps, *temp;
		int consumed;

		consumed = sbc_parse(&parse->sbc, data + offset, size - offset);
		if (consumed <= 0)
			break;

		caps = gst_caps_new_simple("audio/x-sbc",
				"rate", G_TYPE_INT, parse->sbc.rate,
				"channels", G_TYPE_INT, parse->sbc.channels,
				NULL);

		template = gst_static_pad_template_get(&sbc_parse_src_factory);

		temp = gst_caps_intersect(caps,
					gst_pad_template_get_caps(template));

		gst_caps_unref(caps);

		res = gst_pad_alloc_buffer_and_set_caps(parse->srcpad,
						GST_BUFFER_OFFSET_NONE,
						consumed, temp, &output);

		gst_caps_unref(temp);

		if (res != GST_FLOW_OK)
			goto done;

		memcpy(GST_BUFFER_DATA(output), data + offset, consumed);

		res = gst_pad_push(parse->srcpad, output);
		if (res != GST_FLOW_OK)
			goto done;

		offset += consumed;
	}

	if (offset < size)
		parse->buffer = gst_buffer_create_sub(buffer,
							offset, size - offset);

done:
	gst_buffer_unref(buffer);
	gst_object_unref(parse);

	return res;
}

static GstStateChangeReturn sbc_parse_change_state(GstElement *element,
						GstStateChange transition)
{
	GstSbcParse *parse = GST_SBC_PARSE(element);

	switch (transition) {
	case GST_STATE_CHANGE_READY_TO_PAUSED:
		GST_DEBUG("Setup subband codec");
		if (parse->buffer) {
			gst_buffer_unref(parse->buffer);
			parse->buffer = NULL;
		}
		sbc_init(&parse->sbc, 0);
		break;

	case GST_STATE_CHANGE_PAUSED_TO_READY:
		GST_DEBUG("Finish subband codec");
		if (parse->buffer) {
			gst_buffer_unref(parse->buffer);
			parse->buffer = NULL;
		}
		sbc_finish(&parse->sbc);
		break;

	default:
		break;
	}

	return parent_class->change_state(element, transition);
}

static void gst_sbc_parse_base_init(gpointer g_class)
{
	GstElementClass *element_class = GST_ELEMENT_CLASS(g_class);

	gst_element_class_add_pad_template(element_class,
		gst_static_pad_template_get(&sbc_parse_sink_factory));

	gst_element_class_add_pad_template(element_class,
		gst_static_pad_template_get(&sbc_parse_src_factory));

	gst_element_class_set_details(element_class, &sbc_parse_details);
}

static void gst_sbc_parse_class_init(GstSbcParseClass *klass)
{
	GstElementClass *element_class = GST_ELEMENT_CLASS(klass);

	parent_class = g_type_class_peek_parent(klass);

	element_class->change_state = GST_DEBUG_FUNCPTR(sbc_parse_change_state);

	GST_DEBUG_CATEGORY_INIT(sbc_parse_debug, "sbcparse", 0,
						"SBC parsing element");
}

static void gst_sbc_parse_init(GstSbcParse *self, GstSbcParseClass *klass)
{
	self->sinkpad = gst_pad_new_from_static_template(&sbc_parse_sink_factory, "sink");
	gst_pad_set_chain_function(self->sinkpad, GST_DEBUG_FUNCPTR(sbc_parse_chain));
	gst_element_add_pad(GST_ELEMENT(self), self->sinkpad);

	self->srcpad = gst_pad_new_from_static_template(&sbc_parse_src_factory, "src");
	gst_element_add_pad(GST_ELEMENT(self), self->srcpad);
}