path: root/spxdec_filter.c

/* SPDX-License-Identifier: GPL-2.0 */

/** \file spxdec_filter.c Paraslash's ogg/speex decoder. */

/* This file is based on speexdec.c, by Jean-Marc Valin, see below. */

/* Copyright (C) 2002-2006 Jean-Marc Valin
   File: speexdec.c

   Redistribution and use in source and binary forms, with or without
   modification, are permitted provided that the following conditions
   are met:
   
   - Redistributions of source code must retain the above copyright
   notice, this list of conditions and the following disclaimer.
   
   - Redistributions in binary form must reproduce the above copyright
   notice, this list of conditions and the following disclaimer in the
   documentation and/or other materials provided with the distribution.
   
   - Neither the name of the Xiph.org Foundation nor the names of its
   contributors may be used to endorse or promote products derived from
   this software without specific prior written permission.
   
   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR
   CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
   EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
   PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
   PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
   LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
   NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <ogg/ogg.h>
#include <speex/speex.h>
#include <speex/speex_header.h>
#include <speex/speex_stereo.h>
#include <speex/speex_callbacks.h>

#include "para.h"
#include "portable_io.h"
#include "list.h"
#include "sched.h"
#include "buffer_tree.h"
#include "filter.h"
#include "error.h"
#include "string.h"
#include "spx.h"

/** Data specific to the speexdec filter. */
struct private_spxdec_data {
	/** Header information obtained from the first ogg packet. */
	struct spx_header_info shi;
	/** Read from and written to by the Speex routines. */
	SpeexBits bits;
	/* Ogg pages are retrieved from this structure. */
	ogg_sync_state oy;
	/** Extracted from header. */
	int speex_serialno;
	/** Total number of ogg packets retrieved so far. */
	int packet_count;
	/** Needed to find out how much to skip. */
	ogg_int64_t last_granule;
	/** Also needed for skipping packets. */
	int lookahead;
	/** The state information about the current stream. */
	ogg_stream_state os;
	/** Whether \a os is initialized. */
	bool stream_init;
};

static void spxdec_open(struct filter_node *fn)
{
	struct private_spxdec_data *psd = zalloc(sizeof(*psd));

	fn->private_data = psd;
	fn->min_iqs = 200;
	psd->speex_serialno = -1;
}

static void speexdec_close(struct filter_node *fn)
{
	struct private_spxdec_data *psd = fn->private_data;

	if (psd->shi.state) {
		/* Destroy the decoder state */
		speex_decoder_destroy(psd->shi.state);
		/* Destroy the bit-stream struct */
		speex_bits_destroy(&psd->bits);
		if (psd->stream_init)
			ogg_stream_clear(&psd->os);
		ogg_sync_clear(&psd->oy);
	}
	free(psd);
	fn->private_data = NULL;
}

static int speexdec_execute(const struct btr_node *btrn, const char *cmd,
		char **result)
{
	struct filter_node *fn = btr_context(btrn);
	struct private_spxdec_data *psd = fn->private_data;

	return decoder_execute(cmd, psd->shi.sample_rate, psd->shi.channels,
		result);
}

static int speexdec_init(struct filter_node *fn)
{
	struct private_spxdec_data *psd = fn->private_data;

	PARA_INFO_LOG("init\n");
	ogg_sync_init(&psd->oy);
	speex_bits_init(&psd->bits);
	return 1;
}

/**
 * Size of the output buffer.
 *
 * Valid streams have frame sizes in the range from 160 to 640. To avoid buffer
 * overflows, we bail out if the decoder reports a value bigger than this.
 */
#define MAX_FRAME_SIZE 2000

/* Copy Ogg packet to Speex bitstream */
static int speexdec_write_frames(int packet_no,
		struct private_spxdec_data *psd, int skip_samples,
		int page_nb_packets, struct btr_node *btrn)
{
	int i, j;

	for (j = 0; j != psd->shi.nframes; j++) {
		short output[MAX_FRAME_SIZE], *btr_output;
		int skip = skip_samples + psd->lookahead, skip_idx = 0;
		int samples, this_frame_size,
			new_frame_size = psd->shi.frame_size;

		if (speex_decoder_ctl(psd->shi.state, SPEEX_GET_FRAME_SIZE,
				&this_frame_size) == 0) {
			if (this_frame_size > MAX_FRAME_SIZE)
				return -E_SPX_DECODE_OVERFLOW;
		};

		if (speex_decode_int(psd->shi.state, &psd->bits, output) < 0)
			return -E_SPX_DECODE;
		if (speex_bits_remaining(&psd->bits) < 0)
			return -E_SPX_DECODE_OVERFLOW;
		if (psd->shi.channels == 2)
			speex_decode_stereo_int(output, psd->shi.frame_size,
				&psd->shi.stereo);
		if (packet_no == 1 && j == 0 && skip_samples > 0) {
			new_frame_size -= skip;
			skip_idx = skip * psd->shi.channels;
		}
		if (packet_no == page_nb_packets && skip_samples < 0) {
			new_frame_size = psd->shi.nframes * psd->shi.frame_size
				+ skip - j * psd->shi.frame_size;
			if (new_frame_size < 0)
				new_frame_size = 0;
			if (new_frame_size > psd->shi.frame_size)
				new_frame_size = psd->shi.frame_size;
		}
		if (new_frame_size <= 0)
			continue;
		samples = new_frame_size * psd->shi.channels;
		btr_output = arr_alloc(samples, 2);
		for (i = 0; i < samples; i++)
			btr_output[i] = read_u16(output + i + skip_idx);
		btr_add_output((char *)btr_output, samples * 2, btrn);
	}
	return 1;
}

/* Extract all available packets */
static int speexdec_extract_packets(struct private_spxdec_data *psd,
		ogg_stream_state *os, int skip_samples, int page_nb_packets,
		struct btr_node *btrn)
{
	int ret, packet_no;
	bool eos = false;

	for (packet_no = 0;; psd->packet_count++) {
		ogg_packet op;

		if (ogg_stream_packetout(os, &op) != 1)
			return 0;
		if (op.bytes >= 5 && !memcmp(op.packet, "Speex", 5))
			psd->speex_serialno = os->serialno;
		if (psd->speex_serialno == -1)
			return 0;
		if (os->serialno != psd->speex_serialno)
			return 0;
		/* If first packet, process as Speex header */
		if (psd->packet_count == 0) {
			ret = spx_process_header(op.packet, op.bytes, &psd->shi);
			if (ret < 0)
				return ret;
			ret = speex_decoder_ctl(psd->shi.state, SPEEX_GET_LOOKAHEAD,
				&psd->lookahead);
			if (ret < 0)
				return ret;
			if (!psd->shi.nframes)
				psd->shi.nframes = 1;
			PARA_INFO_LOG("frame size: %d\n", psd->shi.frame_size);
			continue;
		}
		if (psd->packet_count == 1) /* ignore comments */
			continue;
		if (psd->packet_count <= 1 + psd->shi.extra_headers)
			continue; /* Ignore extra headers */
		packet_no++;
		/* check end of stream condition */
		if (op.e_o_s && os->serialno == psd->speex_serialno)
			eos = true;
		speex_bits_read_from(&psd->bits, (char *)op.packet,
			op.bytes);
		ret = speexdec_write_frames(packet_no, psd,
			skip_samples, page_nb_packets, btrn);
		if (ret < 0)
			return ret;
		if (eos == true)
			return -E_SPX_EOS;
	}
}

static int compute_skip_samples(ogg_page *og, struct private_spxdec_data *psd)
{
	int ret, page_granule = ogg_page_granulepos(og);

	if (page_granule <= 0)
		return 0;
	if (psd->shi.frame_size == 0)
		return 0;
	ret = ogg_page_packets(og) * psd->shi.frame_size * psd->shi.nframes
		- page_granule + psd->last_granule;
	if (ogg_page_eos(og))
		ret = -ret;
	return ret;
}

static int speexdec_post_monitor(__a_unused struct sched *s, void *context)
{
	struct filter_node *fn = context;
	struct private_spxdec_data *psd = fn->private_data;
	struct btr_node *btrn = fn->btrn;
	int ret, ns;
	ogg_page og;
	char *btr_buf;
	size_t nbytes;

next_buffer:
	ret = ns = btr_node_status(btrn, fn->min_iqs, BTR_NT_INTERNAL);
	btr_merge(btrn, fn->min_iqs);
	if (!psd->shi.state) {
		if (ret <= 0)
			goto fail;
		ret = speexdec_init(fn);
		if (ret <= 0)
			goto fail;
	}
	nbytes = btr_next_buffer(btrn, &btr_buf);
	nbytes = PARA_MIN(nbytes, (size_t)200);
	if (nbytes > 0) {
		char *data = ogg_sync_buffer(&psd->oy, nbytes);
		memcpy(data, btr_buf, nbytes);
		btr_consume(btrn, nbytes);
		ogg_sync_wrote(&psd->oy, nbytes);
	}
	/* Loop for all complete pages we got */
	while (ogg_sync_pageout(&psd->oy, &og) == 1) {
		int skip_samples;

		if (psd->stream_init == false) {
			ogg_stream_init(&psd->os, ogg_page_serialno(&og));
			psd->stream_init = true;
		}
		if (ogg_page_serialno(&og) != psd->os.serialno)
			ogg_stream_reset_serialno(&psd->os, ogg_page_serialno(&og));
		/* Add page to the bitstream */
		ogg_stream_pagein(&psd->os, &og);
		skip_samples = compute_skip_samples(&og, psd);
		psd->last_granule = ogg_page_granulepos(&og);
		ret = speexdec_extract_packets(psd, &psd->os, skip_samples,
			ogg_page_packets(&og), btrn);
		if (ret < 0)
			goto fail;
	}
	if (ns > 0)
		goto next_buffer;
	ret = ns;
fail:
	if (ret < 0)
		btr_remove_node(&fn->btrn);
	return ret;
}

/** \cond doxygen_ignore */
const struct filter lsg_filter_cmd_com_spxdec_user_data = {
	.open = spxdec_open,
	.close = speexdec_close,
	.pre_monitor = generic_filter_pre_monitor,
	.post_monitor = speexdec_post_monitor,
	.execute = speexdec_execute,
};
/** \endcond */