125 lines
3.9 KiB
C
125 lines
3.9 KiB
C
/*
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* SBC parser
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*
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* Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org>
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "sbc.h"
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#include "parser.h"
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typedef struct SBCParseContext {
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ParseContext pc;
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uint8_t header[3];
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int header_size;
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int buffered_size;
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} SBCParseContext;
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static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext *avctx,
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const uint8_t *data, size_t len)
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{
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static const int sample_rates[4] = { 16000, 32000, 44100, 48000 };
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int sr, blocks, mode, subbands, bitpool, channels, joint;
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int length;
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if (len < 3)
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return -1;
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if (data[0] == MSBC_SYNCWORD && data[1] == 0 && data[2] == 0) {
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av_channel_layout_uninit(&avctx->ch_layout);
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avctx->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC;
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avctx->ch_layout.nb_channels = 1;
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avctx->sample_rate = 16000;
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avctx->frame_size = 120;
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s->duration = avctx->frame_size;
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return 57;
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}
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if (data[0] != SBC_SYNCWORD)
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return -2;
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sr = (data[1] >> 6) & 0x03;
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blocks = (((data[1] >> 4) & 0x03) + 1) << 2;
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mode = (data[1] >> 2) & 0x03;
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subbands = (((data[1] >> 0) & 0x01) + 1) << 2;
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bitpool = data[2];
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channels = mode == SBC_MODE_MONO ? 1 : 2;
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joint = mode == SBC_MODE_JOINT_STEREO;
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length = 4 + (subbands * channels) / 2
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+ ((((mode == SBC_MODE_DUAL_CHANNEL) + 1) * blocks * bitpool
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+ (joint * subbands)) + 7) / 8;
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av_channel_layout_uninit(&avctx->ch_layout);
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avctx->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC;
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avctx->ch_layout.nb_channels = channels;
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avctx->sample_rate = sample_rates[sr];
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avctx->frame_size = subbands * blocks;
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s->duration = avctx->frame_size;
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return length;
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}
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static int sbc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
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const uint8_t **poutbuf, int *poutbuf_size,
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const uint8_t *buf, int buf_size)
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{
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SBCParseContext *pc = s->priv_data;
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int next;
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if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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next = buf_size;
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} else {
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if (pc->header_size) {
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memcpy(pc->header + pc->header_size, buf,
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sizeof(pc->header) - pc->header_size);
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next = sbc_parse_header(s, avctx, pc->header, sizeof(pc->header))
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- pc->buffered_size;
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pc->header_size = 0;
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} else {
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next = sbc_parse_header(s, avctx, buf, buf_size);
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if (next >= buf_size)
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next = -1;
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}
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if (next < 0) {
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pc->header_size = FFMIN(sizeof(pc->header), buf_size);
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memcpy(pc->header, buf, pc->header_size);
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pc->buffered_size = buf_size;
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next = END_NOT_FOUND;
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}
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if (ff_combine_frame(&pc->pc, next, &buf, &buf_size) < 0) {
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*poutbuf = NULL;
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*poutbuf_size = 0;
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return buf_size;
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}
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}
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*poutbuf = buf;
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*poutbuf_size = buf_size;
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return next;
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}
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const AVCodecParser ff_sbc_parser = {
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.codec_ids = { AV_CODEC_ID_SBC },
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.priv_data_size = sizeof(SBCParseContext),
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.parser_parse = sbc_parse,
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.parser_close = ff_parse_close,
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};
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