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/*
* SBC parser
*
* Copyright (C) 2017 Aurelien Jacobs <aurel@gnuage.org>
*
* This file is part of FFmpeg.
*
* FFmpeg 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.
*
* FFmpeg 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 FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "sbc.h"
#include "parser.h"
typedef struct SBCParseContext {
ParseContext pc;
uint8_t header[3];
int header_size;
int buffered_size;
} SBCParseContext;
static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext *avctx,
const uint8_t *data, size_t len)
{
static const int sample_rates[4] = { 16000, 32000, 44100, 48000 };
int sr, blocks, mode, subbands, bitpool, channels, joint;
int length;
if (len < 3)
return -1;
if (data[0] == MSBC_SYNCWORD && data[1] == 0 && data[2] == 0) {
av_channel_layout_uninit(&avctx->ch_layout);
avctx->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC;
avctx->ch_layout.nb_channels = 1;
avctx->sample_rate = 16000;
avctx->frame_size = 120;
s->duration = avctx->frame_size;
return 57;
}
if (data[0] != SBC_SYNCWORD)
return -2;
sr = (data[1] >> 6) & 0x03;
blocks = (((data[1] >> 4) & 0x03) + 1) << 2;
mode = (data[1] >> 2) & 0x03;
subbands = (((data[1] >> 0) & 0x01) + 1) << 2;
bitpool = data[2];
channels = mode == SBC_MODE_MONO ? 1 : 2;
joint = mode == SBC_MODE_JOINT_STEREO;
length = 4 + (subbands * channels) / 2
+ ((((mode == SBC_MODE_DUAL_CHANNEL) + 1) * blocks * bitpool
+ (joint * subbands)) + 7) / 8;
av_channel_layout_uninit(&avctx->ch_layout);
avctx->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC;
avctx->ch_layout.nb_channels = channels;
avctx->sample_rate = sample_rates[sr];
avctx->frame_size = subbands * blocks;
s->duration = avctx->frame_size;
return length;
}
static int sbc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
SBCParseContext *pc = s->priv_data;
int next;
if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
next = buf_size;
} else {
if (pc->header_size) {
memcpy(pc->header + pc->header_size, buf,
sizeof(pc->header) - pc->header_size);
next = sbc_parse_header(s, avctx, pc->header, sizeof(pc->header))
- pc->buffered_size;
pc->header_size = 0;
} else {
next = sbc_parse_header(s, avctx, buf, buf_size);
if (next >= buf_size)
next = -1;
}
if (next < 0) {
pc->header_size = FFMIN(sizeof(pc->header), buf_size);
memcpy(pc->header, buf, pc->header_size);
pc->buffered_size = buf_size;
next = END_NOT_FOUND;
}
if (ff_combine_frame(&pc->pc, next, &buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
}
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
}
const AVCodecParser ff_sbc_parser = {
.codec_ids = { AV_CODEC_ID_SBC },
.priv_data_size = sizeof(SBCParseContext),
.parser_parse = sbc_parse,
.parser_close = ff_parse_close,
};
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