1/*
2 * SBC parser
3 *
4 * Copyright (C) 2017  Aurelien Jacobs <aurel@gnuage.org>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#include "sbc.h"
24#include "parser.h"
25
26typedef struct SBCParseContext {
27    ParseContext pc;
28    uint8_t header[3];
29    int header_size;
30    int buffered_size;
31} SBCParseContext;
32
33static int sbc_parse_header(AVCodecParserContext *s, AVCodecContext *avctx,
34                            const uint8_t *data, size_t len)
35{
36    static const int sample_rates[4] = { 16000, 32000, 44100, 48000 };
37    int sr, blocks, mode, subbands, bitpool, channels, joint;
38    int length;
39
40    if (len < 3)
41        return -1;
42
43    if (data[0] == MSBC_SYNCWORD && data[1] == 0 && data[2] == 0) {
44        av_channel_layout_uninit(&avctx->ch_layout);
45        avctx->ch_layout.order       = AV_CHANNEL_ORDER_UNSPEC;
46        avctx->ch_layout.nb_channels = 1;
47        avctx->sample_rate = 16000;
48        avctx->frame_size = 120;
49        s->duration = avctx->frame_size;
50        return 57;
51    }
52
53    if (data[0] != SBC_SYNCWORD)
54        return -2;
55
56    sr       =   (data[1] >> 6) & 0x03;
57    blocks   = (((data[1] >> 4) & 0x03) + 1) << 2;
58    mode     =   (data[1] >> 2) & 0x03;
59    subbands = (((data[1] >> 0) & 0x01) + 1) << 2;
60    bitpool  = data[2];
61
62    channels = mode == SBC_MODE_MONO ? 1 : 2;
63    joint    = mode == SBC_MODE_JOINT_STEREO;
64
65    length = 4 + (subbands * channels) / 2
66             + ((((mode == SBC_MODE_DUAL_CHANNEL) + 1) * blocks * bitpool
67                 + (joint * subbands)) + 7) / 8;
68
69    av_channel_layout_uninit(&avctx->ch_layout);
70    avctx->ch_layout.order       = AV_CHANNEL_ORDER_UNSPEC;
71    avctx->ch_layout.nb_channels = channels;
72    avctx->sample_rate = sample_rates[sr];
73    avctx->frame_size = subbands * blocks;
74    s->duration = avctx->frame_size;
75    return length;
76}
77
78static int sbc_parse(AVCodecParserContext *s, AVCodecContext *avctx,
79                     const uint8_t **poutbuf, int *poutbuf_size,
80                     const uint8_t *buf, int buf_size)
81{
82    SBCParseContext *pc = s->priv_data;
83    int next;
84
85    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
86        next = buf_size;
87    } else {
88        if (pc->header_size) {
89            memcpy(pc->header + pc->header_size, buf,
90                   sizeof(pc->header) - pc->header_size);
91            next = sbc_parse_header(s, avctx, pc->header, sizeof(pc->header))
92                 - pc->buffered_size;
93            pc->header_size = 0;
94        } else {
95            next = sbc_parse_header(s, avctx, buf, buf_size);
96            if (next >= buf_size)
97                next = -1;
98        }
99
100        if (next < 0) {
101            pc->header_size = FFMIN(sizeof(pc->header), buf_size);
102            memcpy(pc->header, buf, pc->header_size);
103            pc->buffered_size = buf_size;
104            next = END_NOT_FOUND;
105        }
106
107        if (ff_combine_frame(&pc->pc, next, &buf, &buf_size) < 0) {
108            *poutbuf      = NULL;
109            *poutbuf_size = 0;
110            return buf_size;
111        }
112    }
113
114    *poutbuf      = buf;
115    *poutbuf_size = buf_size;
116    return next;
117}
118
119const AVCodecParser ff_sbc_parser = {
120    .codec_ids      = { AV_CODEC_ID_SBC },
121    .priv_data_size = sizeof(SBCParseContext),
122    .parser_parse   = sbc_parse,
123    .parser_close   = ff_parse_close,
124};
125