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
26 typedef struct SBCParseContext {
27 ParseContext pc;
28 uint8_t header[3];
29 int header_size;
30 int buffered_size;
31 } SBCParseContext;
32
sbc_parse_header(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t * data,size_t len)33 static 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
sbc_parse(AVCodecParserContext * s,AVCodecContext * avctx,const uint8_t ** poutbuf,int * poutbuf_size,const uint8_t * buf,int buf_size)78 static 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
119 const 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