FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavformat/lc3.c
Date: 2026-09-24 20:08:24
Exec Total Coverage
Lines: 4 103 3.9%
Functions: 1 6 16.7%
Branches: 2 62 3.2%

Line Branch Exec Source
1 /*
2 * LC3 muxer and demuxer
3 * Copyright (C) 2024 Antoine Soulier <asoulier@google.com>
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 /**
23 * @file
24 * Based on the file format specified by :
25 *
26 * - Bluetooth SIG - Low Complexity Communication Codec Test Suite
27 * https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=502301
28 * 3.2.8.2 Reference LC3 Codec Bitstream Format
29 *
30 * - ETSI TI 103 634 V1.4.1 - Low Complexity Communication Codec plus
31 * https://www.etsi.org/deliver/etsi_ts/103600_103699/103634/01.04.01_60/ts_103634v010401p.pdf
32 * LC3plus conformance script package
33 */
34
35 #include "config_components.h"
36
37 #include "libavcodec/packet.h"
38 #include "libavutil/intreadwrite.h"
39
40 #include "avformat.h"
41 #include "avio.h"
42 #include "demux.h"
43 #include "internal.h"
44 #include "mux.h"
45
46 ✗ static int check_frame_length(void *avcl, int srate_hz, int frame_us)
47 {
48 ✗ if (srate_hz != 8000 && srate_hz != 16000 && srate_hz != 24000 &&
49 ✗ srate_hz != 32000 && srate_hz != 48000 && srate_hz != 96000) {
50 ✗ if (avcl)
51 ✗ av_log(avcl, AV_LOG_ERROR,
52 "Invalid LC3 sample rate: %d Hz.\n", srate_hz);
53 ✗ return -1;
54 }
55
56 ✗ if (frame_us != 2500 && frame_us != 5000 &&
57 ✗ frame_us != 7500 && frame_us != 10000) {
58 ✗ if (avcl)
59 ✗ av_log(avcl, AV_LOG_ERROR,
60 ✗ "Invalid LC3 frame duration: %.1f ms.\n", frame_us / 1000.f);
61 ✗ return -1;
62 }
63
64 ✗ return 0;
65 }
66
67 #if CONFIG_LC3_DEMUXER
68
69 typedef struct LC3DemuxContext {
70 int frame_samples;
71 int64_t end_dts;
72 } LC3DemuxContext;
73
74 8064 static int lc3_read_probe(const AVProbeData *p)
75 {
76 int frame_us, srate_hz;
77
78
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8064 if (p->buf_size < 12)
79 ✗ return 0;
80
81
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8064 if (AV_RB16(p->buf + 0) != 0x1ccc ||
82 ✗ AV_RL16(p->buf + 2) < 9 * sizeof(uint16_t))
83 8064 return 0;
84
85 ✗ srate_hz = AV_RL16(p->buf + 4) * 100;
86 ✗ frame_us = AV_RL16(p->buf + 10) * 10;
87 ✗ if (check_frame_length(NULL, srate_hz, frame_us) < 0)
88 ✗ return 0;
89
90 ✗ return AVPROBE_SCORE_MAX;
91 }
92
93 ✗ static int lc3_read_header(AVFormatContext *s)
94 {
95 ✗ LC3DemuxContext *lc3 = s->priv_data;
96 ✗ AVStream *st = NULL;
97 uint16_t tag, hdr_size;
98 uint32_t length;
99 int srate_hz, frame_us, channels, bit_rate;
100 int ep_mode, hr_mode;
101 int num_extra_params;
102 int delay, ret;
103
104 ✗ tag = avio_rb16(s->pb);
105 ✗ hdr_size = avio_rl16(s->pb);
106
107 ✗ if (tag != 0x1ccc || hdr_size < 9 * sizeof(uint16_t))
108 ✗ return AVERROR_INVALIDDATA;
109
110 ✗ num_extra_params = hdr_size / sizeof(uint16_t) - 9;
111
112 ✗ srate_hz = avio_rl16(s->pb) * 100;
113 ✗ bit_rate = avio_rl16(s->pb) * 100;
114 ✗ channels = avio_rl16(s->pb);
115 ✗ frame_us = avio_rl16(s->pb) * 10;
116 ✗ ep_mode = avio_rl16(s->pb) != 0;
117 ✗ length = avio_rl32(s->pb);
118 ✗ hr_mode = num_extra_params >= 1 && avio_rl16(s->pb);
119
120 ✗ if (check_frame_length(s, srate_hz, frame_us) < 0)
121 ✗ return AVERROR_INVALIDDATA;
122
123 ✗ st = avformat_new_stream(s, NULL);
124 ✗ if (!st)
125 ✗ return AVERROR(ENOMEM);
126
127 ✗ avpriv_set_pts_info(st, 64, 1, srate_hz);
128 ✗ avpriv_update_cur_dts(s, st, 0);
129 ✗ st->duration = length;
130
131 ✗ st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
132 ✗ st->codecpar->codec_id = AV_CODEC_ID_LC3;
133 ✗ st->codecpar->sample_rate = srate_hz;
134 ✗ st->codecpar->bit_rate = bit_rate;
135 ✗ st->codecpar->ch_layout.nb_channels = channels;
136
137 ✗ if ((ret = ff_alloc_extradata(st->codecpar, 6)) < 0)
138 ✗ return ret;
139
140 ✗ AV_WL16(st->codecpar->extradata + 0, frame_us / 10);
141 ✗ AV_WL16(st->codecpar->extradata + 2, ep_mode);
142 ✗ AV_WL16(st->codecpar->extradata + 4, hr_mode);
143
144 ✗ lc3->frame_samples = av_rescale(frame_us, srate_hz, 1000*1000);
145
146 ✗ delay = av_rescale(frame_us == 7500 ? 4000 : 2500, srate_hz, 1000*1000);
147 ✗ lc3->end_dts = length ? length + delay : -1;
148
149 ✗ return 0;
150 }
151
152 ✗ static int lc3_read_packet(AVFormatContext *s, AVPacket *pkt)
153 {
154 ✗ LC3DemuxContext *lc3 = s->priv_data;
155 ✗ AVStream *st = s->streams[0];
156 ✗ AVIOContext *pb = s->pb;
157 ✗ int64_t pos = avio_tell(pb);
158 int64_t remaining_samples;
159 int ret;
160
161 ✗ ret = av_get_packet(s->pb, pkt, avio_rl16(pb));
162 ✗ if (ret < 0)
163 ✗ return ret;
164
165 ✗ pkt->pos = pos;
166
167 ✗ remaining_samples = lc3->end_dts < 0 ? lc3->frame_samples :
168 ✗ FFMAX(lc3->end_dts - ffstream(st)->cur_dts, 0);
169 ✗ pkt->duration = FFMIN(lc3->frame_samples, remaining_samples);
170
171 ✗ return 0;
172 }
173
174 const FFInputFormat ff_lc3_demuxer = {
175 .p.name = "lc3",
176 .p.long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity Communication Codec)"),
177 .p.extensions = "lc3",
178 .p.flags = AVFMT_GENERIC_INDEX,
179 .priv_data_size = sizeof(LC3DemuxContext),
180 .read_probe = lc3_read_probe,
181 .read_header = lc3_read_header,
182 .read_packet = lc3_read_packet,
183 };
184
185 #endif /* CONFIG_LC3_DEMUXER */
186
187 #if CONFIG_LC3_MUXER
188
189 ✗ static int lc3_write_header(AVFormatContext *s)
190 {
191 ✗ AVStream *st = s->streams[0];
192 ✗ int channels = st->codecpar->ch_layout.nb_channels;
193 ✗ int srate_hz = st->codecpar->sample_rate;
194 ✗ int bit_rate = st->codecpar->bit_rate;
195 int frame_us, ep_mode, hr_mode;
196 ✗ uint32_t nb_samples = av_rescale_q(
197 ✗ st->duration, st->time_base, (AVRational){ 1, srate_hz });
198
199 ✗ if (st->codecpar->extradata_size < 6)
200 ✗ return AVERROR_INVALIDDATA;
201
202 ✗ frame_us = AV_RL16(st->codecpar->extradata + 0) * 10;
203 ✗ ep_mode = AV_RL16(st->codecpar->extradata + 2) != 0;
204 ✗ hr_mode = AV_RL16(st->codecpar->extradata + 4) != 0;
205
206 ✗ if (check_frame_length(s, srate_hz, frame_us) < 0)
207 ✗ return AVERROR_INVALIDDATA;
208
209 ✗ avio_wb16(s->pb, 0x1ccc);
210 ✗ avio_wl16(s->pb, (9 + hr_mode) * sizeof(uint16_t));
211 ✗ avio_wl16(s->pb, srate_hz / 100);
212 ✗ avio_wl16(s->pb, bit_rate / 100);
213 ✗ avio_wl16(s->pb, channels);
214 ✗ avio_wl16(s->pb, frame_us / 10);
215 ✗ avio_wl16(s->pb, ep_mode);
216 ✗ avio_wl32(s->pb, nb_samples);
217 ✗ if (hr_mode)
218 ✗ avio_wl16(s->pb, hr_mode);
219
220 ✗ return 0;
221 }
222
223 ✗ static int lc3_write_packet(AVFormatContext *s, AVPacket *pkt)
224 {
225 ✗ avio_wl16(s->pb, pkt->size);
226 ✗ avio_write(s->pb, pkt->data, pkt->size);
227 ✗ return 0;
228 }
229
230 const FFOutputFormat ff_lc3_muxer = {
231 .p.name = "lc3",
232 .p.long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity Communication Codec)"),
233 .p.extensions = "lc3",
234 .p.audio_codec = AV_CODEC_ID_LC3,
235 .p.video_codec = AV_CODEC_ID_NONE,
236 .p.subtitle_codec = AV_CODEC_ID_NONE,
237 .p.flags = AVFMT_NOTIMESTAMPS,
238 .flags_internal = FF_OFMT_FLAG_MAX_ONE_OF_EACH |
239 FF_OFMT_FLAG_ONLY_DEFAULT_CODECS,
240 .write_header = lc3_write_header,
241 .write_packet = lc3_write_packet,
242 };
243
244 #endif /* CONFIG_LC3_MUXER */
245