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avformat/lc3: add file format for LC3/LC3plus transport

A file format is described in Bluetooth SIG LC3 and ETSI TS 103 634, for test purpose.

Antoine SOULIER committed 2 years ago

Commit 257bc2a1 parent b2bc4ac5 files · +263 −0Browse files

Showing the changes to libavformat (3 of 5 files). Show all

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3 files
  1. libavformat/Makefile +2 −0
  2. libavformat/allformats.c +2 −0
  3. libavformat/lc3.c +252 −0
libavformat/Makefile+2−0
@@ -332,6 +332,8 @@ OBJS-$(CONFIG_KVAG_DEMUXER) += kvag.o · 331 unmodified lines
332OBJS-$(CONFIG_KVAG_MUXER) += kvag.o rawenc.o332OBJS-$(CONFIG_KVAG_MUXER) += kvag.o rawenc.o
333OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o333OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o
334OBJS-$(CONFIG_LATM_MUXER) += latmenc.o rawenc.o334OBJS-$(CONFIG_LATM_MUXER) += latmenc.o rawenc.o
335OBJS-$(CONFIG_LC3_DEMUXER) += lc3.o
336OBJS-$(CONFIG_LC3_MUXER) += lc3.o
335OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o337OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o
336OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o338OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o
337OBJS-$(CONFIG_LUODAT_DEMUXER) += luodatdec.o339OBJS-$(CONFIG_LUODAT_DEMUXER) += luodatdec.o
libavformat/allformats.c+2−0
@@ -252,6 +252,8 @@ extern const FFInputFormat ff_kvag_demuxer; · 251 unmodified lines
252extern const FFOutputFormat ff_kvag_muxer;252extern const FFOutputFormat ff_kvag_muxer;
253extern const FFInputFormat ff_laf_demuxer;253extern const FFInputFormat ff_laf_demuxer;
254extern const FFOutputFormat ff_latm_muxer;254extern const FFOutputFormat ff_latm_muxer;
255extern const FFInputFormat ff_lc3_demuxer;
256extern const FFOutputFormat ff_lc3_muxer;
255extern const FFInputFormat ff_lmlm4_demuxer;257extern const FFInputFormat ff_lmlm4_demuxer;
256extern const FFInputFormat ff_loas_demuxer;258extern const FFInputFormat ff_loas_demuxer;
257extern const FFInputFormat ff_luodat_demuxer;259extern const FFInputFormat ff_luodat_demuxer;
libavformat/lc3.c+252−0
@@ -0,0 +1,252 @@
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
46static 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
69typedef struct LC3DemuxContext {
70 int frame_samples;
71 int64_t end_dts;
72} LC3DemuxContext;
73
74static int lc3_read_probe(const AVProbeData *p)
75{
76 int frame_us, srate_hz;
77
78 if (p->buf_size < 12)
79 return 0;
80
81 if (AV_RB16(p->buf + 0) != 0x1ccc ||
82 AV_RL16(p->buf + 2) < 9 * sizeof(uint16_t))
83 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
93static 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
152static 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
174const 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
189static av_cold int lc3_muxer_init(AVFormatContext *s)
190{
191 if (s->nb_streams != 1) {
192 av_log(s, AV_LOG_ERROR, "This muxer only supports a single stream.\n");
193 return AVERROR(EINVAL);
194 }
195
196 return 0;
197}
198
199static int lc3_write_header(AVFormatContext *s)
200{
201 AVStream *st = s->streams[0];
202 int channels = st->codecpar->ch_layout.nb_channels;
203 int srate_hz = st->codecpar->sample_rate;
204 int bit_rate = st->codecpar->bit_rate;
205 int frame_us, ep_mode, hr_mode;
206 uint32_t nb_samples = av_rescale_q(
207 st->duration, st->time_base, (AVRational){ 1, srate_hz });
208
209 if (st->codecpar->extradata_size < 6)
210 return AVERROR_INVALIDDATA;
211
212 frame_us = AV_RL16(st->codecpar->extradata + 0) * 10;
213 ep_mode = AV_RL16(st->codecpar->extradata + 2) != 0;
214 hr_mode = AV_RL16(st->codecpar->extradata + 4) != 0;
215
216 if (check_frame_length(s, srate_hz, frame_us) < 0)
217 return AVERROR_INVALIDDATA;
218
219 avio_wb16(s->pb, 0x1ccc);
220 avio_wl16(s->pb, (9 + hr_mode) * sizeof(uint16_t));
221 avio_wl16(s->pb, srate_hz / 100);
222 avio_wl16(s->pb, bit_rate / 100);
223 avio_wl16(s->pb, channels);
224 avio_wl16(s->pb, frame_us / 10);
225 avio_wl16(s->pb, ep_mode);
226 avio_wl32(s->pb, nb_samples);
227 if (hr_mode)
228 avio_wl16(s->pb, hr_mode);
229
230 return 0;
231}
232
233static int lc3_write_packet(AVFormatContext *s, AVPacket *pkt)
234{
235 avio_wl16(s->pb, pkt->size);
236 avio_write(s->pb, pkt->data, pkt->size);
237 return 0;
238}
239
240const FFOutputFormat ff_lc3_muxer = {
241 .p.name = "lc3",
242 .p.long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity Communication Codec)"),
243 .p.extensions = "lc3",
244 .p.audio_codec = AV_CODEC_ID_LC3,
245 .p.video_codec = AV_CODEC_ID_NONE,
246 .p.flags = AVFMT_NOTIMESTAMPS,
247 .init = lc3_muxer_init,
248 .write_header = lc3_write_header,
249 .write_packet = lc3_write_packet,
250};
251
252#endif /* CONFIG_LC3_MUXER */

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