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| | 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 | static 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 | |
| | 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 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 | |
| | 199 | static 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 | |
| | 233 | static 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 | |
| | 240 | const 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 */ |