[FFmpeg-devel] [PATCH] avformat/lc3: Add file format for LC3/LC3plus transport
Antoine Soulier
asoulier at google.com
Wed Apr 10 20:41:39 EEST 2024
Sorry for that, I missed the rebasing.
I have followed your recommendations, and put the muxer/demuxer in the same
file.
Here is the patch:
>From f85989288a99130eb3583d5ae9c5bf441e961ed4 Mon Sep 17 00:00:00 2001
From: Antoine SOULIER <asoulier at google.com>
Date: Thu, 4 Apr 2024 22:38:03 +0000
Subject: [PATCH] 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. This is the format implemented here.
---
Changelog | 1 +
doc/muxers.texi | 8 ++
libavformat/Makefile | 2 +
libavformat/allformats.c | 2 +
libavformat/lc3.c | 248 +++++++++++++++++++++++++++++++++++++++
5 files changed, 261 insertions(+)
create mode 100644 libavformat/lc3.c
diff --git a/Changelog b/Changelog
index b7a1af4083..5c8f505211 100644
--- a/Changelog
+++ b/Changelog
@@ -5,6 +5,7 @@ version <next>:
- Raw Captions with Time (RCWT) closed caption demuxer
- LC3/LC3plus decoding/encoding using external library liblc3
- ffmpeg CLI filtergraph chaining
+- LC3/LC3plus demuxer and muxer
version 7.0:
diff --git a/doc/muxers.texi b/doc/muxers.texi
index 4b30970b78..032f48410e 100644
--- a/doc/muxers.texi
+++ b/doc/muxers.texi
@@ -2703,6 +2703,14 @@ This muxer accepts a single audio stream containing
PCM data.
@section ivf
On2 IVF muxer.
+ at section lc3
+Bluetooth SIG Low Complexity Communication Codec audio (LC3), or
+ETSI TS 103 634 Low Complexity Communication Codec plus (LC3plus).
+
+This muxer accepts a single @code{lc3} audio stream.
+
+ at section matroska
+
IVF was developed by On2 Technologies (formerly known as Duck
Corporation), to store internally developed codecs.
diff --git a/libavformat/Makefile b/libavformat/Makefile
index 9981799cc9..8efe26b6df 100644
--- a/libavformat/Makefile
+++ b/libavformat/Makefile
@@ -332,6 +332,8 @@ OBJS-$(CONFIG_KVAG_DEMUXER) += kvag.o
OBJS-$(CONFIG_KVAG_MUXER) += kvag.o rawenc.o
OBJS-$(CONFIG_LAF_DEMUXER) += lafdec.o
OBJS-$(CONFIG_LATM_MUXER) += latmenc.o rawenc.o
+OBJS-$(CONFIG_LC3_DEMUXER) += lc3.o
+OBJS-$(CONFIG_LC3_MUXER) += lc3.o
OBJS-$(CONFIG_LMLM4_DEMUXER) += lmlm4.o
OBJS-$(CONFIG_LOAS_DEMUXER) += loasdec.o rawdec.o
OBJS-$(CONFIG_LUODAT_DEMUXER) += luodatdec.o
diff --git a/libavformat/allformats.c b/libavformat/allformats.c
index ae925dcf60..305fa46532 100644
--- a/libavformat/allformats.c
+++ b/libavformat/allformats.c
@@ -252,6 +252,8 @@ extern const FFInputFormat ff_kvag_demuxer;
extern const FFOutputFormat ff_kvag_muxer;
extern const FFInputFormat ff_laf_demuxer;
extern const FFOutputFormat ff_latm_muxer;
+extern const FFInputFormat ff_lc3_demuxer;
+extern const FFOutputFormat ff_lc3_muxer;
extern const FFInputFormat ff_lmlm4_demuxer;
extern const FFInputFormat ff_loas_demuxer;
extern const FFInputFormat ff_luodat_demuxer;
diff --git a/libavformat/lc3.c b/libavformat/lc3.c
new file mode 100644
index 0000000000..8b1ec62589
--- /dev/null
+++ b/libavformat/lc3.c
@@ -0,0 +1,248 @@
+/*
+ * LC3 demuxer
+ * Copyright (C) 2024 Antoine Soulier <asoulier at google.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
02110-1301 USA
+ */
+
+/**
+ * @file
+ * Based on the file format specified by :
+ *
+ * - Bluetooth SIG - Low Complexity Communication Codec Test Suite
+ *
https://www.bluetooth.org/docman/handlers/downloaddoc.ashx?doc_id=502301
+ * 3.2.8.2 Reference LC3 Codec Bitstream Format
+ *
+ * - ETSI TI 103 634 V1.4.1 - Low Complexity Communication Codec plus
+ *
https://www.etsi.org/deliver/etsi_ts/103600_103699/103634/01.04.01_60/ts_103634v010401p.pdf
+ * LC3plus conformance script package
+ */
+
+#include "config_components.h"
+
+#include "libavcodec/packet.h"
+#include "libavutil/intreadwrite.h"
+
+#include "avformat.h"
+#include "avio.h"
+#include "demux.h"
+#include "internal.h"
+#include "mux.h"
+
+typedef struct LC3DemuxContext {
+ int frame_samples;
+ int64_t end_dts;
+} LC3DemuxContext;
+
+static int check_frame_length(int srate_hz, int frame_us)
+{
+ if (srate_hz != 8000 && srate_hz != 16000 && srate_hz != 24000 &&
+ srate_hz != 32000 && srate_hz != 48000 && srate_hz != 96000)
+ return -1;
+
+ if (frame_us != 2500 && frame_us != 5000 &&
+ frame_us != 7500 && frame_us != 10000)
+ return -1;
+
+ return 0;
+}
+
+static int lc3_read_probe(const AVProbeData *p)
+{
+ int frame_us, srate_hz;
+
+ if (p->buf_size < 12)
+ return 0;
+
+ if (AV_RB16(p->buf + 0) != 0x1ccc ||
+ AV_RL16(p->buf + 2) < 9 * sizeof(uint16_t))
+ return 0;
+
+ srate_hz = AV_RL16(p->buf + 4) * 100;
+ frame_us = AV_RL16(p->buf + 10) * 10;
+ if (check_frame_length(srate_hz, frame_us) < 0)
+ return 0;
+
+ return AVPROBE_SCORE_MAX;
+}
+
+static int lc3_read_header(AVFormatContext *s)
+{
+ LC3DemuxContext *lc3 = s->priv_data;
+ AVStream *st = NULL;
+ uint16_t tag, hdr_size;
+ uint32_t length;
+ int srate_hz, frame_us, channels, bit_rate;
+ int ep_mode, hr_mode;
+ int num_extra_params;
+ int delay, ret;
+
+ tag = avio_rb16(s->pb);
+ hdr_size = avio_rl16(s->pb);
+
+ if (tag != 0x1ccc || hdr_size < 9 * sizeof(uint16_t))
+ return AVERROR_INVALIDDATA;
+
+ num_extra_params = hdr_size / sizeof(uint16_t) - 9;
+
+ srate_hz = avio_rl16(s->pb) * 100;
+ bit_rate = avio_rl16(s->pb) * 100;
+ channels = avio_rl16(s->pb);
+ frame_us = avio_rl16(s->pb) * 10;
+ ep_mode = avio_rl16(s->pb) != 0;
+ length = avio_rl32(s->pb);
+ hr_mode = num_extra_params >= 1 && avio_rl16(s->pb);
+
+ if (check_frame_length(srate_hz, frame_us) < 0) {
+ av_log(s, AV_LOG_ERROR, "Invalid LC3 sample rate: %d Hz, "
+ "frame duration: %.1f ms.\n",
+ srate_hz, frame_us / 1000.f);
+ return AVERROR_INVALIDDATA;
+ }
+
+ st = avformat_new_stream(s, NULL);
+ if (!st)
+ return AVERROR(ENOMEM);
+
+ avpriv_set_pts_info(st, 64, 1, srate_hz);
+ avpriv_update_cur_dts(s, st, 0);
+ st->duration = length;
+
+ st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
+ st->codecpar->codec_id = AV_CODEC_ID_LC3;
+ st->codecpar->sample_rate = srate_hz;
+ st->codecpar->bit_rate = bit_rate;
+ st->codecpar->ch_layout.nb_channels = channels;
+
+ if ((ret = ff_alloc_extradata(st->codecpar, 6)) < 0)
+ return ret;
+
+ AV_WL16(st->codecpar->extradata + 0, frame_us / 10);
+ AV_WL16(st->codecpar->extradata + 2, ep_mode);
+ AV_WL16(st->codecpar->extradata + 4, hr_mode);
+
+ lc3->frame_samples = av_rescale(frame_us, srate_hz, 1000*1000);
+
+ delay = av_rescale(frame_us == 7500 ? 4000 : 2500, srate_hz,
1000*1000);
+ lc3->end_dts = length ? length + delay : -1;
+
+ return 0;
+}
+
+static int lc3_read_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ LC3DemuxContext *lc3 = s->priv_data;
+ AVStream *st = s->streams[0];
+ AVIOContext *pb = s->pb;
+ int64_t pos = avio_tell(pb);
+ int64_t remaining_samples;
+ int ret;
+
+ ret = av_get_packet(s->pb, pkt, avio_rl16(pb));
+ if (ret < 0)
+ return ret;
+
+ pkt->pos = pos;
+
+ remaining_samples = lc3->end_dts < 0 ? lc3->frame_samples :
+ FFMAX(lc3->end_dts - ffstream(st)->cur_dts, 0);
+ pkt->duration = FFMIN(lc3->frame_samples, remaining_samples);
+
+ return 0;
+}
+
+static av_cold int lc3_muxer_init(AVFormatContext *s)
+{
+ if (s->nb_streams != 1) {
+ av_log(s, AV_LOG_ERROR, "This muxer only supports a single
stream.\n");
+ return AVERROR(EINVAL);
+ }
+
+ return 0;
+}
+
+static int lc3_write_header(AVFormatContext *s)
+{
+ AVStream *st = s->streams[0];
+ int channels = st->codecpar->ch_layout.nb_channels;
+ int srate_hz = st->codecpar->sample_rate;
+ int bit_rate = st->codecpar->bit_rate;
+ int frame_us, ep_mode, hr_mode;
+ uint32_t nb_samples = av_rescale_q(
+ st->duration, st->time_base, (AVRational){ 1, srate_hz });
+
+ if (st->codecpar->extradata_size < 6)
+ return AVERROR_INVALIDDATA;
+
+ frame_us = AV_RL16(st->codecpar->extradata + 0) * 10;
+ ep_mode = AV_RL16(st->codecpar->extradata + 2) != 0;
+ hr_mode = AV_RL16(st->codecpar->extradata + 4) != 0;
+
+ if (check_frame_length(srate_hz, frame_us) < 0) {
+ av_log(s, AV_LOG_ERROR, "Invalid LC3 sample rate: %d Hz, "
+ "frame duration: %.1f ms.\n",
+ srate_hz, frame_us / 1000.f);
+ return AVERROR_INVALIDDATA;
+ }
+
+ avio_wb16(s->pb, 0x1ccc);
+ avio_wl16(s->pb, (9 + hr_mode) * sizeof(uint16_t));
+ avio_wl16(s->pb, srate_hz / 100);
+ avio_wl16(s->pb, bit_rate / 100);
+ avio_wl16(s->pb, channels);
+ avio_wl16(s->pb, frame_us / 10);
+ avio_wl16(s->pb, ep_mode);
+ avio_wl32(s->pb, nb_samples);
+ if (hr_mode)
+ avio_wl16(s->pb, hr_mode);
+
+ return 0;
+}
+
+static int lc3_write_packet(AVFormatContext *s, AVPacket *pkt)
+{
+ avio_wl16(s->pb, pkt->size);
+ avio_write(s->pb, pkt->data, pkt->size);
+ return 0;
+}
+
+#if CONFIG_LC3_DEMUXER
+const FFInputFormat ff_lc3_demuxer = {
+ .p.name = "lc3",
+ .p.long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity
Communication Codec)"),
+ .p.extensions = "lc3",
+ .p.flags = AVFMT_GENERIC_INDEX,
+ .priv_data_size = sizeof(LC3DemuxContext),
+ .read_probe = lc3_read_probe,
+ .read_header = lc3_read_header,
+ .read_packet = lc3_read_packet,
+};
+#endif
+
+#if CONFIG_LC3_MUXER
+const FFOutputFormat ff_lc3_muxer = {
+ .p.name = "lc3",
+ .p.long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity
Communication Codec)"),
+ .p.extensions = "lc3",
+ .p.audio_codec = AV_CODEC_ID_LC3,
+ .p.video_codec = AV_CODEC_ID_NONE,
+ .p.flags = AVFMT_NOTIMESTAMPS,
+ .init = lc3_muxer_init,
+ .write_header = lc3_write_header,
+ .write_packet = lc3_write_packet,
+};
+#endif
--
2.44.0.683.g7961c838ac-goog
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