[FFmpeg-devel] [PATCH] avformat/lc3: Add file format for LC3/LC3plus transport
Antoine Soulier
asoulier at google.com
Sat Apr 13 02:46:29 EEST 2024
Thanks.
On Fri, Apr 12, 2024 at 6:05 AM Stefano Sabatini <stefasab at gmail.com> wrote:
> On date Wednesday 2024-04-10 16:46:55 -0700, ffmpeg-devel Mailing List
> wrote:
> > Sure, I thought these warnings were disabled while looking at codec2.c
> > Sorry for the bad merge of the doc.
>
> > From 975040408f32431efc3fae0a0b8c048f02159515 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 | 6 +
> > libavformat/Makefile | 2 +
> > libavformat/allformats.c | 2 +
> > libavformat/lc3.c | 253 +++++++++++++++++++++++++++++++++++++++
> > 5 files changed, 264 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..4c14323d50 100644
> > --- a/doc/muxers.texi
> > +++ b/doc/muxers.texi
> > @@ -2725,6 +2725,12 @@ games such as "Real War", and "Real War: Rogue
> States".
> >
> > This muxer accepts a single @samp{adpcm_ima_ssi} audio stream.
> >
> > + 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.
>
> nit++: @samp{lc3} for consistency
>
> > +
> > @section lrc
> > LRC lyrics file format muxer.
> >
> > 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..e27727145b
> > --- /dev/null
> > +++ b/libavformat/lc3.c
> > @@ -0,0 +1,253 @@
> > +/*
> > + * LC3 demuxer
>
> nit: LC3 demuxer and muxer
>
> > + * 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"
> > +
> > +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;
> > +}
> > +
> > +#if CONFIG_LC3_DEMUXER
> > +
> > +typedef struct LC3DemuxContext {
> > + int frame_samples;
> > + int64_t end_dts;
> > +} LC3DemuxContext;
> > +
> > +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);
>
> you can move the log to the function, by passing a log context (this
> way you can provide more context in the error message and specify what
> failed between rate and duration) - or skip the log in case a NULL log
> context is provided for the probe case
>
> but I don't think this is really blocking
>
> [...]
>
> Looks good to me otherwise, thanks.
>
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