On date Tuesday 2024-03-26 16:47:36 +0000, ffmpeg-devel Mailing List wrote:
> The LC3 audio codec is the default codec of Bluetooth LE audio.
> This is a wrapper over the liblc3 library (https://github.com/google/liblc3).
>
> Signed-off-by: Antoine Soulier <asoul...@google.com>
> Signed-off-by: Antoine SOULIER <asoul...@google.com>
> ---
> libavcodec/Makefile | 3 +
> libavcodec/allcodecs.c | 3 +
> libavcodec/codec_desc.c | 14 +++
> libavcodec/codec_id.h | 2 +
> libavcodec/liblc3dec.c | 146 ++++++++++++++++++++++++++++++
> libavcodec/liblc3enc.c | 191 ++++++++++++++++++++++++++++++++++++++++
> 6 files changed, 359 insertions(+)
> create mode 100644 libavcodec/liblc3dec.c
> create mode 100644 libavcodec/liblc3enc.c
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index 708434ac76..7d2cf3076d 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -1123,6 +1123,9 @@ OBJS-$(CONFIG_LIBILBC_ENCODER) += libilbc.o
> OBJS-$(CONFIG_LIBJXL_DECODER) += libjxldec.o libjxl.o
> OBJS-$(CONFIG_LIBJXL_ENCODER) += libjxlenc.o libjxl.o
> OBJS-$(CONFIG_LIBKVAZAAR_ENCODER) += libkvazaar.o
> +OBJS-$(CONFIG_LIBLC3_ENCODER) += liblc3enc.o
> +OBJS-$(CONFIG_LIBLC3_LC3_DECODER) += liblc3dec.o
> +OBJS-$(CONFIG_LIBLC3_LC3PLUS_DECODER) += liblc3dec.o
> OBJS-$(CONFIG_LIBMP3LAME_ENCODER) += libmp3lame.o
> OBJS-$(CONFIG_LIBOPENCORE_AMRNB_DECODER) += libopencore-amr.o
> OBJS-$(CONFIG_LIBOPENCORE_AMRNB_ENCODER) += libopencore-amr.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index 2386b450a6..29aedaeac6 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -776,6 +776,9 @@ extern const FFCodec ff_libilbc_encoder;
> extern const FFCodec ff_libilbc_decoder;
> extern const FFCodec ff_libjxl_decoder;
> extern const FFCodec ff_libjxl_encoder;
> +extern const FFCodec ff_liblc3_encoder;
> +extern const FFCodec ff_liblc3_lc3_decoder;
> +extern const FFCodec ff_liblc3_lc3plus_decoder;
> extern const FFCodec ff_libmp3lame_encoder;
> extern const FFCodec ff_libopencore_amrnb_encoder;
> extern const FFCodec ff_libopencore_amrnb_decoder;
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index 3bab86db62..230bba2a09 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -3425,6 +3425,20 @@ static const AVCodecDescriptor codec_descriptors[] = {
> .long_name = NULL_IF_CONFIG_SMALL("QOA (Quite OK Audio)"),
> .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
> },
> + {
> + .id = AV_CODEC_ID_LC3,
> + .type = AVMEDIA_TYPE_AUDIO,
> + .name = "lc3",
> + .long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity Communication
> Codec)"),
> + .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
> + },
> + {
> + .id = AV_CODEC_ID_LC3_PLUS,
> + .type = AVMEDIA_TYPE_AUDIO,
> + .name = "lc3_plus",
> + .long_name = NULL_IF_CONFIG_SMALL("LC3plus (Low Complexity
> Communication Codec plus)"),
> + .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
> + },
>
> /* subtitle codecs */
> {
> diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
> index c8dc21da74..7e4cb39049 100644
> --- a/libavcodec/codec_id.h
> +++ b/libavcodec/codec_id.h
> @@ -543,6 +543,8 @@ enum AVCodecID {
> AV_CODEC_ID_AC4,
> AV_CODEC_ID_OSQ,
> AV_CODEC_ID_QOA,
> + AV_CODEC_ID_LC3,
> + AV_CODEC_ID_LC3_PLUS,
>
> /* subtitle codecs */
> AV_CODEC_ID_FIRST_SUBTITLE = 0x17000, ///< A dummy ID pointing
> at the start of subtitle codecs.
> diff --git a/libavcodec/liblc3dec.c b/libavcodec/liblc3dec.c
> new file mode 100644
> index 0000000000..e97cecc68f
> --- /dev/null
> +++ b/libavcodec/liblc3dec.c
> @@ -0,0 +1,146 @@
> +/*
> + * LC3 decoder wrapper
> + * Copyright (C) 2024 Antoine Soulier <asoul...@google.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * Permission to use, copy, modify, and/or distribute this software for any
> + * purpose with or without fee is hereby granted, provided that the above
> + * copyright notice and this permission notice appear in all copies.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> + */
> +
> +#include <lc3.h>
> +
> +#include "libavutil/intreadwrite.h"
> +
> +#include "avcodec.h"
> +#include "codec.h"
> +#include "codec_internal.h"
> +#include "decode.h"
> +#include "internal.h"
> +
> +#define DECODER_MAX_CHANNELS 2
> +
> +typedef struct LibLC3DecContext {
> + int frame_us, srate_hz;
> + bool hr_mode;
> + lc3_decoder_t decoder[DECODER_MAX_CHANNELS];
> +} LibLC3DecContext;
> +
> +static av_cold int liblc3_decode_init(AVCodecContext *avctx)
> +{
> + LibLC3DecContext *liblc3 = avctx->priv_data;
> + int channels = avctx->ch_layout.nb_channels;
> + unsigned decoder_size;
> +
> + if (avctx->extradata_size < 2)
> + return AVERROR_INVALIDDATA;
> +
> + liblc3->frame_us = AV_RL16(avctx->extradata + 0);
> + liblc3->srate_hz = avctx->sample_rate;
> + liblc3->hr_mode = avctx->extradata_size >= 6 &&
> + AV_RL16(avctx->extradata + 4);
> +
> + av_log(avctx, AV_LOG_INFO,
> + "Decoding %.1f ms frames\n", liblc3->frame_us / 1e3f);
1e3f might be replaced by a symbolic constant/macro
> + if (liblc3->hr_mode)
> + av_log(avctx, AV_LOG_INFO, "High-resolution mode enabled\n");
> +
> + decoder_size = lc3_hr_decoder_size(
> + liblc3->hr_mode, liblc3->frame_us, liblc3->srate_hz);
> + if (!decoder_size)
> + return AVERROR_INVALIDDATA;
> +
> + for (int ch = 0; ch < channels; ch++) {
> + liblc3->decoder[ch] = lc3_hr_setup_decoder(liblc3->hr_mode,
> + liblc3->frame_us, liblc3->srate_hz, 0, av_malloc(decoder_size));
> + if (!liblc3->decoder[ch])
> + return AVERROR(ENOMEM);
> + }
> +
> + avctx->sample_fmt = AV_SAMPLE_FMT_FLTP;
> + avctx->delay = lc3_hr_delay_samples(
> + liblc3->hr_mode, liblc3->frame_us, liblc3->srate_hz);
> + avctx->internal->skip_samples = avctx->delay;
> +
> + return 0;
> +}
> +
> +static av_cold int liblc3_decode_close(AVCodecContext *avctx)
> +{
> + LibLC3DecContext *liblc3 = avctx->priv_data;
> + int channels = avctx->ch_layout.nb_channels;
> +
> + for (int ch = 0; ch < channels; ch++)
> + av_free(liblc3->decoder[ch]);
> +
> + return 0;
> +}
> +
> +static int liblc3_decode(AVCodecContext *avctx, AVFrame *frame,
> + int *got_frame_ptr, AVPacket *avpkt)
> +{
> + LibLC3DecContext *liblc3 = avctx->priv_data;
> + int channels = avctx->ch_layout.nb_channels;
> + uint8_t *in = avpkt->data;
> + int block_bytes, ret;
> +
> + frame->nb_samples = lc3_hr_frame_samples(
> + liblc3->hr_mode, liblc3->frame_us, liblc3->srate_hz);
> + if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
> + return ret;
> +
> + block_bytes = avpkt->size;
> + for (int ch = 0; ch < channels; ch++) {
> + int frame_bytes = block_bytes / channels
> + + (ch < block_bytes % channels);
> +
> +
> + ret = lc3_decode(liblc3->decoder[ch], in, frame_bytes,
> + LC3_PCM_FORMAT_FLOAT, frame->data[ch], 1);
> + if (ret < 0)
> + return AVERROR_INVALIDDATA;
> +
> + in += frame_bytes;
> + }
> +
> + frame->nb_samples = FFMIN(frame->nb_samples, avpkt->duration);
> +
> + *got_frame_ptr = 1;
> +
> + return avpkt->size;
> +}
> +
> +const FFCodec ff_liblc3_lc3_decoder = {
> + .p.name = "liblc3",
> + CODEC_LONG_NAME("LC3 (Low Complexity Communication Codec)"),
> + .p.type = AVMEDIA_TYPE_AUDIO,
> + .p.id = AV_CODEC_ID_LC3,
> + .p.capabilities = AV_CODEC_CAP_DR1,
> + .p.wrapper_name = "liblc3",
> + .priv_data_size = sizeof(LibLC3DecContext),
> + .init = liblc3_decode_init,
> + .close = liblc3_decode_close,
> + FF_CODEC_DECODE_CB(liblc3_decode),
> +};
> +
> +const FFCodec ff_liblc3_lc3plus_decoder = {
> + .p.name = "liblc3",
> + CODEC_LONG_NAME("LC3plus (Low Complexity Communication Codec plus)"),
> + .p.type = AVMEDIA_TYPE_AUDIO,
> + .p.id = AV_CODEC_ID_LC3_PLUS,
> + .p.capabilities = AV_CODEC_CAP_DR1,
> + .p.wrapper_name = "liblc3",
> + .priv_data_size = sizeof(LibLC3DecContext),
> + .init = liblc3_decode_init,
> + .close = liblc3_decode_close,
> + FF_CODEC_DECODE_CB(liblc3_decode),
> +};
> diff --git a/libavcodec/liblc3enc.c b/libavcodec/liblc3enc.c
> new file mode 100644
> index 0000000000..6495742c04
> --- /dev/null
> +++ b/libavcodec/liblc3enc.c
> @@ -0,0 +1,191 @@
> +/*
> + * LC3 encoder wrapper
> + * Copyright (C) 2024 Antoine Soulier <asoul...@google.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * Permission to use, copy, modify, and/or distribute this software for any
> + * purpose with or without fee is hereby granted, provided that the above
> + * copyright notice and this permission notice appear in all copies.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
> + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
> + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
> + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
> + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
> + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
> + */
> +
> +#include <lc3.h>
> +
> +#include "libavutil/intreadwrite.h"
> +#include "libavutil/opt.h"
> +
> +#include "avcodec.h"
> +#include "codec.h"
> +#include "codec_internal.h"
> +#include "encode.h"
> +
> +#define ENCODER_MAX_CHANNELS 2
> +
> +typedef struct LibLC3EncOpts {
> + float frame_duration;
> + bool hr_mode;
> +} LibLC3EncOpts;
> +
> +typedef struct LibLC3EncContext {
> + AVClass *av_class;
> + LibLC3EncOpts opts;
> + int block_bytes;
> + lc3_encoder_t encoder[ENCODER_MAX_CHANNELS];
> +} LibLC3EncContext;
> +
> +static av_cold int liblc3_encode_init(AVCodecContext *avctx)
> +{
> + LibLC3EncContext *liblc3 = avctx->priv_data;
> + bool hr_mode = liblc3->opts.hr_mode;
> + int frame_us = liblc3->opts.frame_duration * 1000;
> + int srate_hz = avctx->sample_rate;
> + int channels = avctx->ch_layout.nb_channels;
> + int effective_bit_rate;
> + unsigned encoder_size;
> +
> + if (frame_us != 2500 && frame_us != 5000 &&
> + frame_us != 7500 && frame_us != 10000 ) {
> + av_log(avctx, AV_LOG_ERROR,
> + "Unsupported frame duration %.1f ms\n", frame_us / 1e3f);
> + return AVERROR(EINVAL);
> + }
> +
> + hr_mode |= srate_hz > 48000;
> + hr_mode &= srate_hz >= 48000;
> +
> + if (frame_us <= 5000 || hr_mode)
> + avctx->codec_id = AV_CODEC_ID_LC3_PLUS;
> +
> + if (frame_us == 7500 && hr_mode) {
> + av_log(avctx, AV_LOG_ERROR,
> + "High-reolution mode not supported with 7.5 ms frames\n");
typo
> + return AVERROR(EINVAL);
> + }
> +
> + av_log(avctx, AV_LOG_INFO, "Encoding %.1f ms frames\n", frame_us / 1e3f);
> + if (hr_mode)
> + av_log(avctx, AV_LOG_INFO, "High-resolution mode enabled\n");
> +
> + liblc3->block_bytes = lc3_hr_frame_block_bytes(
> + hr_mode, frame_us, srate_hz, channels, avctx->bit_rate);
> +
> + effective_bit_rate = lc3_hr_resolve_bitrate(
> + hr_mode, frame_us, srate_hz, liblc3->block_bytes);
> +
> + if (avctx->bit_rate != effective_bit_rate)
> + av_log(avctx, AV_LOG_WARNING,
> + "Bitrate changed to %d bps\n", effective_bit_rate);
> + avctx->bit_rate = effective_bit_rate;
> +
> + encoder_size = lc3_hr_encoder_size(frame_us, frame_us, srate_hz);
> + if (!encoder_size)
> + return AVERROR(EINVAL);
> +
> + for (int ch = 0; ch < channels; ch++) {
> + liblc3->encoder[ch] = lc3_hr_setup_encoder(
> + hr_mode, frame_us, srate_hz, 0, av_malloc(encoder_size));
not sure if this can fail for different reasons (e.g. if it performs
validation), if this is the case maybe you want to add an explicit
check for malloc/ENOMEM
[...]
No more comments from me, thanks.
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