mirror of https://git.ffmpeg.org/ffmpeg.git
212 lines
6.7 KiB
C
212 lines
6.7 KiB
C
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/*
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* LC3 encoder wrapper
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* Copyright (C) 2024 Antoine Soulier <asoulier@google.com>
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*
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* This file is part of FFmpeg.
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*
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* Permission to use, copy, modify, and/or distribute this software for any
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* purpose with or without fee is hereby granted, provided that the above
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* copyright notice and this permission notice appear in all copies.
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*
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* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
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* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
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* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
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* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
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* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
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* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
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* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
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*/
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#include <lc3.h>
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#include "libavutil/intreadwrite.h"
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#include "libavutil/opt.h"
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#include "libavutil/mem.h"
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#include "avcodec.h"
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#include "codec.h"
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#include "codec_internal.h"
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#include "encode.h"
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#define ENCODER_MAX_CHANNELS 2
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typedef struct LibLC3EncOpts {
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float frame_duration;
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int hr_mode;
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} LibLC3EncOpts;
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typedef struct LibLC3EncContext {
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const AVClass *av_class;
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LibLC3EncOpts opts;
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int block_bytes;
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void *encoder_mem;
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lc3_encoder_t encoder[ENCODER_MAX_CHANNELS];
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int delay_samples;
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int remaining_samples;
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} LibLC3EncContext;
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static av_cold int liblc3_encode_init(AVCodecContext *avctx)
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{
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LibLC3EncContext *liblc3 = avctx->priv_data;
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bool hr_mode = liblc3->opts.hr_mode;
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int frame_us = liblc3->opts.frame_duration * 1000;
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int srate_hz = avctx->sample_rate;
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int channels = avctx->ch_layout.nb_channels;
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int effective_bit_rate;
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unsigned encoder_size;
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if (frame_us != 2500 && frame_us != 5000 &&
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frame_us != 7500 && frame_us != 10000 ) {
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av_log(avctx, AV_LOG_ERROR,
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"Unsupported frame duration %.1f ms.\n", frame_us / 1000.f);
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return AVERROR(EINVAL);
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}
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hr_mode |= srate_hz > 48000;
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hr_mode &= srate_hz >= 48000;
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if (frame_us == 7500 && hr_mode) {
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av_log(avctx, AV_LOG_ERROR,
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"High-resolution mode is not supported with 7.5 ms frames.\n");
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return AVERROR(EINVAL);
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}
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av_log(avctx, AV_LOG_INFO, "Encoding %.1f ms frames.\n", frame_us / 1000.f);
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if (hr_mode)
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av_log(avctx, AV_LOG_INFO, "High-resolution mode is enabled.\n");
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liblc3->block_bytes = lc3_hr_frame_block_bytes(
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hr_mode, frame_us, srate_hz, channels, avctx->bit_rate);
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effective_bit_rate = lc3_hr_resolve_bitrate(
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hr_mode, frame_us, srate_hz, liblc3->block_bytes);
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if (avctx->bit_rate != effective_bit_rate)
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av_log(avctx, AV_LOG_WARNING,
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"Bitrate changed to %d bps.\n", effective_bit_rate);
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avctx->bit_rate = effective_bit_rate;
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encoder_size = lc3_hr_encoder_size(hr_mode, frame_us, srate_hz);
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if (!encoder_size)
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return AVERROR(EINVAL);
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liblc3->encoder_mem = av_malloc_array(channels, encoder_size);
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if (!liblc3->encoder_mem)
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return AVERROR(ENOMEM);
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for (int ch = 0; ch < channels; ch++) {
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liblc3->encoder[ch] = lc3_hr_setup_encoder(
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hr_mode, frame_us, srate_hz, 0,
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(char *)liblc3->encoder_mem + ch * encoder_size);
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}
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avctx->extradata = av_mallocz(6 + AV_INPUT_BUFFER_PADDING_SIZE);
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if (!avctx->extradata)
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return AVERROR(ENOMEM);
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AV_WL16(avctx->extradata + 0, frame_us / 10);
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AV_WL16(avctx->extradata + 2, 0);
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AV_WL16(avctx->extradata + 4, hr_mode);
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avctx->extradata_size = 6;
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avctx->frame_size = av_rescale(frame_us, srate_hz, 1000*1000);
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liblc3->delay_samples = lc3_hr_delay_samples(hr_mode, frame_us, srate_hz);
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liblc3->remaining_samples = 0;
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return 0;
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}
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static av_cold int liblc3_encode_close(AVCodecContext *avctx)
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{
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LibLC3EncContext *liblc3 = avctx->priv_data;
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av_freep(&liblc3->encoder_mem);
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return 0;
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}
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static int liblc3_encode(AVCodecContext *avctx, AVPacket *pkt,
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const AVFrame *frame, int *got_packet_ptr)
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{
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LibLC3EncContext *liblc3 = avctx->priv_data;
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int block_bytes = liblc3->block_bytes;
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int channels = avctx->ch_layout.nb_channels;
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void *zero_frame = NULL;
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uint8_t *data_ptr;
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int ret;
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if ((ret = ff_get_encode_buffer(avctx, pkt, block_bytes, 0)) < 0)
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return ret;
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if (frame) {
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int padding = frame->nb_samples - frame->duration;
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liblc3->remaining_samples = FFMAX(liblc3->delay_samples - padding, 0);
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} else {
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if (!liblc3->remaining_samples)
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return 0;
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liblc3->remaining_samples = 0;
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zero_frame = av_mallocz(avctx->frame_size * sizeof(float));
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if (!zero_frame)
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return AVERROR(ENOMEM);
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}
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data_ptr = pkt->data;
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for (int ch = 0; ch < channels; ch++) {
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const float *pcm = zero_frame ? zero_frame : frame->data[ch];
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int nbytes = block_bytes / channels + (ch < block_bytes % channels);
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lc3_encode(liblc3->encoder[ch],
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LC3_PCM_FORMAT_FLOAT, pcm, 1, nbytes, data_ptr);
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data_ptr += nbytes;
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}
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if (zero_frame)
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av_free(zero_frame);
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*got_packet_ptr = 1;
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return 0;
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}
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#define OFFSET(x) offsetof(LibLC3EncContext, opts.x)
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#define FLAGS AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM
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static const AVOption options[] = {
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{ "frame_duration", "Duration of a frame in milliseconds",
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OFFSET(frame_duration), AV_OPT_TYPE_FLOAT,
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{ .dbl = 10.0 }, 2.5, 10.0, FLAGS },
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{ "high_resolution", "Enable High-Resolution mode (48 KHz or 96 KHz)",
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OFFSET(hr_mode), AV_OPT_TYPE_BOOL,
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{ .i64 = 0 }, 0, 1, FLAGS },
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{ NULL }
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};
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static const AVClass class = {
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.class_name = "liblc3 encoder",
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.item_name = av_default_item_name,
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.option = options,
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.version = LIBAVUTIL_VERSION_INT,
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};
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const FFCodec ff_liblc3_encoder = {
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.p.name = "liblc3",
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CODEC_LONG_NAME("LC3 (Low Complexity Communication Codec)"),
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.p.type = AVMEDIA_TYPE_AUDIO,
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.p.id = AV_CODEC_ID_LC3,
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.p.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_DELAY,
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.p.ch_layouts = (const AVChannelLayout[])
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{ { AV_CHANNEL_ORDER_UNSPEC, 1 },
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{ AV_CHANNEL_ORDER_UNSPEC, 2 }, { 0 } },
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.p.supported_samplerates = (const int [])
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{ 96000, 48000, 32000, 24000, 16000, 8000, 0 },
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.p.sample_fmts = (const enum AVSampleFormat[])
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{ AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_NONE },
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.p.priv_class = &class,
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.p.wrapper_name = "liblc3",
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.priv_data_size = sizeof(LibLC3EncContext),
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.init = liblc3_encode_init,
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.close = liblc3_encode_close,
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FF_CODEC_ENCODE_CB(liblc3_encode),
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};
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