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/*
* LC3 decoder wrapper
* Copyright (C) 2024 Antoine Soulier <asoulier@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/mem.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, hr_mode;
void *decoder_mem;
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;
int ep_mode;
unsigned decoder_size;
if (avctx->extradata_size < 6)
return AVERROR_INVALIDDATA;
if (channels < 0 || channels > DECODER_MAX_CHANNELS) {
av_log(avctx, AV_LOG_ERROR,
"Invalid number of channels %d. Max %d channels are accepted\n",
channels, DECODER_MAX_CHANNELS);
return AVERROR(EINVAL);
}
liblc3->frame_us = AV_RL16(avctx->extradata + 0) * 10;
liblc3->srate_hz = avctx->sample_rate;
ep_mode = AV_RL16(avctx->extradata + 2);
liblc3->hr_mode = AV_RL16(avctx->extradata + 4);
if (ep_mode != 0) {
av_log(avctx, AV_LOG_ERROR,
"Error protection mode is not supported.\n");
return AVERROR(EINVAL);
}
av_log(avctx, AV_LOG_INFO,
"Decoding %.1f ms frames.\n", liblc3->frame_us / 1000.f);
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;
liblc3->decoder_mem = av_malloc_array(channels, decoder_size);
if (!liblc3->decoder_mem)
return AVERROR(ENOMEM);
for (int ch = 0; ch < channels; ch++) {
liblc3->decoder[ch] = lc3_hr_setup_decoder(
liblc3->hr_mode, liblc3->frame_us, liblc3->srate_hz, 0,
(char *)liblc3->decoder_mem + ch * decoder_size);
}
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;
av_freep(&liblc3->decoder_mem);
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 = av_rescale(
liblc3->frame_us, liblc3->srate_hz, 1000*1000);
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
block_bytes = avpkt->size;
for (int ch = 0; ch < channels; ch++) {
int nbytes = block_bytes / channels + (ch < block_bytes % channels);
ret = lc3_decode(liblc3->decoder[ch], in, nbytes,
LC3_PCM_FORMAT_FLOAT, frame->data[ch], 1);
if (ret < 0)
return AVERROR_INVALIDDATA;
in += nbytes;
}
frame->nb_samples = FFMIN(frame->nb_samples, avpkt->duration);
*got_frame_ptr = 1;
return avpkt->size;
}
const FFCodec ff_liblc3_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),
.caps_internal = FF_CODEC_CAP_INIT_CLEANUP,
.init = liblc3_decode_init,
.close = liblc3_decode_close,
FF_CODEC_DECODE_CB(liblc3_decode),
};
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