mirror of https://github.com/mpv-player/mpv
438 lines
13 KiB
C
438 lines
13 KiB
C
/*
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* audio filter for runtime AC-3 encoding with libavcodec.
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*
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* Copyright (C) 2007 Ulion <ulion A gmail P com>
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*
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* This file is part of mpv.
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*
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* mpv is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* mpv is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with mpv. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <inttypes.h>
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#include <assert.h>
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#include <libavcodec/avcodec.h>
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#include <libavutil/intreadwrite.h>
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#include <libavutil/common.h>
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#include <libavutil/bswap.h>
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#include <libavutil/mem.h>
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#include "config.h"
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#include "common/av_common.h"
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#include "common/common.h"
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#include "af.h"
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#include "audio/audio_buffer.h"
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#include "audio/chmap_sel.h"
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#include "audio/fmt-conversion.h"
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#define AC3_MAX_CHANNELS 6
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#define AC3_MAX_CODED_FRAME_SIZE 3840
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#define AC3_FRAME_SIZE (6 * 256)
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const uint16_t ac3_bitrate_tab[19] = {
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32, 40, 48, 56, 64, 80, 96, 112, 128,
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160, 192, 224, 256, 320, 384, 448, 512, 576, 640
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};
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// Data for specific instances of this filter
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typedef struct af_ac3enc_s {
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struct AVCodec *lavc_acodec;
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struct AVCodecContext *lavc_actx;
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int bit_rate;
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struct mp_audio *input; // frame passed to libavcodec
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struct mp_audio *pending; // unconsumed input data
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int in_samples; // samples of input per AC3 frame
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int out_samples; // upper bound on encoded output per AC3 frame
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int64_t encoder_buffered;
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int cfg_add_iec61937_header;
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int cfg_bit_rate;
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int cfg_min_channel_num;
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char *cfg_encoder;
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char **cfg_avopts;
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} af_ac3enc_t;
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// fmt carries the input format. Change it to the best next-possible format
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// the encoder likely accepts.
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static void select_encode_format(AVCodecContext *c, struct mp_audio *fmt)
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{
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int formats[AF_FORMAT_COUNT];
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af_get_best_sample_formats(fmt->format, formats);
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for (int n = 0; formats[n]; n++) {
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const enum AVSampleFormat *lf = c->codec->sample_fmts;
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for (int i = 0; lf && lf[i] != AV_SAMPLE_FMT_NONE; i++) {
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int mpfmt = af_from_avformat(lf[i]);
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if (mpfmt && mpfmt == formats[n]) {
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mp_audio_set_format(fmt, mpfmt);
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goto done_fmt;
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}
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}
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}
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done_fmt: ;
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int rate =
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af_select_best_samplerate(fmt->rate, c->codec->supported_samplerates);
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if (rate > 0)
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fmt->rate = rate;
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struct mp_chmap_sel sel = {0};
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const uint64_t *lch = c->codec->channel_layouts;
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for (int n = 0; lch && lch[n]; n++) {
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struct mp_chmap chmap = {0};
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mp_chmap_from_lavc(&chmap, lch[n]);
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mp_chmap_sel_add_map(&sel, &chmap);
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}
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struct mp_chmap res = fmt->channels;
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mp_chmap_sel_adjust(&sel, &res);
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if (!mp_chmap_is_empty(&res))
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mp_audio_set_channels(fmt, &res);
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}
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// Initialization and runtime control
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static int control(struct af_instance *af, int cmd, void *arg)
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{
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af_ac3enc_t *s = af->priv;
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static const int default_bit_rate[AC3_MAX_CHANNELS+1] = \
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{0, 96000, 192000, 256000, 384000, 448000, 448000};
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switch (cmd){
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case AF_CONTROL_REINIT: {
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struct mp_audio *in = arg;
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struct mp_audio orig_in = *in;
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if (!af_fmt_is_pcm(in->format) || in->nch < s->cfg_min_channel_num)
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return AF_DETACH;
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// At least currently, the AC3 encoder doesn't export sample rates.
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in->rate = 48000;
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select_encode_format(s->lavc_actx, in);
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af->data->rate = in->rate;
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mp_audio_set_format(af->data, AF_FORMAT_S_AC3);
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mp_audio_set_num_channels(af->data, 2);
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if (!mp_audio_config_equals(in, &orig_in))
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return AF_FALSE;
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if (s->cfg_add_iec61937_header) {
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s->out_samples = AC3_FRAME_SIZE;
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} else {
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s->out_samples = AC3_MAX_CODED_FRAME_SIZE / af->data->sstride;
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}
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mp_audio_copy_config(s->input, in);
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talloc_free(s->pending);
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s->pending = NULL;
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MP_DBG(af, "reinit: %d, %d, %d.\n", in->nch, in->rate, s->in_samples);
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int bit_rate = s->bit_rate ? s->bit_rate : default_bit_rate[in->nch];
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if (s->lavc_actx->channels != in->nch ||
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s->lavc_actx->sample_rate != in->rate ||
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s->lavc_actx->bit_rate != bit_rate)
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{
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avcodec_close(s->lavc_actx);
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// Put sample parameters
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s->lavc_actx->sample_fmt = af_to_avformat(in->format);
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s->lavc_actx->channels = in->nch;
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s->lavc_actx->channel_layout = mp_chmap_to_lavc(&in->channels);
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s->lavc_actx->sample_rate = in->rate;
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s->lavc_actx->bit_rate = bit_rate;
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if (avcodec_open2(s->lavc_actx, s->lavc_acodec, NULL) < 0) {
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MP_ERR(af, "Couldn't open codec %s, br=%d.\n", "ac3", bit_rate);
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return AF_ERROR;
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}
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if (s->lavc_actx->frame_size < 1) {
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MP_ERR(af, "encoder didn't specify input frame size\n");
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return AF_ERROR;
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}
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}
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s->in_samples = s->lavc_actx->frame_size;
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mp_audio_realloc(s->input, s->in_samples);
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s->input->samples = 0;
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s->encoder_buffered = 0;
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return AF_OK;
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}
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case AF_CONTROL_RESET:
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if (avcodec_is_open(s->lavc_actx))
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avcodec_flush_buffers(s->lavc_actx);
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talloc_free(s->pending);
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s->pending = NULL;
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s->input->samples = 0;
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s->encoder_buffered = 0;
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return AF_OK;
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}
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return AF_UNKNOWN;
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}
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// Deallocate memory
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static void uninit(struct af_instance* af)
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{
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af_ac3enc_t *s = af->priv;
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if (s) {
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if(s->lavc_actx) {
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avcodec_close(s->lavc_actx);
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av_free(s->lavc_actx);
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}
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talloc_free(s->pending);
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}
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}
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static void update_delay(struct af_instance *af)
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{
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af_ac3enc_t *s = af->priv;
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af->delay = ((s->pending ? s->pending->samples : 0) + s->input->samples +
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s->encoder_buffered) / (double)s->input->rate;
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}
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static int filter_frame(struct af_instance *af, struct mp_audio *audio)
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{
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af_ac3enc_t *s = af->priv;
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// filter_output must have been called until no output was produced.
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if (s->pending && s->pending->samples)
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MP_ERR(af, "broken data flow\n");
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talloc_free(s->pending);
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s->pending = audio;
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update_delay(af);
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return 0;
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}
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static void swap_16(uint16_t *ptr, size_t size)
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{
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for (size_t n = 0; n < size; n++)
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ptr[n] = av_bswap16(ptr[n]);
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}
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// Copy data from input frame to encode frame (because libavcodec wants a full
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// AC3 frame for encoding, while filter input frames can be smaller or larger).
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// Return true if the frame is complete.
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static bool fill_buffer(struct af_instance *af)
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{
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af_ac3enc_t *s = af->priv;
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af->delay = 0;
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if (s->pending) {
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if (!mp_audio_is_writeable(s->input))
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assert(s->input->samples == 0); // we can't have sent a partial frame
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mp_audio_realloc_min(s->input, s->in_samples);
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int copy = MPMIN(s->in_samples - s->input->samples, s->pending->samples);
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s->input->samples += copy;
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mp_audio_copy(s->input, s->input->samples - copy, s->pending, 0, copy);
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mp_audio_skip_samples(s->pending, copy);
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}
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update_delay(af);
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return s->input->samples >= s->in_samples;
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}
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// Return <0 on error, 0 on need more input, 1 on success (and *frame set).
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// To actually advance the read pointer, set s->input->samples=0 afterwards.
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static int read_input_frame(struct af_instance *af, AVFrame *frame)
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{
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af_ac3enc_t *s = af->priv;
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if (!fill_buffer(af))
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return 0; // need more input
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if (mp_audio_to_avframe(s->input, frame) < 0)
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return -1;
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return 1;
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}
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static int filter_out(struct af_instance *af)
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{
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af_ac3enc_t *s = af->priv;
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if (!s->pending)
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return 0;
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AVFrame *frame = av_frame_alloc();
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if (!frame) {
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MP_FATAL(af, "Could not allocate memory \n");
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return -1;
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}
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int err = -1;
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AVPacket pkt = {0};
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av_init_packet(&pkt);
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// Send input as long as it wants.
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while (1) {
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err = read_input_frame(af, frame);
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if (err < 0)
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goto done;
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if (err == 0)
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break;
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err = -1;
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int lavc_ret = avcodec_send_frame(s->lavc_actx, frame);
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// On EAGAIN, we're supposed to read remaining output.
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if (lavc_ret == AVERROR(EAGAIN))
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break;
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if (lavc_ret < 0) {
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MP_FATAL(af, "Encode failed.\n");
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goto done;
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}
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s->encoder_buffered += s->input->samples;
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s->input->samples = 0;
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}
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int lavc_ret = avcodec_receive_packet(s->lavc_actx, &pkt);
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if (lavc_ret == AVERROR(EAGAIN)) {
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// Need to buffer more input.
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err = 0;
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goto done;
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}
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if (lavc_ret < 0) {
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MP_FATAL(af, "Encode failed.\n");
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goto done;
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}
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MP_DBG(af, "avcodec_encode_audio got %d, pending %d.\n",
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pkt.size, s->pending->samples + s->input->samples);
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s->encoder_buffered -= AC3_FRAME_SIZE;
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struct mp_audio *out =
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mp_audio_pool_get(af->out_pool, af->data, s->out_samples);
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if (!out)
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goto done;
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mp_audio_copy_attributes(out, s->pending);
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int frame_size = pkt.size;
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int header_len = 0;
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char hdr[8];
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if (s->cfg_add_iec61937_header && pkt.size > 5) {
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int bsmod = pkt.data[5] & 0x7;
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int len = frame_size;
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frame_size = AC3_FRAME_SIZE * 2 * 2;
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header_len = 8;
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AV_WL16(hdr, 0xF872); // iec 61937 syncword 1
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AV_WL16(hdr + 2, 0x4E1F); // iec 61937 syncword 2
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hdr[5] = bsmod; // bsmod
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hdr[4] = 0x01; // data-type ac3
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AV_WL16(hdr + 6, len << 3); // number of bits in payload
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}
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if (frame_size > out->samples * out->sstride)
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abort();
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char *buf = (char *)out->planes[0];
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memcpy(buf, hdr, header_len);
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memcpy(buf + header_len, pkt.data, pkt.size);
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memset(buf + header_len + pkt.size, 0,
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frame_size - (header_len + pkt.size));
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swap_16((uint16_t *)(buf + header_len), pkt.size / 2);
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out->samples = frame_size / out->sstride;
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af_add_output_frame(af, out);
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err = 0;
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done:
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av_packet_unref(&pkt);
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av_frame_free(&frame);
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update_delay(af);
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return err;
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}
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static int af_open(struct af_instance* af){
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af_ac3enc_t *s = af->priv;
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af->control=control;
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af->uninit=uninit;
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af->filter_frame = filter_frame;
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af->filter_out = filter_out;
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s->lavc_acodec = avcodec_find_encoder_by_name(s->cfg_encoder);
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if (!s->lavc_acodec) {
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MP_ERR(af, "Couldn't find encoder %s.\n", s->cfg_encoder);
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return AF_ERROR;
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}
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s->lavc_actx = avcodec_alloc_context3(s->lavc_acodec);
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if (!s->lavc_actx) {
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MP_ERR(af, "Audio LAVC, couldn't allocate context!\n");
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return AF_ERROR;
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}
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if (mp_set_avopts(af->log, s->lavc_actx, s->cfg_avopts) < 0)
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return AF_ERROR;
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// For this one, we require the decoder to expert lists of all supported
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// parameters. (Not all decoders do that, but the ones we're interested
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// in do.)
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if (!s->lavc_acodec->sample_fmts ||
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!s->lavc_acodec->channel_layouts)
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{
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MP_ERR(af, "Audio encoder doesn't list supported parameters.\n");
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return AF_ERROR;
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}
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s->input = talloc_zero(s, struct mp_audio);
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if (s->cfg_bit_rate) {
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int i;
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for (i = 0; i < 19; i++) {
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if (ac3_bitrate_tab[i] == s->cfg_bit_rate) {
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s->bit_rate = ac3_bitrate_tab[i] * 1000;
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break;
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}
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}
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if (i >= 19) {
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MP_WARN(af, "unable set unsupported bitrate %d, use default "
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"bitrate (check manpage to see supported bitrates).\n",
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s->cfg_bit_rate);
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}
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}
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return AF_OK;
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}
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#define OPT_BASE_STRUCT struct af_ac3enc_s
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const struct af_info af_info_lavcac3enc = {
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.info = "runtime encode to ac3 using libavcodec",
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.name = "lavcac3enc",
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.open = af_open,
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.priv_size = sizeof(struct af_ac3enc_s),
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.priv_defaults = &(const struct af_ac3enc_s){
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.cfg_add_iec61937_header = 1,
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.cfg_bit_rate = 640,
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.cfg_min_channel_num = 3,
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.cfg_encoder = "ac3",
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},
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.options = (const struct m_option[]) {
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OPT_FLAG("tospdif", cfg_add_iec61937_header, 0),
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OPT_CHOICE_OR_INT("bitrate", cfg_bit_rate, 0, 32, 640,
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({"auto", 0}, {"default", 0})),
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OPT_INTRANGE("minch", cfg_min_channel_num, 0, 2, 6),
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OPT_STRING("encoder", cfg_encoder, 0),
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OPT_KEYVALUELIST("o", cfg_avopts, 0),
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{0}
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},
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};
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