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92 lines
3.2 KiB
C
92 lines
3.2 KiB
C
/* Copyright (c) 2022 Amazon
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Written by Jan Buethe */
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/*
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions
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are met:
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- Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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- Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in the
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documentation and/or other materials provided with the distribution.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
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OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
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EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
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PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <string.h>
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#ifdef HAVE_CONFIG_H
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#include "config.h"
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#endif
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#include "os_support.h"
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#include "dred_decoder.h"
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#include "dred_coding.h"
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#include "celt/entdec.h"
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/* From http://graphics.stanford.edu/~seander/bithacks.html#FixedSignExtend */
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static int sign_extend(int x, int b) {
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int m = 1U << (b - 1);
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return (x ^ m) - m;
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}
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int dred_ec_decode(OpusDRED *dec, const opus_uint8 *bytes, int num_bytes, int min_feature_frames)
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{
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const opus_uint16 *p0 = DRED_rdovae_get_p0_pointer();
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const opus_uint16 *quant_scales = DRED_rdovae_get_quant_scales_pointer();
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const opus_uint16 *r = DRED_rdovae_get_r_pointer();
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ec_dec ec;
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int q_level;
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int i;
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int offset;
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int q0;
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int dQ;
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/* since features are decoded in quadruples, it makes no sense to go with an uneven number of redundancy frames */
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celt_assert(DRED_NUM_REDUNDANCY_FRAMES % 2 == 0);
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/* decode initial state and initialize RDOVAE decoder */
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ec_dec_init(&ec, (unsigned char*)bytes, num_bytes);
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dec->dred_offset = sign_extend(ec_dec_uint(&ec, 32), 5);
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q0 = ec_dec_uint(&ec, 16);
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dQ = ec_dec_uint(&ec, 8);
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/*printf("%d %d %d\n", dred_offset, q0, dQ);*/
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dred_decode_state(&ec, dec->state);
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/* decode newest to oldest and store oldest to newest */
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for (i = 0; i < IMIN(DRED_NUM_REDUNDANCY_FRAMES, (min_feature_frames+1)/2); i += 2)
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{
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/* FIXME: Figure out how to avoid missing a last frame that would take up < 8 bits. */
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if (8*num_bytes - ec_tell(&ec) <= 7)
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break;
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q_level = compute_quantizer(q0, dQ, i/2);
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offset = q_level * DRED_LATENT_DIM;
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dred_decode_latents(
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&ec,
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&dec->latents[(i/2)*DRED_LATENT_DIM],
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quant_scales + offset,
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r + offset,
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p0 + offset
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);
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offset = 2 * i * DRED_NUM_FEATURES;
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}
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dec->process_stage = 1;
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dec->nb_latents = i/2;
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return i/2;
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}
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