xref: /third_party/ffmpeg/libavcodec/opus_rc.h (revision cabdff1a)
1/*
2 * Copyright (c) 2012 Andrew D'Addesio
3 * Copyright (c) 2013-2014 Mozilla Corporation
4 * Copyright (c) 2017 Rostislav Pehlivanov <atomnuker@gmail.com>
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23#ifndef AVCODEC_OPUS_RC_H
24#define AVCODEC_OPUS_RC_H
25
26#include <stdint.h>
27#include "get_bits.h"
28
29#define OPUS_MAX_PACKET_SIZE 1275
30
31#define opus_ilog(i) (av_log2(i) + !!(i))
32
33typedef struct RawBitsContext {
34    const uint8_t *position;
35    uint32_t bytes;
36    uint32_t cachelen;
37    uint32_t cacheval;
38} RawBitsContext;
39
40typedef struct OpusRangeCoder {
41    GetBitContext gb;
42    RawBitsContext rb;
43    uint32_t range;
44    uint32_t value;
45    uint32_t total_bits;
46
47    /* Encoder */
48    uint8_t buf[OPUS_MAX_PACKET_SIZE + 12]; /* memcpy vs (memmove + overreading) */
49    uint8_t *rng_cur;                      /* Current range coded byte */
50    int ext;                               /* Awaiting propagation */
51    int rem;                               /* Carryout flag */
52
53    /* Encoding stats */
54    int waste;
55} OpusRangeCoder;
56
57/**
58 * CELT: estimate bits of entropy that have thus far been consumed for the
59 *       current CELT frame, to integer and fractional (1/8th bit) precision
60 */
61static av_always_inline uint32_t opus_rc_tell(const OpusRangeCoder *rc)
62{
63    return rc->total_bits - av_log2(rc->range) - 1;
64}
65
66static av_always_inline uint32_t opus_rc_tell_frac(const OpusRangeCoder *rc)
67{
68    uint32_t i, total_bits, rcbuffer, range;
69
70    total_bits = rc->total_bits << 3;
71    rcbuffer   = av_log2(rc->range) + 1;
72    range      = rc->range >> (rcbuffer-16);
73
74    for (i = 0; i < 3; i++) {
75        int bit;
76        range = range * range >> 15;
77        bit = range >> 16;
78        rcbuffer = rcbuffer << 1 | bit;
79        range >>= bit;
80    }
81
82    return total_bits - rcbuffer;
83}
84
85uint32_t ff_opus_rc_dec_cdf(OpusRangeCoder *rc, const uint16_t *cdf);
86void     ff_opus_rc_enc_cdf(OpusRangeCoder *rc, int val, const uint16_t *cdf);
87
88uint32_t ff_opus_rc_dec_log(OpusRangeCoder *rc, uint32_t bits);
89void     ff_opus_rc_enc_log(OpusRangeCoder *rc, int val, uint32_t bits);
90
91uint32_t ff_opus_rc_dec_uint_step(OpusRangeCoder *rc, int k0);
92void     ff_opus_rc_enc_uint_step(OpusRangeCoder *rc, uint32_t val, int k0);
93
94uint32_t ff_opus_rc_dec_uint_tri(OpusRangeCoder *rc, int qn);
95void     ff_opus_rc_enc_uint_tri(OpusRangeCoder *rc, uint32_t k, int qn);
96
97uint32_t ff_opus_rc_dec_uint(OpusRangeCoder *rc, uint32_t size);
98void     ff_opus_rc_enc_uint(OpusRangeCoder *rc, uint32_t val, uint32_t size);
99
100uint32_t ff_opus_rc_get_raw(OpusRangeCoder *rc, uint32_t count);
101void     ff_opus_rc_put_raw(OpusRangeCoder *rc, uint32_t val, uint32_t count);
102
103int      ff_opus_rc_dec_laplace(OpusRangeCoder *rc, uint32_t symbol, int decay);
104void     ff_opus_rc_enc_laplace(OpusRangeCoder *rc, int *value, uint32_t symbol, int decay);
105
106int      ff_opus_rc_dec_init(OpusRangeCoder *rc, const uint8_t *data, int size);
107void     ff_opus_rc_dec_raw_init(OpusRangeCoder *rc, const uint8_t *rightend, uint32_t bytes);
108
109void     ff_opus_rc_enc_end(OpusRangeCoder *rc, uint8_t *dst, int size);
110void     ff_opus_rc_enc_init(OpusRangeCoder *rc);
111
112#define OPUS_RC_CHECKPOINT_UPDATE(rc) \
113    rc_rollback_bits = opus_rc_tell_frac(rc); \
114    rc_rollback_ctx  = *rc
115
116#define OPUS_RC_CHECKPOINT_SPAWN(rc) \
117    uint32_t rc_rollback_bits = opus_rc_tell_frac(rc); \
118    OpusRangeCoder rc_rollback_ctx = *rc \
119
120#define OPUS_RC_CHECKPOINT_BITS(rc) \
121    (opus_rc_tell_frac(rc) - rc_rollback_bits)
122
123#define OPUS_RC_CHECKPOINT_ROLLBACK(rc) \
124    memcpy(rc, &rc_rollback_ctx, sizeof(OpusRangeCoder)); \
125
126#endif /* AVCODEC_OPUS_RC_H */
127