/* * Copyright (c) 2012 Andrew D'Addesio * Copyright (c) 2013-2014 Mozilla Corporation * Copyright (c) 2017 Rostislav Pehlivanov <atomnuker@gmail.com> * * This file is part of FFmpeg. * * FFmpeg is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * FFmpeg is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public * License along with FFmpeg; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ #include "rc.h" #define OPUS_RC_BITS 32#define OPUS_RC_SYM  8#define OPUS_RC_CEIL ((1 << OPUS_RC_SYM) - 1)#define OPUS_RC_TOP (1u << 31)#define OPUS_RC_BOT (OPUS_RC_TOP >> OPUS_RC_SYM)#define OPUS_RC_SHIFT (OPUS_RC_BITS - OPUS_RC_SYM - 1) static av_always_inline void opus_rc_enc_carryout(OpusRangeCoder *rc, int cbuf){    const int cb = cbuf >> OPUS_RC_SYM, mb = (OPUS_RC_CEIL + cb) & OPUS_RC_CEIL;    if (cbuf == OPUS_RC_CEIL) {        rc->ext++;        return;    }    rc->rng_cur[0] = rc->rem + cb;    rc->rng_cur += (rc->rem >= 0);    for (; rc->ext > 0; rc->ext--)        *rc->rng_cur++ = mb;    av_assert0(rc->rng_cur < rc->rb.position);    rc->rem = cbuf & OPUS_RC_CEIL; /* Propagate */} static av_always_inline void opus_rc_dec_normalize(OpusRangeCoder *rc){    while (rc->range <= OPUS_RC_BOT) {        rc->value = ((rc->value << OPUS_RC_SYM) | (get_bits(&rc->gb, OPUS_RC_SYM) ^ OPUS_RC_CEIL)) & (OPUS_RC_TOP - 1);        rc->range     <<= OPUS_RC_SYM;        rc->total_bits += OPUS_RC_SYM;    }} static av_always_inline void opus_rc_enc_normalize(OpusRangeCoder *rc){    while (rc->range <= OPUS_RC_BOT) {        opus_rc_enc_carryout(rc, rc->value >> OPUS_RC_SHIFT);        rc->value = (rc->value << OPUS_RC_SYM) & (OPUS_RC_TOP - 1);        rc->range     <<= OPUS_RC_SYM;        rc->total_bits += OPUS_RC_SYM;    }} static av_always_inline void opus_rc_dec_update(OpusRangeCoder *rc, uint32_t scale,                                                uint32_t low, uint32_t high,                                                uint32_t total){    rc->value -= scale * (total - high);    rc->range  = low ? scale * (high - low)                      : rc->range - scale * (total - high);    opus_rc_dec_normalize(rc);} /* Main encoding function, this needs to go fast */static av_always_inline void opus_rc_enc_update(OpusRangeCoder *rc, uint32_t b, uint32_t p,                                                uint32_t p_tot, const int ptwo){    uint32_t rscaled, cnd = !!b;    if (ptwo) /* Whole function is inlined so hopefully branch is optimized out */        rscaled = rc->range >> ff_log2(p_tot);    else        rscaled = rc->range/p_tot;    rc->value +=    cnd*(rc->range - rscaled*(p_tot - b));    rc->range  = (!cnd)*(rc->range - rscaled*(p_tot - p)) + cnd*rscaled*(p - b);    opus_rc_enc_normalize(rc);} uint32_t ff_opus_rc_dec_cdf(OpusRangeCoder *rc, const uint16_t *cdf){    unsigned int k, scale, total, symbol, low, high;     total = *cdf++;     scale   = rc->range / total;    symbol = rc->value / scale + 1;    symbol = total - FFMIN(symbol, total);     for (k = 0; cdf[k] <= symbol; k++);    high = cdf[k];    low  = k ? cdf[k-1] : 0;     opus_rc_dec_update(rc, scale, low, high, total);     return k;} void ff_opus_rc_enc_cdf(OpusRangeCoder *rc, int val, const uint16_t *cdf){    opus_rc_enc_update(rc, (!!val)*cdf[val], cdf[val + 1], cdf[0], 1);} uint32_t ff_opus_rc_dec_log(OpusRangeCoder *rc, uint32_t bits){    uint32_t k, scale;    scale = rc->range >> bits; // in this case, scale = symbol     if (rc->value >= scale) {        rc->value -= scale;        rc->range -= scale;        k = 0;    } else {        rc->range = scale;        k = 1;    }    opus_rc_dec_normalize(rc);    return k;} void ff_opus_rc_enc_log(OpusRangeCoder *rc, int val, uint32_t bits){    bits = (1 << bits) - 1;    opus_rc_enc_update(rc, (!!val)*bits, bits + !!val, bits + 1, 1);} /** * CELT: read 1-25 raw bits at the end of the frame, backwards byte-wise */uint32_t ff_opus_rc_get_raw(OpusRangeCoder *rc, uint32_t count){    uint32_t value = 0;     while (rc->rb.bytes && rc->rb.cachelen < count) {        rc->rb.cacheval |= *--rc->rb.position << rc->rb.cachelen;        rc->rb.cachelen += 8;        rc->rb.bytes--;    }     value = av_zero_extend(rc->rb.cacheval, count);    rc->rb.cacheval    >>= count;    rc->rb.cachelen     -= count;    rc->total_bits      += count;     return value;} /** * CELT: write 0 - 31 bits to the rawbits buffer */void ff_opus_rc_put_raw(OpusRangeCoder *rc, uint32_t val, uint32_t count){    const int to_write = FFMIN(32 - rc->rb.cachelen, count);     rc->total_bits += count;    rc->rb.cacheval |= av_zero_extend(val, to_write) << rc->rb.cachelen;    rc->rb.cachelen = (rc->rb.cachelen + to_write) % 32;     if (!rc->rb.cachelen && count) {        AV_WB32((uint8_t *)rc->rb.position, rc->rb.cacheval);        rc->rb.bytes    += 4;        rc->rb.position -= 4;        rc->rb.cachelen = count - to_write;        rc->rb.cacheval = av_zero_extend(val >> to_write, rc->rb.cachelen);        av_assert0(rc->rng_cur < rc->rb.position);    }} /** * CELT: read a uniform distribution */uint32_t ff_opus_rc_dec_uint(OpusRangeCoder *rc, uint32_t size){    uint32_t bits, k, scale, total;     bits  = opus_ilog(size - 1);    total = (bits > 8) ? ((size - 1) >> (bits - 8)) + 1 : size;     scale  = rc->range / total;    k      = rc->value / scale + 1;    k      = total - FFMIN(k, total);    opus_rc_dec_update(rc, scale, k, k + 1, total);     if (bits > 8) {        k = k << (bits - 8) | ff_opus_rc_get_raw(rc, bits - 8);        return FFMIN(k, size - 1);    } else        return k;} /** * CELT: write a uniformly distributed integer */void ff_opus_rc_enc_uint(OpusRangeCoder *rc, uint32_t val, uint32_t size){    const int ps = FFMAX(opus_ilog(size - 1) - 8, 0);    opus_rc_enc_update(rc, val >> ps, (val >> ps) + 1, ((size - 1) >> ps) + 1, 0);    ff_opus_rc_put_raw(rc, val, ps);} uint32_t ff_opus_rc_dec_uint_step(OpusRangeCoder *rc, int k0){    /* Use a probability of 3 up to itheta=8192 and then use 1 after */    uint32_t k, scale, symbol, total = (k0+1)*3 + k0;    scale  = rc->range / total;    symbol = rc->value / scale + 1;    symbol = total - FFMIN(symbol, total);     k = (symbol < (k0+1)*3) ? symbol/3 : symbol - (k0+1)*2;     opus_rc_dec_update(rc, scale, (k <= k0) ? 3*(k+0) : (k-1-k0) + 3*(k0+1),                       (k <= k0) ? 3*(k+1) : (k-0-k0) + 3*(k0+1), total);    return k;} void ff_opus_rc_enc_uint_step(OpusRangeCoder *rc, uint32_t val, int k0){    const uint32_t a = val <= k0, b = 2*a + 1;    k0 = (k0 + 1) << 1;    val = b*(val + k0) - 3*a*k0;    opus_rc_enc_update(rc, val, val + b, (k0 << 1) - 1, 0);} uint32_t ff_opus_rc_dec_uint_tri(OpusRangeCoder *rc, int qn){    uint32_t k, scale, symbol, total, low, center;     total = ((qn>>1) + 1) * ((qn>>1) + 1);    scale   = rc->range / total;    center = rc->value / scale + 1;    center = total - FFMIN(center, total);     if (center < total >> 1) {        k      = (ff_sqrt(8 * center + 1) - 1) >> 1;        low    = k * (k + 1) >> 1;        symbol = k + 1;    } else {        k      = (2*(qn + 1) - ff_sqrt(8*(total - center - 1) + 1)) >> 1;        low    = total - ((qn + 1 - k) * (qn + 2 - k) >> 1);        symbol = qn + 1 - k;    }     opus_rc_dec_update(rc, scale, low, low + symbol, total);     return k;} void ff_opus_rc_enc_uint_tri(OpusRangeCoder *rc, uint32_t k, int qn){    uint32_t symbol, low, total;     total = ((qn>>1) + 1) * ((qn>>1) + 1);     if (k <= qn >> 1) {        low    = k * (k + 1) >> 1;        symbol = k + 1;    } else {        low    = total - ((qn + 1 - k) * (qn + 2 - k) >> 1);        symbol = qn + 1 - k;    }     opus_rc_enc_update(rc, low, low + symbol, total, 0);} int ff_opus_rc_dec_laplace(OpusRangeCoder *rc, uint32_t symbol, int decay){    /* extends the range coder to model a Laplace distribution */    int value = 0;    uint32_t scale, low = 0, center;     scale  = rc->range >> 15;    center = rc->value / scale + 1;    center = (1 << 15) - FFMIN(center, 1 << 15);     if (center >= symbol) {        value++;        low = symbol;        symbol = 1 + ((32768 - 32 - symbol) * (16384-decay) >> 15);         while (symbol > 1 && center >= low + 2 * symbol) {            value++;            symbol *= 2;            low    += symbol;            symbol  = (((symbol - 2) * decay) >> 15) + 1;        }         if (symbol <= 1) {            int distance = (center - low) >> 1;            value += distance;            low   += 2 * distance;        }         if (center < low + symbol)            value *= -1;        else            low += symbol;    }     opus_rc_dec_update(rc, scale, low, FFMIN(low + symbol, 32768), 32768);     return value;} void ff_opus_rc_enc_laplace(OpusRangeCoder *rc, int *value, uint32_t symbol, int decay){    uint32_t low = symbol;    int i = 1, val = FFABS(*value), pos = *value > 0;    if (!val) {        opus_rc_enc_update(rc, 0, symbol, 1 << 15, 1);        return;    }    symbol = ((32768 - 32 - symbol)*(16384 - decay)) >> 15;    for (; i < val && symbol; i++) {        low   += (symbol << 1) + 2;        symbol = (symbol*decay) >> 14;    }    if (symbol) {        low += (++symbol)*pos;    } else {        const int distance = FFMIN(val - i, (((32768 - low) - !pos) >> 1) - 1);        low   += pos + (distance << 1);        symbol = FFMIN(1, 32768 - low);        *value = FFSIGN(*value)*(distance + i);    }    opus_rc_enc_update(rc, low, low + symbol, 1 << 15, 1);} int ff_opus_rc_dec_init(OpusRangeCoder *rc, const uint8_t *data, int size){    int ret = init_get_bits8(&rc->gb, data, size);    if (ret < 0)        return ret;     rc->range = 128;    rc->value = 127 - get_bits(&rc->gb, 7);    rc->total_bits = 9;    opus_rc_dec_normalize(rc);     return 0;} void ff_opus_rc_dec_raw_init(OpusRangeCoder *rc, const uint8_t *rightend, uint32_t bytes){    rc->rb.position = rightend;    rc->rb.bytes    = bytes;    rc->rb.cachelen = 0;    rc->rb.cacheval = 0;} void ff_opus_rc_enc_end(OpusRangeCoder *rc, uint8_t *dst, int size){    int rng_bytes, bits = OPUS_RC_BITS - opus_ilog(rc->range);    uint32_t mask = (OPUS_RC_TOP - 1) >> bits;    uint32_t end = (rc->value + mask) & ~mask;     if ((end | mask) >= rc->value + rc->range) {        bits++;        mask >>= 1;        end = (rc->value + mask) & ~mask;    }     /* Finish what's left */    while (bits > 0) {        opus_rc_enc_carryout(rc, end >> OPUS_RC_SHIFT);        end = (end << OPUS_RC_SYM) & (OPUS_RC_TOP - 1);        bits -= OPUS_RC_SYM;    }     /* Flush out anything left or marked */    if (rc->rem >= 0 || rc->ext > 0)        opus_rc_enc_carryout(rc, 0);     rng_bytes = rc->rng_cur - rc->buf;    memcpy(dst, rc->buf, rng_bytes);     rc->waste = size*8 - (rc->rb.bytes*8 + rc->rb.cachelen) - rng_bytes*8;     /* Put the rawbits part, if any */    if (rc->rb.bytes || rc->rb.cachelen) {        int i, lap;        uint8_t *rb_src, *rb_dst;        ff_opus_rc_put_raw(rc, 0, 32 - rc->rb.cachelen);        rb_src = rc->buf + OPUS_MAX_FRAME_SIZE + 12 - rc->rb.bytes;        rb_dst = dst + FFMAX(size - rc->rb.bytes, 0);        lap = &dst[rng_bytes] - rb_dst;        for (i = 0; i < lap; i++)            rb_dst[i] |= rb_src[i];        memcpy(&rb_dst[lap], &rb_src[lap], FFMAX(rc->rb.bytes - lap, 0));    }} void ff_opus_rc_enc_init(OpusRangeCoder *rc){    rc->value = 0;    rc->range = OPUS_RC_TOP;    rc->total_bits = OPUS_RC_BITS + 1;    rc->rem = -1;    rc->ext =  0;    rc->rng_cur = rc->buf;    ff_opus_rc_dec_raw_init(rc, rc->buf + OPUS_MAX_FRAME_SIZE + 8, 0);}