avcodec/scpr: add version 3 support

Signed-off-by: Paul B Mahol <onemda@gmail.com>

1 files changed, 1207 insertions, 0 deletions

diff --git a/libavcodec/scpr3.c b/libavcodec/scpr3.c
new file mode 100644
index 0000000..b59a8cc
--- /dev/null
+++ b/libavcodec/scpr3.c
@@ -0,0 +1,1207 @@
+/*
+ * ScreenPressor version 3 decoder
+ *
+ * Copyright (c) 2017 Paul B Mahol
+ *
+ * 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 <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "libavutil/qsort.h"
+
+#include "avcodec.h"
+#include "bytestream.h"
+#include "internal.h"
+#include "scpr.h"
+
+static void renew_table3(uint32_t nsym, uint32_t *cntsum,
+                         uint16_t *freqs, uint16_t *freqs1,
+                         uint16_t *cnts, uint8_t *dectab)
+{
+    uint32_t a = 0, b = 4096 / nsym, c = b - (b >> 1);
+
+    *cntsum = c * nsym;
+
+    for (int d = 0; d < nsym; d++) {
+        freqs[d] = b;
+        freqs1[d] = a;
+        cnts[d] = c;
+        for (int q = a + 128 - 1 >> 7, f = (a + b - 1 >> 7) + 1; q < f; q++)
+            dectab[q] = d;
+
+        a += b;
+    }
+}
+
+static void reinit_tables3(SCPRContext * s)
+{
+    for (int i = 0; i < 3; i++) {
+        for (int j = 0; j < 4096; j++) {
+            PixelModel3 *m = &s->pixel_model3[i][j];
+            m->type = 0;
+        }
+    }
+
+    for (int i = 0; i < 6; i++) {
+        renew_table3(256, &s->run_model3[i].cntsum,
+                     s->run_model3[i].freqs[0], s->run_model3[i].freqs[1],
+                     s->run_model3[i].cnts, s->run_model3[i].dectab);
+    }
+
+    renew_table3(256, &s->range_model3.cntsum,
+                 s->range_model3.freqs[0], s->range_model3.freqs[1],
+                 s->range_model3.cnts, s->range_model3.dectab);
+
+    renew_table3(5, &s->fill_model3.cntsum,
+                 s->fill_model3.freqs[0], s->fill_model3.freqs[1],
+                 s->fill_model3.cnts, s->fill_model3.dectab);
+
+    renew_table3(256, &s->count_model3.cntsum,
+                 s->count_model3.freqs[0], s->count_model3.freqs[1],
+                 s->count_model3.cnts, s->count_model3.dectab);
+
+    for (int i = 0; i < 4; i++) {
+        renew_table3(16, &s->sxy_model3[i].cntsum,
+                     s->sxy_model3[i].freqs[0], s->sxy_model3[i].freqs[1],
+                     s->sxy_model3[i].cnts, s->sxy_model3[i].dectab);
+    }
+
+    for (int i = 0; i < 2; i++) {
+        renew_table3(512, &s->mv_model3[i].cntsum,
+                     s->mv_model3[i].freqs[0], s->mv_model3[i].freqs[1],
+                     s->mv_model3[i].cnts, s->mv_model3[i].dectab);
+    }
+
+    for (int i = 0; i < 6; i++) {
+        renew_table3(6, &s->op_model3[i].cntsum,
+                     s->op_model3[i].freqs[0], s->op_model3[i].freqs[1],
+                     s->op_model3[i].cnts, s->op_model3[i].dectab);
+    }
+}
+
+static int decode3(GetByteContext *gb, RangeCoder *rc, uint32_t a, uint32_t b)
+{
+    uint32_t code = a * (rc->code >> 12) + (rc->code & 0xFFF) - b;
+
+    while (code < 0x800000 && bytestream2_get_bytes_left(gb) > 0)
+        code = bytestream2_get_byteu(gb) | (code << 8);
+    rc->code = code;
+
+    return 0;
+}
+
+static void rescale(PixelModel3 *m, int *totfr)
+{
+    uint32_t a;
+
+    a = 256 - m->size;
+    for (int b = 0; b < m->size; b++) {
+        m->freqs[b] -= m->freqs[b] >> 1;
+        a += m->freqs[b];
+    }
+
+    *totfr = a;
+}
+
+static int add_symbol(PixelModel3 *m, int index, uint32_t symbol, int *totfr, int max)
+{
+    if (m->size == max)
+        return 0;
+
+    for (int c = m->size - 1; c >= index; c--) {
+        m->symbols[c + 1] = m->symbols[c];
+        m->freqs[c + 1] = m->freqs[c];
+    }
+
+    m->symbols[index] = symbol;
+    m->freqs[index] = 50;
+    m->size++;
+
+    if (m->maxpos >= index)
+        m->maxpos++;
+
+    *totfr += 50;
+    if (*totfr + 50 > 4096)
+        rescale(m, totfr);
+
+    return 1;
+}
+
+static int decode_adaptive45(PixelModel3 *m, int rccode, uint32_t *value,
+                             uint16_t *a, uint16_t *b, uint32_t *c, int max)
+{
+    uint32_t q, g, maxpos, d, e = *c, totfr = *c;
+    int ret;
+
+    for (d = 0; e <= 2048; d++)
+        e <<= 1;
+    maxpos = m->maxpos;
+    rccode >>= d;
+    *c = m->freqs[maxpos];
+    m->freqs[maxpos] += 4096 - e >> d;
+
+    for (q = 0, g = 0, e = 0; q < m->size; q++) {
+        uint32_t f = m->symbols[q];
+        uint32_t p = e + f - g;
+        uint32_t k = m->freqs[q];
+
+        if (rccode < p) {
+            *value = rccode - e + g;
+            *b = rccode << d;
+            *a = 1 << d;
+            m->freqs[maxpos] = *c;
+            ret = add_symbol(m, q, *value, &totfr, max);
+            *c = totfr;
+            return ret;
+        }
+
+        if (p + k > rccode) {
+            *value = f;
+            e += *value - g;
+            *b = e << d;
+            *a = k << d;
+            m->freqs[maxpos] = *c;
+            m->freqs[q] += 50;
+            totfr += 50;
+            if ((q != maxpos) && (m->freqs[q] > m->freqs[maxpos]))
+                m->maxpos = q;
+            if (totfr + 50 > 4096)
+                rescale(m, &totfr);
+            *c = totfr;
+            return 1;
+        }
+
+        e += f - g + k;
+        g = f + 1;
+    }
+
+    m->freqs[maxpos] = *c;
+    *value = g + rccode - e;
+    *b = rccode << d;
+    *a = 1 << d;
+    ret = add_symbol(m, q, *value, &totfr, max);
+    *c = totfr;
+    return ret;
+}
+
+static int update_model6_to_7(PixelModel3 *m)
+{
+    PixelModel3 n = {0};
+    int c, d, e, f, k, p, length, i, j, index;
+    uint16_t *freqs, *freqs1, *cnts;
+
+    n.type = 7;
+
+    length = m->length;
+    freqs = n.freqs;
+    freqs1 = n.freqs1;
+    cnts = n.cnts;
+    n.cntsum = m->cnts[length];
+    for (i = 0; i < length; i++) {
+        if (!m->cnts[i])
+            continue;
+        index = m->symbols[i];
+        freqs[index] = m->freqs[2 * i];
+        freqs1[index] = m->freqs[2 * i + 1];
+        cnts[index] = m->cnts[i];
+    }
+    c = 1 << m->fshift;
+    d = c - (c >> 1);
+    for (j = 0, e = 0; j < 256; j++) {
+        f = freqs[j];
+        if (!f) {
+            f = c;
+            freqs[j] = c;
+            freqs1[j] = e;
+            cnts[j] = d;
+        }
+        p = (e + 127) >> 7;
+        k = ((f + e - 1) >> 7) + 1;
+        for (i = 0; i < k - p; i++)
+            n.dectab[p + i] = j;
+        e += f;
+    }
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static void calc_sum(PixelModel3 *m)
+{
+    uint32_t a;
+    int len;
+
+    len = m->length;
+    a = 256 - m->size << (m->fshift > 0 ? m->fshift - 1 : 0);
+    for (int c = 0; c < len; c++)
+        a += m->cnts[c];
+    m->cnts[len] = a;
+}
+
+static void rescale_dec(PixelModel3 *m)
+{
+    uint16_t cnts[256] = {0};
+    uint16_t freqs[512] = {0};
+    int b, c, e, g;
+    uint32_t a;
+
+    for (a = 1 << (0 < m->fshift ? m->fshift - 1 : 0), b = 0; b < 256; b++)
+        cnts[b] = a;
+
+    for (a = 0, b = m->size; a < b; a++)
+        cnts[m->symbols[a]] = m->cnts[a];
+
+    for (b = a = 0; b < 256; b++) {
+        freqs[2 * b] = cnts[b];
+        freqs[2 * b + 1] = a;
+        a += cnts[b];
+    }
+
+    if (m->fshift > 0)
+        m->fshift--;
+
+    a = 256 - m->size << (0 < m->fshift ? m->fshift - 1 : 0);
+    for (b = 0, c = m->size; b < c; b++) {
+        m->cnts[b] -= m->cnts[b] >> 1;
+        a = a + m->cnts[b];
+        e = m->symbols[b];
+        g = freqs[2 * e + 1];
+        m->freqs[2 * b] = freqs[2 * e];
+        m->freqs[2 * b + 1] = g;
+    }
+    m->cnts[m->length] = a;
+}
+
+static int update_model5_to_6(PixelModel3 *m, uint8_t value)
+{
+    PixelModel3 n = {0};
+    int c, d, e, f, g, k, q, p;
+
+    n.type = 6;
+    n.length = 32;
+
+    for (c = m->size, d = 256 - c, e = 0; e < c; e++)
+        d = d + m->freqs[e];
+
+    for (e = 0; d <= 2048; e++)
+        d <<= 1;
+
+    for (q = d = 0, g = q = 0; g < c; g++) {
+        p = m->symbols[g];
+        d = d + (p - q);
+        q = m->freqs[g];
+        k = q << e;
+        n.freqs[2 * g] = k;
+        n.freqs[2 * g + 1] = d << e;
+        n.cnts[g] = k - (k >> 1);
+        n.symbols[g] = p;
+        d += q;
+        q = p + 1;
+    }
+
+    n.fshift = e;
+    e = 1 << n.fshift;
+    d = 0;
+    if (value > 0) {
+        d = -1;
+        for (p = f = g = 0; p < c; p++) {
+            k = n.symbols[p];
+            if (k > d && k < value) {
+                d = k;
+                g = n.freqs[2 * p];
+                f = n.freqs[2 * p + 1];
+            }
+        }
+        d = 0 < g ? f + g + (value - d - 1 << n.fshift) : value << n.fshift;
+    }
+    n.freqs[2 * c] = e;
+    n.freqs[2 * c + 1] = d;
+    n.cnts[c] = e - (e >> 1);
+    n.symbols[c] = value;
+    n.size = c + 1;
+    e = 25 << n.fshift;
+    n.cnts[c] += e;
+    n.cnts[32] += e;
+    if (n.cnts[32] + e > 4096)
+        rescale_dec(&n);
+
+    calc_sum(&n);
+    for (c = 0, e = n.size - 1; c < e; c++) {
+        for (g = c + 1, f = n.size; g < f; g++) {
+            if (q = n.freqs[2 * g], k = n.freqs[2 * c], q > k) {
+                int l = n.freqs[2 * c + 1];
+                int h = n.freqs[2 * g + 1];
+                n.freqs[2 * c] = q;
+                n.freqs[2 * c + 1] = h;
+                n.freqs[2 * g] = k;
+                n.freqs[2 * g + 1] = l;
+                FFSWAP(uint16_t, n.cnts[c], n.cnts[g]);
+                FFSWAP(uint8_t, n.symbols[c], n.symbols[g]);
+            }
+        }
+    }
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static void grow_dec(PixelModel3 *m)
+{
+    int a;
+
+    a = 2 * m->length;
+    m->cnts[2 * m->length] = m->cnts[m->length];
+    m->length = a;
+}
+
+static int add_dec(PixelModel3 *m, int sym, int f1, int f2)
+{
+    int size;
+
+    if (m->size >= 40 || m->size >= m->length)
+        return -1;
+
+    size = m->size;
+    m->symbols[size] = sym;
+    m->freqs[2 * size] = f1;
+    m->freqs[2 * size + 1] = f2;
+    m->cnts[size] = f1 - (f1 >> 1);
+    m->size++;
+
+    return size;
+}
+
+static void incr_cntdec(PixelModel3 *m, int a)
+{
+    int b, len, d, e, g;
+
+    b = 25 << m->fshift;
+    len = m->length;
+    m->cnts[a] += b;
+    m->cnts[len] += b;
+    if (a > 0 && m->cnts[a] > m->cnts[a - 1]) {
+        FFSWAP(uint16_t, m->cnts[a], m->cnts[a - 1]);
+        d = m->freqs[2 * a];
+        e = m->freqs[2 * a + 1];
+        g = m->freqs[2 * (a - 1) + 1];
+        m->freqs[2 * a] = m->freqs[2 * (a - 1)];
+        m->freqs[2 * a + 1] = g;
+        g = a - 1;
+        m->freqs[2 * g] = d;
+        m->freqs[2 * g + 1] = e;
+        FFSWAP(uint8_t, m->symbols[a], m->symbols[a - 1]);
+    }
+
+    if (m->cnts[len] + b > 4096)
+        rescale_dec(m);
+}
+
+static int decode_adaptive6(PixelModel3 *m, uint32_t code, uint32_t *value,
+                            uint16_t *a, uint16_t *b)
+{
+    int c, d, e, f, g, q;
+
+    for (c = 0, d = 0, e = 0, f = 0, g = 0, q = m->size; g < q; g++) {
+        uint32_t p = m->freqs[2 * g + 1];
+
+        if (p <= code) {
+            uint32_t k = m->freqs[2 * g];
+
+            if (p + k > code) {
+                *value = m->symbols[g];
+                *a = k;
+                *b = p;
+                incr_cntdec(m, g);
+                return 1;
+            }
+
+            if (p >= d) {
+                c = k;
+                d = p;
+                e = m->symbols[g];
+            }
+        }
+    }
+
+    g = 1 << m->fshift;
+    q = f = 0;
+
+    if (c > 0) {
+        f = code - (d + c) >> m->fshift;
+        q = f + e + 1;
+        f = d + c + (f << m->fshift);
+    } else {
+        q = code >> m->fshift;
+        f = q << m->fshift;
+    }
+
+    *a = g;
+    *b = f;
+    *value = q;
+
+    c = add_dec(m, q, g, f);
+    if (c < 0) {
+        if (m->length == 64)
+            return 0;
+        grow_dec(m);
+        c = add_dec(m, q, g, f);
+    }
+
+    incr_cntdec(m, c);
+    return 1;
+}
+
+static int cmpbytes(const void *p1, const void *p2)
+{
+    int left  = *(const uint8_t *)p1;
+    int right = *(const uint8_t *)p2;
+    return FFDIFFSIGN(left, right);
+}
+
+static int update_model1_to_2(PixelModel3 *m, uint32_t val)
+{
+    PixelModel3 n = {0};
+    int i, b;
+
+    n.type = 2;
+    n.size = m->size + 1;
+    b = m->size;
+    for (i = 0; i < b; i++)
+        n.symbols[i] = m->symbols[i];
+    n.symbols[b] = val;
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static int update_model1_to_4(PixelModel3 *m, uint32_t val)
+{
+    PixelModel3 n = {0};
+    int size, i;
+
+    size = m->size;
+    n.type = 4;
+    n.size = size;
+    for (i = 0; i < n.size; i++) {
+        n.symbols[i] = m->symbols[i];
+    }
+    AV_QSORT(n.symbols, size, uint8_t, cmpbytes);
+    for (i = 0; i < n.size; i++) {
+        if (val == n.symbols[i]) {
+            n.freqs[i] = 100;
+            n.maxpos = i;
+        } else {
+            n.freqs[i] = 50;
+        }
+    }
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static int update_model1_to_5(PixelModel3 *m, uint32_t val)
+{
+    PixelModel3 n = {0};
+    int i, size, freqs;
+    uint32_t a;
+
+    size = m->size;
+    n.size = size;
+    for (i = 0; i < size; i++) {
+        n.symbols[i] = m->symbols[i];
+    }
+    AV_QSORT(n.symbols, size, uint8_t, cmpbytes);
+    size = n.size;
+    for (i = 0; i < size; i++) {
+        if (val == n.symbols[i]) {
+            n.freqs[i] = 100;
+            n.maxpos = i;
+        } else {
+            n.freqs[i] = 50;
+        }
+    }
+    a = 256 - size;
+    for (i = 0; i < size; i++, a += freqs)
+        freqs = n.freqs[i];
+    n.type = 5;
+    n.cntsum = a;
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static int decode_static1(PixelModel3 *m, uint32_t val)
+{
+    uint32_t size;
+
+    size = m->size;
+    for (int i = 0; i < size; i++) {
+        if (val == m->symbols[i]) {
+            if (size <= 4)
+                return update_model1_to_4(m, val);
+            else
+                return update_model1_to_5(m, val);
+        }
+    }
+
+    if (size >= 14)
+        return update_model1_to_2(m, val);
+
+    m->symbols[size] = val;
+    m->size++;
+    return 0;
+}
+
+static int update_model2_to_6(PixelModel3 *m, uint8_t value, int a4)
+{
+    PixelModel3 n = {0};
+    int c, d, e, f, g, q;
+
+    n.type = 6;
+    n.length = a4;
+
+    memset(n.symbols, 1u, a4);
+
+    c = m->size;
+    d = 256 - c + (64 * c + 64);
+    for (e = 0; d <= 2048; e++) {
+        d <<= 1;
+    }
+
+    g = q = 0;
+    AV_QSORT(m->symbols, c, uint8_t, cmpbytes);
+    for (f = d = 0; f < c; f++) {
+        int p = f;
+        int k = m->symbols[p];
+        int l;
+        g = g + (k - q);
+
+        if (k == value) {
+            d = p;
+            q = 128;
+        } else {
+            q = 64;
+        }
+        l = q << e;
+        n.freqs[2 * p] = l;
+        n.freqs[2 * p + 1] = g << e;
+        n.symbols[p] = k;
+        n.cnts[p] = l - (l >> 1);
+        g += q;
+        q = k + 1;
+    }
+    n.size = c;
+    n.fshift = e;
+    calc_sum(&n);
+
+    if (d > 0) {
+        c = n.freqs[0];
+        e = n.freqs[1];
+        g = n.freqs[2 * d + 1];
+        n.freqs[0] = n.freqs[2 * d];
+        n.freqs[1] = g;
+        n.freqs[2 * d] = c;
+        n.freqs[2 * d + 1] = e;
+        FFSWAP(uint16_t, n.cnts[0], n.cnts[d]);
+        FFSWAP(uint8_t, n.symbols[0], n.symbols[d]);
+    }
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static int update_model2_to_3(PixelModel3 *m, uint32_t val)
+{
+    PixelModel3 n = {0};
+    uint32_t size;
+
+    n.type = 3;
+    n.size = m->size + 1;
+
+    size = m->size;
+    for (int i = 0; i < size; i++)
+        n.symbols[i] = m->symbols[i];
+    n.symbols[size] = val;
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static int decode_static2(PixelModel3 *m, uint32_t val)
+{
+    uint32_t size;
+
+    size = m->size;
+    for (int i = 0; i < size; i++) {
+        if (val == m->symbols[i]) {
+            int a;
+
+            if (m->size <= 32)
+                a = 32;
+            else
+                a = 64;
+            return update_model2_to_6(m, val, a);
+        }
+    }
+
+    if (size >= 64)
+        return update_model2_to_3(m, val);
+
+    m->symbols[size] = val;
+    m->size++;
+
+    return 0;
+}
+
+static int update_model3_to_7(PixelModel3 *m, uint8_t value)
+{
+    PixelModel3 n = {0};
+    int c, d, e, f, g, q;
+
+    n.type = 7;
+
+    for (c = 0; c < 256; c++) {
+        d = c;
+        n.freqs[d] = 1;
+        n.cnts[d] = 1;
+    }
+
+    for (c = m->size, d = (4096 - (256 - c)) / (c + 1) | 0, e = d - (d >> 1), g = 0; g < c;) {
+        q = g++;
+        q = m->symbols[q];
+        n.freqs[q] = d;
+        n.cnts[q] = e;
+    }
+    n.freqs[value] += d;
+    n.cnts[value] += 16;
+    for (d = c = n.cntsum = 0; 256 > d; d++) {
+        e = d;
+        n.cntsum += n.cnts[e];
+        n.freqs1[e] = c;
+        for (g = n.freqs[e], q = c + 128 - 1 >> 7, f = (c + g - 1 >> 7) + 1; q < f; q++) {
+            n.dectab[q] = e;
+        }
+        c += g;
+    }
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static int decode_static3(PixelModel3 *m, uint32_t val)
+{
+    uint32_t size = m->size;
+
+    for (int i = 0; i < size; i++) {
+        if (val == m->symbols[i])
+            return update_model3_to_7(m, val);
+    }
+
+    if (size >= 256)
+        return 0;
+
+    m->symbols[size] = val;
+    m->size++;
+    return 0;
+}
+
+static void sync_code3(GetByteContext *gb, RangeCoder *rc)
+{
+    rc->code1++;
+    if (rc->code1 == 0x20000) {
+        rc->code = bytestream2_get_le32(gb);
+        rc->code1 = 0;
+    }
+}
+
+static int decode_value3(SCPRContext *s, uint32_t max, uint32_t *cntsum,
+                         uint16_t *freqs1, uint16_t *freqs2,
+                         uint16_t *cnts, uint8_t *dectable,
+                         uint32_t *value)
+{
+    GetByteContext *gb = &s->gb;
+    RangeCoder *rc = &s->rc;
+    uint32_t r, y, a, b, e, g, q;
+
+    r = dectable[(rc->code & 0xFFFu) >> 7];
+    if (r < max) {
+        while (freqs2[r + 1] <= (rc->code & 0xFFF)) {
+            if (++r >= max)
+                break;
+        }
+    }
+
+    if (r > max)
+        return AVERROR_INVALIDDATA;
+
+    cnts[r] += 16;
+    a = freqs1[r];
+    b = freqs2[r];
+    *cntsum += 16;
+    if (*cntsum + 16 > 4096) {
+        *cntsum = 0;
+        for (int c = 0, i = 0; i < max + 1; i++) {
+            e = cnts[i];
+            freqs2[i] = c;
+            freqs1[i] = e;
+            g = (c + 127) >> 7;
+            c += e;
+            q = ((c - 1) >> 7) + 1;
+            if (q > g) {
+                for (int j = 0; j < q - g; j++)
+                    dectable[j + g] = i;
+            }
+            y = e - (e >> 1);
+            cnts[i] = y;
+            *cntsum += y;
+        }
+    }
+
+    decode3(gb, rc, a, b);
+    sync_code3(gb, rc);
+
+    *value = r;
+
+    return 0;
+}
+
+static void calc_sum5(PixelModel3 *m)
+{
+    uint32_t a;
+
+    a = 256 - m->size;
+    for (int b = 0; b < m->size; b++)
+        a += m->freqs[b];
+    m->cntsum = a;
+}
+
+static int update_model4_to_5(PixelModel3 *m, uint32_t value)
+{
+    PixelModel3 n = {0};
+    int c, e, g, totfr;
+
+    n.type = 5;
+
+    for (c = 0, e = 0; c < m->size && m->symbols[c] < value; c++) {
+        n.symbols[c] = m->symbols[c];
+        e += n.freqs[c] = m->freqs[c];
+    }
+
+    g = c;
+    n.symbols[g] = value;
+    e += n.freqs[g++] = 50;
+    for (; c < m->size; g++, c++) {
+        n.symbols[g] = m->symbols[c];
+        e += n.freqs[g] = m->freqs[c];
+    }
+    n.size = m->size + 1;
+    if (e > 4096)
+        rescale(&n, &totfr);
+
+    calc_sum5(&n);
+
+    memcpy(m, &n, sizeof(n));
+
+    return 0;
+}
+
+static int decode_unit3(SCPRContext *s, PixelModel3 *m, uint32_t code, uint32_t *value)
+{
+    GetByteContext *gb = &s->gb;
+    RangeCoder *rc = &s->rc;
+    uint16_t a = 0, b = 0;
+    uint32_t param;
+    int type;
+
+    type = m->type;
+    switch (type) {
+    case 0:
+        *value = bytestream2_get_byte(&s->gb);
+        m->type = 1;
+        m->size = 1;
+        m->symbols[0] = *value;
+        sync_code3(gb, rc);
+        break;
+    case 1:
+        *value = bytestream2_get_byte(&s->gb);
+        decode_static1(m, *value);
+        sync_code3(gb, rc);
+        break;
+    case 2:
+        *value = bytestream2_get_byte(&s->gb);
+        decode_static2(m, *value);
+        sync_code3(gb, rc);
+        break;
+    case 3:
+        *value = bytestream2_get_byte(&s->gb);
+        decode_static3(m, *value);
+        sync_code3(gb, rc);
+        break;
+    case 4:
+        param = m->freqs[0] + m->freqs[1] + m->freqs[2] + m->freqs[3] + 256 - m->size;
+        if (!decode_adaptive45(m, code, value, &a, &b, &param, 4))
+            update_model4_to_5(m, *value);
+        decode3(gb, rc, a, b);
+        sync_code3(gb, rc);
+        break;
+    case 5:
+        if (!decode_adaptive45(m, code, value, &a, &b, &m->cntsum, 16))
+            update_model5_to_6(m, *value);
+        decode3(gb, rc, a, b);
+        sync_code3(gb, rc);
+        break;
+    case 6:
+        if (!decode_adaptive6(m, code, value, &a, &b)) {
+            update_model6_to_7(m);
+        }
+        decode3(gb, rc, a, b);
+        sync_code3(gb, rc);
+        break;
+    case 7:
+        return decode_value3(s, 255, &m->cntsum,
+                             m->freqs, m->freqs1,
+                             m->cnts, m->dectab, value);
+    }
+
+    if (*value > 255)
+        return AVERROR_INVALIDDATA;
+
+    return 0;
+}
+
+static int decode_units3(SCPRContext * s, uint32_t *red,
+                         uint32_t *green, uint32_t *blue,
+                         int *cx, int *cx1)
+{
+    RangeCoder *rc = &s->rc;
+    int ret;
+
+    ret = decode_unit3(s, &s->pixel_model3[0][*cx + *cx1], rc->code & 0xFFF, red);
+    if (ret < 0)
+        return ret;
+
+    *cx1 = (*cx << 6) & 0xFC0;
+    *cx = *red >> 2;
+
+    ret = decode_unit3(s, &s->pixel_model3[1][*cx + *cx1], rc->code & 0xFFF, green);
+    if (ret < 0)
+        return ret;
+
+    *cx1 = (*cx << 6) & 0xFC0;
+    *cx = *green >> 2;
+
+    ret = decode_unit3(s, &s->pixel_model3[2][*cx + *cx1], rc->code & 0xFFF, blue);
+    if (ret < 0)
+        return ret;
+
+    *cx1 = (*cx << 6) & 0xFC0;
+    *cx = *blue >> 2;
+
+    return 0;
+}
+
+static void init_rangecoder3(RangeCoder *rc, GetByteContext *gb)
+{
+    rc->code  = bytestream2_get_le32(gb);
+    rc->code1 = 0;
+}
+
+static int decompress_i3(AVCodecContext *avctx, uint32_t *dst, int linesize)
+{
+    SCPRContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    RangeCoder *rc = &s->rc;
+    int cx = 0, cx1 = 0, k = 0;
+    int run, off, y = 0, x = 0, ret;
+    uint32_t backstep = linesize - avctx->width;
+    uint32_t clr = 0, lx, ly, ptype, r, g, b;
+
+    bytestream2_skip(gb, 1);
+    init_rangecoder3(rc, gb);
+    reinit_tables3(s);
+
+    while (k < avctx->width + 1) {
+        ret = decode_units3(s, &r, &g, &b, &cx, &cx1);
+        if (ret < 0)
+            return ret;
+        ret = decode_value3(s, 255, &s->run_model3[0].cntsum,
+                            s->run_model3[0].freqs[0],
+                            s->run_model3[0].freqs[1],
+                            s->run_model3[0].cnts,
+                            s->run_model3[0].dectab, &run);
+        if (ret < 0)
+            return ret;
+        if (run <= 0)
+            return AVERROR_INVALIDDATA;
+
+        clr = (b << 16) + (g << 8) + r;
+        k += run;
+        while (run-- > 0) {
+            if (y >= avctx->height)
+                return AVERROR_INVALIDDATA;
+
+            dst[y * linesize + x] = clr;
+            lx = x;
+            ly = y;
+            x++;
+            if (x >= avctx->width) {
+                x = 0;
+                y++;
+            }
+        }
+    }
+    off = -linesize - 1;
+    ptype = 0;
+
+    while (x < avctx->width && y < avctx->height) {
+        ret = decode_value3(s, 5, &s->op_model3[ptype].cntsum,
+                            s->op_model3[ptype].freqs[0],
+                            s->op_model3[ptype].freqs[1],
+                            s->op_model3[ptype].cnts,
+                            s->op_model3[ptype].dectab, &ptype);
+        if (ret < 0)
+            return ret;
+        if (ptype == 0) {
+            ret = decode_units3(s, &r, &g, &b, &cx, &cx1);
+            if (ret < 0)
+                return ret;
+            clr = (b << 16) + (g << 8) + r;
+        }
+        if (ptype > 5)
+            return AVERROR_INVALIDDATA;
+        ret = decode_value3(s, 255, &s->run_model3[ptype].cntsum,
+                            s->run_model3[ptype].freqs[0],
+                            s->run_model3[ptype].freqs[1],
+                            s->run_model3[ptype].cnts,
+                            s->run_model3[ptype].dectab, &run);
+        if (ret < 0)
+            return ret;
+        if (run <= 0)
+            return AVERROR_INVALIDDATA;
+
+        ret = decode_run_i(avctx, ptype, run, &x, &y, clr,
+                           dst, linesize, &lx, &ly,
+                           backstep, off, &cx, &cx1);
+        if (run < 0)
+            return ret;
+    }
+
+    return 0;
+}
+
+static int decompress_p3(AVCodecContext *avctx,
+                         uint32_t *dst, int linesize,
+                         uint32_t *prev, int plinesize)
+{
+    SCPRContext *s = avctx->priv_data;
+    GetByteContext *gb = &s->gb;
+    int ret, temp, min, max, x, y, cx = 0, cx1 = 0;
+    int backstep = linesize - avctx->width;
+    int mvx = 0, mvy = 0;
+
+    if (bytestream2_get_byte(gb) == 0)
+        return 1;
+    init_rangecoder3(&s->rc, gb);
+
+    ret  = decode_value3(s, 255, &s->range_model3.cntsum,
+                         s->range_model3.freqs[0],
+                         s->range_model3.freqs[1],
+                         s->range_model3.cnts,
+                         s->range_model3.dectab, &min);
+    ret |= decode_value3(s, 255, &s->range_model3.cntsum,
+                         s->range_model3.freqs[0],
+                         s->range_model3.freqs[1],
+                         s->range_model3.cnts,
+                         s->range_model3.dectab, &temp);
+    min += temp << 8;
+    ret |= decode_value3(s, 255, &s->range_model3.cntsum,
+                         s->range_model3.freqs[0],
+                         s->range_model3.freqs[1],
+                         s->range_model3.cnts,
+                         s->range_model3.dectab, &max);
+    ret |= decode_value3(s, 255, &s->range_model3.cntsum,
+                         s->range_model3.freqs[0],
+                         s->range_model3.freqs[1],
+                         s->range_model3.cnts,
+                         s->range_model3.dectab, &temp);
+    if (ret < 0)
+        return ret;
+
+    max += temp << 8;
+    if (min > max || min >= s->nbcount)
+        return AVERROR_INVALIDDATA;
+
+    memset(s->blocks, 0, sizeof(*s->blocks) * s->nbcount);
+
+    while (min <= max) {
+        int fill, count;
+
+        ret  = decode_value3(s, 4, &s->fill_model3.cntsum,
+                             s->fill_model3.freqs[0],
+                             s->fill_model3.freqs[1],
+                             s->fill_model3.cnts,
+                             s->fill_model3.dectab, &fill);
+        ret |= decode_value3(s, 255, &s->count_model3.cntsum,
+                             s->count_model3.freqs[0],
+                             s->count_model3.freqs[1],
+                             s->count_model3.cnts,
+                             s->count_model3.dectab, &count);
+        if (ret < 0)
+            return ret;
+        if (count <= 0)
+            return AVERROR_INVALIDDATA;
+
+        while (min < s->nbcount && count-- > 0) {
+            s->blocks[min++] = fill;
+        }
+    }
+
+    for (y = 0; y < s->nby; y++) {
+        for (x = 0; x < s->nbx; x++) {
+            int sy1 = 0, sy2 = 16, sx1 = 0, sx2 = 16;
+
+            if (s->blocks[y * s->nbx + x] == 0)
+                continue;
+
+            if (((s->blocks[y * s->nbx + x] + 1) & 1) > 0) {
+                ret  = decode_value3(s, 15, &s->sxy_model3[0].cntsum,
+                                     s->sxy_model3[0].freqs[0],
+                                     s->sxy_model3[0].freqs[1],
+                                     s->sxy_model3[0].cnts,
+                                     s->sxy_model3[0].dectab, &sx1);
+                ret |= decode_value3(s, 15, &s->sxy_model3[1].cntsum,
+                                     s->sxy_model3[1].freqs[0],
+                                     s->sxy_model3[1].freqs[1],
+                                     s->sxy_model3[1].cnts,
+                                     s->sxy_model3[1].dectab, &sy1);
+                ret |= decode_value3(s, 15, &s->sxy_model3[2].cntsum,
+                                     s->sxy_model3[2].freqs[0],
+                                     s->sxy_model3[2].freqs[1],
+                                     s->sxy_model3[2].cnts,
+                                     s->sxy_model3[2].dectab, &sx2);
+                ret |= decode_value3(s, 15, &s->sxy_model3[3].cntsum,
+                                     s->sxy_model3[3].freqs[0],
+                                     s->sxy_model3[3].freqs[1],
+                                     s->sxy_model3[3].cnts,
+                                     s->sxy_model3[3].dectab, &sy2);
+                if (ret < 0)
+                    return ret;
+
+                sx2++;
+                sy2++;
+            }
+            if (((s->blocks[y * s->nbx + x] + 3) & 2) > 0) {
+                int i, a, b, c, j, by = y * 16, bx = x * 16;
+                uint32_t code;
+
+                a = s->rc.code & 0xFFF;
+                c = 1;
+
+                if (a < 0x800)
+                    c = 0;
+                b = 2048;
+                if (!c)
+                    b = 0;
+
+                code = a + ((s->rc.code >> 1) & 0xFFFFF800) - b;
+                while (code < 0x800000 && bytestream2_get_bytes_left(gb) > 0)
+                    code = bytestream2_get_byteu(gb) | (code << 8);
+                s->rc.code = code;
+
+                sync_code3(gb, &s->rc);
+
+                if (!c) {
+                    ret  = decode_value3(s, 511, &s->mv_model3[0].cntsum,
+                                         s->mv_model3[0].freqs[0],
+                                         s->mv_model3[0].freqs[1],
+                                         s->mv_model3[0].cnts,
+                                         s->mv_model3[0].dectab, &mvx);
+                    ret |= decode_value3(s, 511, &s->mv_model3[1].cntsum,
+                                         s->mv_model3[1].freqs[0],
+                                         s->mv_model3[1].freqs[1],
+                                         s->mv_model3[1].cnts,
+                                         s->mv_model3[1].dectab, &mvy);
+                    if (ret < 0)
+                        return ret;
+
+                    mvx -= 256;
+                    mvy -= 256;
+                }
+
+                if (by + mvy + sy1 < 0 || bx + mvx + sx1 < 0 ||
+                    by + mvy + sy1 >= avctx->height || bx + mvx + sx1 >= avctx->width)
+                    return AVERROR_INVALIDDATA;
+
+                for (i = 0; i < sy2 - sy1 && (by + sy1 + i) < avctx->height && (by + mvy + sy1 + i) < avctx->height; i++) {
+                    for (j = 0; j < sx2 - sx1 && (bx + sx1 + j) < avctx->width && (bx + mvx + sx1 + j) < avctx->width; j++) {
+                        dst[(by + i + sy1) * linesize + bx + sx1 + j] = prev[(by + mvy + sy1 + i) * plinesize + bx + sx1 + mvx + j];
+                    }
+                }
+            } else {
+                int run, bx = x * 16 + sx1, by = y * 16 + sy1;
+                uint32_t clr, ptype = 0, r, g, b;
+
+                for (; by < y * 16 + sy2 && by < avctx->height;) {
+                    ret = decode_value3(s, 5, &s->op_model3[ptype].cntsum,
+                                        s->op_model3[ptype].freqs[0],
+                                        s->op_model3[ptype].freqs[1],
+                                        s->op_model3[ptype].cnts,
+                                        s->op_model3[ptype].dectab, &ptype);
+                    if (ret < 0)
+                        return ret;
+                    if (ptype == 0) {
+                        ret = decode_units3(s, &r, &g, &b, &cx, &cx1);
+                        if (ret < 0)
+                            return ret;
+
+                        clr = (b << 16) + (g << 8) + r;
+                    }
+                    if (ptype > 5)
+                        return AVERROR_INVALIDDATA;
+                    ret = decode_value3(s, 255, &s->run_model3[ptype].cntsum,
+                                        s->run_model3[ptype].freqs[0],
+                                        s->run_model3[ptype].freqs[1],
+                                        s->run_model3[ptype].cnts,
+                                        s->run_model3[ptype].dectab, &run);
+                    if (ret < 0)
+                        return ret;
+                    if (run <= 0)
+                        return AVERROR_INVALIDDATA;
+
+                    ret = decode_run_p(avctx, ptype, run, x, y, clr,
+                                       dst, prev, linesize, plinesize, &bx, &by,
+                                       backstep, sx1, sx2, &cx, &cx1);
+                    if (ret < 0)
+                        return ret;
+                }
+            }
+        }
+    }
+
+    return 0;
+}