blob: 7f9fa8d60ccd46090e8dbbe83802d08641ba590b
| 1 | /* |
| 2 | * JPEG-LS common code |
| 3 | * Copyright (c) 2003 Michael Niedermayer |
| 4 | * Copyright (c) 2006 Konstantin Shishkov |
| 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 | /** |
| 24 | * @file |
| 25 | * JPEG-LS common code. |
| 26 | */ |
| 27 | |
| 28 | #include "internal.h" |
| 29 | #include "jpegls.h" |
| 30 | |
| 31 | void ff_jpegls_init_state(JLSState *state) |
| 32 | { |
| 33 | int i; |
| 34 | |
| 35 | state->twonear = state->near * 2 + 1; |
| 36 | state->range = (state->maxval + state->twonear - 1) / state->twonear + 1; |
| 37 | |
| 38 | // QBPP = ceil(log2(RANGE)) |
| 39 | for (state->qbpp = 0; (1 << state->qbpp) < state->range; state->qbpp++) |
| 40 | ; |
| 41 | |
| 42 | state->bpp = FFMAX(av_log2(state->maxval) + 1, 2); |
| 43 | state->limit = 2*(state->bpp + FFMAX(state->bpp, 8)) - state->qbpp; |
| 44 | |
| 45 | for (i = 0; i < 367; i++) { |
| 46 | state->A[i] = FFMAX(state->range + 32 >> 6, 2); |
| 47 | state->N[i] = 1; |
| 48 | } |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * Custom value clipping function used in T1, T2, T3 calculation |
| 53 | */ |
| 54 | static inline int iso_clip(int v, int vmin, int vmax) |
| 55 | { |
| 56 | if (v > vmax || v < vmin) |
| 57 | return vmin; |
| 58 | else |
| 59 | return v; |
| 60 | } |
| 61 | |
| 62 | void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all) |
| 63 | { |
| 64 | const int basic_t1 = 3; |
| 65 | const int basic_t2 = 7; |
| 66 | const int basic_t3 = 21; |
| 67 | int factor; |
| 68 | |
| 69 | if (s->maxval == 0 || reset_all) |
| 70 | s->maxval = (1 << s->bpp) - 1; |
| 71 | |
| 72 | if (s->maxval >= 128) { |
| 73 | factor = FFMIN(s->maxval, 4095) + 128 >> 8; |
| 74 | |
| 75 | if (s->T1 == 0 || reset_all) |
| 76 | s->T1 = iso_clip(factor * (basic_t1 - 2) + 2 + 3 * s->near, |
| 77 | s->near + 1, s->maxval); |
| 78 | if (s->T2 == 0 || reset_all) |
| 79 | s->T2 = iso_clip(factor * (basic_t2 - 3) + 3 + 5 * s->near, |
| 80 | s->T1, s->maxval); |
| 81 | if (s->T3 == 0 || reset_all) |
| 82 | s->T3 = iso_clip(factor * (basic_t3 - 4) + 4 + 7 * s->near, |
| 83 | s->T2, s->maxval); |
| 84 | } else { |
| 85 | factor = 256 / (s->maxval + 1); |
| 86 | |
| 87 | if (s->T1 == 0 || reset_all) |
| 88 | s->T1 = iso_clip(FFMAX(2, basic_t1 / factor + 3 * s->near), |
| 89 | s->near + 1, s->maxval); |
| 90 | if (s->T2 == 0 || reset_all) |
| 91 | s->T2 = iso_clip(FFMAX(3, basic_t2 / factor + 5 * s->near), |
| 92 | s->T1, s->maxval); |
| 93 | if (s->T3 == 0 || reset_all) |
| 94 | s->T3 = iso_clip(FFMAX(4, basic_t3 / factor + 7 * s->near), |
| 95 | s->T2, s->maxval); |
| 96 | } |
| 97 | |
| 98 | if (s->reset == 0 || reset_all) |
| 99 | s->reset = 64; |
| 100 | ff_dlog(NULL, "[JPEG-LS RESET] T=%i,%i,%i\n", s->T1, s->T2, s->T3); |
| 101 | } |
| 102 |