| 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 | #ifndef AVCODEC_JPEGLS_H |
| 29 | #define AVCODEC_JPEGLS_H |
| 30 | |
| 31 | #include "libavutil/common.h" |
| 32 | #include "avcodec.h" |
| 33 | #include "internal.h" |
| 34 | |
| 35 | typedef struct JpeglsContext { |
| 36 | AVCodecContext *avctx; |
| 37 | } JpeglsContext; |
| 38 | |
| 39 | typedef struct JLSState { |
| 40 | int T1, T2, T3; |
| 41 | int A[367], B[367], C[365], N[367]; |
| 42 | int limit, reset, bpp, qbpp, maxval, range; |
| 43 | int near, twonear; |
| 44 | int run_index[4]; |
| 45 | } JLSState; |
| 46 | |
| 47 | /** |
| 48 | * Calculate initial JPEG-LS parameters |
| 49 | */ |
| 50 | void ff_jpegls_init_state(JLSState *state); |
| 51 | |
| 52 | /** |
| 53 | * Calculate quantized gradient value, used for context determination |
| 54 | */ |
| 55 | static inline int ff_jpegls_quantize(JLSState *s, int v) |
| 56 | { |
| 57 | if (v == 0) |
| 58 | return 0; |
| 59 | if (v < 0) { |
| 60 | if (v <= -s->T3) |
| 61 | return -4; |
| 62 | if (v <= -s->T2) |
| 63 | return -3; |
| 64 | if (v <= -s->T1) |
| 65 | return -2; |
| 66 | if (v < -s->near) |
| 67 | return -1; |
| 68 | return 0; |
| 69 | } else { |
| 70 | if (v <= s->near) |
| 71 | return 0; |
| 72 | if (v < s->T1) |
| 73 | return 1; |
| 74 | if (v < s->T2) |
| 75 | return 2; |
| 76 | if (v < s->T3) |
| 77 | return 3; |
| 78 | return 4; |
| 79 | } |
| 80 | } |
| 81 | |
| 82 | /** |
| 83 | * Calculate JPEG-LS codec values |
| 84 | */ |
| 85 | void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all); |
| 86 | |
| 87 | static inline void ff_jpegls_downscale_state(JLSState *state, int Q) |
| 88 | { |
| 89 | if (state->N[Q] == state->reset) { |
| 90 | state->A[Q] >>= 1; |
| 91 | state->B[Q] >>= 1; |
| 92 | state->N[Q] >>= 1; |
| 93 | } |
| 94 | state->N[Q]++; |
| 95 | } |
| 96 | |
| 97 | static inline int ff_jpegls_update_state_regular(JLSState *state, |
| 98 | int Q, int err) |
| 99 | { |
| 100 | if(FFABS(err) > 0xFFFF) |
| 101 | return -0x10000; |
| 102 | state->A[Q] += FFABS(err); |
| 103 | err *= state->twonear; |
| 104 | state->B[Q] += err; |
| 105 | |
| 106 | ff_jpegls_downscale_state(state, Q); |
| 107 | |
| 108 | if (state->B[Q] <= -state->N[Q]) { |
| 109 | state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]); |
| 110 | if (state->C[Q] > -128) |
| 111 | state->C[Q]--; |
| 112 | } else if (state->B[Q] > 0) { |
| 113 | state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0); |
| 114 | if (state->C[Q] < 127) |
| 115 | state->C[Q]++; |
| 116 | } |
| 117 | |
| 118 | return err; |
| 119 | } |
| 120 | |
| 121 | #define R(a, i) (bits == 8 ? ((uint8_t *)(a))[i] : ((uint16_t *)(a))[i]) |
| 122 | #define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v)) |
| 123 | |
| 124 | #endif /* AVCODEC_JPEGLS_H */ |