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 35typedef struct JpeglsContext { 36 AVCodecContext *avctx; 37} JpeglsContext; 38 39typedef 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 */ 50void ff_jpegls_init_state(JLSState *state); 51 52/** 53 * Calculate quantized gradient value, used for context determination 54 */ 55static 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 */ 85void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all); 86 87static 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 97static 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 */ 125