125 lines
3.1 KiB
C
125 lines
3.1 KiB
C
/*
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* JPEG-LS common code
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* Copyright (c) 2003 Michael Niedermayer
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* Copyright (c) 2006 Konstantin Shishkov
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* JPEG-LS common code.
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*/
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#ifndef AVCODEC_JPEGLS_H
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#define AVCODEC_JPEGLS_H
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#include "libavutil/common.h"
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#include "avcodec.h"
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#include "internal.h"
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typedef struct JpeglsContext {
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AVCodecContext *avctx;
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} JpeglsContext;
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typedef struct JLSState {
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int T1, T2, T3;
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int A[367], B[367], C[365], N[367];
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int limit, reset, bpp, qbpp, maxval, range;
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int near, twonear;
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int run_index[4];
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} JLSState;
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/**
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* Calculate initial JPEG-LS parameters
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*/
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void ff_jpegls_init_state(JLSState *state);
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/**
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* Calculate quantized gradient value, used for context determination
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*/
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static inline int ff_jpegls_quantize(JLSState *s, int v)
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{
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if (v == 0)
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return 0;
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if (v < 0) {
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if (v <= -s->T3)
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return -4;
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if (v <= -s->T2)
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return -3;
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if (v <= -s->T1)
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return -2;
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if (v < -s->near)
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return -1;
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return 0;
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} else {
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if (v <= s->near)
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return 0;
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if (v < s->T1)
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return 1;
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if (v < s->T2)
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return 2;
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if (v < s->T3)
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return 3;
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return 4;
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}
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}
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/**
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* Calculate JPEG-LS codec values
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*/
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void ff_jpegls_reset_coding_parameters(JLSState *s, int reset_all);
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static inline void ff_jpegls_downscale_state(JLSState *state, int Q)
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{
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if (state->N[Q] == state->reset) {
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state->A[Q] >>= 1;
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state->B[Q] >>= 1;
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state->N[Q] >>= 1;
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}
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state->N[Q]++;
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}
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static inline int ff_jpegls_update_state_regular(JLSState *state,
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int Q, int err)
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{
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if(FFABS(err) > 0xFFFF)
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return -0x10000;
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state->A[Q] += FFABS(err);
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err *= state->twonear;
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state->B[Q] += err;
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ff_jpegls_downscale_state(state, Q);
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if (state->B[Q] <= -state->N[Q]) {
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state->B[Q] = FFMAX(state->B[Q] + state->N[Q], 1 - state->N[Q]);
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if (state->C[Q] > -128)
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state->C[Q]--;
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} else if (state->B[Q] > 0) {
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state->B[Q] = FFMIN(state->B[Q] - state->N[Q], 0);
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if (state->C[Q] < 127)
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state->C[Q]++;
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}
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return err;
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}
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#define R(a, i) (bits == 8 ? ((uint8_t *)(a))[i] : ((uint16_t *)(a))[i])
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#define W(a, i, v) (bits == 8 ? (((uint8_t *)(a))[i] = v) : (((uint16_t *)(a))[i] = v))
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#endif /* AVCODEC_JPEGLS_H */
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