mirror of
https://github.com/xenia-project/FFmpeg.git
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2912e87a6c
Signed-off-by: Mans Rullgard <mans@mansr.com>
523 lines
15 KiB
C
523 lines
15 KiB
C
/*
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* Lagarith lossless decoder
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* Copyright (c) 2009 Nathan Caldwell <saintdev (at) gmail.com>
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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 libavcodec/lagarith.c
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* Lagarith lossless decoder
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* @author Nathan Caldwell
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*/
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#include "avcodec.h"
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#include "get_bits.h"
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#include "mathops.h"
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#include "dsputil.h"
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#include "lagarithrac.h"
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enum LagarithFrameType {
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FRAME_RAW = 1, /*!< uncompressed */
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FRAME_U_RGB24 = 2, /*!< unaligned RGB24 */
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FRAME_ARITH_YUY2 = 3, /*!< arithmetic coded YUY2 */
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FRAME_ARITH_RGB24 = 4, /*!< arithmetic coded RGB24 */
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FRAME_SOLID_GRAY = 5, /*!< solid grayscale color frame */
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FRAME_SOLID_COLOR = 6, /*!< solid non-grayscale color frame */
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FRAME_OLD_ARITH_RGB = 7, /*!< obsolete arithmetic coded RGB (no longer encoded by upstream since version 1.1.0) */
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FRAME_ARITH_RGBA = 8, /*!< arithmetic coded RGBA */
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FRAME_SOLID_RGBA = 9, /*!< solid RGBA color frame */
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FRAME_ARITH_YV12 = 10, /*!< arithmetic coded YV12 */
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FRAME_REDUCED_RES = 11, /*!< reduced resolution YV12 frame */
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};
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typedef struct LagarithContext {
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AVCodecContext *avctx;
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AVFrame picture;
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DSPContext dsp;
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int zeros; /*!< number of consecutive zero bytes encountered */
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int zeros_rem; /*!< number of zero bytes remaining to output */
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} LagarithContext;
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/**
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* Compute the 52bit mantissa of 1/(double)denom.
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* This crazy format uses floats in an entropy coder and we have to match x86
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* rounding exactly, thus ordinary floats aren't portable enough.
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* @param denom denominator
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* @return 52bit mantissa
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* @see softfloat_mul
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*/
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static uint64_t softfloat_reciprocal(uint32_t denom)
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{
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int shift = av_log2(denom - 1) + 1;
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uint64_t ret = (1ULL << 52) / denom;
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uint64_t err = (1ULL << 52) - ret * denom;
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ret <<= shift;
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err <<= shift;
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err += denom / 2;
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return ret + err / denom;
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}
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/**
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* (uint32_t)(x*f), where f has the given mantissa, and exponent 0
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* Used in combination with softfloat_reciprocal computes x/(double)denom.
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* @param x 32bit integer factor
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* @param mantissa mantissa of f with exponent 0
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* @return 32bit integer value (x*f)
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* @see softfloat_reciprocal
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*/
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static uint32_t softfloat_mul(uint32_t x, uint64_t mantissa)
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{
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uint64_t l = x * (mantissa & 0xffffffff);
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uint64_t h = x * (mantissa >> 32);
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h += l >> 32;
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l &= 0xffffffff;
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l += 1 << av_log2(h >> 21);
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h += l >> 32;
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return h >> 20;
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}
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static uint8_t lag_calc_zero_run(int8_t x)
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{
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return (x << 1) ^ (x >> 7);
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}
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static int lag_decode_prob(GetBitContext *gb, uint32_t *value)
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{
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static const uint8_t series[] = { 1, 2, 3, 5, 8, 13, 21 };
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int i;
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int bit = 0;
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int bits = 0;
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int prevbit = 0;
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unsigned val;
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for (i = 0; i < 7; i++) {
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if (prevbit && bit)
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break;
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prevbit = bit;
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bit = get_bits1(gb);
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if (bit && !prevbit)
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bits += series[i];
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}
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bits--;
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if (bits < 0 || bits > 31) {
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*value = 0;
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return -1;
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} else if (bits == 0) {
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*value = 0;
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return 0;
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}
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val = get_bits_long(gb, bits);
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val |= 1 << bits;
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*value = val - 1;
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return 0;
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}
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static int lag_read_prob_header(lag_rac *rac, GetBitContext *gb)
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{
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int i, j, scale_factor;
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unsigned prob, cumulative_target;
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unsigned cumul_prob = 0;
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unsigned scaled_cumul_prob = 0;
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rac->prob[0] = 0;
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rac->prob[257] = UINT_MAX;
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/* Read probabilities from bitstream */
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for (i = 1; i < 257; i++) {
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if (lag_decode_prob(gb, &rac->prob[i]) < 0) {
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av_log(rac->avctx, AV_LOG_ERROR, "Invalid probability encountered.\n");
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return -1;
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}
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if ((uint64_t)cumul_prob + rac->prob[i] > UINT_MAX) {
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av_log(rac->avctx, AV_LOG_ERROR, "Integer overflow encountered in cumulative probability calculation.\n");
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return -1;
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}
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cumul_prob += rac->prob[i];
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if (!rac->prob[i]) {
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if (lag_decode_prob(gb, &prob)) {
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av_log(rac->avctx, AV_LOG_ERROR, "Invalid probability run encountered.\n");
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return -1;
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}
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if (prob > 257 - i)
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prob = 257 - i;
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for (j = 0; j < prob; j++)
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rac->prob[++i] = 0;
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}
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}
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if (!cumul_prob) {
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av_log(rac->avctx, AV_LOG_ERROR, "All probabilities are 0!\n");
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return -1;
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}
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/* Scale probabilities so cumulative probability is an even power of 2. */
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scale_factor = av_log2(cumul_prob);
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if (cumul_prob & (cumul_prob - 1)) {
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uint64_t mul = softfloat_reciprocal(cumul_prob);
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for (i = 1; i < 257; i++) {
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rac->prob[i] = softfloat_mul(rac->prob[i], mul);
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scaled_cumul_prob += rac->prob[i];
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}
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scale_factor++;
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cumulative_target = 1 << scale_factor;
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if (scaled_cumul_prob > cumulative_target) {
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av_log(rac->avctx, AV_LOG_ERROR,
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"Scaled probabilities are larger than target!\n");
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return -1;
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}
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scaled_cumul_prob = cumulative_target - scaled_cumul_prob;
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for (i = 1; scaled_cumul_prob; i = (i & 0x7f) + 1) {
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if (rac->prob[i]) {
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rac->prob[i]++;
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scaled_cumul_prob--;
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}
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/* Comment from reference source:
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* if (b & 0x80 == 0) { // order of operations is 'wrong'; it has been left this way
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* // since the compression change is negligable and fixing it
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* // breaks backwards compatibilty
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* b =- (signed int)b;
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* b &= 0xFF;
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* } else {
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* b++;
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* b &= 0x7f;
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* }
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*/
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}
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}
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rac->scale = scale_factor;
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/* Fill probability array with cumulative probability for each symbol. */
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for (i = 1; i < 257; i++)
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rac->prob[i] += rac->prob[i - 1];
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return 0;
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}
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static void add_lag_median_prediction(uint8_t *dst, uint8_t *src1,
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uint8_t *diff, int w, int *left,
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int *left_top)
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{
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/* This is almost identical to add_hfyu_median_prediction in dsputil.h.
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* However the &0xFF on the gradient predictor yealds incorrect output
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* for lagarith.
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*/
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int i;
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uint8_t l, lt;
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l = *left;
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lt = *left_top;
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for (i = 0; i < w; i++) {
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l = mid_pred(l, src1[i], l + src1[i] - lt) + diff[i];
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lt = src1[i];
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dst[i] = l;
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}
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*left = l;
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*left_top = lt;
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}
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static void lag_pred_line(LagarithContext *l, uint8_t *buf,
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int width, int stride, int line)
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{
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int L, TL;
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if (!line) {
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/* Left prediction only for first line */
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L = l->dsp.add_hfyu_left_prediction(buf + 1, buf + 1,
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width - 1, buf[0]);
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return;
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} else if (line == 1) {
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/* Second line, left predict first pixel, the rest of the line is median predicted */
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/* FIXME: In the case of RGB this pixel is top predicted */
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TL = buf[-stride];
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} else {
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/* Top left is 2 rows back, last pixel */
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TL = buf[width - (2 * stride) - 1];
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}
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/* Left pixel is actually prev_row[width] */
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L = buf[width - stride - 1];
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add_lag_median_prediction(buf, buf - stride, buf,
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width, &L, &TL);
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}
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static int lag_decode_line(LagarithContext *l, lag_rac *rac,
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uint8_t *dst, int width, int stride,
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int esc_count)
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{
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int i = 0;
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int ret = 0;
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if (!esc_count)
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esc_count = -1;
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/* Output any zeros remaining from the previous run */
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handle_zeros:
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if (l->zeros_rem) {
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int count = FFMIN(l->zeros_rem, width - i);
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memset(dst + i, 0, count);
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i += count;
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l->zeros_rem -= count;
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}
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while (i < width) {
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dst[i] = lag_get_rac(rac);
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ret++;
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if (dst[i])
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l->zeros = 0;
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else
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l->zeros++;
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i++;
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if (l->zeros == esc_count) {
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int index = lag_get_rac(rac);
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ret++;
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l->zeros = 0;
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l->zeros_rem = lag_calc_zero_run(index);
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goto handle_zeros;
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}
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}
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return ret;
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}
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static int lag_decode_zero_run_line(LagarithContext *l, uint8_t *dst,
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const uint8_t *src, int width,
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int esc_count)
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{
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int i = 0;
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int count;
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uint8_t zero_run = 0;
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const uint8_t *start = src;
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uint8_t mask1 = -(esc_count < 2);
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uint8_t mask2 = -(esc_count < 3);
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uint8_t *end = dst + (width - 2);
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output_zeros:
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if (l->zeros_rem) {
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count = FFMIN(l->zeros_rem, width - i);
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memset(dst, 0, count);
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l->zeros_rem -= count;
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dst += count;
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}
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while (dst < end) {
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i = 0;
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while (!zero_run && dst + i < end) {
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i++;
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zero_run =
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!(src[i] | (src[i + 1] & mask1) | (src[i + 2] & mask2));
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}
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if (zero_run) {
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zero_run = 0;
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i += esc_count;
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memcpy(dst, src, i);
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dst += i;
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l->zeros_rem = lag_calc_zero_run(src[i]);
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src += i + 1;
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goto output_zeros;
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} else {
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memcpy(dst, src, i);
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src += i;
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}
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}
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return start - src;
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}
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static int lag_decode_arith_plane(LagarithContext *l, uint8_t *dst,
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int width, int height, int stride,
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const uint8_t *src, int src_size)
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{
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int i = 0;
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int read = 0;
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uint32_t length;
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uint32_t offset = 1;
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int esc_count = src[0];
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GetBitContext gb;
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lag_rac rac;
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rac.avctx = l->avctx;
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l->zeros = 0;
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if (esc_count < 4) {
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length = width * height;
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if (esc_count && AV_RL32(src + 1) < length) {
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length = AV_RL32(src + 1);
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offset += 4;
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}
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init_get_bits(&gb, src + offset, src_size * 8);
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if (lag_read_prob_header(&rac, &gb) < 0)
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return -1;
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lag_rac_init(&rac, &gb, length - stride);
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for (i = 0; i < height; i++)
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read += lag_decode_line(l, &rac, dst + (i * stride), width,
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stride, esc_count);
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if (read > length)
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av_log(l->avctx, AV_LOG_WARNING,
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"Output more bytes than length (%d of %d)\n", read,
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length);
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} else if (esc_count < 8) {
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esc_count -= 4;
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if (esc_count > 0) {
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/* Zero run coding only, no range coding. */
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for (i = 0; i < height; i++)
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src += lag_decode_zero_run_line(l, dst + (i * stride), src,
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width, esc_count);
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} else {
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/* Plane is stored uncompressed */
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for (i = 0; i < height; i++) {
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memcpy(dst + (i * stride), src, width);
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src += width;
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}
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}
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} else if (esc_count == 0xff) {
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/* Plane is a solid run of given value */
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for (i = 0; i < height; i++)
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memset(dst + i * stride, src[1], width);
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/* Do not apply prediction.
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Note: memset to 0 above, setting first value to src[1]
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and applying prediction gives the same result. */
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return 0;
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} else {
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av_log(l->avctx, AV_LOG_ERROR,
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"Invalid zero run escape code! (%#x)\n", esc_count);
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return -1;
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}
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for (i = 0; i < height; i++) {
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lag_pred_line(l, dst, width, stride, i);
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dst += stride;
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}
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return 0;
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}
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/**
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* Decode a frame.
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* @param avctx codec context
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* @param data output AVFrame
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* @param data_size size of output data or 0 if no picture is returned
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* @param avpkt input packet
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* @return number of consumed bytes on success or negative if decode fails
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*/
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static int lag_decode_frame(AVCodecContext *avctx,
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void *data, int *data_size, AVPacket *avpkt)
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{
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const uint8_t *buf = avpkt->data;
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int buf_size = avpkt->size;
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LagarithContext *l = avctx->priv_data;
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AVFrame *const p = &l->picture;
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uint8_t frametype = 0;
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uint32_t offset_gu = 0, offset_bv = 0, offset_ry = 9;
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AVFrame *picture = data;
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if (p->data[0])
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avctx->release_buffer(avctx, p);
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p->reference = 0;
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p->key_frame = 1;
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frametype = buf[0];
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offset_gu = AV_RL32(buf + 1);
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offset_bv = AV_RL32(buf + 5);
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switch (frametype) {
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case FRAME_ARITH_YV12:
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avctx->pix_fmt = PIX_FMT_YUV420P;
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if (avctx->get_buffer(avctx, p) < 0) {
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av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
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return -1;
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}
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lag_decode_arith_plane(l, p->data[0], avctx->width, avctx->height,
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p->linesize[0], buf + offset_ry,
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buf_size);
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lag_decode_arith_plane(l, p->data[2], avctx->width / 2,
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avctx->height / 2, p->linesize[2],
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buf + offset_gu, buf_size);
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lag_decode_arith_plane(l, p->data[1], avctx->width / 2,
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avctx->height / 2, p->linesize[1],
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buf + offset_bv, buf_size);
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break;
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default:
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av_log(avctx, AV_LOG_ERROR,
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"Unsupported Lagarith frame type: %#x\n", frametype);
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return -1;
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}
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*picture = *p;
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*data_size = sizeof(AVFrame);
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return buf_size;
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}
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static av_cold int lag_decode_init(AVCodecContext *avctx)
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{
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LagarithContext *l = avctx->priv_data;
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l->avctx = avctx;
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dsputil_init(&l->dsp, avctx);
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return 0;
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}
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static av_cold int lag_decode_end(AVCodecContext *avctx)
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{
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LagarithContext *l = avctx->priv_data;
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if (l->picture.data[0])
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avctx->release_buffer(avctx, &l->picture);
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return 0;
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}
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AVCodec ff_lagarith_decoder = {
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"lagarith",
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AVMEDIA_TYPE_VIDEO,
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CODEC_ID_LAGARITH,
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sizeof(LagarithContext),
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lag_decode_init,
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NULL,
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lag_decode_end,
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lag_decode_frame,
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CODEC_CAP_DR1,
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.long_name = NULL_IF_CONFIG_SMALL("Lagarith lossless"),
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};
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