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/*
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 * LOCO codec
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 * Copyright (c) 2005 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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/**
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 * @file loco.c
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 * LOCO codec.
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 */
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#include "avcodec.h"
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#include "common.h"
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#include "bitstream.h"
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#include "golomb.h"
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enum LOCO_MODE {LOCO_UNKN=0, LOCO_CYUY2=-1, LOCO_CRGB=-2, LOCO_CRGBA=-3, LOCO_CYV12=-4,
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 LOCO_YUY2=1, LOCO_UYVY=2, LOCO_RGB=3, LOCO_RGBA=4, LOCO_YV12=5};
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typedef struct LOCOContext{
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    AVCodecContext *avctx;
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    AVFrame pic;
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    int lossy;
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    int mode;
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} LOCOContext;
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typedef struct RICEContext{
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    GetBitContext gb;
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    int save, run, run2; /* internal rice decoder state */
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    int sum, count; /* sum and count for getting rice parameter */
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    int lossy;
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}RICEContext;
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static int loco_get_rice_param(RICEContext *r)
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{
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    int cnt = 0;
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    int val = r->count;
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    while(r->sum > val && cnt < 9) {
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        val <<= 1;
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        cnt++;
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    }
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    return cnt;
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}
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static inline void loco_update_rice_param(RICEContext *r, int val)
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{
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    r->sum += val;
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    r->count++;
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    if(r->count == 16) {
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        r->sum >>= 1;
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        r->count >>= 1;
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    }
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}
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static inline int loco_get_rice(RICEContext *r)
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{
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    int v;
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    if (r->run > 0) { /* we have zero run */
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        r->run--;
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        loco_update_rice_param(r, 0);
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        return 0;
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    }
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    v = get_ur_golomb_jpegls(&r->gb, loco_get_rice_param(r), INT_MAX, 0);
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    loco_update_rice_param(r, (v+1)>>1);
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    if (!v) {
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        if (r->save >= 0) {
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            r->run = get_ur_golomb_jpegls(&r->gb, 2, INT_MAX, 0);
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            if(r->run > 1)
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                r->save += r->run + 1;
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            else
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                r->save -= 3;
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        }
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        else
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            r->run2++;
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    } else {
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        v = ((v>>1) + r->lossy) ^ -(v&1);
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        if (r->run2 > 0) {
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            if (r->run2 > 2)
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                r->save += r->run2;
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            else
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                r->save -= 3;
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            r->run2 = 0;
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        }
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    }
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    return v;
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}
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/* LOCO main predictor - LOCO-I/JPEG-LS predictor */
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static inline int loco_predict(uint8_t* data, int stride, int step)
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{
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    int a, b, c;
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    a = data[-stride];
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    b = data[-step];
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    c = data[-stride - step];
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    return mid_pred(a, a + b - c, b);
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}
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static int loco_decode_plane(LOCOContext *l, uint8_t *data, int width, int height,
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                             int stride, uint8_t *buf, int buf_size, int step)
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{
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    RICEContext rc;
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    int val;
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    int i, j;
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    init_get_bits(&rc.gb, buf, buf_size*8);
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    rc.save = 0;
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    rc.run = 0;
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    rc.run2 = 0;
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    rc.lossy = l->lossy;
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    rc.sum = 8;
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    rc.count = 1;
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    /* restore top left pixel */
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    val = loco_get_rice(&rc);
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    data[0] = 128 + val;
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    /* restore top line */
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    for (i = 1; i < width; i++) {
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        val = loco_get_rice(&rc);
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        data[i * step] = data[i * step - step] + val;
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    }
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    data += stride;
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    for (j = 1; j < height; j++) {
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        /* restore left column */
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        val = loco_get_rice(&rc);
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        data[0] = data[-stride] + val;
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        /* restore all other pixels */
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        for (i = 1; i < width; i++) {
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            val = loco_get_rice(&rc);
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            data[i * step] = loco_predict(&data[i * step], stride, step) + val;
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        }
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        data += stride;
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    }
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    return ((get_bits_count(&rc.gb) + 7) >> 3);
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}
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static int decode_frame(AVCodecContext *avctx,
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                        void *data, int *data_size,
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                        uint8_t *buf, int buf_size)
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{
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    LOCOContext * const l = avctx->priv_data;
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    AVFrame * const p= (AVFrame*)&l->pic;
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    int decoded;
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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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    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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    p->key_frame = 1;
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    switch(l->mode) {
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    case LOCO_CYUY2: case LOCO_YUY2: case LOCO_UYVY:
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        decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
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                                    p->linesize[0], buf, buf_size, 1);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[1], avctx->width / 2, avctx->height,
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                                    p->linesize[1], buf, buf_size, 1);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[2], avctx->width / 2, avctx->height,
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                                    p->linesize[2], buf, buf_size, 1);
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        break;
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    case LOCO_CYV12: case LOCO_YV12:
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        decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
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                                    p->linesize[0], buf, buf_size, 1);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[2], avctx->width / 2, avctx->height / 2,
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                                    p->linesize[2], buf, buf_size, 1);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[1], avctx->width / 2, avctx->height / 2,
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                                    p->linesize[1], buf, buf_size, 1);
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        break;
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    case LOCO_CRGB: case LOCO_RGB:
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        decoded = loco_decode_plane(l, p->data[0] + p->linesize[0]*(avctx->height-1), avctx->width, avctx->height,
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                                    -p->linesize[0], buf, buf_size, 3);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[0] + p->linesize[0]*(avctx->height-1) + 1, avctx->width, avctx->height,
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                                    -p->linesize[0], buf, buf_size, 3);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[0] + p->linesize[0]*(avctx->height-1) + 2, avctx->width, avctx->height,
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                                    -p->linesize[0], buf, buf_size, 3);
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        break;
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    case LOCO_RGBA:
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        decoded = loco_decode_plane(l, p->data[0], avctx->width, avctx->height,
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                                    p->linesize[0], buf, buf_size, 4);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[0] + 1, avctx->width, avctx->height,
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                                    p->linesize[0], buf, buf_size, 4);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[0] + 2, avctx->width, avctx->height,
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                                    p->linesize[0], buf, buf_size, 4);
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        buf += decoded; buf_size -= decoded;
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        decoded = loco_decode_plane(l, p->data[0] + 3, avctx->width, avctx->height,
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                                    p->linesize[0], buf, buf_size, 4);
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        break;
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame*)data = l->pic;
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    return buf_size;
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}
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static int decode_init(AVCodecContext *avctx){
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    LOCOContext * const l = avctx->priv_data;
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    int version;
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    l->avctx = avctx;
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    if (avctx->extradata_size < 12) {
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        av_log(avctx, AV_LOG_ERROR, "Extradata size must be >= 12 instead of %i\n",
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               avctx->extradata_size);
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        return -1;
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    }
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    version = LE_32(avctx->extradata);
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    switch(version) {
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    case 1:
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        l->lossy = 0;
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        break;
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    case 2:
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        l->lossy = LE_32(avctx->extradata + 8);
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        break;
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    default:
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        l->lossy = LE_32(avctx->extradata + 8);
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        av_log(avctx, AV_LOG_INFO, "This is LOCO codec version %i, please upload file for study\n", version);
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    }
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    l->mode = LE_32(avctx->extradata + 4);
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    switch(l->mode) {
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    case LOCO_CYUY2: case LOCO_YUY2: case LOCO_UYVY:
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        avctx->pix_fmt = PIX_FMT_YUV422P;
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        break;
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    case LOCO_CRGB: case LOCO_RGB:
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        avctx->pix_fmt = PIX_FMT_BGR24;
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        break;
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    case LOCO_CYV12: case LOCO_YV12:
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        avctx->pix_fmt = PIX_FMT_YUV420P;
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        break;
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    case LOCO_CRGBA: case LOCO_RGBA:
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        avctx->pix_fmt = PIX_FMT_RGBA32;
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        break;
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    default:
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        av_log(avctx, AV_LOG_INFO, "Unknown colorspace, index = %i\n", l->mode);
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        return -1;
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    }
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    if(avctx->debug & FF_DEBUG_PICT_INFO)
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        av_log(avctx, AV_LOG_INFO, "lossy:%i, version:%i, mode: %i\n", l->lossy, version, l->mode);
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    return 0;
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}
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AVCodec loco_decoder = {
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    "loco",
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    CODEC_TYPE_VIDEO,
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    CODEC_ID_LOCO,
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    sizeof(LOCOContext),
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    decode_init,
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    NULL,
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    NULL,
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    decode_frame,
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    CODEC_CAP_DR1,
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};