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ffmpeg / libavcodec / kmvc.c @ 72415b2a

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/*
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 * KMVC decoder
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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 libavcodec/kmvc.c
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 * Karl Morton's Video Codec decoder
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 */
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#include <stdio.h>
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#include <stdlib.h>
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#include "avcodec.h"
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#include "bytestream.h"
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#define KMVC_KEYFRAME 0x80
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#define KMVC_PALETTE  0x40
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#define KMVC_METHOD   0x0F
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/*
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 * Decoder context
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 */
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typedef struct KmvcContext {
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    AVCodecContext *avctx;
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    AVFrame pic;
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    int setpal;
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    int palsize;
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    uint32_t pal[256];
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    uint8_t *cur, *prev;
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    uint8_t *frm0, *frm1;
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} KmvcContext;
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typedef struct BitBuf {
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    int bits;
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    int bitbuf;
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} BitBuf;
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#define BLK(data, x, y)  data[(x) + (y) * 320]
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#define kmvc_init_getbits(bb, src)  bb.bits = 7; bb.bitbuf = *src++;
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#define kmvc_getbit(bb, src, res) {\
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    res = 0; \
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    if (bb.bitbuf & (1 << bb.bits)) res = 1; \
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    bb.bits--; \
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    if(bb.bits == -1) { \
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        bb.bitbuf = *src++; \
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        bb.bits = 7; \
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    } \
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}
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static void kmvc_decode_intra_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h)
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{
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    BitBuf bb;
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    int res, val;
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    int i, j;
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    int bx, by;
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    int l0x, l1x, l0y, l1y;
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    int mx, my;
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    kmvc_init_getbits(bb, src);
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    for (by = 0; by < h; by += 8)
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        for (bx = 0; bx < w; bx += 8) {
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            kmvc_getbit(bb, src, res);
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            if (!res) {         // fill whole 8x8 block
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                val = *src++;
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                for (i = 0; i < 64; i++)
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                    BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
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            } else {            // handle four 4x4 subblocks
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                for (i = 0; i < 4; i++) {
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                    l0x = bx + (i & 1) * 4;
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                    l0y = by + (i & 2) * 2;
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                    kmvc_getbit(bb, src, res);
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                    if (!res) {
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                        kmvc_getbit(bb, src, res);
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                        if (!res) {     // fill whole 4x4 block
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                            val = *src++;
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                            for (j = 0; j < 16; j++)
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                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
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                        } else {        // copy block from already decoded place
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                            val = *src++;
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                            mx = val & 0xF;
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                            my = val >> 4;
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                            for (j = 0; j < 16; j++)
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                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
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                                    BLK(ctx->cur, l0x + (j & 3) - mx, l0y + (j >> 2) - my);
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                        }
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                    } else {    // descend to 2x2 sub-sub-blocks
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                        for (j = 0; j < 4; j++) {
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                            l1x = l0x + (j & 1) * 2;
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                            l1y = l0y + (j & 2);
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                            kmvc_getbit(bb, src, res);
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                            if (!res) {
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                                kmvc_getbit(bb, src, res);
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                                if (!res) {     // fill whole 2x2 block
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                                    val = *src++;
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                                    BLK(ctx->cur, l1x, l1y) = val;
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                                    BLK(ctx->cur, l1x + 1, l1y) = val;
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                                    BLK(ctx->cur, l1x, l1y + 1) = val;
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                                    BLK(ctx->cur, l1x + 1, l1y + 1) = val;
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                                } else {        // copy block from already decoded place
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                                    val = *src++;
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                                    mx = val & 0xF;
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                                    my = val >> 4;
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                                    BLK(ctx->cur, l1x, l1y) = BLK(ctx->cur, l1x - mx, l1y - my);
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                                    BLK(ctx->cur, l1x + 1, l1y) =
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                                        BLK(ctx->cur, l1x + 1 - mx, l1y - my);
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                                    BLK(ctx->cur, l1x, l1y + 1) =
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                                        BLK(ctx->cur, l1x - mx, l1y + 1 - my);
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                                    BLK(ctx->cur, l1x + 1, l1y + 1) =
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                                        BLK(ctx->cur, l1x + 1 - mx, l1y + 1 - my);
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                                }
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                            } else {    // read values for block
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                                BLK(ctx->cur, l1x, l1y) = *src++;
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                                BLK(ctx->cur, l1x + 1, l1y) = *src++;
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                                BLK(ctx->cur, l1x, l1y + 1) = *src++;
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                                BLK(ctx->cur, l1x + 1, l1y + 1) = *src++;
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                            }
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                        }
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                    }
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                }
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            }
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        }
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}
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static void kmvc_decode_inter_8x8(KmvcContext * ctx, const uint8_t * src, int w, int h)
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{
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    BitBuf bb;
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    int res, val;
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    int i, j;
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    int bx, by;
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    int l0x, l1x, l0y, l1y;
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    int mx, my;
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    kmvc_init_getbits(bb, src);
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    for (by = 0; by < h; by += 8)
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        for (bx = 0; bx < w; bx += 8) {
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            kmvc_getbit(bb, src, res);
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            if (!res) {
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                kmvc_getbit(bb, src, res);
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                if (!res) {     // fill whole 8x8 block
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                    val = *src++;
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                    for (i = 0; i < 64; i++)
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                        BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) = val;
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                } else {        // copy block from previous frame
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                    for (i = 0; i < 64; i++)
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                        BLK(ctx->cur, bx + (i & 0x7), by + (i >> 3)) =
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                            BLK(ctx->prev, bx + (i & 0x7), by + (i >> 3));
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                }
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            } else {            // handle four 4x4 subblocks
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                for (i = 0; i < 4; i++) {
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                    l0x = bx + (i & 1) * 4;
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                    l0y = by + (i & 2) * 2;
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                    kmvc_getbit(bb, src, res);
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                    if (!res) {
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                        kmvc_getbit(bb, src, res);
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                        if (!res) {     // fill whole 4x4 block
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                            val = *src++;
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                            for (j = 0; j < 16; j++)
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                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) = val;
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                        } else {        // copy block
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                            val = *src++;
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                            mx = (val & 0xF) - 8;
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                            my = (val >> 4) - 8;
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                            for (j = 0; j < 16; j++)
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                                BLK(ctx->cur, l0x + (j & 3), l0y + (j >> 2)) =
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                                    BLK(ctx->prev, l0x + (j & 3) + mx, l0y + (j >> 2) + my);
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                        }
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                    } else {    // descend to 2x2 sub-sub-blocks
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                        for (j = 0; j < 4; j++) {
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                            l1x = l0x + (j & 1) * 2;
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                            l1y = l0y + (j & 2);
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                            kmvc_getbit(bb, src, res);
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                            if (!res) {
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                                kmvc_getbit(bb, src, res);
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                                if (!res) {     // fill whole 2x2 block
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                                    val = *src++;
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                                    BLK(ctx->cur, l1x, l1y) = val;
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                                    BLK(ctx->cur, l1x + 1, l1y) = val;
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                                    BLK(ctx->cur, l1x, l1y + 1) = val;
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                                    BLK(ctx->cur, l1x + 1, l1y + 1) = val;
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                                } else {        // copy block
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                                    val = *src++;
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                                    mx = (val & 0xF) - 8;
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                                    my = (val >> 4) - 8;
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                                    BLK(ctx->cur, l1x, l1y) = BLK(ctx->prev, l1x + mx, l1y + my);
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                                    BLK(ctx->cur, l1x + 1, l1y) =
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                                        BLK(ctx->prev, l1x + 1 + mx, l1y + my);
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                                    BLK(ctx->cur, l1x, l1y + 1) =
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                                        BLK(ctx->prev, l1x + mx, l1y + 1 + my);
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                                    BLK(ctx->cur, l1x + 1, l1y + 1) =
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                                        BLK(ctx->prev, l1x + 1 + mx, l1y + 1 + my);
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                                }
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                            } else {    // read values for block
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                                BLK(ctx->cur, l1x, l1y) = *src++;
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                                BLK(ctx->cur, l1x + 1, l1y) = *src++;
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                                BLK(ctx->cur, l1x, l1y + 1) = *src++;
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                                BLK(ctx->cur, l1x + 1, l1y + 1) = *src++;
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                            }
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                        }
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                    }
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                }
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            }
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        }
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}
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static int decode_frame(AVCodecContext * avctx, 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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    KmvcContext *const ctx = avctx->priv_data;
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    uint8_t *out, *src;
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    int i;
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    int header;
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    int blocksize;
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    if (ctx->pic.data[0])
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        avctx->release_buffer(avctx, &ctx->pic);
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    ctx->pic.reference = 1;
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    ctx->pic.buffer_hints = FF_BUFFER_HINTS_VALID;
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    if (avctx->get_buffer(avctx, &ctx->pic) < 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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    header = *buf++;
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    /* blocksize 127 is really palette change event */
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    if (buf[0] == 127) {
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        buf += 3;
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        for (i = 0; i < 127; i++) {
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            ctx->pal[i + (header & 0x81)] = AV_RB24(buf);
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            buf += 4;
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        }
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        buf -= 127 * 4 + 3;
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    }
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    if (header & KMVC_KEYFRAME) {
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        ctx->pic.key_frame = 1;
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        ctx->pic.pict_type = FF_I_TYPE;
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    } else {
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        ctx->pic.key_frame = 0;
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        ctx->pic.pict_type = FF_P_TYPE;
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    }
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    /* if palette has been changed, copy it from palctrl */
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    if (ctx->avctx->palctrl && ctx->avctx->palctrl->palette_changed) {
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        memcpy(ctx->pal, ctx->avctx->palctrl->palette, AVPALETTE_SIZE);
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        ctx->setpal = 1;
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        ctx->avctx->palctrl->palette_changed = 0;
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    }
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    if (header & KMVC_PALETTE) {
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        ctx->pic.palette_has_changed = 1;
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        // palette starts from index 1 and has 127 entries
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        for (i = 1; i <= ctx->palsize; i++) {
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            ctx->pal[i] = bytestream_get_be24(&buf);
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        }
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    }
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    if (ctx->setpal) {
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        ctx->setpal = 0;
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        ctx->pic.palette_has_changed = 1;
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    }
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    /* make the palette available on the way out */
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    memcpy(ctx->pic.data[1], ctx->pal, 1024);
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    blocksize = *buf++;
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    if (blocksize != 8 && blocksize != 127) {
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        av_log(avctx, AV_LOG_ERROR, "Block size = %i\n", blocksize);
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        return -1;
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    }
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    memset(ctx->cur, 0, 320 * 200);
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    switch (header & KMVC_METHOD) {
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    case 0:
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    case 1: // used in palette changed event
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        memcpy(ctx->cur, ctx->prev, 320 * 200);
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        break;
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    case 3:
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        kmvc_decode_intra_8x8(ctx, buf, avctx->width, avctx->height);
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        break;
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    case 4:
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        kmvc_decode_inter_8x8(ctx, buf, avctx->width, avctx->height);
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        break;
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    default:
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        av_log(avctx, AV_LOG_ERROR, "Unknown compression method %i\n", header & KMVC_METHOD);
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        return -1;
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    }
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    out = ctx->pic.data[0];
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    src = ctx->cur;
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    for (i = 0; i < avctx->height; i++) {
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        memcpy(out, src, avctx->width);
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        src += 320;
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        out += ctx->pic.linesize[0];
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    }
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    /* flip buffers */
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    if (ctx->cur == ctx->frm0) {
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        ctx->cur = ctx->frm1;
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        ctx->prev = ctx->frm0;
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    } else {
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        ctx->cur = ctx->frm0;
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        ctx->prev = ctx->frm1;
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    }
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    *data_size = sizeof(AVFrame);
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    *(AVFrame *) data = ctx->pic;
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    /* always report that the buffer was completely consumed */
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    return buf_size;
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}
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/*
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 * Init kmvc decoder
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 */
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static av_cold int decode_init(AVCodecContext * avctx)
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{
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    KmvcContext *const c = avctx->priv_data;
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    int i;
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    c->avctx = avctx;
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    if (avctx->width > 320 || avctx->height > 200) {
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        av_log(avctx, AV_LOG_ERROR, "KMVC supports frames <= 320x200\n");
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        return -1;
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    }
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    c->frm0 = av_mallocz(320 * 200);
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    c->frm1 = av_mallocz(320 * 200);
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    c->cur = c->frm0;
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    c->prev = c->frm1;
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    for (i = 0; i < 256; i++) {
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        c->pal[i] = i * 0x10101;
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    }
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    if (avctx->extradata_size < 12) {
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        av_log(NULL, 0, "Extradata missing, decoding may not work properly...\n");
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        c->palsize = 127;
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    } else {
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        c->palsize = AV_RL16(avctx->extradata + 10);
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    }
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    if (avctx->extradata_size == 1036) {        // palette in extradata
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        uint8_t *src = avctx->extradata + 12;
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        for (i = 0; i < 256; i++) {
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            c->pal[i] = AV_RL32(src);
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            src += 4;
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        }
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        c->setpal = 1;
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        if (c->avctx->palctrl) {
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            c->avctx->palctrl->palette_changed = 0;
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        }
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    }
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    return 0;
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}
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/*
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 * Uninit kmvc decoder
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 */
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static av_cold int decode_end(AVCodecContext * avctx)
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{
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    KmvcContext *const c = avctx->priv_data;
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    av_freep(&c->frm0);
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    av_freep(&c->frm1);
398
    if (c->pic.data[0])
399
        avctx->release_buffer(avctx, &c->pic);
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401
    return 0;
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}
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AVCodec kmvc_decoder = {
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    "kmvc",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_KMVC,
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    sizeof(KmvcContext),
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    decode_init,
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    NULL,
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    decode_end,
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    decode_frame,
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    CODEC_CAP_DR1,
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    .long_name = NULL_IF_CONFIG_SMALL("Karl Morton's video codec"),
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};