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ffmpeg / libavcodec / tiertexseqv.c @ 2912e87a

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/*
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 * Tiertex Limited SEQ Video Decoder
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 * Copyright (c) 2006 Gregory Montoir (cyx@users.sourceforge.net)
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 *
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 * This file is part of Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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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 * Tiertex Limited SEQ video decoder
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 */
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#include "avcodec.h"
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#define ALT_BITSTREAM_READER_LE
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#include "get_bits.h"
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typedef struct SeqVideoContext {
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    AVCodecContext *avctx;
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    AVFrame frame;
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} SeqVideoContext;
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static const unsigned char *seq_unpack_rle_block(const unsigned char *src, unsigned char *dst, int dst_size)
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{
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    int i, len, sz;
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    GetBitContext gb;
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    int code_table[64];
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    /* get the rle codes (at most 64 bytes) */
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    init_get_bits(&gb, src, 64 * 8);
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    for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {
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        code_table[i] = get_sbits(&gb, 4);
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        sz += FFABS(code_table[i]);
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    }
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    src += (get_bits_count(&gb) + 7) / 8;
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    /* do the rle unpacking */
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    for (i = 0; i < 64 && dst_size > 0; i++) {
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        len = code_table[i];
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        if (len < 0) {
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            len = -len;
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            memset(dst, *src++, FFMIN(len, dst_size));
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        } else {
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            memcpy(dst, src, FFMIN(len, dst_size));
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            src += len;
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        }
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        dst += len;
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        dst_size -= len;
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    }
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    return src;
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}
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static const unsigned char *seq_decode_op1(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
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{
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    const unsigned char *color_table;
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    int b, i, len, bits;
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    GetBitContext gb;
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    unsigned char block[8 * 8];
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    len = *src++;
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    if (len & 0x80) {
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        switch (len & 3) {
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        case 1:
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            src = seq_unpack_rle_block(src, block, sizeof(block));
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            for (b = 0; b < 8; b++) {
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                memcpy(dst, &block[b * 8], 8);
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                dst += seq->frame.linesize[0];
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            }
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            break;
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        case 2:
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            src = seq_unpack_rle_block(src, block, sizeof(block));
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            for (i = 0; i < 8; i++) {
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                for (b = 0; b < 8; b++)
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                    dst[b * seq->frame.linesize[0]] = block[i * 8 + b];
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                ++dst;
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            }
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            break;
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        }
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    } else {
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        color_table = src;
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        src += len;
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        bits = ff_log2_tab[len - 1] + 1;
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        init_get_bits(&gb, src, bits * 8 * 8); src += bits * 8;
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        for (b = 0; b < 8; b++) {
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            for (i = 0; i < 8; i++)
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                dst[i] = color_table[get_bits(&gb, bits)];
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            dst += seq->frame.linesize[0];
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        }
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    }
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    return src;
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}
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static const unsigned char *seq_decode_op2(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
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{
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    int i;
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    for (i = 0; i < 8; i++) {
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        memcpy(dst, src, 8);
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        src += 8;
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        dst += seq->frame.linesize[0];
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    }
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    return src;
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}
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static const unsigned char *seq_decode_op3(SeqVideoContext *seq, const unsigned char *src, unsigned char *dst)
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{
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    int pos, offset;
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    do {
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        pos = *src++;
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        offset = ((pos >> 3) & 7) * seq->frame.linesize[0] + (pos & 7);
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        dst[offset] = *src++;
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    } while (!(pos & 0x80));
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    return src;
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}
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static void seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)
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{
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    GetBitContext gb;
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    int flags, i, j, x, y, op;
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    unsigned char c[3];
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    unsigned char *dst;
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    uint32_t *palette;
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    flags = *data++;
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    if (flags & 1) {
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        palette = (uint32_t *)seq->frame.data[1];
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        for (i = 0; i < 256; i++) {
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            for (j = 0; j < 3; j++, data++)
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                c[j] = (*data << 2) | (*data >> 4);
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            palette[i] = AV_RB24(c);
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        }
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        seq->frame.palette_has_changed = 1;
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    }
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    if (flags & 2) {
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        init_get_bits(&gb, data, 128 * 8); data += 128;
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        for (y = 0; y < 128; y += 8)
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            for (x = 0; x < 256; x += 8) {
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                dst = &seq->frame.data[0][y * seq->frame.linesize[0] + x];
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                op = get_bits(&gb, 2);
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                switch (op) {
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                case 1:
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                    data = seq_decode_op1(seq, data, dst);
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                    break;
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                case 2:
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                    data = seq_decode_op2(seq, data, dst);
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                    break;
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                case 3:
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                    data = seq_decode_op3(seq, data, dst);
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                    break;
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                }
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            }
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    }
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}
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static av_cold int seqvideo_decode_init(AVCodecContext *avctx)
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{
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    SeqVideoContext *seq = avctx->priv_data;
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    seq->avctx = avctx;
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    avctx->pix_fmt = PIX_FMT_PAL8;
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    seq->frame.data[0] = NULL;
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    return 0;
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}
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static int seqvideo_decode_frame(AVCodecContext *avctx,
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                                 void *data, int *data_size,
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                                 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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    SeqVideoContext *seq = avctx->priv_data;
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    seq->frame.reference = 1;
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    seq->frame.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
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    if (avctx->reget_buffer(avctx, &seq->frame)) {
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        av_log(seq->avctx, AV_LOG_ERROR, "tiertexseqvideo: reget_buffer() failed\n");
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        return -1;
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    }
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    seqvideo_decode(seq, buf, buf_size);
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    *data_size = sizeof(AVFrame);
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    *(AVFrame *)data = seq->frame;
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    return buf_size;
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}
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static av_cold int seqvideo_decode_end(AVCodecContext *avctx)
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{
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    SeqVideoContext *seq = avctx->priv_data;
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    if (seq->frame.data[0])
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        avctx->release_buffer(avctx, &seq->frame);
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    return 0;
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}
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AVCodec ff_tiertexseqvideo_decoder = {
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    "tiertexseqvideo",
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    AVMEDIA_TYPE_VIDEO,
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    CODEC_ID_TIERTEXSEQVIDEO,
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    sizeof(SeqVideoContext),
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    seqvideo_decode_init,
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    NULL,
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    seqvideo_decode_end,
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    seqvideo_decode_frame,
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    CODEC_CAP_DR1,
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    .long_name = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"),
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};