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https://github.com/xenia-project/FFmpeg.git
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9ea6d2149e
Some decoders may not need a writable buffer in some specific cases, but only a reference to the existing buffer with updated frame properties instead, for the purpose of returning duplicate frames. For this, the FF_REGET_BUFFER_FLAG_READONLY flag is added, which will prevent potential allocations and buffer copies when they are not needed. Signed-off-by: James Almer <jamrial@gmail.com>
275 lines
7.8 KiB
C
275 lines
7.8 KiB
C
/*
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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 FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Tiertex Limited SEQ video decoder
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*/
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#define BITSTREAM_READER_LE
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#include "avcodec.h"
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#include "get_bits.h"
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#include "internal.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,
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const unsigned char *src_end,
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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 */
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init_get_bits(&gb, src, (src_end - src) * 8);
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for (i = 0, sz = 0; i < 64 && sz < dst_size; i++) {
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if (get_bits_left(&gb) < 4)
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return NULL;
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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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if (src_end - src < 1)
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return NULL;
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memset(dst, *src++, FFMIN(len, dst_size));
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} else {
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if (src_end - src < len)
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return NULL;
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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,
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const unsigned char *src,
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const unsigned char *src_end,
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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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if (src_end - src < 1)
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return NULL;
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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, src_end, 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, src_end, 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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if (len <= 0)
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return NULL;
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bits = ff_log2_tab[len - 1] + 1;
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if (src_end - src < len + 8 * bits)
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return NULL;
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color_table = src;
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src += len;
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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,
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const unsigned char *src,
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const unsigned char *src_end,
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unsigned char *dst)
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{
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int i;
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if (src_end - src < 8 * 8)
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return NULL;
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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,
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const unsigned char *src,
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const unsigned char *src_end,
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unsigned char *dst)
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{
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int pos, offset;
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do {
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if (src_end - src < 2)
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return NULL;
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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 int seqvideo_decode(SeqVideoContext *seq, const unsigned char *data, int data_size)
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{
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const unsigned char *data_end = data + data_size;
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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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if (data_end - data < 256 * 3)
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return AVERROR_INVALIDDATA;
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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] = 0xFFU << 24 | 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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if (data_end - data < 128)
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return AVERROR_INVALIDDATA;
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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, data_end, dst);
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break;
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case 2:
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data = seq_decode_op2(seq, data, data_end, dst);
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break;
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case 3:
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data = seq_decode_op3(seq, data, data_end, dst);
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break;
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}
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if (!data)
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return AVERROR_INVALIDDATA;
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}
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}
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return 0;
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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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int ret;
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seq->avctx = avctx;
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avctx->pix_fmt = AV_PIX_FMT_PAL8;
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ret = ff_set_dimensions(avctx, 256, 128);
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if (ret < 0)
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return ret;
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seq->frame = av_frame_alloc();
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if (!seq->frame)
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return AVERROR(ENOMEM);
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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 *got_frame,
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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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int ret;
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SeqVideoContext *seq = avctx->priv_data;
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if ((ret = ff_reget_buffer(avctx, seq->frame, 0)) < 0)
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return ret;
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if (seqvideo_decode(seq, buf, buf_size))
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return AVERROR_INVALIDDATA;
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if ((ret = av_frame_ref(data, seq->frame)) < 0)
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return ret;
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*got_frame = 1;
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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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av_frame_free(&seq->frame);
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return 0;
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}
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AVCodec ff_tiertexseqvideo_decoder = {
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.name = "tiertexseqvideo",
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.long_name = NULL_IF_CONFIG_SMALL("Tiertex Limited SEQ video"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_TIERTEXSEQVIDEO,
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.priv_data_size = sizeof(SeqVideoContext),
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.init = seqvideo_decode_init,
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.close = seqvideo_decode_end,
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.decode = seqvideo_decode_frame,
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.capabilities = AV_CODEC_CAP_DR1,
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};
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