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def97856de
Express bitfields more simply. Signed-off-by: Vittorio Giovara <vittorio.giovara@gmail.com>
445 lines
13 KiB
C
445 lines
13 KiB
C
/*
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* Wing Commander/Xan Video Decoder
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* Copyright (C) 2011 Konstantin Shishkov
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* based on work by Mike Melanson
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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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#include "avcodec.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/mem.h"
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#include "bytestream.h"
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#define BITSTREAM_READER_LE
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#include "get_bits.h"
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#include "internal.h"
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typedef struct XanContext {
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AVCodecContext *avctx;
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AVFrame *pic;
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uint8_t *y_buffer;
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uint8_t *scratch_buffer;
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int buffer_size;
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GetByteContext gb;
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} XanContext;
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static av_cold int xan_decode_end(AVCodecContext *avctx)
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{
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XanContext *s = avctx->priv_data;
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av_frame_free(&s->pic);
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av_freep(&s->y_buffer);
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av_freep(&s->scratch_buffer);
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return 0;
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}
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static av_cold int xan_decode_init(AVCodecContext *avctx)
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{
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XanContext *s = avctx->priv_data;
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s->avctx = avctx;
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avctx->pix_fmt = AV_PIX_FMT_YUV420P;
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if (avctx->height < 8) {
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av_log(avctx, AV_LOG_ERROR, "Invalid frame height: %d.\n", avctx->height);
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return AVERROR(EINVAL);
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}
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if (avctx->width & 1) {
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av_log(avctx, AV_LOG_ERROR, "Invalid frame width: %d.\n", avctx->width);
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return AVERROR(EINVAL);
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}
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s->buffer_size = avctx->width * avctx->height;
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s->y_buffer = av_malloc(s->buffer_size);
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if (!s->y_buffer)
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return AVERROR(ENOMEM);
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s->scratch_buffer = av_malloc(s->buffer_size + 130);
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if (!s->scratch_buffer) {
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av_freep(&s->y_buffer);
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return AVERROR(ENOMEM);
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}
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s->pic = av_frame_alloc();
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if (!s->pic) {
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xan_decode_end(avctx);
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return AVERROR(ENOMEM);
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}
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return 0;
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}
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static int xan_unpack_luma(XanContext *s,
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uint8_t *dst, const int dst_size)
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{
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int tree_size, eof;
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int bits, mask;
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int tree_root, node;
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const uint8_t *dst_end = dst + dst_size;
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GetByteContext tree = s->gb;
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int start_off = bytestream2_tell(&tree);
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tree_size = bytestream2_get_byte(&s->gb);
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eof = bytestream2_get_byte(&s->gb);
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tree_root = eof + tree_size;
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bytestream2_skip(&s->gb, tree_size * 2);
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node = tree_root;
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bits = bytestream2_get_byte(&s->gb);
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mask = 0x80;
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for (;;) {
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int bit = !!(bits & mask);
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mask >>= 1;
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bytestream2_seek(&tree, start_off + node*2 + bit - eof * 2, SEEK_SET);
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node = bytestream2_get_byte(&tree);
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if (node == eof)
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break;
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if (node < eof) {
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*dst++ = node;
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if (dst > dst_end)
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break;
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node = tree_root;
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}
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if (!mask) {
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if (bytestream2_get_bytes_left(&s->gb) <= 0)
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break;
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bits = bytestream2_get_byteu(&s->gb);
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mask = 0x80;
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}
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}
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return dst != dst_end ? AVERROR_INVALIDDATA : 0;
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}
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/* almost the same as in xan_wc3 decoder */
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static int xan_unpack(XanContext *s,
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uint8_t *dest, const int dest_len)
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{
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uint8_t opcode;
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int size;
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uint8_t *orig_dest = dest;
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const uint8_t *dest_end = dest + dest_len;
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while (dest < dest_end) {
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if (bytestream2_get_bytes_left(&s->gb) <= 0)
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return AVERROR_INVALIDDATA;
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opcode = bytestream2_get_byteu(&s->gb);
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if (opcode < 0xe0) {
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int size2, back;
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if ((opcode & 0x80) == 0) {
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size = opcode & 3;
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back = ((opcode & 0x60) << 3) + bytestream2_get_byte(&s->gb) + 1;
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size2 = ((opcode & 0x1c) >> 2) + 3;
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} else if ((opcode & 0x40) == 0) {
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size = bytestream2_peek_byte(&s->gb) >> 6;
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back = (bytestream2_get_be16(&s->gb) & 0x3fff) + 1;
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size2 = (opcode & 0x3f) + 4;
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} else {
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size = opcode & 3;
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back = ((opcode & 0x10) << 12) + bytestream2_get_be16(&s->gb) + 1;
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size2 = ((opcode & 0x0c) << 6) + bytestream2_get_byte(&s->gb) + 5;
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if (size + size2 > dest_end - dest)
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break;
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}
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if (dest + size + size2 > dest_end ||
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dest - orig_dest + size < back)
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return AVERROR_INVALIDDATA;
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bytestream2_get_buffer(&s->gb, dest, size);
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dest += size;
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av_memcpy_backptr(dest, back, size2);
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dest += size2;
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} else {
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int finish = opcode >= 0xfc;
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size = finish ? opcode & 3 : ((opcode & 0x1f) << 2) + 4;
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if (dest_end - dest < size)
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return AVERROR_INVALIDDATA;
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bytestream2_get_buffer(&s->gb, dest, size);
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dest += size;
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if (finish)
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break;
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}
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}
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return dest - orig_dest;
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}
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static int xan_decode_chroma(AVCodecContext *avctx, unsigned chroma_off)
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{
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XanContext *s = avctx->priv_data;
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uint8_t *U, *V;
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int val, uval, vval;
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int i, j;
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const uint8_t *src, *src_end;
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const uint8_t *table;
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int mode, offset, dec_size, table_size;
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if (!chroma_off)
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return 0;
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if (chroma_off + 4 >= bytestream2_get_bytes_left(&s->gb)) {
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av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
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return AVERROR_INVALIDDATA;
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}
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bytestream2_seek(&s->gb, chroma_off + 4, SEEK_SET);
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mode = bytestream2_get_le16(&s->gb);
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table = s->gb.buffer;
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table_size = bytestream2_get_le16(&s->gb);
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offset = table_size * 2;
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table_size += 1;
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if (offset >= bytestream2_get_bytes_left(&s->gb)) {
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av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
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return AVERROR_INVALIDDATA;
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}
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bytestream2_skip(&s->gb, offset);
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memset(s->scratch_buffer, 0, s->buffer_size);
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dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size);
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if (dec_size < 0) {
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av_log(avctx, AV_LOG_ERROR, "Chroma unpacking failed\n");
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return dec_size;
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}
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U = s->pic->data[1];
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V = s->pic->data[2];
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src = s->scratch_buffer;
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src_end = src + dec_size;
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if (mode) {
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for (j = 0; j < avctx->height >> 1; j++) {
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for (i = 0; i < avctx->width >> 1; i++) {
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val = *src++;
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if (val && val < table_size) {
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val = AV_RL16(table + (val << 1));
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uval = (val >> 3) & 0xF8;
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vval = (val >> 8) & 0xF8;
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U[i] = uval | (uval >> 5);
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V[i] = vval | (vval >> 5);
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}
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if (src == src_end)
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return 0;
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}
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U += s->pic->linesize[1];
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V += s->pic->linesize[2];
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}
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if (avctx->height & 1) {
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memcpy(U, U - s->pic->linesize[1], avctx->width >> 1);
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memcpy(V, V - s->pic->linesize[2], avctx->width >> 1);
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}
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} else {
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uint8_t *U2 = U + s->pic->linesize[1];
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uint8_t *V2 = V + s->pic->linesize[2];
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for (j = 0; j < avctx->height >> 2; j++) {
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for (i = 0; i < avctx->width >> 1; i += 2) {
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val = *src++;
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if (val && val < table_size) {
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val = AV_RL16(table + (val << 1));
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uval = (val >> 3) & 0xF8;
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vval = (val >> 8) & 0xF8;
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U[i] = U[i+1] = U2[i] = U2[i+1] = uval | (uval >> 5);
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V[i] = V[i+1] = V2[i] = V2[i+1] = vval | (vval >> 5);
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}
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}
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U += s->pic->linesize[1] * 2;
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V += s->pic->linesize[2] * 2;
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U2 += s->pic->linesize[1] * 2;
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V2 += s->pic->linesize[2] * 2;
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}
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if (avctx->height & 3) {
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int lines = ((avctx->height + 1) >> 1) - (avctx->height >> 2) * 2;
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memcpy(U, U - lines * s->pic->linesize[1], lines * s->pic->linesize[1]);
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memcpy(V, V - lines * s->pic->linesize[2], lines * s->pic->linesize[2]);
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}
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}
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return 0;
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}
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static int xan_decode_frame_type0(AVCodecContext *avctx)
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{
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XanContext *s = avctx->priv_data;
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uint8_t *ybuf, *prev_buf, *src = s->scratch_buffer;
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unsigned chroma_off, corr_off;
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int cur, last;
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int i, j;
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int ret;
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chroma_off = bytestream2_get_le32(&s->gb);
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corr_off = bytestream2_get_le32(&s->gb);
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if ((ret = xan_decode_chroma(avctx, chroma_off)) != 0)
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return ret;
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if (corr_off >= (s->gb.buffer_end - s->gb.buffer_start)) {
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av_log(avctx, AV_LOG_WARNING, "Ignoring invalid correction block position\n");
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corr_off = 0;
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}
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bytestream2_seek(&s->gb, 12, SEEK_SET);
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ret = xan_unpack_luma(s, src, s->buffer_size >> 1);
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if (ret) {
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av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
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return ret;
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}
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ybuf = s->y_buffer;
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last = *src++;
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ybuf[0] = last << 1;
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for (j = 1; j < avctx->width - 1; j += 2) {
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cur = (last + *src++) & 0x1F;
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ybuf[j] = last + cur;
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ybuf[j+1] = cur << 1;
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last = cur;
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}
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ybuf[j] = last << 1;
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prev_buf = ybuf;
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ybuf += avctx->width;
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for (i = 1; i < avctx->height; i++) {
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last = ((prev_buf[0] >> 1) + *src++) & 0x1F;
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ybuf[0] = last << 1;
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for (j = 1; j < avctx->width - 1; j += 2) {
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cur = ((prev_buf[j + 1] >> 1) + *src++) & 0x1F;
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ybuf[j] = last + cur;
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ybuf[j+1] = cur << 1;
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last = cur;
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}
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ybuf[j] = last << 1;
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prev_buf = ybuf;
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ybuf += avctx->width;
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}
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if (corr_off) {
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int dec_size;
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bytestream2_seek(&s->gb, 8 + corr_off, SEEK_SET);
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dec_size = xan_unpack(s, s->scratch_buffer, s->buffer_size / 2);
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if (dec_size < 0)
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dec_size = 0;
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for (i = 0; i < dec_size; i++)
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s->y_buffer[i*2+1] = (s->y_buffer[i*2+1] + (s->scratch_buffer[i] << 1)) & 0x3F;
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}
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src = s->y_buffer;
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ybuf = s->pic->data[0];
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for (j = 0; j < avctx->height; j++) {
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for (i = 0; i < avctx->width; i++)
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ybuf[i] = (src[i] << 2) | (src[i] >> 3);
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src += avctx->width;
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ybuf += s->pic->linesize[0];
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}
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return 0;
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}
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static int xan_decode_frame_type1(AVCodecContext *avctx)
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{
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XanContext *s = avctx->priv_data;
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uint8_t *ybuf, *src = s->scratch_buffer;
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int cur, last;
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int i, j;
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int ret;
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if ((ret = xan_decode_chroma(avctx, bytestream2_get_le32(&s->gb))) != 0)
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return ret;
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bytestream2_seek(&s->gb, 16, SEEK_SET);
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ret = xan_unpack_luma(s, src,
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s->buffer_size >> 1);
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if (ret) {
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av_log(avctx, AV_LOG_ERROR, "Luma decoding failed\n");
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return ret;
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}
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ybuf = s->y_buffer;
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for (i = 0; i < avctx->height; i++) {
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last = (ybuf[0] + (*src++ << 1)) & 0x3F;
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ybuf[0] = last;
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for (j = 1; j < avctx->width - 1; j += 2) {
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cur = (ybuf[j + 1] + (*src++ << 1)) & 0x3F;
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ybuf[j] = (last + cur) >> 1;
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ybuf[j+1] = cur;
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last = cur;
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}
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ybuf[j] = last;
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ybuf += avctx->width;
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}
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src = s->y_buffer;
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ybuf = s->pic->data[0];
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for (j = 0; j < avctx->height; j++) {
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for (i = 0; i < avctx->width; i++)
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ybuf[i] = (src[i] << 2) | (src[i] >> 3);
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src += avctx->width;
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ybuf += s->pic->linesize[0];
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}
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return 0;
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}
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static int xan_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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XanContext *s = avctx->priv_data;
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int ftype;
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int ret;
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if ((ret = ff_reget_buffer(avctx, s->pic))) {
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av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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return ret;
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}
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bytestream2_init(&s->gb, avpkt->data, avpkt->size);
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ftype = bytestream2_get_le32(&s->gb);
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switch (ftype) {
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case 0:
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ret = xan_decode_frame_type0(avctx);
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break;
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case 1:
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ret = xan_decode_frame_type1(avctx);
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break;
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default:
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av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
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return AVERROR_INVALIDDATA;
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}
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if (ret)
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return ret;
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if ((ret = av_frame_ref(data, s->pic)) < 0)
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return ret;
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*got_frame = 1;
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return avpkt->size;
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}
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AVCodec ff_xan_wc4_decoder = {
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.name = "xan_wc4",
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.long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
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.type = AVMEDIA_TYPE_VIDEO,
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.id = AV_CODEC_ID_XAN_WC4,
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.priv_data_size = sizeof(XanContext),
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.init = xan_decode_init,
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.close = xan_decode_end,
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.decode = xan_decode_frame,
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.capabilities = AV_CODEC_CAP_DR1,
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};
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