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ffmpeg / libavcodec / xxan.c @ 2912e87a

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/*
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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 "bytestream.h"
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#define ALT_BITSTREAM_READER_LE
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#include "get_bits.h"
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// for av_memcpy_backptr
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#include "libavutil/lzo.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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} XanContext;
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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 = PIX_FMT_YUV420P;
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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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    return 0;
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}
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static int xan_unpack_luma(const uint8_t *src, const int src_size,
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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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   const uint8_t *tree;
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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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   const uint8_t *src_end = src + src_size;
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   tree_size = *src++;
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   eof       = *src++;
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   tree      = src - eof * 2 - 2;
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   tree_root = eof + tree_size;
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   src += tree_size * 2;
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   node = tree_root;
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   bits = *src++;
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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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       node = tree[node*2 + bit];
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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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           bits = *src++;
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           if (src > src_end)
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               break;
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           mask = 0x80;
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       }
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   }
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   return dst != dst_end;
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}
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/* almost the same as in xan_wc3 decoder */
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static int xan_unpack(uint8_t *dest, const int dest_len,
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                      const uint8_t *src, const int src_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 *src_end = src + src_len;
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    const uint8_t *dest_end = dest + dest_len;
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    while (dest < dest_end) {
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        opcode = *src++;
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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) + *src++ + 1;
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                size2 = ((opcode & 0x1c) >> 2) + 3;
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            } else if ((opcode & 0x40) == 0) {
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                size  = *src >> 6;
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                back  = (bytestream_get_be16(&src) & 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) + bytestream_get_be16(&src) + 1;
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                size2 = ((opcode & 0x0c) <<  6) + *src++ + 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 (src + size > src_end || dest + size + size2 > dest_end)
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                return -1;
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            bytestream_get_buffer(&src, 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 (src + size > src_end || dest + size > dest_end)
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                return -1;
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            bytestream_get_buffer(&src, 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, AVPacket *avpkt)
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{
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    const uint8_t *buf = avpkt->data;
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    XanContext *s = avctx->priv_data;
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    uint8_t *U, *V;
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    unsigned chroma_off;
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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;
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    chroma_off = AV_RL32(buf + 4);
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    if (!chroma_off)
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        return 0;
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    if (chroma_off + 10 >= avpkt->size) {
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        av_log(avctx, AV_LOG_ERROR, "Invalid chroma block position\n");
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        return -1;
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    }
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    src    = avpkt->data + 4 + chroma_off;
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    table  = src + 2;
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    mode   = bytestream_get_le16(&src);
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    offset = bytestream_get_le16(&src) * 2;
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    if (src - avpkt->data >= avpkt->size - offset) {
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        av_log(avctx, AV_LOG_ERROR, "Invalid chroma block offset\n");
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        return -1;
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    }
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    memset(s->scratch_buffer, 0, s->buffer_size);
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    dec_size = xan_unpack(s->scratch_buffer, s->buffer_size, src + offset,
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                          avpkt->size - offset - (src - avpkt->data));
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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 -1;
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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) {
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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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    } 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) {
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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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    }
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    return 0;
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}
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static int xan_decode_frame_type0(AVCodecContext *avctx, AVPacket *avpkt)
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{
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    const uint8_t *buf = avpkt->data;
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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, size;
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    int i, j;
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    int ret;
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    corr_off   = AV_RL32(buf + 8);
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    chroma_off = AV_RL32(buf + 4);
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    if ((ret = xan_decode_chroma(avctx, avpkt)) != 0)
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        return ret;
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    size = avpkt->size - 4;
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    if (corr_off >= avpkt->size) {
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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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    if (corr_off)
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        size = corr_off;
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    if (chroma_off)
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        size = FFMIN(size, chroma_off);
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    ret = xan_unpack_luma(buf + 12, size, 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 corr_end, dec_size;
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        corr_end = avpkt->size;
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        if (chroma_off > corr_off)
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            corr_end = chroma_off;
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        dec_size = xan_unpack(s->scratch_buffer, s->buffer_size,
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                              avpkt->data + 8 + corr_off,
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                              corr_end - corr_off);
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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, AVPacket *avpkt)
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{
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    const uint8_t *buf = avpkt->data;
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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, avpkt)) != 0)
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        return ret;
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    ret = xan_unpack_luma(buf + 16, avpkt->size - 16, src,
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                          s->buffer_size >> 1);
335
    if (ret) {
336
        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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363
    return 0;
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}
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static int xan_decode_frame(AVCodecContext *avctx,
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                            void *data, int *data_size,
368
                            AVPacket *avpkt)
369
{
370
    XanContext *s = avctx->priv_data;
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    int ftype;
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    int ret;
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    s->pic.reference = 1;
375
    s->pic.buffer_hints = FF_BUFFER_HINTS_VALID |
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                          FF_BUFFER_HINTS_PRESERVE |
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                          FF_BUFFER_HINTS_REUSABLE;
378
    if ((ret = avctx->reget_buffer(avctx, &s->pic))) {
379
        av_log(s->avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
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        return ret;
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    }
382

    
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    ftype = AV_RL32(avpkt->data);
384
    switch (ftype) {
385
    case 0:
386
        ret = xan_decode_frame_type0(avctx, avpkt);
387
        break;
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    case 1:
389
        ret = xan_decode_frame_type1(avctx, avpkt);
390
        break;
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    default:
392
        av_log(avctx, AV_LOG_ERROR, "Unknown frame type %d\n", ftype);
393
        return -1;
394
    }
395
    if (ret)
396
        return ret;
397

    
398
    *data_size = sizeof(AVFrame);
399
    *(AVFrame*)data = s->pic;
400

    
401
    return avpkt->size;
402
}
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404
static av_cold int xan_decode_end(AVCodecContext *avctx)
405
{
406
    XanContext *s = avctx->priv_data;
407

    
408
    if (s->pic.data[0])
409
        avctx->release_buffer(avctx, &s->pic);
410

    
411
    av_freep(&s->y_buffer);
412
    av_freep(&s->scratch_buffer);
413

    
414
    return 0;
415
}
416

    
417
AVCodec ff_xan_wc4_decoder = {
418
    "xan_wc4",
419
    AVMEDIA_TYPE_VIDEO,
420
    CODEC_ID_XAN_WC4,
421
    sizeof(XanContext),
422
    xan_decode_init,
423
    NULL,
424
    xan_decode_end,
425
    xan_decode_frame,
426
    CODEC_CAP_DR1,
427
    .long_name = NULL_IF_CONFIG_SMALL("Wing Commander IV / Xxan"),
428
};
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