malloc padding to avoid reading past the malloc()ed area.
[libav.git] / libavcodec / wnv1.c
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1/*
2 * Winnov WNV1 codec
3 * Copyright (c) 2005 Konstantin Shishkov
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 *
19 */
20
21/**
22 * @file wnv1.c
23 * Winnov WNV1 codec.
24 */
25
26#include "avcodec.h"
27#include "common.h"
083b80b5 28#include "bitstream.h"
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29
30
31typedef struct WNV1Context{
32 AVCodecContext *avctx;
33 AVFrame pic;
34
35 int shift;
083b80b5 36 GetBitContext gb;
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37} WNV1Context;
38
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39static uint16_t code_tab[16][2]={
40{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
41{0x000,1},
42{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
43};
44
45#define CODE_VLC_BITS 9
46static VLC code_vlc;
47
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48/* returns modified base_value */
49static inline int wnv1_get_code(WNV1Context *w, int base_value)
50{
083b80b5 51 int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
a8a15e9d 52
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53 if(v==15)
54 return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
55 else
56 return base_value + ((v - 7)<<w->shift);
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57}
58
59static int decode_frame(AVCodecContext *avctx,
60 void *data, int *data_size,
61 uint8_t *buf, int buf_size)
62{
63 WNV1Context * const l = avctx->priv_data;
64 AVFrame * const p= (AVFrame*)&l->pic;
65 unsigned char *Y,*U,*V;
66 int i, j;
67 int prev_y = 0, prev_u = 0, prev_v = 0;
68
69 if(p->data[0])
70 avctx->release_buffer(avctx, p);
71
72 p->reference = 0;
73 if(avctx->get_buffer(avctx, p) < 0){
74 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
75 return -1;
76 }
77 p->key_frame = 1;
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78
79 for(i=8; i<buf_size; i++)
80 buf[i]= ff_reverse[ buf[i] ]; //FIXME ensure that the buffer is modifyable or use a temp one
81 init_get_bits(&l->gb, buf+8, (buf_size-8)*8);
82
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83 if (buf[2] >> 4 == 6)
84 l->shift = 2;
85 else {
86 l->shift = 8 - (buf[2] >> 4);
87 if (l->shift > 4) {
88 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
89 l->shift = 4;
90 }
91 if (l->shift < 1) {
92 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
93 l->shift = 1;
94 }
95 }
96
97 Y = p->data[0];
98 U = p->data[1];
99 V = p->data[2];
100 for (j = 0; j < avctx->height; j++) {
101 for (i = 0; i < avctx->width / 2; i++) {
102 Y[i * 2] = wnv1_get_code(l, prev_y);
103 prev_u = U[i] = wnv1_get_code(l, prev_u);
104 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
105 prev_v = V[i] = wnv1_get_code(l, prev_v);
106 }
107 Y += p->linesize[0];
108 U += p->linesize[1];
109 V += p->linesize[2];
110 }
111
112
113 *data_size = sizeof(AVFrame);
114 *(AVFrame*)data = l->pic;
115
116 return buf_size;
117}
118
119static int decode_init(AVCodecContext *avctx){
120 WNV1Context * const l = avctx->priv_data;
121
122 l->avctx = avctx;
123 avctx->pix_fmt = PIX_FMT_YUV422P;
124
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125 if(!code_vlc.table){
126 init_vlc(&code_vlc, CODE_VLC_BITS, 16,
127 &code_tab[0][1], 4, 2,
128 &code_tab[0][0], 4, 2, 1);
129 }
130
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131 return 0;
132}
133
134AVCodec wnv1_decoder = {
135 "wnv1",
136 CODEC_TYPE_VIDEO,
137 CODEC_ID_WNV1,
138 sizeof(WNV1Context),
139 decode_init,
140 NULL,
141 NULL,
142 decode_frame,
143 CODEC_CAP_DR1,
144};