xan: remove a trivially true if().
[libav.git] / libavcodec / wnv1.c
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1/*
2 * Winnov WNV1 codec
3 * Copyright (c) 2005 Konstantin Shishkov
4 *
2912e87a 5 * This file is part of Libav.
b78e7197 6 *
2912e87a 7 * Libav is free software; you can redistribute it and/or
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8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
b78e7197 10 * version 2.1 of the License, or (at your option) any later version.
a8a15e9d 11 *
2912e87a 12 * Libav is distributed in the hope that it will be useful,
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13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
2912e87a 18 * License along with Libav; if not, write to the Free Software
5509bffa 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
a8a15e9d 20 */
115329f1 21
a8a15e9d 22/**
ba87f080 23 * @file
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24 * Winnov WNV1 codec.
25 */
115329f1 26
a8a15e9d 27#include "avcodec.h"
9106a698 28#include "get_bits.h"
594d4d5d 29#include "internal.h"
d5c62122 30#include "mathops.h"
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31
32
33typedef struct WNV1Context{
34 AVCodecContext *avctx;
35 AVFrame pic;
36
37 int shift;
083b80b5 38 GetBitContext gb;
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39} WNV1Context;
40
cf2baeb3 41static const uint16_t code_tab[16][2]={
083b80b5 42{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
115329f1 43{0x000,1},
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44{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
45};
46
47#define CODE_VLC_BITS 9
48static VLC code_vlc;
49
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50/* returns modified base_value */
51static inline int wnv1_get_code(WNV1Context *w, int base_value)
52{
083b80b5 53 int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
a8a15e9d 54
083b80b5 55 if(v==15)
d5c62122 56 return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
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57 else
58 return base_value + ((v - 7)<<w->shift);
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59}
60
115329f1 61static int decode_frame(AVCodecContext *avctx,
df9b9567 62 void *data, int *got_frame,
7a00bbad 63 AVPacket *avpkt)
a8a15e9d 64{
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65 const uint8_t *buf = avpkt->data;
66 int buf_size = avpkt->size;
a8a15e9d 67 WNV1Context * const l = avctx->priv_data;
562b6c74 68 AVFrame * const p = &l->pic;
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69 unsigned char *Y,*U,*V;
70 int i, j;
71 int prev_y = 0, prev_u = 0, prev_v = 0;
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72 uint8_t *rbuf;
73
74 rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
75 if(!rbuf){
76 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
77 return -1;
78 }
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79
80 if(p->data[0])
81 avctx->release_buffer(avctx, p);
82
83 p->reference = 0;
594d4d5d 84 if(ff_get_buffer(avctx, p) < 0){
a8a15e9d 85 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
b7093975 86 av_free(rbuf);
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87 return -1;
88 }
89 p->key_frame = 1;
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90
91 for(i=8; i<buf_size; i++)
d5c62122 92 rbuf[i]= ff_reverse[ buf[i] ];
b7093975 93 init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8);
083b80b5 94
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95 if (buf[2] >> 4 == 6)
96 l->shift = 2;
97 else {
98 l->shift = 8 - (buf[2] >> 4);
99 if (l->shift > 4) {
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100 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
101 buf[2] >> 4);
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102 l->shift = 4;
103 }
104 if (l->shift < 1) {
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105 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
106 buf[2] >> 4);
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107 l->shift = 1;
108 }
109 }
115329f1 110
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111 Y = p->data[0];
112 U = p->data[1];
113 V = p->data[2];
114 for (j = 0; j < avctx->height; j++) {
115 for (i = 0; i < avctx->width / 2; i++) {
116 Y[i * 2] = wnv1_get_code(l, prev_y);
117 prev_u = U[i] = wnv1_get_code(l, prev_u);
118 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
119 prev_v = V[i] = wnv1_get_code(l, prev_v);
120 }
121 Y += p->linesize[0];
122 U += p->linesize[1];
123 V += p->linesize[2];
124 }
125
115329f1 126
df9b9567 127 *got_frame = 1;
a8a15e9d 128 *(AVFrame*)data = l->pic;
b7093975 129 av_free(rbuf);
115329f1 130
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131 return buf_size;
132}
133
98a6fff9 134static av_cold int decode_init(AVCodecContext *avctx){
a8a15e9d 135 WNV1Context * const l = avctx->priv_data;
bd4110f9 136 static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
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137
138 l->avctx = avctx;
716d413c 139 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
a8a15e9d 140
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141 code_vlc.table = code_table;
142 code_vlc.table_allocated = 1 << CODE_VLC_BITS;
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143 init_vlc(&code_vlc, CODE_VLC_BITS, 16,
144 &code_tab[0][1], 4, 2,
145 &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
083b80b5 146
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147 return 0;
148}
149
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150static av_cold int decode_end(AVCodecContext *avctx){
151 WNV1Context * const l = avctx->priv_data;
152 AVFrame *pic = &l->pic;
153
154 if (pic->data[0])
155 avctx->release_buffer(avctx, pic);
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156
157 return 0;
158}
159
d36beb3f 160AVCodec ff_wnv1_decoder = {
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161 .name = "wnv1",
162 .type = AVMEDIA_TYPE_VIDEO,
36ef5369 163 .id = AV_CODEC_ID_WNV1,
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164 .priv_data_size = sizeof(WNV1Context),
165 .init = decode_init,
166 .close = decode_end,
167 .decode = decode_frame,
168 .capabilities = CODEC_CAP_DR1,
00c3b67b 169 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
a8a15e9d 170};