ffmpeg / libavcodec / wnv1.c @ d36beb3f
History | View | Annotate | Download (4.47 KB)
1 |
/*
|
---|---|
2 |
* Winnov WNV1 codec
|
3 |
* Copyright (c) 2005 Konstantin Shishkov
|
4 |
*
|
5 |
* This file is part of FFmpeg.
|
6 |
*
|
7 |
* FFmpeg is free software; you can redistribute it and/or
|
8 |
* modify it under the terms of the GNU Lesser General Public
|
9 |
* License as published by the Free Software Foundation; either
|
10 |
* version 2.1 of the License, or (at your option) any later version.
|
11 |
*
|
12 |
* FFmpeg is distributed in the hope that it will be useful,
|
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
|
18 |
* License along with FFmpeg; if not, write to the Free Software
|
19 |
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
20 |
*/
|
21 |
|
22 |
/**
|
23 |
* @file
|
24 |
* Winnov WNV1 codec.
|
25 |
*/
|
26 |
|
27 |
#include "avcodec.h" |
28 |
#include "get_bits.h" |
29 |
#include "libavutil/common.h" |
30 |
|
31 |
|
32 |
typedef struct WNV1Context{ |
33 |
AVCodecContext *avctx; |
34 |
AVFrame pic; |
35 |
|
36 |
int shift;
|
37 |
GetBitContext gb; |
38 |
} WNV1Context; |
39 |
|
40 |
static const uint16_t code_tab[16][2]={ |
41 |
{0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3}, |
42 |
{0x000,1}, |
43 |
{0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8} |
44 |
}; |
45 |
|
46 |
#define CODE_VLC_BITS 9 |
47 |
static VLC code_vlc;
|
48 |
|
49 |
/* returns modified base_value */
|
50 |
static inline int wnv1_get_code(WNV1Context *w, int base_value) |
51 |
{ |
52 |
int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1); |
53 |
|
54 |
if(v==15) |
55 |
return av_reverse[ get_bits(&w->gb, 8 - w->shift) ]; |
56 |
else
|
57 |
return base_value + ((v - 7)<<w->shift); |
58 |
} |
59 |
|
60 |
static int decode_frame(AVCodecContext *avctx, |
61 |
void *data, int *data_size, |
62 |
AVPacket *avpkt) |
63 |
{ |
64 |
const uint8_t *buf = avpkt->data;
|
65 |
int buf_size = avpkt->size;
|
66 |
WNV1Context * const l = avctx->priv_data;
|
67 |
AVFrame * const p= (AVFrame*)&l->pic;
|
68 |
unsigned char *Y,*U,*V; |
69 |
int i, j;
|
70 |
int prev_y = 0, prev_u = 0, prev_v = 0; |
71 |
uint8_t *rbuf; |
72 |
|
73 |
rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); |
74 |
if(!rbuf){
|
75 |
av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
|
76 |
return -1; |
77 |
} |
78 |
|
79 |
if(p->data[0]) |
80 |
avctx->release_buffer(avctx, p); |
81 |
|
82 |
p->reference = 0;
|
83 |
if(avctx->get_buffer(avctx, p) < 0){ |
84 |
av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
|
85 |
av_free(rbuf); |
86 |
return -1; |
87 |
} |
88 |
p->key_frame = 1;
|
89 |
|
90 |
for(i=8; i<buf_size; i++) |
91 |
rbuf[i]= av_reverse[ buf[i] ]; |
92 |
init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8); |
93 |
|
94 |
if (buf[2] >> 4 == 6) |
95 |
l->shift = 2;
|
96 |
else {
|
97 |
l->shift = 8 - (buf[2] >> 4); |
98 |
if (l->shift > 4) { |
99 |
av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); |
100 |
l->shift = 4;
|
101 |
} |
102 |
if (l->shift < 1) { |
103 |
av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4); |
104 |
l->shift = 1;
|
105 |
} |
106 |
} |
107 |
|
108 |
Y = p->data[0];
|
109 |
U = p->data[1];
|
110 |
V = p->data[2];
|
111 |
for (j = 0; j < avctx->height; j++) { |
112 |
for (i = 0; i < avctx->width / 2; i++) { |
113 |
Y[i * 2] = wnv1_get_code(l, prev_y);
|
114 |
prev_u = U[i] = wnv1_get_code(l, prev_u); |
115 |
prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]); |
116 |
prev_v = V[i] = wnv1_get_code(l, prev_v); |
117 |
} |
118 |
Y += p->linesize[0];
|
119 |
U += p->linesize[1];
|
120 |
V += p->linesize[2];
|
121 |
} |
122 |
|
123 |
|
124 |
*data_size = sizeof(AVFrame);
|
125 |
*(AVFrame*)data = l->pic; |
126 |
av_free(rbuf); |
127 |
|
128 |
return buf_size;
|
129 |
} |
130 |
|
131 |
static av_cold int decode_init(AVCodecContext *avctx){ |
132 |
WNV1Context * const l = avctx->priv_data;
|
133 |
static VLC_TYPE code_table[1 << CODE_VLC_BITS][2]; |
134 |
|
135 |
l->avctx = avctx; |
136 |
avctx->pix_fmt = PIX_FMT_YUV422P; |
137 |
|
138 |
code_vlc.table = code_table; |
139 |
code_vlc.table_allocated = 1 << CODE_VLC_BITS;
|
140 |
init_vlc(&code_vlc, CODE_VLC_BITS, 16,
|
141 |
&code_tab[0][1], 4, 2, |
142 |
&code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC); |
143 |
|
144 |
return 0; |
145 |
} |
146 |
|
147 |
static av_cold int decode_end(AVCodecContext *avctx){ |
148 |
WNV1Context * const l = avctx->priv_data;
|
149 |
AVFrame *pic = &l->pic; |
150 |
|
151 |
if (pic->data[0]) |
152 |
avctx->release_buffer(avctx, pic); |
153 |
|
154 |
return 0; |
155 |
} |
156 |
|
157 |
AVCodec ff_wnv1_decoder = { |
158 |
"wnv1",
|
159 |
AVMEDIA_TYPE_VIDEO, |
160 |
CODEC_ID_WNV1, |
161 |
sizeof(WNV1Context),
|
162 |
decode_init, |
163 |
NULL,
|
164 |
decode_end, |
165 |
decode_frame, |
166 |
CODEC_CAP_DR1, |
167 |
.long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
|
168 |
}; |