3 * Copyright (c) 2005 Konstantin Shishkov
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
33 typedef struct WNV1Context
{
34 AVCodecContext
*avctx
;
41 static const uint16_t code_tab
[16][2]={
42 {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
44 {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
47 #define CODE_VLC_BITS 9
50 /* returns modified base_value */
51 static inline int wnv1_get_code(WNV1Context
*w
, int base_value
)
53 int v
= get_vlc2(&w
->gb
, code_vlc
.table
, CODE_VLC_BITS
, 1);
56 return ff_reverse
[ get_bits(&w
->gb
, 8 - w
->shift
) ];
58 return base_value
+ ((v
- 7)<<w
->shift
);
61 static int decode_frame(AVCodecContext
*avctx
,
62 void *data
, int *data_size
,
65 const uint8_t *buf
= avpkt
->data
;
66 int buf_size
= avpkt
->size
;
67 WNV1Context
* const l
= avctx
->priv_data
;
68 AVFrame
* const p
= &l
->pic
;
69 unsigned char *Y
,*U
,*V
;
71 int prev_y
= 0, prev_u
= 0, prev_v
= 0;
74 rbuf
= av_malloc(buf_size
+ FF_INPUT_BUFFER_PADDING_SIZE
);
76 av_log(avctx
, AV_LOG_ERROR
, "Cannot allocate temporary buffer\n");
81 avctx
->release_buffer(avctx
, p
);
84 if(ff_get_buffer(avctx
, p
) < 0){
85 av_log(avctx
, AV_LOG_ERROR
, "get_buffer() failed\n");
91 for(i
=8; i
<buf_size
; i
++)
92 rbuf
[i
]= ff_reverse
[ buf
[i
] ];
93 init_get_bits(&l
->gb
, rbuf
+8, (buf_size
-8)*8);
98 l
->shift
= 8 - (buf
[2] >> 4);
100 av_log_ask_for_sample(avctx
, "Unknown WNV1 frame header value %i\n",
105 av_log_ask_for_sample(avctx
, "Unknown WNV1 frame header value %i\n",
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
);
127 *data_size
= sizeof(AVFrame
);
128 *(AVFrame
*)data
= l
->pic
;
134 static av_cold
int decode_init(AVCodecContext
*avctx
){
135 WNV1Context
* const l
= avctx
->priv_data
;
136 static VLC_TYPE code_table
[1 << CODE_VLC_BITS
][2];
139 avctx
->pix_fmt
= AV_PIX_FMT_YUV422P
;
141 code_vlc
.table
= code_table
;
142 code_vlc
.table_allocated
= 1 << CODE_VLC_BITS
;
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
);
150 static av_cold
int decode_end(AVCodecContext
*avctx
){
151 WNV1Context
* const l
= avctx
->priv_data
;
152 AVFrame
*pic
= &l
->pic
;
155 avctx
->release_buffer(avctx
, pic
);
160 AVCodec ff_wnv1_decoder
= {
162 .type
= AVMEDIA_TYPE_VIDEO
,
163 .id
= AV_CODEC_ID_WNV1
,
164 .priv_data_size
= sizeof(WNV1Context
),
167 .decode
= decode_frame
,
168 .capabilities
= CODEC_CAP_DR1
,
169 .long_name
= NULL_IF_CONFIG_SMALL("Winnov WNV1"),