3 * Copyright (c) 2005 Konstantin Shishkov
5 * This file is part of FFmpeg.
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.
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.
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
23 * @file libavcodec/wnv1.c
28 #include "bitstream.h"
31 typedef struct WNV1Context
{
32 AVCodecContext
*avctx
;
39 static const uint16_t code_tab
[16][2]={
40 {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
42 {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
45 #define CODE_VLC_BITS 9
48 /* returns modified base_value */
49 static inline int wnv1_get_code(WNV1Context
*w
, int base_value
)
51 int v
= get_vlc2(&w
->gb
, code_vlc
.table
, CODE_VLC_BITS
, 1);
54 return ff_reverse
[ get_bits(&w
->gb
, 8 - w
->shift
) ];
56 return base_value
+ ((v
- 7)<<w
->shift
);
59 static int decode_frame(AVCodecContext
*avctx
,
60 void *data
, int *data_size
,
61 const uint8_t *buf
, int buf_size
)
63 WNV1Context
* const l
= avctx
->priv_data
;
64 AVFrame
* const p
= (AVFrame
*)&l
->pic
;
65 unsigned char *Y
,*U
,*V
;
67 int prev_y
= 0, prev_u
= 0, prev_v
= 0;
70 rbuf
= av_malloc(buf_size
+ FF_INPUT_BUFFER_PADDING_SIZE
);
72 av_log(avctx
, AV_LOG_ERROR
, "Cannot allocate temporary buffer\n");
77 avctx
->release_buffer(avctx
, p
);
80 if(avctx
->get_buffer(avctx
, p
) < 0){
81 av_log(avctx
, AV_LOG_ERROR
, "get_buffer() failed\n");
87 for(i
=8; i
<buf_size
; i
++)
88 rbuf
[i
]= ff_reverse
[ buf
[i
] ];
89 init_get_bits(&l
->gb
, rbuf
+8, (buf_size
-8)*8);
94 l
->shift
= 8 - (buf
[2] >> 4);
96 av_log(avctx
, AV_LOG_ERROR
, "Unknown WNV1 frame header value %i, please upload file for study\n", buf
[2] >> 4);
100 av_log(avctx
, AV_LOG_ERROR
, "Unknown WNV1 frame header value %i, please upload file for study\n", buf
[2] >> 4);
108 for (j
= 0; j
< avctx
->height
; j
++) {
109 for (i
= 0; i
< avctx
->width
/ 2; i
++) {
110 Y
[i
* 2] = wnv1_get_code(l
, prev_y
);
111 prev_u
= U
[i
] = wnv1_get_code(l
, prev_u
);
112 prev_y
= Y
[(i
* 2) + 1] = wnv1_get_code(l
, Y
[i
* 2]);
113 prev_v
= V
[i
] = wnv1_get_code(l
, prev_v
);
121 *data_size
= sizeof(AVFrame
);
122 *(AVFrame
*)data
= l
->pic
;
128 static av_cold
int decode_init(AVCodecContext
*avctx
){
129 WNV1Context
* const l
= avctx
->priv_data
;
132 avctx
->pix_fmt
= PIX_FMT_YUV422P
;
135 init_vlc(&code_vlc
, CODE_VLC_BITS
, 16,
136 &code_tab
[0][1], 4, 2,
137 &code_tab
[0][0], 4, 2, 1);
143 AVCodec wnv1_decoder
= {
153 .long_name
= NULL_IF_CONFIG_SMALL("Winnov WNV1"),