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
30 #include "bitstream.h"
33 typedef struct WNV1Context{
34 AVCodecContext *avctx;
41 static 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,
63 uint8_t *buf, int buf_size)
65 WNV1Context * const l = avctx->priv_data;
66 AVFrame * const p= (AVFrame*)&l->pic;
67 unsigned char *Y,*U,*V;
69 int prev_y = 0, prev_u = 0, prev_v = 0;
72 avctx->release_buffer(avctx, p);
75 if(avctx->get_buffer(avctx, p) < 0){
76 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
81 for(i=8; i<buf_size; i++)
82 buf[i]= ff_reverse[ buf[i] ]; //FIXME ensure that the buffer is modifyable or use a temp one
83 init_get_bits(&l->gb, buf+8, (buf_size-8)*8);
88 l->shift = 8 - (buf[2] >> 4);
90 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
94 av_log(avctx, AV_LOG_ERROR, "Unknown WNV1 frame header value %i, please upload file for study\n", buf[2] >> 4);
102 for (j = 0; j < avctx->height; j++) {
103 for (i = 0; i < avctx->width / 2; i++) {
104 Y[i * 2] = wnv1_get_code(l, prev_y);
105 prev_u = U[i] = wnv1_get_code(l, prev_u);
106 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
107 prev_v = V[i] = wnv1_get_code(l, prev_v);
115 *data_size = sizeof(AVFrame);
116 *(AVFrame*)data = l->pic;
121 static int decode_init(AVCodecContext *avctx){
122 WNV1Context * const l = avctx->priv_data;
125 avctx->pix_fmt = PIX_FMT_YUV422P;
128 init_vlc(&code_vlc, CODE_VLC_BITS, 16,
129 &code_tab[0][1], 4, 2,
130 &code_tab[0][0], 4, 2, 1);
136 AVCodec wnv1_decoder = {