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
32 typedef struct WNV1Context{
33 AVCodecContext *avctx;
40 static const uint16_t code_tab[16][2]={
41 {0x1FD,9}, {0xFD,8}, {0x7D,7}, {0x3D,6}, {0x1D,5}, {0x0D,4}, {0x005,3},
43 {0x004,3}, {0x0C,4}, {0x1C,5}, {0x3C,6}, {0x7C,7}, {0xFC,8}, {0x1FC,9}, {0xFF,8}
46 #define CODE_VLC_BITS 9
49 /* returns modified base_value */
50 static inline int wnv1_get_code(WNV1Context *w, int base_value)
52 int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1);
55 return ff_reverse[ get_bits(&w->gb, 8 - w->shift) ];
57 return base_value + ((v - 7)<<w->shift);
60 static int decode_frame(AVCodecContext *avctx,
61 void *data, int *data_size,
64 const uint8_t *buf = avpkt->data;
65 int buf_size = avpkt->size;
66 WNV1Context * const l = avctx->priv_data;
67 AVFrame * const p = &l->pic;
68 unsigned char *Y,*U,*V;
70 int prev_y = 0, prev_u = 0, prev_v = 0;
74 av_log(avctx, AV_LOG_ERROR, "buf_size %d is too small\n", buf_size);
75 return AVERROR_INVALIDDATA;
78 rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
80 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
85 avctx->release_buffer(avctx, p);
88 if(avctx->get_buffer(avctx, p) < 0){
89 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
95 for(i=8; i<buf_size; i++)
96 rbuf[i]= ff_reverse[ buf[i] ];
97 init_get_bits(&l->gb, rbuf+8, (buf_size-8)*8);
102 l->shift = 8 - (buf[2] >> 4);
104 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
109 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
118 for (j = 0; j < avctx->height; j++) {
119 for (i = 0; i < avctx->width / 2; i++) {
120 Y[i * 2] = wnv1_get_code(l, prev_y);
121 prev_u = U[i] = wnv1_get_code(l, prev_u);
122 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
123 prev_v = V[i] = wnv1_get_code(l, prev_v);
131 *data_size = sizeof(AVFrame);
132 *(AVFrame*)data = l->pic;
138 static av_cold int decode_init(AVCodecContext *avctx){
139 WNV1Context * const l = avctx->priv_data;
140 static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
143 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
144 avcodec_get_frame_defaults(&l->pic);
146 code_vlc.table = code_table;
147 code_vlc.table_allocated = 1 << CODE_VLC_BITS;
148 init_vlc(&code_vlc, CODE_VLC_BITS, 16,
149 &code_tab[0][1], 4, 2,
150 &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
155 static av_cold int decode_end(AVCodecContext *avctx){
156 WNV1Context * const l = avctx->priv_data;
157 AVFrame *pic = &l->pic;
160 avctx->release_buffer(avctx, pic);
165 AVCodec ff_wnv1_decoder = {
167 .type = AVMEDIA_TYPE_VIDEO,
168 .id = AV_CODEC_ID_WNV1,
169 .priv_data_size = sizeof(WNV1Context),
172 .decode = decode_frame,
173 .capabilities = CODEC_CAP_DR1,
174 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),