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 *got_frame,
65 WNV1Context * const l = avctx->priv_data;
66 const uint8_t *buf = avpkt->data;
67 int buf_size = avpkt->size;
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");
77 return AVERROR(ENOMEM);
81 avctx->release_buffer(avctx, p);
84 if ((ret = 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);
128 *(AVFrame*)data = l->pic;
134 static av_cold int decode_init(AVCodecContext *avctx)
136 WNV1Context * const l = avctx->priv_data;
137 static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
140 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
142 code_vlc.table = code_table;
143 code_vlc.table_allocated = 1 << CODE_VLC_BITS;
144 init_vlc(&code_vlc, CODE_VLC_BITS, 16,
145 &code_tab[0][1], 4, 2,
146 &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
151 static av_cold int decode_end(AVCodecContext *avctx)
153 WNV1Context * const l = avctx->priv_data;
154 AVFrame *pic = &l->pic;
157 avctx->release_buffer(avctx, pic);
162 AVCodec ff_wnv1_decoder = {
164 .type = AVMEDIA_TYPE_VIDEO,
165 .id = AV_CODEC_ID_WNV1,
166 .priv_data_size = sizeof(WNV1Context),
169 .decode = decode_frame,
170 .capabilities = CODEC_CAP_DR1,
171 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),