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
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;
75 av_log(avctx, AV_LOG_ERROR, "buf_size %d is too small\n", buf_size);
76 return AVERROR_INVALIDDATA;
79 rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
81 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
82 return AVERROR(ENOMEM);
86 avctx->release_buffer(avctx, p);
89 if ((ret = ff_get_buffer(avctx, p)) < 0) {
90 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
96 for (i = 8; i < buf_size; i++)
97 rbuf[i] = ff_reverse[buf[i]];
98 init_get_bits(&l->gb, rbuf + 8, (buf_size - 8) * 8);
100 if (buf[2] >> 4 == 6)
103 l->shift = 8 - (buf[2] >> 4);
105 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
110 av_log_ask_for_sample(avctx, "Unknown WNV1 frame header value %i\n",
119 for (j = 0; j < avctx->height; j++) {
120 for (i = 0; i < avctx->width / 2; i++) {
121 Y[i * 2] = wnv1_get_code(l, prev_y);
122 prev_u = U[i] = wnv1_get_code(l, prev_u);
123 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
124 prev_v = V[i] = wnv1_get_code(l, prev_v);
133 *(AVFrame*)data = l->pic;
139 static av_cold int decode_init(AVCodecContext *avctx)
141 WNV1Context * const l = avctx->priv_data;
142 static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
145 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
146 avcodec_get_frame_defaults(&l->pic);
148 code_vlc.table = code_table;
149 code_vlc.table_allocated = 1 << CODE_VLC_BITS;
150 init_vlc(&code_vlc, CODE_VLC_BITS, 16,
151 &code_tab[0][1], 4, 2,
152 &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
157 static av_cold int decode_end(AVCodecContext *avctx)
159 WNV1Context * const l = avctx->priv_data;
160 AVFrame *pic = &l->pic;
163 avctx->release_buffer(avctx, pic);
168 AVCodec ff_wnv1_decoder = {
170 .type = AVMEDIA_TYPE_VIDEO,
171 .id = AV_CODEC_ID_WNV1,
172 .priv_data_size = sizeof(WNV1Context),
175 .decode = decode_frame,
176 .capabilities = CODEC_CAP_DR1,
177 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),