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
27 #define BITSTREAM_READER_LE
32 static const uint8_t code_tab[16][2] = {
33 { 7, 1 }, { 8, 3 }, { 6, 3 }, { 9, 4 }, { 5, 4 }, { 10, 5 }, { 4, 5 },
34 { 11, 6 }, { 3, 6 }, { 12, 7 }, { 2, 7 }, { 13, 8 }, { 1, 8 }, { 14, 9 },
38 #define CODE_VLC_BITS 9
41 /* returns modified base_value */
42 static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
44 int v = get_vlc2(gb, code_vlc.table, CODE_VLC_BITS, 1);
47 return get_bits(gb, 8 - shift) << shift;
49 return base_value + v * (1 << shift);
52 static int decode_frame(AVCodecContext *avctx,
53 void *data, int *got_frame,
56 const uint8_t *buf = avpkt->data;
57 int buf_size = avpkt->size;
58 AVFrame * const p = data;
60 unsigned char *Y,*U,*V;
62 int prev_y = 0, prev_u = 0, prev_v = 0;
64 if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {
65 av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);
66 return AVERROR_INVALIDDATA;
69 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
73 if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0)
79 shift = 8 - (buf[2] >> 4);
81 avpriv_request_sample(avctx,
82 "Unknown WNV1 frame header value %i",
87 avpriv_request_sample(avctx,
88 "Unknown WNV1 frame header value %i",
97 for (j = 0; j < avctx->height; j++) {
98 for (i = 0; i < avctx->width / 2; i++) {
99 Y[i * 2] = wnv1_get_code(&gb, shift, prev_y);
100 prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u);
101 prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]);
102 prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v);
115 static av_cold int decode_init(AVCodecContext *avctx)
117 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
119 INIT_VLC_STATIC_FROM_LENGTHS(&code_vlc, CODE_VLC_BITS, 16,
121 &code_tab[0][0], 2, 1,
122 -7, INIT_VLC_OUTPUT_LE, 1 << CODE_VLC_BITS);
126 AVCodec ff_wnv1_decoder = {
128 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
129 .type = AVMEDIA_TYPE_VIDEO,
130 .id = AV_CODEC_ID_WNV1,
132 .decode = decode_frame,
133 .capabilities = AV_CODEC_CAP_DR1,