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1 | /* |
2 | * Winnov WNV1 codec | |
3 | * Copyright (c) 2005 Konstantin Shishkov | |
4 | * | |
5 | * This file is part of FFmpeg. | |
6 | * | |
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. | |
11 | * | |
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. | |
16 | * | |
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 | |
20 | */ | |
21 | ||
22 | /** | |
23 | * @file | |
24 | * Winnov WNV1 codec. | |
25 | */ | |
26 | ||
27 | #include "avcodec.h" | |
28 | #include "get_bits.h" | |
29 | #include "internal.h" | |
30 | #include "mathops.h" | |
31 | ||
32 | ||
33 | typedef struct WNV1Context { | |
34 | int shift; | |
35 | GetBitContext gb; | |
36 | } WNV1Context; | |
37 | ||
38 | static const uint16_t code_tab[16][2] = { | |
39 | { 0x1FD, 9 }, { 0xFD, 8 }, { 0x7D, 7 }, { 0x3D, 6 }, { 0x1D, 5 }, { 0x0D, 4 }, { 0x005, 3 }, | |
40 | { 0x000, 1 }, | |
41 | { 0x004, 3 }, { 0x0C, 4 }, { 0x1C, 5 }, { 0x3C, 6 }, { 0x7C, 7 }, { 0xFC, 8 }, { 0x1FC, 9 }, { 0xFF, 8 } | |
42 | }; | |
43 | ||
44 | #define CODE_VLC_BITS 9 | |
45 | static VLC code_vlc; | |
46 | ||
47 | /* returns modified base_value */ | |
48 | static inline int wnv1_get_code(WNV1Context *w, int base_value) | |
49 | { | |
50 | int v = get_vlc2(&w->gb, code_vlc.table, CODE_VLC_BITS, 1); | |
51 | ||
52 | if (v == 15) | |
53 | return ff_reverse[get_bits(&w->gb, 8 - w->shift)]; | |
54 | else | |
55 | return base_value + ((v - 7) << w->shift); | |
56 | } | |
57 | ||
58 | static int decode_frame(AVCodecContext *avctx, | |
59 | void *data, int *got_frame, | |
60 | AVPacket *avpkt) | |
61 | { | |
62 | WNV1Context * const l = avctx->priv_data; | |
63 | const uint8_t *buf = avpkt->data; | |
64 | int buf_size = avpkt->size; | |
65 | AVFrame * const p = data; | |
66 | unsigned char *Y,*U,*V; | |
67 | int i, j, ret; | |
68 | int prev_y = 0, prev_u = 0, prev_v = 0; | |
69 | uint8_t *rbuf; | |
70 | ||
71 | if (buf_size <= 8) { | |
72 | av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size); | |
73 | return AVERROR_INVALIDDATA; | |
74 | } | |
75 | ||
76 | rbuf = av_malloc(buf_size + FF_INPUT_BUFFER_PADDING_SIZE); | |
77 | if (!rbuf) { | |
78 | av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n"); | |
79 | return AVERROR(ENOMEM); | |
80 | } | |
81 | memset(rbuf + buf_size, 0, FF_INPUT_BUFFER_PADDING_SIZE); | |
82 | ||
83 | if ((ret = ff_get_buffer(avctx, p, 0)) < 0) { | |
84 | av_free(rbuf); | |
85 | return ret; | |
86 | } | |
87 | p->key_frame = 1; | |
88 | ||
89 | for (i = 8; i < buf_size; i++) | |
90 | rbuf[i] = ff_reverse[buf[i]]; | |
91 | init_get_bits(&l->gb, rbuf + 8, (buf_size - 8) * 8); | |
92 | ||
93 | if (buf[2] >> 4 == 6) | |
94 | l->shift = 2; | |
95 | else { | |
96 | l->shift = 8 - (buf[2] >> 4); | |
97 | if (l->shift > 4) { | |
98 | avpriv_request_sample(avctx, | |
99 | "Unknown WNV1 frame header value %i", | |
100 | buf[2] >> 4); | |
101 | l->shift = 4; | |
102 | } | |
103 | if (l->shift < 1) { | |
104 | avpriv_request_sample(avctx, | |
105 | "Unknown WNV1 frame header value %i", | |
106 | buf[2] >> 4); | |
107 | l->shift = 1; | |
108 | } | |
109 | } | |
110 | ||
111 | Y = p->data[0]; | |
112 | U = p->data[1]; | |
113 | V = p->data[2]; | |
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); | |
120 | } | |
121 | Y += p->linesize[0]; | |
122 | U += p->linesize[1]; | |
123 | V += p->linesize[2]; | |
124 | } | |
125 | ||
126 | ||
127 | *got_frame = 1; | |
128 | av_free(rbuf); | |
129 | ||
130 | return buf_size; | |
131 | } | |
132 | ||
133 | static av_cold int decode_init(AVCodecContext *avctx) | |
134 | { | |
135 | static VLC_TYPE code_table[1 << CODE_VLC_BITS][2]; | |
136 | ||
137 | avctx->pix_fmt = AV_PIX_FMT_YUV422P; | |
138 | ||
139 | code_vlc.table = code_table; | |
140 | code_vlc.table_allocated = 1 << CODE_VLC_BITS; | |
141 | init_vlc(&code_vlc, CODE_VLC_BITS, 16, | |
142 | &code_tab[0][1], 4, 2, | |
143 | &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC); | |
144 | ||
145 | return 0; | |
146 | } | |
147 | ||
148 | AVCodec ff_wnv1_decoder = { | |
149 | .name = "wnv1", | |
150 | .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"), | |
151 | .type = AVMEDIA_TYPE_VIDEO, | |
152 | .id = AV_CODEC_ID_WNV1, | |
153 | .priv_data_size = sizeof(WNV1Context), | |
154 | .init = decode_init, | |
155 | .decode = decode_frame, | |
156 | .capabilities = CODEC_CAP_DR1, | |
157 | }; |