e973f7ecc5314722d20b7e057e816b01a573385b
[libav.git] / libavcodec / wnv1.c
1 /*
2 * Winnov WNV1 codec
3 * Copyright (c) 2005 Konstantin Shishkov
4 *
5 * This file is part of Libav.
6 *
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.
11 *
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.
16 *
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
20 */
21
22 /**
23 * @file
24 * Winnov WNV1 codec.
25 */
26
27 #include "avcodec.h"
28 #include "bitstream.h"
29 #include "internal.h"
30 #include "mathops.h"
31
32
33 typedef struct WNV1Context {
34 AVCodecContext *avctx;
35
36 int shift;
37 BitstreamContext bc;
38 } WNV1Context;
39
40 static const uint16_t code_tab[16][2] = {
41 { 0x1FD, 9 }, { 0xFD, 8 }, { 0x7D, 7 }, { 0x3D, 6 }, { 0x1D, 5 }, { 0x0D, 4 }, { 0x005, 3 },
42 { 0x000, 1 },
43 { 0x004, 3 }, { 0x0C, 4 }, { 0x1C, 5 }, { 0x3C, 6 }, { 0x7C, 7 }, { 0xFC, 8 }, { 0x1FC, 9 }, { 0xFF, 8 }
44 };
45
46 #define CODE_VLC_BITS 9
47 static VLC code_vlc;
48
49 /* returns modified base_value */
50 static inline int wnv1_get_code(WNV1Context *w, int base_value)
51 {
52 int v = bitstream_read_vlc(&w->bc, code_vlc.table, CODE_VLC_BITS, 1);
53
54 if (v == 15)
55 return ff_reverse[bitstream_read(&w->bc, 8 - w->shift)];
56 else
57 return base_value + ((v - 7) << w->shift);
58 }
59
60 static int decode_frame(AVCodecContext *avctx,
61 void *data, int *got_frame,
62 AVPacket *avpkt)
63 {
64 WNV1Context * const l = avctx->priv_data;
65 const uint8_t *buf = avpkt->data;
66 int buf_size = avpkt->size;
67 AVFrame * const p = data;
68 unsigned char *Y,*U,*V;
69 int i, j, ret;
70 int prev_y = 0, prev_u = 0, prev_v = 0;
71 uint8_t *rbuf;
72
73 if (buf_size < 8) {
74 av_log(avctx, AV_LOG_ERROR, "Packet is too short\n");
75 return AVERROR_INVALIDDATA;
76 }
77
78 rbuf = av_malloc(buf_size + AV_INPUT_BUFFER_PADDING_SIZE);
79 if (!rbuf) {
80 av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
81 return AVERROR(ENOMEM);
82 }
83
84 if ((ret = ff_get_buffer(avctx, p, 0)) < 0) {
85 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
86 av_free(rbuf);
87 return ret;
88 }
89 p->key_frame = 1;
90
91 for (i = 8; i < buf_size; i++)
92 rbuf[i] = ff_reverse[buf[i]];
93 bitstream_init8(&l->bc, rbuf + 8, buf_size - 8);
94
95 if (buf[2] >> 4 == 6)
96 l->shift = 2;
97 else {
98 l->shift = 8 - (buf[2] >> 4);
99 if (l->shift > 4) {
100 avpriv_request_sample(avctx,
101 "Unknown WNV1 frame header value %i",
102 buf[2] >> 4);
103 l->shift = 4;
104 }
105 if (l->shift < 1) {
106 avpriv_request_sample(avctx,
107 "Unknown WNV1 frame header value %i",
108 buf[2] >> 4);
109 l->shift = 1;
110 }
111 }
112
113 Y = p->data[0];
114 U = p->data[1];
115 V = p->data[2];
116 for (j = 0; j < avctx->height; j++) {
117 for (i = 0; i < avctx->width / 2; i++) {
118 Y[i * 2] = wnv1_get_code(l, prev_y);
119 prev_u = U[i] = wnv1_get_code(l, prev_u);
120 prev_y = Y[(i * 2) + 1] = wnv1_get_code(l, Y[i * 2]);
121 prev_v = V[i] = wnv1_get_code(l, prev_v);
122 }
123 Y += p->linesize[0];
124 U += p->linesize[1];
125 V += p->linesize[2];
126 }
127
128
129 *got_frame = 1;
130 av_free(rbuf);
131
132 return buf_size;
133 }
134
135 static av_cold int decode_init(AVCodecContext *avctx)
136 {
137 WNV1Context * const l = avctx->priv_data;
138 static VLC_TYPE code_table[1 << CODE_VLC_BITS][2];
139
140 l->avctx = avctx;
141 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
142
143 code_vlc.table = code_table;
144 code_vlc.table_allocated = 1 << CODE_VLC_BITS;
145 init_vlc(&code_vlc, CODE_VLC_BITS, 16,
146 &code_tab[0][1], 4, 2,
147 &code_tab[0][0], 4, 2, INIT_VLC_USE_NEW_STATIC);
148
149 return 0;
150 }
151
152 AVCodec ff_wnv1_decoder = {
153 .name = "wnv1",
154 .long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
155 .type = AVMEDIA_TYPE_VIDEO,
156 .id = AV_CODEC_ID_WNV1,
157 .priv_data_size = sizeof(WNV1Context),
158 .init = decode_init,
159 .decode = decode_frame,
160 .capabilities = AV_CODEC_CAP_DR1,
161 };