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 "libavutil/thread.h"
28
29 #define BITSTREAM_READER_LE
30 #include "avcodec.h"
31 #include "codec_internal.h"
32 #include "get_bits.h"
33 #include "internal.h"
34
35 static const uint8_t code_tab[16][2] = {
36 { 7, 1 }, { 8, 3 }, { 6, 3 }, { 9, 4 }, { 5, 4 }, { 10, 5 }, { 4, 5 },
37 { 11, 6 }, { 3, 6 }, { 12, 7 }, { 2, 7 }, { 13, 8 }, { 1, 8 }, { 14, 9 },
38 { 0, 9 }, { 15, 8 }
39 };
40
41 #define CODE_VLC_BITS 9
42 static VLC code_vlc;
43
44 /* returns modified base_value */
wnv1_get_code(GetBitContext *gb, int shift, int base_value)45 static inline int wnv1_get_code(GetBitContext *gb, int shift, int base_value)
46 {
47 int v = get_vlc2(gb, code_vlc.table, CODE_VLC_BITS, 1);
48
49 if (v == 8)
50 return get_bits(gb, 8 - shift) << shift;
51 else
52 return base_value + v * (1 << shift);
53 }
54
decode_frame(AVCodecContext *avctx, AVFrame *p, int *got_frame, AVPacket *avpkt)55 static int decode_frame(AVCodecContext *avctx, AVFrame *p,
56 int *got_frame, AVPacket *avpkt)
57 {
58 const uint8_t *buf = avpkt->data;
59 int buf_size = avpkt->size;
60 GetBitContext gb;
61 unsigned char *Y,*U,*V;
62 int i, j, ret, shift;
63 int prev_y = 0, prev_u = 0, prev_v = 0;
64
65 if (buf_size < 8 + avctx->height * (avctx->width/2)/8) {
66 av_log(avctx, AV_LOG_ERROR, "Packet size %d is too small\n", buf_size);
67 return AVERROR_INVALIDDATA;
68 }
69
70 if ((ret = ff_get_buffer(avctx, p, 0)) < 0)
71 return ret;
72 p->key_frame = 1;
73
74 if ((ret = init_get_bits8(&gb, buf + 8, buf_size - 8)) < 0)
75 return ret;
76
77 if (buf[2] >> 4 == 6)
78 shift = 2;
79 else {
80 shift = 8 - (buf[2] >> 4);
81 if (shift > 4) {
82 avpriv_request_sample(avctx,
83 "Unknown WNV1 frame header value %i",
84 buf[2] >> 4);
85 shift = 4;
86 }
87 if (shift < 1) {
88 avpriv_request_sample(avctx,
89 "Unknown WNV1 frame header value %i",
90 buf[2] >> 4);
91 shift = 1;
92 }
93 }
94
95 Y = p->data[0];
96 U = p->data[1];
97 V = p->data[2];
98 for (j = 0; j < avctx->height; j++) {
99 for (i = 0; i < avctx->width / 2; i++) {
100 Y[i * 2] = wnv1_get_code(&gb, shift, prev_y);
101 prev_u = U[i] = wnv1_get_code(&gb, shift, prev_u);
102 prev_y = Y[(i * 2) + 1] = wnv1_get_code(&gb, shift, Y[i * 2]);
103 prev_v = V[i] = wnv1_get_code(&gb, shift, prev_v);
104 }
105 Y += p->linesize[0];
106 U += p->linesize[1];
107 V += p->linesize[2];
108 }
109
110
111 *got_frame = 1;
112
113 return buf_size;
114 }
115
wnv1_init_static(void)116 static av_cold void wnv1_init_static(void)
117 {
118 INIT_VLC_STATIC_FROM_LENGTHS(&code_vlc, CODE_VLC_BITS, 16,
119 &code_tab[0][1], 2,
120 &code_tab[0][0], 2, 1,
121 -7, INIT_VLC_OUTPUT_LE, 1 << CODE_VLC_BITS);
122 }
123
decode_init(AVCodecContext *avctx)124 static av_cold int decode_init(AVCodecContext *avctx)
125 {
126 static AVOnce init_static_once = AV_ONCE_INIT;
127
128 if (avctx->width <= 1)
129 return AVERROR_INVALIDDATA;
130
131 avctx->pix_fmt = AV_PIX_FMT_YUV422P;
132
133 ff_thread_once(&init_static_once, wnv1_init_static);
134
135 return 0;
136 }
137
138 const FFCodec ff_wnv1_decoder = {
139 .p.name = "wnv1",
140 .p.long_name = NULL_IF_CONFIG_SMALL("Winnov WNV1"),
141 .p.type = AVMEDIA_TYPE_VIDEO,
142 .p.id = AV_CODEC_ID_WNV1,
143 .init = decode_init,
144 FF_CODEC_DECODE_CB(decode_frame),
145 .p.capabilities = AV_CODEC_CAP_DR1,
146 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
147 };
148