blob: 5359411c7619015b108cb40451393551f56154a8
1 | /* |
2 | * Kega Game Video (KGV1) decoder |
3 | * Copyright (c) 2010 Daniel Verkamp |
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 | * Kega Game Video decoder |
25 | */ |
26 | |
27 | #include "libavutil/common.h" |
28 | #include "libavutil/intreadwrite.h" |
29 | #include "libavutil/imgutils.h" |
30 | #include "avcodec.h" |
31 | #include "internal.h" |
32 | |
33 | typedef struct KgvContext { |
34 | uint16_t *frame_buffer; |
35 | uint16_t *last_frame_buffer; |
36 | } KgvContext; |
37 | |
38 | static void decode_flush(AVCodecContext *avctx) |
39 | { |
40 | KgvContext * const c = avctx->priv_data; |
41 | |
42 | av_freep(&c->frame_buffer); |
43 | av_freep(&c->last_frame_buffer); |
44 | } |
45 | |
46 | static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, |
47 | AVPacket *avpkt) |
48 | { |
49 | AVFrame *frame = data; |
50 | const uint8_t *buf = avpkt->data; |
51 | const uint8_t *buf_end = buf + avpkt->size; |
52 | KgvContext * const c = avctx->priv_data; |
53 | int offsets[8]; |
54 | uint8_t *out, *prev; |
55 | int outcnt = 0, maxcnt; |
56 | int w, h, i, res; |
57 | |
58 | if (avpkt->size < 2) |
59 | return AVERROR_INVALIDDATA; |
60 | |
61 | w = (buf[0] + 1) * 8; |
62 | h = (buf[1] + 1) * 8; |
63 | buf += 2; |
64 | |
65 | if (w != avctx->width || h != avctx->height) { |
66 | av_freep(&c->frame_buffer); |
67 | av_freep(&c->last_frame_buffer); |
68 | if ((res = ff_set_dimensions(avctx, w, h)) < 0) |
69 | return res; |
70 | } |
71 | |
72 | if (!c->frame_buffer) { |
73 | c->frame_buffer = av_mallocz(avctx->width * avctx->height * 2); |
74 | c->last_frame_buffer = av_mallocz(avctx->width * avctx->height * 2); |
75 | if (!c->frame_buffer || !c->last_frame_buffer) { |
76 | decode_flush(avctx); |
77 | return AVERROR(ENOMEM); |
78 | } |
79 | } |
80 | |
81 | maxcnt = w * h; |
82 | |
83 | if ((res = ff_get_buffer(avctx, frame, 0)) < 0) |
84 | return res; |
85 | out = (uint8_t*)c->frame_buffer; |
86 | prev = (uint8_t*)c->last_frame_buffer; |
87 | |
88 | for (i = 0; i < 8; i++) |
89 | offsets[i] = -1; |
90 | |
91 | while (outcnt < maxcnt && buf_end - 2 >= buf) { |
92 | int code = AV_RL16(buf); |
93 | buf += 2; |
94 | |
95 | if (!(code & 0x8000)) { |
96 | AV_WN16A(&out[2 * outcnt], code); // rgb555 pixel coded directly |
97 | outcnt++; |
98 | } else { |
99 | int count; |
100 | |
101 | if ((code & 0x6000) == 0x6000) { |
102 | // copy from previous frame |
103 | int oidx = (code >> 10) & 7; |
104 | int start; |
105 | |
106 | count = (code & 0x3FF) + 3; |
107 | |
108 | if (offsets[oidx] < 0) { |
109 | if (buf_end - 3 < buf) |
110 | break; |
111 | offsets[oidx] = AV_RL24(buf); |
112 | buf += 3; |
113 | } |
114 | |
115 | start = (outcnt + offsets[oidx]) % maxcnt; |
116 | |
117 | if (maxcnt - start < count || maxcnt - outcnt < count) |
118 | break; |
119 | |
120 | if (!prev) { |
121 | av_log(avctx, AV_LOG_ERROR, |
122 | "Frame reference does not exist\n"); |
123 | break; |
124 | } |
125 | |
126 | memcpy(out + 2 * outcnt, prev + 2 * start, 2 * count); |
127 | } else { |
128 | // copy from earlier in this frame |
129 | int offset = (code & 0x1FFF) + 1; |
130 | |
131 | if (!(code & 0x6000)) { |
132 | count = 2; |
133 | } else if ((code & 0x6000) == 0x2000) { |
134 | count = 3; |
135 | } else { |
136 | if (buf_end - 1 < buf) |
137 | break; |
138 | count = 4 + *buf++; |
139 | } |
140 | |
141 | if (outcnt < offset || maxcnt - outcnt < count) |
142 | break; |
143 | |
144 | av_memcpy_backptr(out + 2 * outcnt, 2 * offset, 2 * count); |
145 | } |
146 | outcnt += count; |
147 | } |
148 | } |
149 | |
150 | if (outcnt - maxcnt) |
151 | av_log(avctx, AV_LOG_DEBUG, "frame finished with %d diff\n", outcnt - maxcnt); |
152 | |
153 | av_image_copy_plane(frame->data[0], frame->linesize[0], |
154 | (const uint8_t*)c->frame_buffer, avctx->width * 2, |
155 | avctx->width * 2, avctx->height); |
156 | FFSWAP(uint16_t *, c->frame_buffer, c->last_frame_buffer); |
157 | |
158 | *got_frame = 1; |
159 | |
160 | return avpkt->size; |
161 | } |
162 | |
163 | static av_cold int decode_init(AVCodecContext *avctx) |
164 | { |
165 | avctx->pix_fmt = AV_PIX_FMT_RGB555; |
166 | |
167 | return 0; |
168 | } |
169 | |
170 | static av_cold int decode_end(AVCodecContext *avctx) |
171 | { |
172 | decode_flush(avctx); |
173 | return 0; |
174 | } |
175 | |
176 | AVCodec ff_kgv1_decoder = { |
177 | .name = "kgv1", |
178 | .long_name = NULL_IF_CONFIG_SMALL("Kega Game Video"), |
179 | .type = AVMEDIA_TYPE_VIDEO, |
180 | .id = AV_CODEC_ID_KGV1, |
181 | .priv_data_size = sizeof(KgvContext), |
182 | .init = decode_init, |
183 | .close = decode_end, |
184 | .decode = decode_frame, |
185 | .flush = decode_flush, |
186 | .capabilities = AV_CODEC_CAP_DR1, |
187 | }; |
188 |