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1 | /* |
2 | * Interplay C93 video decoder | |
3 | * Copyright (c) 2007 Anssi Hannula <anssi.hannula@gmail.com> | |
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 | #include "avcodec.h" | |
23 | #include "bytestream.h" | |
24 | #include "internal.h" | |
25 | ||
26 | typedef struct { | |
27 | AVFrame *pictures[2]; | |
28 | int currentpic; | |
29 | } C93DecoderContext; | |
30 | ||
31 | typedef enum { | |
32 | C93_8X8_FROM_PREV = 0x02, | |
33 | C93_4X4_FROM_PREV = 0x06, | |
34 | C93_4X4_FROM_CURR = 0x07, | |
35 | C93_8X8_2COLOR = 0x08, | |
36 | C93_4X4_2COLOR = 0x0A, | |
37 | C93_4X4_4COLOR_GRP = 0x0B, | |
38 | C93_4X4_4COLOR = 0x0D, | |
39 | C93_NOOP = 0x0E, | |
40 | C93_8X8_INTRA = 0x0F, | |
41 | } C93BlockType; | |
42 | ||
43 | #define WIDTH 320 | |
44 | #define HEIGHT 192 | |
45 | ||
46 | #define C93_HAS_PALETTE 0x01 | |
47 | #define C93_FIRST_FRAME 0x02 | |
48 | ||
49 | static av_cold int decode_end(AVCodecContext *avctx) | |
50 | { | |
51 | C93DecoderContext * const c93 = avctx->priv_data; | |
52 | ||
53 | av_frame_free(&c93->pictures[0]); | |
54 | av_frame_free(&c93->pictures[1]); | |
55 | ||
56 | return 0; | |
57 | } | |
58 | ||
59 | static av_cold int decode_init(AVCodecContext *avctx) | |
60 | { | |
61 | C93DecoderContext *s = avctx->priv_data; | |
62 | avctx->pix_fmt = AV_PIX_FMT_PAL8; | |
63 | ||
64 | s->pictures[0] = av_frame_alloc(); | |
65 | s->pictures[1] = av_frame_alloc(); | |
66 | if (!s->pictures[0] || !s->pictures[1]) { | |
67 | decode_end(avctx); | |
68 | return AVERROR(ENOMEM); | |
69 | } | |
70 | ||
71 | return 0; | |
72 | } | |
73 | ||
74 | static inline int copy_block(AVCodecContext *avctx, uint8_t *to, | |
75 | uint8_t *from, int offset, int height, int stride) | |
76 | { | |
77 | int i; | |
78 | int width = height; | |
79 | int from_x = offset % WIDTH; | |
80 | int from_y = offset / WIDTH; | |
81 | int overflow = from_x + width - WIDTH; | |
82 | ||
83 | if (!from) { | |
84 | /* silently ignoring predictive blocks in first frame */ | |
85 | return 0; | |
86 | } | |
87 | ||
88 | if (from_y + height > HEIGHT) { | |
89 | av_log(avctx, AV_LOG_ERROR, "invalid offset %d during C93 decoding\n", | |
90 | offset); | |
91 | return AVERROR_INVALIDDATA; | |
92 | } | |
93 | ||
94 | if (overflow > 0) { | |
95 | width -= overflow; | |
96 | for (i = 0; i < height; i++) { | |
97 | memcpy(&to[i*stride+width], &from[(from_y+i)*stride], overflow); | |
98 | } | |
99 | } | |
100 | ||
101 | for (i = 0; i < height; i++) { | |
102 | memcpy(&to[i*stride], &from[(from_y+i)*stride+from_x], width); | |
103 | } | |
104 | ||
105 | return 0; | |
106 | } | |
107 | ||
108 | static inline void draw_n_color(uint8_t *out, int stride, int width, | |
109 | int height, int bpp, uint8_t cols[4], uint8_t grps[4], uint32_t col) | |
110 | { | |
111 | int x, y; | |
112 | for (y = 0; y < height; y++) { | |
113 | if (grps) | |
114 | cols[0] = grps[3 * (y >> 1)]; | |
115 | for (x = 0; x < width; x++) { | |
116 | if (grps) | |
117 | cols[1]= grps[(x >> 1) + 1]; | |
118 | out[x + y*stride] = cols[col & ((1 << bpp) - 1)]; | |
119 | col >>= bpp; | |
120 | } | |
121 | } | |
122 | } | |
123 | ||
124 | static int decode_frame(AVCodecContext *avctx, void *data, | |
125 | int *got_frame, AVPacket *avpkt) | |
126 | { | |
127 | const uint8_t *buf = avpkt->data; | |
128 | int buf_size = avpkt->size; | |
129 | C93DecoderContext * const c93 = avctx->priv_data; | |
130 | AVFrame * const newpic = c93->pictures[c93->currentpic]; | |
131 | AVFrame * const oldpic = c93->pictures[c93->currentpic^1]; | |
132 | GetByteContext gb; | |
133 | uint8_t *out; | |
134 | int stride, ret, i, x, y, b, bt = 0; | |
135 | ||
136 | if ((ret = ff_set_dimensions(avctx, WIDTH, HEIGHT)) < 0) | |
137 | return ret; | |
138 | ||
139 | c93->currentpic ^= 1; | |
140 | ||
141 | if ((ret = ff_reget_buffer(avctx, newpic)) < 0) | |
142 | return ret; | |
143 | ||
144 | stride = newpic->linesize[0]; | |
145 | ||
146 | bytestream2_init(&gb, buf, buf_size); | |
147 | b = bytestream2_get_byte(&gb); | |
148 | if (b & C93_FIRST_FRAME) { | |
149 | newpic->pict_type = AV_PICTURE_TYPE_I; | |
150 | newpic->key_frame = 1; | |
151 | } else { | |
152 | newpic->pict_type = AV_PICTURE_TYPE_P; | |
153 | newpic->key_frame = 0; | |
154 | } | |
155 | ||
156 | for (y = 0; y < HEIGHT; y += 8) { | |
157 | out = newpic->data[0] + y * stride; | |
158 | for (x = 0; x < WIDTH; x += 8) { | |
159 | uint8_t *copy_from = oldpic->data[0]; | |
160 | unsigned int offset, j; | |
161 | uint8_t cols[4], grps[4]; | |
162 | C93BlockType block_type; | |
163 | ||
164 | if (!bt) | |
165 | bt = bytestream2_get_byte(&gb); | |
166 | ||
167 | block_type= bt & 0x0F; | |
168 | switch (block_type) { | |
169 | case C93_8X8_FROM_PREV: | |
170 | offset = bytestream2_get_le16(&gb); | |
171 | if ((ret = copy_block(avctx, out, copy_from, offset, 8, stride)) < 0) | |
172 | return ret; | |
173 | break; | |
174 | ||
175 | case C93_4X4_FROM_CURR: | |
176 | copy_from = newpic->data[0]; | |
177 | case C93_4X4_FROM_PREV: | |
178 | for (j = 0; j < 8; j += 4) { | |
179 | for (i = 0; i < 8; i += 4) { | |
180 | int offset = bytestream2_get_le16(&gb); | |
181 | int from_x = offset % WIDTH; | |
182 | int from_y = offset / WIDTH; | |
183 | if (block_type == C93_4X4_FROM_CURR && from_y == y+j && | |
184 | (FFABS(from_x - x-i) < 4 || FFABS(from_x - x-i) > WIDTH-4)) { | |
185 | avpriv_request_sample(avctx, "block overlap %d %d %d %d\n", from_x, x+i, from_y, y+j); | |
186 | return AVERROR_INVALIDDATA; | |
187 | } | |
188 | if ((ret = copy_block(avctx, &out[j*stride+i], | |
189 | copy_from, offset, 4, stride)) < 0) | |
190 | return ret; | |
191 | } | |
192 | } | |
193 | break; | |
194 | ||
195 | case C93_8X8_2COLOR: | |
196 | bytestream2_get_buffer(&gb, cols, 2); | |
197 | for (i = 0; i < 8; i++) { | |
198 | draw_n_color(out + i*stride, stride, 8, 1, 1, cols, | |
199 | NULL, bytestream2_get_byte(&gb)); | |
200 | } | |
201 | ||
202 | break; | |
203 | ||
204 | case C93_4X4_2COLOR: | |
205 | case C93_4X4_4COLOR: | |
206 | case C93_4X4_4COLOR_GRP: | |
207 | for (j = 0; j < 8; j += 4) { | |
208 | for (i = 0; i < 8; i += 4) { | |
209 | if (block_type == C93_4X4_2COLOR) { | |
210 | bytestream2_get_buffer(&gb, cols, 2); | |
211 | draw_n_color(out + i + j*stride, stride, 4, 4, | |
212 | 1, cols, NULL, bytestream2_get_le16(&gb)); | |
213 | } else if (block_type == C93_4X4_4COLOR) { | |
214 | bytestream2_get_buffer(&gb, cols, 4); | |
215 | draw_n_color(out + i + j*stride, stride, 4, 4, | |
216 | 2, cols, NULL, bytestream2_get_le32(&gb)); | |
217 | } else { | |
218 | bytestream2_get_buffer(&gb, grps, 4); | |
219 | draw_n_color(out + i + j*stride, stride, 4, 4, | |
220 | 1, cols, grps, bytestream2_get_le16(&gb)); | |
221 | } | |
222 | } | |
223 | } | |
224 | break; | |
225 | ||
226 | case C93_NOOP: | |
227 | break; | |
228 | ||
229 | case C93_8X8_INTRA: | |
230 | for (j = 0; j < 8; j++) | |
231 | bytestream2_get_buffer(&gb, out + j*stride, 8); | |
232 | break; | |
233 | ||
234 | default: | |
235 | av_log(avctx, AV_LOG_ERROR, "unexpected type %x at %dx%d\n", | |
236 | block_type, x, y); | |
237 | return AVERROR_INVALIDDATA; | |
238 | } | |
239 | bt >>= 4; | |
240 | out += 8; | |
241 | } | |
242 | } | |
243 | ||
244 | if (b & C93_HAS_PALETTE) { | |
245 | uint32_t *palette = (uint32_t *) newpic->data[1]; | |
246 | for (i = 0; i < 256; i++) { | |
247 | palette[i] = 0xFFU << 24 | bytestream2_get_be24(&gb); | |
248 | } | |
249 | newpic->palette_has_changed = 1; | |
250 | } else { | |
251 | if (oldpic->data[1]) | |
252 | memcpy(newpic->data[1], oldpic->data[1], 256 * 4); | |
253 | } | |
254 | ||
255 | if ((ret = av_frame_ref(data, newpic)) < 0) | |
256 | return ret; | |
257 | *got_frame = 1; | |
258 | ||
259 | return buf_size; | |
260 | } | |
261 | ||
262 | AVCodec ff_c93_decoder = { | |
263 | .name = "c93", | |
264 | .long_name = NULL_IF_CONFIG_SMALL("Interplay C93"), | |
265 | .type = AVMEDIA_TYPE_VIDEO, | |
266 | .id = AV_CODEC_ID_C93, | |
267 | .priv_data_size = sizeof(C93DecoderContext), | |
268 | .init = decode_init, | |
269 | .close = decode_end, | |
270 | .decode = decode_frame, | |
271 | .capabilities = CODEC_CAP_DR1, | |
272 | }; |