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1 | /* |
2 | * CD Graphics Video Decoder | |
3 | * Copyright (c) 2009 Michael Tison | |
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 | /** | |
27 | * @file | |
28 | * @brief CD Graphics Video Decoder | |
29 | * @author Michael Tison | |
30 | * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics | |
31 | * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg | |
32 | */ | |
33 | ||
34 | /// default screen sizes | |
35 | #define CDG_FULL_WIDTH 300 | |
36 | #define CDG_FULL_HEIGHT 216 | |
37 | #define CDG_DISPLAY_WIDTH 294 | |
38 | #define CDG_DISPLAY_HEIGHT 204 | |
39 | #define CDG_BORDER_WIDTH 6 | |
40 | #define CDG_BORDER_HEIGHT 12 | |
41 | ||
42 | /// masks | |
43 | #define CDG_COMMAND 0x09 | |
44 | #define CDG_MASK 0x3F | |
45 | ||
46 | /// instruction codes | |
47 | #define CDG_INST_MEMORY_PRESET 1 | |
48 | #define CDG_INST_BORDER_PRESET 2 | |
49 | #define CDG_INST_TILE_BLOCK 6 | |
50 | #define CDG_INST_SCROLL_PRESET 20 | |
51 | #define CDG_INST_SCROLL_COPY 24 | |
52 | #define CDG_INST_LOAD_PAL_LO 30 | |
53 | #define CDG_INST_LOAD_PAL_HIGH 31 | |
54 | #define CDG_INST_TILE_BLOCK_XOR 38 | |
55 | ||
56 | /// data sizes | |
57 | #define CDG_PACKET_SIZE 24 | |
58 | #define CDG_DATA_SIZE 16 | |
59 | #define CDG_TILE_HEIGHT 12 | |
60 | #define CDG_TILE_WIDTH 6 | |
61 | #define CDG_MINIMUM_PKT_SIZE 6 | |
62 | #define CDG_MINIMUM_SCROLL_SIZE 3 | |
63 | #define CDG_HEADER_SIZE 8 | |
64 | #define CDG_PALETTE_SIZE 16 | |
65 | ||
66 | typedef struct CDGraphicsContext { | |
67 | AVFrame *frame; | |
68 | int hscroll; | |
69 | int vscroll; | |
70 | } CDGraphicsContext; | |
71 | ||
72 | static av_cold int cdg_decode_init(AVCodecContext *avctx) | |
73 | { | |
74 | CDGraphicsContext *cc = avctx->priv_data; | |
75 | ||
76 | cc->frame = av_frame_alloc(); | |
77 | if (!cc->frame) | |
78 | return AVERROR(ENOMEM); | |
79 | ||
80 | avctx->width = CDG_FULL_WIDTH; | |
81 | avctx->height = CDG_FULL_HEIGHT; | |
82 | avctx->pix_fmt = AV_PIX_FMT_PAL8; | |
83 | ||
84 | return 0; | |
85 | } | |
86 | ||
87 | static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data) | |
88 | { | |
89 | int y; | |
90 | int lsize = cc->frame->linesize[0]; | |
91 | uint8_t *buf = cc->frame->data[0]; | |
92 | int color = data[0] & 0x0F; | |
93 | ||
94 | if (!(data[1] & 0x0F)) { | |
95 | /// fill the top and bottom borders | |
96 | memset(buf, color, CDG_BORDER_HEIGHT * lsize); | |
97 | memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize, | |
98 | color, CDG_BORDER_HEIGHT * lsize); | |
99 | ||
100 | /// fill the side borders | |
101 | for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) { | |
102 | memset(buf + y * lsize, color, CDG_BORDER_WIDTH); | |
103 | memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize, | |
104 | color, CDG_BORDER_WIDTH); | |
105 | } | |
106 | } | |
107 | } | |
108 | ||
109 | static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low) | |
110 | { | |
111 | uint8_t r, g, b; | |
112 | uint16_t color; | |
113 | int i; | |
114 | int array_offset = low ? 0 : 8; | |
115 | uint32_t *palette = (uint32_t *) cc->frame->data[1]; | |
116 | ||
117 | for (i = 0; i < 8; i++) { | |
118 | color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F); | |
119 | r = ((color >> 8) & 0x000F) * 17; | |
120 | g = ((color >> 4) & 0x000F) * 17; | |
121 | b = ((color ) & 0x000F) * 17; | |
122 | palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b; | |
123 | } | |
124 | cc->frame->palette_has_changed = 1; | |
125 | } | |
126 | ||
127 | static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b) | |
128 | { | |
129 | unsigned ci, ri; | |
130 | int color; | |
131 | int x, y; | |
132 | int ai; | |
133 | int stride = cc->frame->linesize[0]; | |
134 | uint8_t *buf = cc->frame->data[0]; | |
135 | ||
136 | ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll; | |
137 | ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll; | |
138 | ||
139 | if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT)) | |
140 | return AVERROR(EINVAL); | |
141 | if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH)) | |
142 | return AVERROR(EINVAL); | |
143 | ||
144 | for (y = 0; y < CDG_TILE_HEIGHT; y++) { | |
145 | for (x = 0; x < CDG_TILE_WIDTH; x++) { | |
146 | if (!((data[4 + y] >> (5 - x)) & 0x01)) | |
147 | color = data[0] & 0x0F; | |
148 | else | |
149 | color = data[1] & 0x0F; | |
150 | ||
151 | ai = ci + x + (stride * (ri + y)); | |
152 | if (b) | |
153 | color ^= buf[ai]; | |
154 | buf[ai] = color; | |
155 | } | |
156 | } | |
157 | ||
158 | return 0; | |
159 | } | |
160 | ||
161 | #define UP 2 | |
162 | #define DOWN 1 | |
163 | #define LEFT 2 | |
164 | #define RIGHT 1 | |
165 | ||
166 | static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out, | |
167 | int in_tl_x, int in_tl_y, uint8_t *in, | |
168 | int w, int h, int stride) | |
169 | { | |
170 | int y; | |
171 | ||
172 | in += in_tl_x + in_tl_y * stride; | |
173 | out += out_tl_x + out_tl_y * stride; | |
174 | for (y = 0; y < h; y++) | |
175 | memcpy(out + y * stride, in + y * stride, w); | |
176 | } | |
177 | ||
178 | static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out, | |
179 | int color, int w, int h, int stride) | |
180 | { | |
181 | int y; | |
182 | ||
183 | for (y = tl_y; y < tl_y + h; y++) | |
184 | memset(out + tl_x + y * stride, color, w); | |
185 | } | |
186 | ||
187 | static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out, | |
188 | int in_tl_x, int in_tl_y, uint8_t *in, | |
189 | int color, int w, int h, int stride, int roll) | |
190 | { | |
191 | if (roll) { | |
192 | cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y, | |
193 | in, w, h, stride); | |
194 | } else { | |
195 | cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride); | |
196 | } | |
197 | } | |
198 | ||
199 | static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data, | |
200 | AVFrame *new_frame, int roll_over) | |
201 | { | |
202 | int color; | |
203 | int hscmd, h_off, hinc, vscmd, v_off, vinc; | |
204 | int y; | |
205 | int stride = cc->frame->linesize[0]; | |
206 | uint8_t *in = cc->frame->data[0]; | |
207 | uint8_t *out = new_frame->data[0]; | |
208 | ||
209 | color = data[0] & 0x0F; | |
210 | hscmd = (data[1] & 0x30) >> 4; | |
211 | vscmd = (data[2] & 0x30) >> 4; | |
212 | ||
213 | h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1); | |
214 | v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1); | |
215 | ||
216 | /// find the difference and save the offset for cdg_tile_block usage | |
217 | hinc = h_off - cc->hscroll; | |
218 | vinc = v_off - cc->vscroll; | |
219 | cc->hscroll = h_off; | |
220 | cc->vscroll = v_off; | |
221 | ||
222 | if (vscmd == UP) | |
223 | vinc -= 12; | |
224 | if (vscmd == DOWN) | |
225 | vinc += 12; | |
226 | if (hscmd == LEFT) | |
227 | hinc -= 6; | |
228 | if (hscmd == RIGHT) | |
229 | hinc += 6; | |
230 | ||
231 | if (!hinc && !vinc) | |
232 | return; | |
233 | ||
234 | memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4); | |
235 | ||
236 | for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++) | |
237 | memcpy(out + FFMAX(0, hinc) + stride * y, | |
238 | in + FFMAX(0, hinc) - hinc + (y - vinc) * stride, | |
239 | FFMIN(stride + hinc, stride)); | |
240 | ||
241 | if (vinc > 0) | |
242 | cdg_fill_wrapper(0, 0, out, | |
243 | 0, CDG_FULL_HEIGHT - vinc, in, color, | |
244 | stride, vinc, stride, roll_over); | |
245 | else if (vinc < 0) | |
246 | cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out, | |
247 | 0, 0, in, color, | |
248 | stride, -1 * vinc, stride, roll_over); | |
249 | ||
250 | if (hinc > 0) | |
251 | cdg_fill_wrapper(0, 0, out, | |
252 | CDG_FULL_WIDTH - hinc, 0, in, color, | |
253 | hinc, CDG_FULL_HEIGHT, stride, roll_over); | |
254 | else if (hinc < 0) | |
255 | cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out, | |
256 | 0, 0, in, color, | |
257 | -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over); | |
258 | ||
259 | } | |
260 | ||
261 | static int cdg_decode_frame(AVCodecContext *avctx, | |
262 | void *data, int *got_frame, AVPacket *avpkt) | |
263 | { | |
264 | GetByteContext gb; | |
265 | int buf_size = avpkt->size; | |
266 | int ret; | |
267 | uint8_t command, inst; | |
268 | uint8_t cdg_data[CDG_DATA_SIZE] = {0}; | |
269 | AVFrame *frame = data; | |
270 | CDGraphicsContext *cc = avctx->priv_data; | |
271 | ||
272 | if (buf_size < CDG_MINIMUM_PKT_SIZE) { | |
273 | av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n"); | |
274 | return AVERROR(EINVAL); | |
275 | } | |
276 | if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) { | |
277 | av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n"); | |
278 | return AVERROR(EINVAL); | |
279 | } | |
280 | ||
281 | bytestream2_init(&gb, avpkt->data, avpkt->size); | |
282 | ||
283 | if ((ret = ff_reget_buffer(avctx, cc->frame)) < 0) | |
284 | return ret; | |
285 | if (!avctx->frame_number) { | |
286 | memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height); | |
287 | memset(cc->frame->data[1], 0, AVPALETTE_SIZE); | |
288 | } | |
289 | ||
290 | command = bytestream2_get_byte(&gb); | |
291 | inst = bytestream2_get_byte(&gb); | |
292 | inst &= CDG_MASK; | |
293 | bytestream2_skip(&gb, 2); | |
294 | bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data)); | |
295 | ||
296 | if ((command & CDG_MASK) == CDG_COMMAND) { | |
297 | switch (inst) { | |
298 | case CDG_INST_MEMORY_PRESET: | |
299 | if (!(cdg_data[1] & 0x0F)) | |
300 | memset(cc->frame->data[0], cdg_data[0] & 0x0F, | |
301 | cc->frame->linesize[0] * CDG_FULL_HEIGHT); | |
302 | break; | |
303 | case CDG_INST_LOAD_PAL_LO: | |
304 | case CDG_INST_LOAD_PAL_HIGH: | |
305 | if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) { | |
306 | av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n"); | |
307 | return AVERROR(EINVAL); | |
308 | } | |
309 | ||
310 | cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO); | |
311 | break; | |
312 | case CDG_INST_BORDER_PRESET: | |
313 | cdg_border_preset(cc, cdg_data); | |
314 | break; | |
315 | case CDG_INST_TILE_BLOCK_XOR: | |
316 | case CDG_INST_TILE_BLOCK: | |
317 | if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) { | |
318 | av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n"); | |
319 | return AVERROR(EINVAL); | |
320 | } | |
321 | ||
322 | ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR); | |
323 | if (ret) { | |
324 | av_log(avctx, AV_LOG_ERROR, "tile is out of range\n"); | |
325 | return ret; | |
326 | } | |
327 | break; | |
328 | case CDG_INST_SCROLL_PRESET: | |
329 | case CDG_INST_SCROLL_COPY: | |
330 | if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) { | |
331 | av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n"); | |
332 | return AVERROR(EINVAL); | |
333 | } | |
334 | ||
335 | if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) | |
336 | return ret; | |
337 | ||
338 | cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY); | |
339 | av_frame_unref(cc->frame); | |
340 | ret = av_frame_ref(cc->frame, frame); | |
341 | if (ret < 0) | |
342 | return ret; | |
343 | break; | |
344 | default: | |
345 | break; | |
346 | } | |
347 | ||
348 | if (!frame->data[0]) { | |
349 | ret = av_frame_ref(frame, cc->frame); | |
350 | if (ret < 0) | |
351 | return ret; | |
352 | } | |
353 | *got_frame = 1; | |
354 | } else { | |
355 | *got_frame = 0; | |
356 | } | |
357 | ||
358 | return avpkt->size; | |
359 | } | |
360 | ||
361 | static av_cold int cdg_decode_end(AVCodecContext *avctx) | |
362 | { | |
363 | CDGraphicsContext *cc = avctx->priv_data; | |
364 | ||
365 | av_frame_free(&cc->frame); | |
366 | ||
367 | return 0; | |
368 | } | |
369 | ||
370 | AVCodec ff_cdgraphics_decoder = { | |
371 | .name = "cdgraphics", | |
372 | .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"), | |
373 | .type = AVMEDIA_TYPE_VIDEO, | |
374 | .id = AV_CODEC_ID_CDGRAPHICS, | |
375 | .priv_data_size = sizeof(CDGraphicsContext), | |
376 | .init = cdg_decode_init, | |
377 | .close = cdg_decode_end, | |
378 | .decode = cdg_decode_frame, | |
379 | .capabilities = CODEC_CAP_DR1, | |
380 | }; |