FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/cdgraphics.c
Date: 2024-07-17 14:05:47
Exec Total Coverage
Lines: 101 190 53.2%
Functions: 6 11 54.5%
Branches: 48 105 45.7%

Line Branch Exec Source
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 "codec_internal.h"
25 #include "decode.h"
26
27 /**
28 * @file
29 * @brief CD Graphics Video Decoder
30 * @author Michael Tison
31 * @see http://wiki.multimedia.cx/index.php?title=CD_Graphics
32 * @see http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
33 */
34
35 /// default screen sizes
36 #define CDG_FULL_WIDTH 300
37 #define CDG_FULL_HEIGHT 216
38 #define CDG_DISPLAY_WIDTH 294
39 #define CDG_DISPLAY_HEIGHT 204
40 #define CDG_BORDER_WIDTH 6
41 #define CDG_BORDER_HEIGHT 12
42
43 /// masks
44 #define CDG_COMMAND 0x09
45 #define CDG_MASK 0x3F
46
47 /// instruction codes
48 #define CDG_INST_MEMORY_PRESET 1
49 #define CDG_INST_BORDER_PRESET 2
50 #define CDG_INST_TILE_BLOCK 6
51 #define CDG_INST_SCROLL_PRESET 20
52 #define CDG_INST_SCROLL_COPY 24
53 #define CDG_INST_TRANSPARENT_COL 28
54 #define CDG_INST_LOAD_PAL_LO 30
55 #define CDG_INST_LOAD_PAL_HIGH 31
56 #define CDG_INST_TILE_BLOCK_XOR 38
57
58 /// data sizes
59 #define CDG_PACKET_SIZE 24
60 #define CDG_DATA_SIZE 16
61 #define CDG_TILE_HEIGHT 12
62 #define CDG_TILE_WIDTH 6
63 #define CDG_MINIMUM_PKT_SIZE 6
64 #define CDG_MINIMUM_SCROLL_SIZE 3
65 #define CDG_HEADER_SIZE 8
66 #define CDG_PALETTE_SIZE 16
67
68 typedef struct CDGraphicsContext {
69 AVFrame *frame;
70 int hscroll;
71 int vscroll;
72 uint8_t alpha[CDG_PALETTE_SIZE];
73 int cleared;
74 } CDGraphicsContext;
75
76 2 static av_cold int cdg_decode_init(AVCodecContext *avctx)
77 {
78 2 CDGraphicsContext *cc = avctx->priv_data;
79
80 2 cc->frame = av_frame_alloc();
81
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2 if (!cc->frame)
82 return AVERROR(ENOMEM);
83
84
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34 for (int i = 0; i < CDG_PALETTE_SIZE; i++)
85 32 cc->alpha[i] = 0xFFU;
86
87 2 avctx->pix_fmt = AV_PIX_FMT_PAL8;
88 2 return ff_set_dimensions(avctx, CDG_FULL_WIDTH, CDG_FULL_HEIGHT);
89 }
90
91 6 static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
92 {
93 6 ptrdiff_t lsize = cc->frame->linesize[0];
94 6 uint8_t *buf = cc->frame->data[0];
95 6 int color = data[0] & 0x0F;
96
97
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6 if (!(data[1] & 0x0F)) {
98 /// fill the top and bottom borders
99
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78 for (int y = 0; y < CDG_BORDER_HEIGHT; y++)
100 72 memset(buf + y * lsize, color, cc->frame->width);
101
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78 for (int y = CDG_FULL_HEIGHT-CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT; y++)
102 72 memset(buf + y * lsize, color, cc->frame->width);
103
104 /// fill the side borders
105
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1158 for (int y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
106 1152 memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
107 1152 memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
108 color, CDG_BORDER_WIDTH);
109 }
110 }
111 6 }
112
113 10 static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
114 {
115 uint8_t r, g, b;
116 uint16_t color;
117 int i;
118
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10 int array_offset = low ? 0 : 8;
119 10 uint32_t *palette = (uint32_t *) cc->frame->data[1];
120
121
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90 for (i = 0; i < 8; i++) {
122 80 color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
123 80 r = ((color >> 8) & 0x000F) * 17;
124 80 g = ((color >> 4) & 0x000F) * 17;
125 80 b = ((color ) & 0x000F) * 17;
126 80 palette[i + array_offset] = (uint32_t)cc->alpha[i + array_offset] << 24 | r << 16 | g << 8 | b;
127 }
128 #if FF_API_PALETTE_HAS_CHANGED
129 FF_DISABLE_DEPRECATION_WARNINGS
130 10 cc->frame->palette_has_changed = 1;
131 FF_ENABLE_DEPRECATION_WARNINGS
132 #endif
133 10 }
134
135 189 static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
136 {
137 unsigned ci, ri;
138 int color;
139 int x, y;
140 int ai;
141 189 ptrdiff_t stride = cc->frame->linesize[0];
142 189 uint8_t *buf = cc->frame->data[0];
143
144 189 ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
145 189 ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll;
146
147
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189 if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
148 return AVERROR(EINVAL);
149
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189 if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
150 return AVERROR(EINVAL);
151
152
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2457 for (y = 0; y < CDG_TILE_HEIGHT; y++) {
153
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15876 for (x = 0; x < CDG_TILE_WIDTH; x++) {
154
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13608 if (!((data[4 + y] >> (5 - x)) & 0x01))
155 10669 color = data[0] & 0x0F;
156 else
157 2939 color = data[1] & 0x0F;
158
159 13608 ai = ci + x + (stride * (ri + y));
160
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13608 if (b)
161 13608 color ^= buf[ai];
162 13608 buf[ai] = color;
163 }
164 }
165
166 189 return 0;
167 }
168
169 #define UP 2
170 #define DOWN 1
171 #define LEFT 2
172 #define RIGHT 1
173
174 static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
175 int in_tl_x, int in_tl_y, uint8_t *in,
176 int w, int h, int stride)
177 {
178 int y;
179
180 in += in_tl_x + in_tl_y * stride;
181 out += out_tl_x + out_tl_y * stride;
182 for (y = 0; y < h; y++)
183 memcpy(out + y * stride, in + y * stride, w);
184 }
185
186 static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
187 int color, int w, int h, int stride)
188 {
189 int y;
190
191 for (y = tl_y; y < tl_y + h; y++)
192 memset(out + tl_x + y * stride, color, w);
193 }
194
195 static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
196 int in_tl_x, int in_tl_y, uint8_t *in,
197 int color, int w, int h, int stride, int roll)
198 {
199 if (roll) {
200 cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
201 in, w, h, stride);
202 } else {
203 cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
204 }
205 }
206
207 static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
208 AVFrame *new_frame, int roll_over)
209 {
210 int color;
211 int hscmd, h_off, hinc, vscmd, v_off, vinc;
212 int y;
213 ptrdiff_t stride = cc->frame->linesize[0];
214 uint8_t *in = cc->frame->data[0];
215 uint8_t *out = new_frame->data[0];
216
217 color = data[0] & 0x0F;
218 hscmd = (data[1] & 0x30) >> 4;
219 vscmd = (data[2] & 0x30) >> 4;
220
221 h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1);
222 v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
223
224 /// find the difference and save the offset for cdg_tile_block usage
225 hinc = h_off - cc->hscroll;
226 vinc = cc->vscroll - v_off;
227 cc->hscroll = h_off;
228 cc->vscroll = v_off;
229
230 if (vscmd == UP)
231 vinc -= 12;
232 if (vscmd == DOWN)
233 vinc += 12;
234 if (hscmd == LEFT)
235 hinc -= 6;
236 if (hscmd == RIGHT)
237 hinc += 6;
238
239 if (!hinc && !vinc)
240 return;
241
242 memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4);
243
244 for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
245 memcpy(out + FFMAX(0, hinc) + stride * y,
246 in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
247 FFABS(stride) - FFABS(hinc));
248
249 if (vinc > 0)
250 cdg_fill_wrapper(0, 0, out,
251 0, CDG_FULL_HEIGHT - vinc, in, color,
252 FFABS(stride), vinc, stride, roll_over);
253 else if (vinc < 0)
254 cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
255 0, 0, in, color,
256 FFABS(stride), -1 * vinc, stride, roll_over);
257
258 if (hinc > 0)
259 cdg_fill_wrapper(0, 0, out,
260 CDG_FULL_WIDTH - hinc, 0, in, color,
261 hinc, CDG_FULL_HEIGHT, stride, roll_over);
262 else if (hinc < 0)
263 cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
264 0, 0, in, color,
265 -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
266
267 }
268
269 315 static int cdg_decode_frame(AVCodecContext *avctx, AVFrame *frame,
270 int *got_frame, AVPacket *avpkt)
271 {
272 GetByteContext gb;
273 315 int buf_size = avpkt->size;
274 int ret;
275 uint8_t command, inst;
276 315 uint8_t cdg_data[CDG_DATA_SIZE] = {0};
277 315 CDGraphicsContext *cc = avctx->priv_data;
278
279
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315 if (buf_size < CDG_MINIMUM_PKT_SIZE) {
280 av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
281 return AVERROR(EINVAL);
282 }
283
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315 if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) {
284 av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n");
285 return AVERROR(EINVAL);
286 }
287
288 315 bytestream2_init(&gb, avpkt->data, avpkt->size);
289
290
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315 if ((ret = ff_reget_buffer(avctx, cc->frame, 0)) < 0)
291 return ret;
292
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315 if (!cc->cleared) {
293
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217 for (int y = 0; y < avctx->height; y++)
294 216 memset(cc->frame->data[0] + y * cc->frame->linesize[0], 0, avctx->width);
295 1 memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
296 1 cc->cleared = 1;
297 }
298
299 315 command = bytestream2_get_byte(&gb);
300 315 inst = bytestream2_get_byte(&gb);
301 315 inst &= CDG_MASK;
302 315 bytestream2_skip(&gb, 2);
303 315 bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data));
304
305
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315 if ((command & CDG_MASK) == CDG_COMMAND) {
306
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222 switch (inst) {
307 16 case CDG_INST_MEMORY_PRESET:
308
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16 if (!(cdg_data[1] & 0x0F)) {
309
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217 for (int y = 0; y < avctx->height; y++)
310 216 memset(cc->frame->data[0] + y * cc->frame->linesize[0],
311 216 cdg_data[0] & 0x0F, avctx->width);
312 }
313 16 break;
314 10 case CDG_INST_LOAD_PAL_LO:
315 case CDG_INST_LOAD_PAL_HIGH:
316
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10 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
317 av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
318 return AVERROR(EINVAL);
319 }
320
321 10 cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
322 10 break;
323 6 case CDG_INST_BORDER_PRESET:
324 6 cdg_border_preset(cc, cdg_data);
325 6 break;
326 189 case CDG_INST_TILE_BLOCK_XOR:
327 case CDG_INST_TILE_BLOCK:
328
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189 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
329 av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
330 return AVERROR(EINVAL);
331 }
332
333 189 ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
334
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189 if (ret) {
335 av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
336 return ret;
337 }
338 189 break;
339 case CDG_INST_SCROLL_PRESET:
340 case CDG_INST_SCROLL_COPY:
341 if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
342 av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
343 return AVERROR(EINVAL);
344 }
345
346 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
347 return ret;
348
349 cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY);
350 ret = av_frame_replace(cc->frame, frame);
351 if (ret < 0)
352 return ret;
353 break;
354 1 case CDG_INST_TRANSPARENT_COL:
355
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17 for (int i = 0; i < CDG_PALETTE_SIZE; i++)
356 16 cc->alpha[i] = 255 - ((cdg_data[i] & 0x3f) << 2);
357 1 break;
358 default:
359 break;
360 }
361
362
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222 if (!frame->data[0]) {
363 222 ret = av_frame_ref(frame, cc->frame);
364
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222 if (ret < 0)
365 return ret;
366 }
367 222 *got_frame = 1;
368 } else {
369 93 *got_frame = 0;
370 }
371
372 315 return avpkt->size;
373 }
374
375 static void cdg_decode_flush(AVCodecContext *avctx)
376 {
377 CDGraphicsContext *cc = avctx->priv_data;
378
379 if (!cc->frame->data[0])
380 return;
381
382 for (int y = 0; y < avctx->height; y++)
383 memset(cc->frame->data[0] + y * cc->frame->linesize[0], 0, avctx->width);
384 if (!avctx->frame_num)
385 memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
386 }
387
388 2 static av_cold int cdg_decode_end(AVCodecContext *avctx)
389 {
390 2 CDGraphicsContext *cc = avctx->priv_data;
391
392 2 av_frame_free(&cc->frame);
393
394 2 return 0;
395 }
396
397 const FFCodec ff_cdgraphics_decoder = {
398 .p.name = "cdgraphics",
399 CODEC_LONG_NAME("CD Graphics video"),
400 .p.type = AVMEDIA_TYPE_VIDEO,
401 .p.id = AV_CODEC_ID_CDGRAPHICS,
402 .priv_data_size = sizeof(CDGraphicsContext),
403 .init = cdg_decode_init,
404 .close = cdg_decode_end,
405 FF_CODEC_DECODE_CB(cdg_decode_frame),
406 .flush = cdg_decode_flush,
407 .p.capabilities = AV_CODEC_CAP_DR1,
408 };
409