FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/cdgraphics.c
Date: 2022-11-28 23:49:43
Exec Total Coverage
Lines: 98 182 53.8%
Branches: 40 93 43.0%

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 int y;
94 6 int lsize = cc->frame->linesize[0];
95 6 uint8_t *buf = cc->frame->data[0];
96 6 int color = data[0] & 0x0F;
97
98
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6 if (!(data[1] & 0x0F)) {
99 /// fill the top and bottom borders
100 6 memset(buf, color, CDG_BORDER_HEIGHT * lsize);
101 6 memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
102 6 color, CDG_BORDER_HEIGHT * lsize);
103
104 /// fill the side borders
105
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1158 for (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 10 cc->frame->palette_has_changed = 1;
129 10 }
130
131 180 static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
132 {
133 unsigned ci, ri;
134 int color;
135 int x, y;
136 int ai;
137 180 int stride = cc->frame->linesize[0];
138 180 uint8_t *buf = cc->frame->data[0];
139
140 180 ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
141 180 ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll;
142
143
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180 if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
144 return AVERROR(EINVAL);
145
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180 if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
146 return AVERROR(EINVAL);
147
148
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2340 for (y = 0; y < CDG_TILE_HEIGHT; y++) {
149
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15120 for (x = 0; x < CDG_TILE_WIDTH; x++) {
150
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12960 if (!((data[4 + y] >> (5 - x)) & 0x01))
151 10153 color = data[0] & 0x0F;
152 else
153 2807 color = data[1] & 0x0F;
154
155 12960 ai = ci + x + (stride * (ri + y));
156
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12960 if (b)
157 12960 color ^= buf[ai];
158 12960 buf[ai] = color;
159 }
160 }
161
162 180 return 0;
163 }
164
165 #define UP 2
166 #define DOWN 1
167 #define LEFT 2
168 #define RIGHT 1
169
170 static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
171 int in_tl_x, int in_tl_y, uint8_t *in,
172 int w, int h, int stride)
173 {
174 int y;
175
176 in += in_tl_x + in_tl_y * stride;
177 out += out_tl_x + out_tl_y * stride;
178 for (y = 0; y < h; y++)
179 memcpy(out + y * stride, in + y * stride, w);
180 }
181
182 static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
183 int color, int w, int h, int stride)
184 {
185 int y;
186
187 for (y = tl_y; y < tl_y + h; y++)
188 memset(out + tl_x + y * stride, color, w);
189 }
190
191 static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
192 int in_tl_x, int in_tl_y, uint8_t *in,
193 int color, int w, int h, int stride, int roll)
194 {
195 if (roll) {
196 cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
197 in, w, h, stride);
198 } else {
199 cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
200 }
201 }
202
203 static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
204 AVFrame *new_frame, int roll_over)
205 {
206 int color;
207 int hscmd, h_off, hinc, vscmd, v_off, vinc;
208 int y;
209 int stride = cc->frame->linesize[0];
210 uint8_t *in = cc->frame->data[0];
211 uint8_t *out = new_frame->data[0];
212
213 color = data[0] & 0x0F;
214 hscmd = (data[1] & 0x30) >> 4;
215 vscmd = (data[2] & 0x30) >> 4;
216
217 h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1);
218 v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
219
220 /// find the difference and save the offset for cdg_tile_block usage
221 hinc = h_off - cc->hscroll;
222 vinc = cc->vscroll - v_off;
223 cc->hscroll = h_off;
224 cc->vscroll = v_off;
225
226 if (vscmd == UP)
227 vinc -= 12;
228 if (vscmd == DOWN)
229 vinc += 12;
230 if (hscmd == LEFT)
231 hinc -= 6;
232 if (hscmd == RIGHT)
233 hinc += 6;
234
235 if (!hinc && !vinc)
236 return;
237
238 memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4);
239
240 for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
241 memcpy(out + FFMAX(0, hinc) + stride * y,
242 in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
243 FFABS(stride) - FFABS(hinc));
244
245 if (vinc > 0)
246 cdg_fill_wrapper(0, 0, out,
247 0, CDG_FULL_HEIGHT - vinc, in, color,
248 stride, vinc, stride, roll_over);
249 else if (vinc < 0)
250 cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
251 0, 0, in, color,
252 stride, -1 * vinc, stride, roll_over);
253
254 if (hinc > 0)
255 cdg_fill_wrapper(0, 0, out,
256 CDG_FULL_WIDTH - hinc, 0, in, color,
257 hinc, CDG_FULL_HEIGHT, stride, roll_over);
258 else if (hinc < 0)
259 cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
260 0, 0, in, color,
261 -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
262
263 }
264
265 302 static int cdg_decode_frame(AVCodecContext *avctx, AVFrame *frame,
266 int *got_frame, AVPacket *avpkt)
267 {
268 GetByteContext gb;
269 302 int buf_size = avpkt->size;
270 int ret;
271 uint8_t command, inst;
272 302 uint8_t cdg_data[CDG_DATA_SIZE] = {0};
273 302 CDGraphicsContext *cc = avctx->priv_data;
274
275
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302 if (buf_size < CDG_MINIMUM_PKT_SIZE) {
276 av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
277 return AVERROR(EINVAL);
278 }
279
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302 if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) {
280 av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n");
281 return AVERROR(EINVAL);
282 }
283
284 302 bytestream2_init(&gb, avpkt->data, avpkt->size);
285
286
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302 if ((ret = ff_reget_buffer(avctx, cc->frame, 0)) < 0)
287 return ret;
288
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302 if (!cc->cleared) {
289 1 memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height);
290 1 memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
291 1 cc->cleared = 1;
292 }
293
294 302 command = bytestream2_get_byte(&gb);
295 302 inst = bytestream2_get_byte(&gb);
296 302 inst &= CDG_MASK;
297 302 bytestream2_skip(&gb, 2);
298 302 bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data));
299
300
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302 if ((command & CDG_MASK) == CDG_COMMAND) {
301
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213 switch (inst) {
302 16 case CDG_INST_MEMORY_PRESET:
303
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16 if (!(cdg_data[1] & 0x0F))
304 1 memset(cc->frame->data[0], cdg_data[0] & 0x0F,
305 1 cc->frame->linesize[0] * CDG_FULL_HEIGHT);
306 16 break;
307 10 case CDG_INST_LOAD_PAL_LO:
308 case CDG_INST_LOAD_PAL_HIGH:
309
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10 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
310 av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
311 return AVERROR(EINVAL);
312 }
313
314 10 cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
315 10 break;
316 6 case CDG_INST_BORDER_PRESET:
317 6 cdg_border_preset(cc, cdg_data);
318 6 break;
319 180 case CDG_INST_TILE_BLOCK_XOR:
320 case CDG_INST_TILE_BLOCK:
321
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180 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
322 av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
323 return AVERROR(EINVAL);
324 }
325
326 180 ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
327
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180 if (ret) {
328 av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
329 return ret;
330 }
331 180 break;
332 case CDG_INST_SCROLL_PRESET:
333 case CDG_INST_SCROLL_COPY:
334 if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
335 av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
336 return AVERROR(EINVAL);
337 }
338
339 if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0)
340 return ret;
341
342 cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY);
343 av_frame_unref(cc->frame);
344 ret = av_frame_ref(cc->frame, frame);
345 if (ret < 0)
346 return ret;
347 break;
348 1 case CDG_INST_TRANSPARENT_COL:
349
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17 for (int i = 0; i < CDG_PALETTE_SIZE; i++)
350 16 cc->alpha[i] = 255 - ((cdg_data[i] & 0x3f) << 2);
351 1 break;
352 default:
353 break;
354 }
355
356
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213 if (!frame->data[0]) {
357 213 ret = av_frame_ref(frame, cc->frame);
358
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213 if (ret < 0)
359 return ret;
360 }
361 213 *got_frame = 1;
362 } else {
363 89 *got_frame = 0;
364 }
365
366 302 return avpkt->size;
367 }
368
369 static void cdg_decode_flush(AVCodecContext *avctx)
370 {
371 CDGraphicsContext *cc = avctx->priv_data;
372
373 if (!cc->frame->data[0])
374 return;
375
376 memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height);
377 if (!avctx->frame_number)
378 memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
379 }
380
381 2 static av_cold int cdg_decode_end(AVCodecContext *avctx)
382 {
383 2 CDGraphicsContext *cc = avctx->priv_data;
384
385 2 av_frame_free(&cc->frame);
386
387 2 return 0;
388 }
389
390 const FFCodec ff_cdgraphics_decoder = {
391 .p.name = "cdgraphics",
392 CODEC_LONG_NAME("CD Graphics video"),
393 .p.type = AVMEDIA_TYPE_VIDEO,
394 .p.id = AV_CODEC_ID_CDGRAPHICS,
395 .priv_data_size = sizeof(CDGraphicsContext),
396 .init = cdg_decode_init,
397 .close = cdg_decode_end,
398 FF_CODEC_DECODE_CB(cdg_decode_frame),
399 .flush = cdg_decode_flush,
400 .p.capabilities = AV_CODEC_CAP_DR1,
401 };
402