FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/cdgraphics.c
Date: 2021-09-23 20:34:37
Exec Total Coverage
Lines: 99 183 54.1%
Branches: 38 93 40.9%

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 "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_TRANSPARENT_COL 28
53 #define CDG_INST_LOAD_PAL_LO 30
54 #define CDG_INST_LOAD_PAL_HIGH 31
55 #define CDG_INST_TILE_BLOCK_XOR 38
56
57 /// data sizes
58 #define CDG_PACKET_SIZE 24
59 #define CDG_DATA_SIZE 16
60 #define CDG_TILE_HEIGHT 12
61 #define CDG_TILE_WIDTH 6
62 #define CDG_MINIMUM_PKT_SIZE 6
63 #define CDG_MINIMUM_SCROLL_SIZE 3
64 #define CDG_HEADER_SIZE 8
65 #define CDG_PALETTE_SIZE 16
66
67 typedef struct CDGraphicsContext {
68 AVFrame *frame;
69 int hscroll;
70 int vscroll;
71 int transparency;
72 int cleared;
73 } CDGraphicsContext;
74
75 2 static av_cold int cdg_decode_init(AVCodecContext *avctx)
76 {
77 2 CDGraphicsContext *cc = avctx->priv_data;
78
79 2 cc->frame = av_frame_alloc();
80
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2 if (!cc->frame)
81 return AVERROR(ENOMEM);
82 2 cc->transparency = -1;
83
84 2 avctx->pix_fmt = AV_PIX_FMT_PAL8;
85 2 return ff_set_dimensions(avctx, CDG_FULL_WIDTH, CDG_FULL_HEIGHT);
86 }
87
88 6 static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
89 {
90 int y;
91 6 int lsize = cc->frame->linesize[0];
92 6 uint8_t *buf = cc->frame->data[0];
93 6 int color = data[0] & 0x0F;
94
95
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6 if (!(data[1] & 0x0F)) {
96 /// fill the top and bottom borders
97 6 memset(buf, color, CDG_BORDER_HEIGHT * lsize);
98 6 memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
99 6 color, CDG_BORDER_HEIGHT * lsize);
100
101 /// fill the side borders
102
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1158 for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
103 1152 memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
104 1152 memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
105 color, CDG_BORDER_WIDTH);
106 }
107 }
108 6 }
109
110 10 static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
111 {
112 uint8_t r, g, b;
113 uint16_t color;
114 int i;
115
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10 int array_offset = low ? 0 : 8;
116 10 uint32_t *palette = (uint32_t *) cc->frame->data[1];
117
118
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90 for (i = 0; i < 8; i++) {
119 80 color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
120 80 r = ((color >> 8) & 0x000F) * 17;
121 80 g = ((color >> 4) & 0x000F) * 17;
122 80 b = ((color ) & 0x000F) * 17;
123 80 palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b;
124
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80 if (cc->transparency >= 0)
125 16 palette[cc->transparency] &= 0xFFFFFF;
126 }
127 10 cc->frame->palette_has_changed = 1;
128 10 }
129
130 180 static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
131 {
132 unsigned ci, ri;
133 int color;
134 int x, y;
135 int ai;
136 180 int stride = cc->frame->linesize[0];
137 180 uint8_t *buf = cc->frame->data[0];
138
139 180 ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
140 180 ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll;
141
142
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180 if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
143 return AVERROR(EINVAL);
144
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180 if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
145 return AVERROR(EINVAL);
146
147
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2340 for (y = 0; y < CDG_TILE_HEIGHT; y++) {
148
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15120 for (x = 0; x < CDG_TILE_WIDTH; x++) {
149
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12960 if (!((data[4 + y] >> (5 - x)) & 0x01))
150 10153 color = data[0] & 0x0F;
151 else
152 2807 color = data[1] & 0x0F;
153
154 12960 ai = ci + x + (stride * (ri + y));
155
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12960 if (b)
156 12960 color ^= buf[ai];
157 12960 buf[ai] = color;
158 }
159 }
160
161 180 return 0;
162 }
163
164 #define UP 2
165 #define DOWN 1
166 #define LEFT 2
167 #define RIGHT 1
168
169 static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
170 int in_tl_x, int in_tl_y, uint8_t *in,
171 int w, int h, int stride)
172 {
173 int y;
174
175 in += in_tl_x + in_tl_y * stride;
176 out += out_tl_x + out_tl_y * stride;
177 for (y = 0; y < h; y++)
178 memcpy(out + y * stride, in + y * stride, w);
179 }
180
181 static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
182 int color, int w, int h, int stride)
183 {
184 int y;
185
186 for (y = tl_y; y < tl_y + h; y++)
187 memset(out + tl_x + y * stride, color, w);
188 }
189
190 static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
191 int in_tl_x, int in_tl_y, uint8_t *in,
192 int color, int w, int h, int stride, int roll)
193 {
194 if (roll) {
195 cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
196 in, w, h, stride);
197 } else {
198 cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
199 }
200 }
201
202 static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
203 AVFrame *new_frame, int roll_over)
204 {
205 int color;
206 int hscmd, h_off, hinc, vscmd, v_off, vinc;
207 int y;
208 int stride = cc->frame->linesize[0];
209 uint8_t *in = cc->frame->data[0];
210 uint8_t *out = new_frame->data[0];
211
212 color = data[0] & 0x0F;
213 hscmd = (data[1] & 0x30) >> 4;
214 vscmd = (data[2] & 0x30) >> 4;
215
216 h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1);
217 v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1);
218
219 /// find the difference and save the offset for cdg_tile_block usage
220 hinc = h_off - cc->hscroll;
221 vinc = v_off - cc->vscroll;
222 cc->hscroll = h_off;
223 cc->vscroll = v_off;
224
225 if (vscmd == UP)
226 vinc -= 12;
227 if (vscmd == DOWN)
228 vinc += 12;
229 if (hscmd == LEFT)
230 hinc -= 6;
231 if (hscmd == RIGHT)
232 hinc += 6;
233
234 if (!hinc && !vinc)
235 return;
236
237 memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4);
238
239 for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
240 memcpy(out + FFMAX(0, hinc) + stride * y,
241 in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
242 FFMIN(stride + hinc, stride));
243
244 if (vinc > 0)
245 cdg_fill_wrapper(0, 0, out,
246 0, CDG_FULL_HEIGHT - vinc, in, color,
247 stride, vinc, stride, roll_over);
248 else if (vinc < 0)
249 cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
250 0, 0, in, color,
251 stride, -1 * vinc, stride, roll_over);
252
253 if (hinc > 0)
254 cdg_fill_wrapper(0, 0, out,
255 CDG_FULL_WIDTH - hinc, 0, in, color,
256 hinc, CDG_FULL_HEIGHT, stride, roll_over);
257 else if (hinc < 0)
258 cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
259 0, 0, in, color,
260 -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
261
262 }
263
264 302 static int cdg_decode_frame(AVCodecContext *avctx,
265 void *data, int *got_frame, AVPacket *avpkt)
266 {
267 GetByteContext gb;
268 302 int buf_size = avpkt->size;
269 int ret;
270 uint8_t command, inst;
271 302 uint8_t cdg_data[CDG_DATA_SIZE] = {0};
272 302 AVFrame *frame = data;
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 1 cc->transparency = cdg_data[0] & 0xF;
350 1 break;
351 default:
352 break;
353 }
354
355
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213 if (!frame->data[0]) {
356 213 ret = av_frame_ref(frame, cc->frame);
357
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213 if (ret < 0)
358 return ret;
359 }
360 213 *got_frame = 1;
361 } else {
362 89 *got_frame = 0;
363 }
364
365 302 return avpkt->size;
366 }
367
368 static void cdg_decode_flush(AVCodecContext *avctx)
369 {
370 CDGraphicsContext *cc = avctx->priv_data;
371
372 if (!cc->frame->data[0])
373 return;
374
375 memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height);
376 if (!avctx->frame_number)
377 memset(cc->frame->data[1], 0, AVPALETTE_SIZE);
378 }
379
380 2 static av_cold int cdg_decode_end(AVCodecContext *avctx)
381 {
382 2 CDGraphicsContext *cc = avctx->priv_data;
383
384 2 av_frame_free(&cc->frame);
385
386 2 return 0;
387 }
388
389 const AVCodec ff_cdgraphics_decoder = {
390 .name = "cdgraphics",
391 .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"),
392 .type = AVMEDIA_TYPE_VIDEO,
393 .id = AV_CODEC_ID_CDGRAPHICS,
394 .priv_data_size = sizeof(CDGraphicsContext),
395 .init = cdg_decode_init,
396 .close = cdg_decode_end,
397 .decode = cdg_decode_frame,
398 .flush = cdg_decode_flush,
399 .capabilities = AV_CODEC_CAP_DR1,
400 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE,
401 };
402