1 /*
2 * CDToons video decoder
3 * Copyright (C) 2020 Alyssa Milburn <amilburn@zall.org>
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 /**
23 * @file
24 * CDToons video decoder
25 * @author Alyssa Milburn <amilburn@zall.org>
26 */
27
28 #include <stdint.h>
29
30 #include "libavutil/attributes.h"
31 #include "libavutil/internal.h"
32 #include "avcodec.h"
33 #include "bytestream.h"
34 #include "internal.h"
35
36 #define CDTOONS_HEADER_SIZE 44
37 #define CDTOONS_MAX_SPRITES 1200
38
39 typedef struct CDToonsSprite {
40 uint16_t flags;
41 uint16_t owner_frame;
42 uint16_t start_frame;
43 uint16_t end_frame;
44 unsigned int alloc_size;
45 uint32_t size;
46 uint8_t *data;
47 int active;
48 } CDToonsSprite;
49
50 typedef struct CDToonsContext {
51 AVFrame *frame;
52
53 uint16_t last_pal_id; ///< The index of the active palette sprite.
54 uint32_t pal[256]; ///< The currently-used palette data.
55 CDToonsSprite sprites[CDTOONS_MAX_SPRITES];
56 } CDToonsContext;
57
cdtoons_render_sprite(AVCodecContext * avctx,const uint8_t * data,uint32_t data_size,int dst_x,int dst_y,int width,int height)58 static int cdtoons_render_sprite(AVCodecContext *avctx, const uint8_t *data,
59 uint32_t data_size,
60 int dst_x, int dst_y, int width, int height)
61 {
62 CDToonsContext *c = avctx->priv_data;
63 const uint8_t *next_line = data;
64 const uint8_t *end = data + data_size;;
65 uint16_t line_size;
66 uint8_t *dest;
67 int skip = 0, to_skip, x;
68
69 if (dst_x + width > avctx->width)
70 width = avctx->width - dst_x;
71 if (dst_y + height > avctx->height)
72 height = avctx->height - dst_y;
73
74 if (dst_x < 0) {
75 /* we need to skip the start of the scanlines */
76 skip = -dst_x;
77 if (width <= skip)
78 return 0;
79 dst_x = 0;
80 }
81
82 for (int y = 0; y < height; y++) {
83 /* one scanline at a time, size is provided */
84 data = next_line;
85 if (data > end - 2)
86 return 1;
87 line_size = bytestream_get_be16(&data);
88 next_line = data + line_size;
89 if (dst_y + y < 0)
90 continue;
91
92 dest = c->frame->data[0] + (dst_y + y) * c->frame->linesize[0] + dst_x;
93
94 to_skip = skip;
95 x = 0;
96 while (x < width - skip) {
97 int raw, size;
98 uint8_t val;
99
100 if (data >= end)
101 return 1;
102
103 val = bytestream_get_byte(&data);
104 raw = !(val & 0x80);
105 size = (int)(val & 0x7F) + 1;
106
107 /* skip the start of a scanline if it is off-screen */
108 if (to_skip >= size) {
109 to_skip -= size;
110 if (raw) {
111 data += size;
112 } else {
113 data += 1;
114 }
115 if (data > next_line)
116 return 1;
117 continue;
118 } else if (to_skip) {
119 size -= to_skip;
120 if (raw)
121 data += to_skip;
122 to_skip = 0;
123 if (data > next_line)
124 return 1;
125 }
126
127 if (x + size >= width - skip)
128 size = width - skip - x;
129
130 /* either raw data, or a run of a single color */
131 if (raw) {
132 memcpy(dest + x, data, size);
133 data += size;
134 if (data > next_line)
135 return 1;
136 } else {
137 uint8_t color = bytestream_get_byte(&data);
138 /* ignore transparent runs */
139 if (color)
140 memset(dest + x, color, size);
141 }
142 x += size;
143 }
144 }
145
146 return 0;
147 }
148
cdtoons_decode_frame(AVCodecContext * avctx,void * data,int * got_frame,AVPacket * avpkt)149 static int cdtoons_decode_frame(AVCodecContext *avctx, void *data,
150 int *got_frame, AVPacket *avpkt)
151 {
152 CDToonsContext *c = avctx->priv_data;
153 const uint8_t *buf = avpkt->data;
154 const uint8_t *eod = avpkt->data + avpkt->size;
155 const int buf_size = avpkt->size;
156 uint16_t frame_id;
157 uint8_t background_color;
158 uint16_t sprite_count, sprite_offset;
159 uint8_t referenced_count;
160 uint16_t palette_id;
161 uint8_t palette_set;
162 int ret;
163 int saw_embedded_sprites = 0;
164
165 if (buf_size < CDTOONS_HEADER_SIZE)
166 return AVERROR_INVALIDDATA;
167
168 if ((ret = ff_reget_buffer(avctx, c->frame, 0)) < 0)
169 return ret;
170
171 /* a lot of the header is useless junk in the absence of
172 * dirty rectangling etc */
173 buf += 2; /* version? (always 9?) */
174 frame_id = bytestream_get_be16(&buf);
175 buf += 2; /* blocks_valid_until */
176 buf += 1;
177 background_color = bytestream_get_byte(&buf);
178 buf += 16; /* clip rect, dirty rect */
179 buf += 4; /* flags */
180 sprite_count = bytestream_get_be16(&buf);
181 sprite_offset = bytestream_get_be16(&buf);
182 buf += 2; /* max block id? */
183 referenced_count = bytestream_get_byte(&buf);
184 buf += 1;
185 palette_id = bytestream_get_be16(&buf);
186 palette_set = bytestream_get_byte(&buf);
187 buf += 5;
188
189 /* read new sprites introduced in this frame */
190 buf = avpkt->data + sprite_offset;
191 while (sprite_count--) {
192 uint32_t size;
193 uint16_t sprite_id;
194
195 if (buf + 14 > eod)
196 return AVERROR_INVALIDDATA;
197
198 sprite_id = bytestream_get_be16(&buf);
199 if (sprite_id >= CDTOONS_MAX_SPRITES) {
200 av_log(avctx, AV_LOG_ERROR,
201 "Sprite ID %d is too high.\n", sprite_id);
202 return AVERROR_INVALIDDATA;
203 }
204 if (c->sprites[sprite_id].active) {
205 av_log(avctx, AV_LOG_ERROR,
206 "Sprite ID %d is a duplicate.\n", sprite_id);
207 return AVERROR_INVALIDDATA;
208 }
209
210 c->sprites[sprite_id].flags = bytestream_get_be16(&buf);
211 size = bytestream_get_be32(&buf);
212 if (size < 14) {
213 av_log(avctx, AV_LOG_ERROR,
214 "Sprite only has %d bytes of data.\n", size);
215 return AVERROR_INVALIDDATA;
216 }
217 size -= 14;
218 c->sprites[sprite_id].size = size;
219 c->sprites[sprite_id].owner_frame = frame_id;
220 c->sprites[sprite_id].start_frame = bytestream_get_be16(&buf);
221 c->sprites[sprite_id].end_frame = bytestream_get_be16(&buf);
222 buf += 2;
223
224 if (size > buf_size || buf + size > eod)
225 return AVERROR_INVALIDDATA;
226
227 av_fast_padded_malloc(&c->sprites[sprite_id].data, &c->sprites[sprite_id].alloc_size, size);
228 if (!c->sprites[sprite_id].data)
229 return AVERROR(ENOMEM);
230
231 c->sprites[sprite_id].active = 1;
232
233 bytestream_get_buffer(&buf, c->sprites[sprite_id].data, size);
234 }
235
236 /* render any embedded sprites */
237 while (buf < eod) {
238 uint32_t tag, size;
239 if (buf + 8 > eod) {
240 av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for embedded sprites.\n");
241 return AVERROR_INVALIDDATA;
242 }
243 tag = bytestream_get_be32(&buf);
244 size = bytestream_get_be32(&buf);
245 if (tag == MKBETAG('D', 'i', 'f', 'f')) {
246 uint16_t diff_count;
247 if (buf + 10 > eod) {
248 av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for Diff frame.\n");
249 return AVERROR_INVALIDDATA;
250 }
251 diff_count = bytestream_get_be16(&buf);
252 buf += 8; /* clip rect? */
253 for (int i = 0; i < diff_count; i++) {
254 int16_t top, left;
255 uint16_t diff_size, width, height;
256
257 if (buf + 16 > eod) {
258 av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for Diff frame header.\n");
259 return AVERROR_INVALIDDATA;
260 }
261
262 top = bytestream_get_be16(&buf);
263 left = bytestream_get_be16(&buf);
264 buf += 4; /* bottom, right */
265 diff_size = bytestream_get_be32(&buf);
266 width = bytestream_get_be16(&buf);
267 height = bytestream_get_be16(&buf);
268 if (diff_size < 4 || diff_size - 4 > eod - buf) {
269 av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data for Diff frame data.\n");
270 return AVERROR_INVALIDDATA;
271 }
272 if (cdtoons_render_sprite(avctx, buf + 4, diff_size - 8,
273 left, top, width, height)) {
274 av_log(avctx, AV_LOG_WARNING, "Ran beyond end of sprite while rendering.\n");
275 }
276 buf += diff_size - 4;
277 }
278 saw_embedded_sprites = 1;
279 } else {
280 /* we don't care about any other entries */
281 if (size < 8 || size - 8 > eod - buf) {
282 av_log(avctx, AV_LOG_WARNING, "Ran out of data for ignored entry (size %X, %d left).\n", size, (int)(eod - buf));
283 return AVERROR_INVALIDDATA;
284 }
285 buf += (size - 8);
286 }
287 }
288
289 /* was an intra frame? */
290 if (saw_embedded_sprites)
291 goto done;
292
293 /* render any referenced sprites */
294 buf = avpkt->data + CDTOONS_HEADER_SIZE;
295 eod = avpkt->data + sprite_offset;
296 for (int i = 0; i < referenced_count; i++) {
297 const uint8_t *block_data;
298 uint16_t sprite_id, width, height;
299 int16_t top, left, right;
300
301 if (buf + 10 > eod) {
302 av_log(avctx, AV_LOG_WARNING, "Ran (seriously) out of data when rendering.\n");
303 return AVERROR_INVALIDDATA;
304 }
305
306 sprite_id = bytestream_get_be16(&buf);
307 top = bytestream_get_be16(&buf);
308 left = bytestream_get_be16(&buf);
309 buf += 2; /* bottom */
310 right = bytestream_get_be16(&buf);
311
312 if ((i == 0) && (sprite_id == 0)) {
313 /* clear background */
314 memset(c->frame->data[0], background_color,
315 c->frame->linesize[0] * avctx->height);
316 }
317
318 if (!right)
319 continue;
320 if (sprite_id >= CDTOONS_MAX_SPRITES) {
321 av_log(avctx, AV_LOG_ERROR,
322 "Sprite ID %d is too high.\n", sprite_id);
323 return AVERROR_INVALIDDATA;
324 }
325
326 block_data = c->sprites[sprite_id].data;
327 if (!c->sprites[sprite_id].active) {
328 /* this can happen when seeking around */
329 av_log(avctx, AV_LOG_WARNING, "Sprite %d is missing.\n", sprite_id);
330 continue;
331 }
332 if (c->sprites[sprite_id].size < 14) {
333 av_log(avctx, AV_LOG_ERROR, "Sprite %d is too small.\n", sprite_id);
334 continue;
335 }
336
337 height = bytestream_get_be16(&block_data);
338 width = bytestream_get_be16(&block_data);
339 block_data += 10;
340 if (cdtoons_render_sprite(avctx, block_data,
341 c->sprites[sprite_id].size - 14,
342 left, top, width, height)) {
343 av_log(avctx, AV_LOG_WARNING, "Ran beyond end of sprite while rendering.\n");
344 }
345 }
346
347 if (palette_id && (palette_id != c->last_pal_id)) {
348 if (palette_id >= CDTOONS_MAX_SPRITES) {
349 av_log(avctx, AV_LOG_ERROR,
350 "Palette ID %d is too high.\n", palette_id);
351 return AVERROR_INVALIDDATA;
352 }
353 if (!c->sprites[palette_id].active) {
354 /* this can happen when seeking around */
355 av_log(avctx, AV_LOG_WARNING,
356 "Palette ID %d is missing.\n", palette_id);
357 goto done;
358 }
359 if (c->sprites[palette_id].size != 256 * 2 * 3) {
360 av_log(avctx, AV_LOG_ERROR,
361 "Palette ID %d is wrong size (%d).\n",
362 palette_id, c->sprites[palette_id].size);
363 return AVERROR_INVALIDDATA;
364 }
365 c->last_pal_id = palette_id;
366 if (!palette_set) {
367 uint8_t *palette_data = c->sprites[palette_id].data;
368 for (int i = 0; i < 256; i++) {
369 /* QuickTime-ish palette: 16-bit RGB components */
370 unsigned r, g, b;
371 r = *palette_data;
372 g = *(palette_data + 2);
373 b = *(palette_data + 4);
374 c->pal[i] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
375 palette_data += 6;
376 }
377 /* first palette entry indicates transparency */
378 c->pal[0] = 0;
379 c->frame->palette_has_changed = 1;
380 }
381 }
382
383 done:
384 /* discard outdated blocks */
385 for (int i = 0; i < CDTOONS_MAX_SPRITES; i++) {
386 if (c->sprites[i].end_frame > frame_id)
387 continue;
388 c->sprites[i].active = 0;
389 }
390
391 memcpy(c->frame->data[1], c->pal, AVPALETTE_SIZE);
392
393 if ((ret = av_frame_ref(data, c->frame)) < 0)
394 return ret;
395
396 *got_frame = 1;
397
398 /* always report that the buffer was completely consumed */
399 return buf_size;
400 }
401
cdtoons_decode_init(AVCodecContext * avctx)402 static av_cold int cdtoons_decode_init(AVCodecContext *avctx)
403 {
404 CDToonsContext *c = avctx->priv_data;
405
406 avctx->pix_fmt = AV_PIX_FMT_PAL8;
407 c->last_pal_id = 0;
408 c->frame = av_frame_alloc();
409 if (!c->frame)
410 return AVERROR(ENOMEM);
411
412 return 0;
413 }
414
cdtoons_flush(AVCodecContext * avctx)415 static void cdtoons_flush(AVCodecContext *avctx)
416 {
417 CDToonsContext *c = avctx->priv_data;
418
419 c->last_pal_id = 0;
420 for (int i = 0; i < CDTOONS_MAX_SPRITES; i++)
421 c->sprites[i].active = 0;
422 }
423
cdtoons_decode_end(AVCodecContext * avctx)424 static av_cold int cdtoons_decode_end(AVCodecContext *avctx)
425 {
426 CDToonsContext *c = avctx->priv_data;
427
428 for (int i = 0; i < CDTOONS_MAX_SPRITES; i++) {
429 av_freep(&c->sprites[i].data);
430 c->sprites[i].active = 0;
431 }
432
433 av_frame_free(&c->frame);
434
435 return 0;
436 }
437
438 AVCodec ff_cdtoons_decoder = {
439 .name = "cdtoons",
440 .long_name = NULL_IF_CONFIG_SMALL("CDToons video"),
441 .type = AVMEDIA_TYPE_VIDEO,
442 .id = AV_CODEC_ID_CDTOONS,
443 .priv_data_size = sizeof(CDToonsContext),
444 .init = cdtoons_decode_init,
445 .close = cdtoons_decode_end,
446 .decode = cdtoons_decode_frame,
447 .capabilities = AV_CODEC_CAP_DR1,
448 .flush = cdtoons_flush,
449 };
450