CD+G demuxer and decoder
[libav.git] / libavcodec / cdgraphics.c
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a3d995c1
MT
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
25/**
26 * @file libavcodec/cdgraphics.c
27 * @brief CD Graphics Video Decoder
28 * @author Michael Tison
29 * @sa http://wiki.multimedia.cx/index.php?title=CD_Graphics
30 * @sa http://www.ccs.neu.edu/home/bchafy/cdb/info/cdg
31 */
32
33/// default screen sizes
34#define CDG_FULL_WIDTH 300
35#define CDG_FULL_HEIGHT 216
36#define CDG_DISPLAY_WIDTH 294
37#define CDG_DISPLAY_HEIGHT 204
38#define CDG_BORDER_WIDTH 6
39#define CDG_BORDER_HEIGHT 12
40
41/// masks
42#define CDG_COMMAND 0x09
43#define CDG_MASK 0x3F
44
45/// instruction codes
46#define CDG_INST_MEMORY_PRESET 1
47#define CDG_INST_BORDER_PRESET 2
48#define CDG_INST_TILE_BLOCK 6
49#define CDG_INST_SCROLL_PRESET 20
50#define CDG_INST_SCROLL_COPY 24
51#define CDG_INST_LOAD_PAL_LO 30
52#define CDG_INST_LOAD_PAL_HIGH 31
53#define CDG_INST_TILE_BLOCK_XOR 38
54
55/// data sizes
56#define CDG_PACKET_SIZE 24
57#define CDG_DATA_SIZE 16
58#define CDG_TILE_HEIGHT 12
59#define CDG_TILE_WIDTH 6
60#define CDG_MINIMUM_PKT_SIZE 6
61#define CDG_MINIMUM_SCROLL_SIZE 3
62#define CDG_HEADER_SIZE 8
63#define CDG_PALETTE_SIZE 16
64
65typedef struct CDGraphicsContext {
66 AVFrame frame;
67 int hscroll;
68 int vscroll;
69} CDGraphicsContext;
70
71static void cdg_init_frame(AVFrame *frame)
72{
73 avcodec_get_frame_defaults(frame);
74 frame->reference = 1;
75 frame->buffer_hints = FF_BUFFER_HINTS_VALID |
76 FF_BUFFER_HINTS_PRESERVE |
77 FF_BUFFER_HINTS_REUSABLE;
78}
79
80static av_cold int cdg_decode_init(AVCodecContext *avctx)
81{
82 CDGraphicsContext *cc = avctx->priv_data;
83
84 cdg_init_frame(&cc->frame);
85
86 avctx->width = CDG_FULL_WIDTH;
87 avctx->height = CDG_FULL_HEIGHT;
88 avctx->pix_fmt = PIX_FMT_PAL8;
89
90 return 0;
91}
92
93static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data)
94{
95 int y;
96 int lsize = cc->frame.linesize[0];
97 uint8_t *buf = cc->frame.data[0];
98 int color = data[0] & 0x0F;
99
100 if (!(data[1] & 0x0F)) {
101 /// fill the top and bottom borders
102 memset(buf, color, CDG_BORDER_HEIGHT * lsize);
103 memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize,
104 color, CDG_BORDER_HEIGHT * lsize);
105
106 /// fill the side borders
107 for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) {
108 memset(buf + y * lsize, color, CDG_BORDER_WIDTH);
109 memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize,
110 color, CDG_BORDER_WIDTH);
111 }
112 }
113}
114
115static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low)
116{
117 uint8_t r, g, b;
118 uint16_t color;
119 int i;
120 int array_offset = low ? 0 : 8;
121 uint32_t *palette = (uint32_t *) cc->frame.data[1];
122
123 for (i = 0; i < 8; i++) {
124 color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F);
125 r = ((color >> 8) & 0x000F) * 17;
126 g = ((color >> 4) & 0x000F) * 17;
127 b = ((color ) & 0x000F) * 17;
128 palette[i + array_offset] = r << 16 | g << 8 | b;
129 }
130 cc->frame.palette_has_changed = 1;
131}
132
133static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b)
134{
135 unsigned ci, ri;
136 int color;
137 int x, y;
138 int ai;
139 int stride = cc->frame.linesize[0];
140 uint8_t *buf = cc->frame.data[0];
141
142 ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll;
143 ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll;
144
145 if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT))
146 return AVERROR(EINVAL);
147 if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH))
148 return AVERROR(EINVAL);
149
150 for (y = 0; y < CDG_TILE_HEIGHT; y++) {
151 for (x = 0; x < CDG_TILE_WIDTH; x++) {
152 if (!((data[4 + y] >> (5 - x)) & 0x01))
153 color = data[0] & 0x0F;
154 else
155 color = data[1] & 0x0F;
156
157 ai = ci + x + (stride * (ri + y));
158 if (b)
159 color ^= buf[ai];
160 buf[ai] = color;
161 }
162 }
163
164 return 0;
165}
166
167#define UP 2
168#define DOWN 1
169#define LEFT 2
170#define RIGHT 1
171
172static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out,
173 int in_tl_x, int in_tl_y, uint8_t *in,
174 int w, int h, int stride)
175{
176 int y;
177
178 in += in_tl_x + in_tl_y * stride;
179 out += out_tl_x + out_tl_y * stride;
180 for (y = 0; y < h; y++)
181 memcpy(out + y * stride, in + y * stride, w);
182}
183
184static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out,
185 int color, int w, int h, int stride)
186{
187 int y;
188
189 for (y = tl_y; y < tl_y + h; y++)
190 memset(out + tl_x + y * stride, color, w);
191}
192
193static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out,
194 int in_tl_x, int in_tl_y, uint8_t *in,
195 int color, int w, int h, int stride, int roll)
196{
197 if (roll) {
198 cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y,
199 in, w, h, stride);
200 } else {
201 cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride);
202 }
203}
204
205static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data,
206 AVFrame *new_frame, int roll_over)
207{
208 int color;
209 int hscmd, h_off, hinc, vscmd, v_off, vinc;
210 int y;
211 int stride = cc->frame.linesize[0];
212 uint8_t *in = cc->frame.data[0];
213 uint8_t *out = new_frame->data[0];
214
215 color = data[0] & 0x0F;
216 hscmd = (data[1] & 0x30) >> 4;
217 vscmd = (data[2] & 0x30) >> 4;
218
219 h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1);
220 v_off = FFMIN(data[2] & 0x07, CDG_BORDER_HEIGHT - 1);
221
222 /// find the difference and save the offset for cdg_tile_block usage
223 hinc = h_off - cc->hscroll;
224 vinc = v_off - cc->vscroll;
225 cc->hscroll = h_off;
226 cc->vscroll = v_off;
227
228 if (vscmd == UP)
229 vinc -= 12;
230 if (vscmd == DOWN)
231 vinc += 12;
232 if (hscmd == LEFT)
233 hinc -= 6;
234 if (hscmd == RIGHT)
235 hinc += 6;
236
237 if (!hinc && !vinc)
238 return;
239
240 memcpy(new_frame->data[1], cc->frame.data[1], CDG_PALETTE_SIZE * 4);
241
242 for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++)
243 memcpy(out + FFMAX(0, hinc) + stride * y,
244 in + FFMAX(0, hinc) - hinc + (y - vinc) * stride,
245 FFMIN(stride + hinc, stride));
246
247 if (vinc > 0)
248 cdg_fill_wrapper(0, 0, out,
249 0, CDG_FULL_HEIGHT - vinc, in, color,
250 stride, vinc, stride, roll_over);
251 else if (vinc < 0)
252 cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out,
253 0, 0, in, color,
254 stride, -1 * vinc, stride, roll_over);
255
256 if (hinc > 0)
257 cdg_fill_wrapper(0, 0, out,
258 CDG_FULL_WIDTH - hinc, 0, in, color,
259 hinc, CDG_FULL_HEIGHT, stride, roll_over);
260 else if (hinc < 0)
261 cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out,
262 0, 0, in, color,
263 -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over);
264
265}
266
267static int cdg_decode_frame(AVCodecContext *avctx,
268 void *data, int *data_size, AVPacket *avpkt)
269{
270 const uint8_t *buf = avpkt->data;
271 int buf_size = avpkt->size;
272 int ret;
273 uint8_t command, inst;
274 uint8_t cdg_data[CDG_DATA_SIZE];
275 AVFrame new_frame;
276 CDGraphicsContext *cc = avctx->priv_data;
277
278 if (buf_size < CDG_MINIMUM_PKT_SIZE) {
279 av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n");
280 return AVERROR(EINVAL);
281 }
282
283 ret = avctx->reget_buffer(avctx, &cc->frame);
284 if (ret) {
285 av_log(avctx, AV_LOG_ERROR, "reget_buffer() failed\n");
286 return ret;
287 }
288
289 command = bytestream_get_byte(&buf);
290 inst = bytestream_get_byte(&buf);
291 inst &= CDG_MASK;
292 buf += 2; /// skipping 2 unneeded bytes
293 bytestream_get_buffer(&buf, cdg_data, buf_size - CDG_HEADER_SIZE);
294
295 if ((command & CDG_MASK) == CDG_COMMAND) {
296 switch (inst) {
297 case CDG_INST_MEMORY_PRESET:
298 if (!(cdg_data[1] & 0x0F))
299 memset(cc->frame.data[0], cdg_data[0] & 0x0F,
300 cc->frame.linesize[0] * CDG_FULL_HEIGHT);
301 break;
302 case CDG_INST_LOAD_PAL_LO:
303 case CDG_INST_LOAD_PAL_HIGH:
304 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
305 av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n");
306 return AVERROR(EINVAL);
307 }
308
309 cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO);
310 break;
311 case CDG_INST_BORDER_PRESET:
312 cdg_border_preset(cc, cdg_data);
313 break;
314 case CDG_INST_TILE_BLOCK_XOR:
315 case CDG_INST_TILE_BLOCK:
316 if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) {
317 av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n");
318 return AVERROR(EINVAL);
319 }
320
321 ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR);
322 if (ret) {
323 av_log(avctx, AV_LOG_ERROR, "tile is out of range\n");
324 return ret;
325 }
326 break;
327 case CDG_INST_SCROLL_PRESET:
328 case CDG_INST_SCROLL_COPY:
329 if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) {
330 av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n");
331 return AVERROR(EINVAL);
332 }
333
334 cdg_init_frame(&new_frame);
335 ret = avctx->get_buffer(avctx, &new_frame);
336 if (ret) {
337 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
338 return ret;
339 }
340
341 cdg_scroll(cc, cdg_data, &new_frame, inst == CDG_INST_SCROLL_COPY);
342 avctx->release_buffer(avctx, &cc->frame);
343 cc->frame = new_frame;
344 break;
345 default:
346 break;
347 }
348
349 *data_size = sizeof(AVFrame);
350 } else {
351 *data_size = 0;
352 buf_size = 0;
353 }
354
355 *(AVFrame *) data = cc->frame;
356 return buf_size;
357}
358
359static av_cold int cdg_decode_end(AVCodecContext *avctx)
360{
361 CDGraphicsContext *cc = avctx->priv_data;
362
363 if (cc->frame.data[0])
364 avctx->release_buffer(avctx, &cc->frame);
365
366 return 0;
367}
368
369AVCodec cdgraphics_decoder = {
370 "cdgraphics",
371 CODEC_TYPE_VIDEO,
372 CODEC_ID_CDGRAPHICS,
373 sizeof(CDGraphicsContext),
374 cdg_decode_init,
375 NULL,
376 cdg_decode_end,
377 cdg_decode_frame,
378 CODEC_CAP_DR1,
379 .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"),
380};