| 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_LOAD_PAL_LO 30 |
| 53 | #define CDG_INST_LOAD_PAL_HIGH 31 |
| 54 | #define CDG_INST_TILE_BLOCK_XOR 38 |
| 55 | |
| 56 | /// data sizes |
| 57 | #define CDG_PACKET_SIZE 24 |
| 58 | #define CDG_DATA_SIZE 16 |
| 59 | #define CDG_TILE_HEIGHT 12 |
| 60 | #define CDG_TILE_WIDTH 6 |
| 61 | #define CDG_MINIMUM_PKT_SIZE 6 |
| 62 | #define CDG_MINIMUM_SCROLL_SIZE 3 |
| 63 | #define CDG_HEADER_SIZE 8 |
| 64 | #define CDG_PALETTE_SIZE 16 |
| 65 | |
| 66 | typedef struct CDGraphicsContext { |
| 67 | AVFrame *frame; |
| 68 | int hscroll; |
| 69 | int vscroll; |
| 70 | } CDGraphicsContext; |
| 71 | |
| 72 | static av_cold int cdg_decode_init(AVCodecContext *avctx) |
| 73 | { |
| 74 | CDGraphicsContext *cc = avctx->priv_data; |
| 75 | |
| 76 | cc->frame = av_frame_alloc(); |
| 77 | if (!cc->frame) |
| 78 | return AVERROR(ENOMEM); |
| 79 | |
| 80 | avctx->width = CDG_FULL_WIDTH; |
| 81 | avctx->height = CDG_FULL_HEIGHT; |
| 82 | avctx->pix_fmt = AV_PIX_FMT_PAL8; |
| 83 | |
| 84 | return 0; |
| 85 | } |
| 86 | |
| 87 | static void cdg_border_preset(CDGraphicsContext *cc, uint8_t *data) |
| 88 | { |
| 89 | int y; |
| 90 | int lsize = cc->frame->linesize[0]; |
| 91 | uint8_t *buf = cc->frame->data[0]; |
| 92 | int color = data[0] & 0x0F; |
| 93 | |
| 94 | if (!(data[1] & 0x0F)) { |
| 95 | /// fill the top and bottom borders |
| 96 | memset(buf, color, CDG_BORDER_HEIGHT * lsize); |
| 97 | memset(buf + (CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT) * lsize, |
| 98 | color, CDG_BORDER_HEIGHT * lsize); |
| 99 | |
| 100 | /// fill the side borders |
| 101 | for (y = CDG_BORDER_HEIGHT; y < CDG_FULL_HEIGHT - CDG_BORDER_HEIGHT; y++) { |
| 102 | memset(buf + y * lsize, color, CDG_BORDER_WIDTH); |
| 103 | memset(buf + CDG_FULL_WIDTH - CDG_BORDER_WIDTH + y * lsize, |
| 104 | color, CDG_BORDER_WIDTH); |
| 105 | } |
| 106 | } |
| 107 | } |
| 108 | |
| 109 | static void cdg_load_palette(CDGraphicsContext *cc, uint8_t *data, int low) |
| 110 | { |
| 111 | uint8_t r, g, b; |
| 112 | uint16_t color; |
| 113 | int i; |
| 114 | int array_offset = low ? 0 : 8; |
| 115 | uint32_t *palette = (uint32_t *) cc->frame->data[1]; |
| 116 | |
| 117 | for (i = 0; i < 8; i++) { |
| 118 | color = (data[2 * i] << 6) + (data[2 * i + 1] & 0x3F); |
| 119 | r = ((color >> 8) & 0x000F) * 17; |
| 120 | g = ((color >> 4) & 0x000F) * 17; |
| 121 | b = ((color ) & 0x000F) * 17; |
| 122 | palette[i + array_offset] = 0xFFU << 24 | r << 16 | g << 8 | b; |
| 123 | } |
| 124 | cc->frame->palette_has_changed = 1; |
| 125 | } |
| 126 | |
| 127 | static int cdg_tile_block(CDGraphicsContext *cc, uint8_t *data, int b) |
| 128 | { |
| 129 | unsigned ci, ri; |
| 130 | int color; |
| 131 | int x, y; |
| 132 | int ai; |
| 133 | int stride = cc->frame->linesize[0]; |
| 134 | uint8_t *buf = cc->frame->data[0]; |
| 135 | |
| 136 | ri = (data[2] & 0x1F) * CDG_TILE_HEIGHT + cc->vscroll; |
| 137 | ci = (data[3] & 0x3F) * CDG_TILE_WIDTH + cc->hscroll; |
| 138 | |
| 139 | if (ri > (CDG_FULL_HEIGHT - CDG_TILE_HEIGHT)) |
| 140 | return AVERROR(EINVAL); |
| 141 | if (ci > (CDG_FULL_WIDTH - CDG_TILE_WIDTH)) |
| 142 | return AVERROR(EINVAL); |
| 143 | |
| 144 | for (y = 0; y < CDG_TILE_HEIGHT; y++) { |
| 145 | for (x = 0; x < CDG_TILE_WIDTH; x++) { |
| 146 | if (!((data[4 + y] >> (5 - x)) & 0x01)) |
| 147 | color = data[0] & 0x0F; |
| 148 | else |
| 149 | color = data[1] & 0x0F; |
| 150 | |
| 151 | ai = ci + x + (stride * (ri + y)); |
| 152 | if (b) |
| 153 | color ^= buf[ai]; |
| 154 | buf[ai] = color; |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | return 0; |
| 159 | } |
| 160 | |
| 161 | #define UP 2 |
| 162 | #define DOWN 1 |
| 163 | #define LEFT 2 |
| 164 | #define RIGHT 1 |
| 165 | |
| 166 | static void cdg_copy_rect_buf(int out_tl_x, int out_tl_y, uint8_t *out, |
| 167 | int in_tl_x, int in_tl_y, uint8_t *in, |
| 168 | int w, int h, int stride) |
| 169 | { |
| 170 | int y; |
| 171 | |
| 172 | in += in_tl_x + in_tl_y * stride; |
| 173 | out += out_tl_x + out_tl_y * stride; |
| 174 | for (y = 0; y < h; y++) |
| 175 | memcpy(out + y * stride, in + y * stride, w); |
| 176 | } |
| 177 | |
| 178 | static void cdg_fill_rect_preset(int tl_x, int tl_y, uint8_t *out, |
| 179 | int color, int w, int h, int stride) |
| 180 | { |
| 181 | int y; |
| 182 | |
| 183 | for (y = tl_y; y < tl_y + h; y++) |
| 184 | memset(out + tl_x + y * stride, color, w); |
| 185 | } |
| 186 | |
| 187 | static void cdg_fill_wrapper(int out_tl_x, int out_tl_y, uint8_t *out, |
| 188 | int in_tl_x, int in_tl_y, uint8_t *in, |
| 189 | int color, int w, int h, int stride, int roll) |
| 190 | { |
| 191 | if (roll) { |
| 192 | cdg_copy_rect_buf(out_tl_x, out_tl_y, out, in_tl_x, in_tl_y, |
| 193 | in, w, h, stride); |
| 194 | } else { |
| 195 | cdg_fill_rect_preset(out_tl_x, out_tl_y, out, color, w, h, stride); |
| 196 | } |
| 197 | } |
| 198 | |
| 199 | static void cdg_scroll(CDGraphicsContext *cc, uint8_t *data, |
| 200 | AVFrame *new_frame, int roll_over) |
| 201 | { |
| 202 | int color; |
| 203 | int hscmd, h_off, hinc, vscmd, v_off, vinc; |
| 204 | int y; |
| 205 | int stride = cc->frame->linesize[0]; |
| 206 | uint8_t *in = cc->frame->data[0]; |
| 207 | uint8_t *out = new_frame->data[0]; |
| 208 | |
| 209 | color = data[0] & 0x0F; |
| 210 | hscmd = (data[1] & 0x30) >> 4; |
| 211 | vscmd = (data[2] & 0x30) >> 4; |
| 212 | |
| 213 | h_off = FFMIN(data[1] & 0x07, CDG_BORDER_WIDTH - 1); |
| 214 | v_off = FFMIN(data[2] & 0x0F, CDG_BORDER_HEIGHT - 1); |
| 215 | |
| 216 | /// find the difference and save the offset for cdg_tile_block usage |
| 217 | hinc = h_off - cc->hscroll; |
| 218 | vinc = v_off - cc->vscroll; |
| 219 | cc->hscroll = h_off; |
| 220 | cc->vscroll = v_off; |
| 221 | |
| 222 | if (vscmd == UP) |
| 223 | vinc -= 12; |
| 224 | if (vscmd == DOWN) |
| 225 | vinc += 12; |
| 226 | if (hscmd == LEFT) |
| 227 | hinc -= 6; |
| 228 | if (hscmd == RIGHT) |
| 229 | hinc += 6; |
| 230 | |
| 231 | if (!hinc && !vinc) |
| 232 | return; |
| 233 | |
| 234 | memcpy(new_frame->data[1], cc->frame->data[1], CDG_PALETTE_SIZE * 4); |
| 235 | |
| 236 | for (y = FFMAX(0, vinc); y < FFMIN(CDG_FULL_HEIGHT + vinc, CDG_FULL_HEIGHT); y++) |
| 237 | memcpy(out + FFMAX(0, hinc) + stride * y, |
| 238 | in + FFMAX(0, hinc) - hinc + (y - vinc) * stride, |
| 239 | FFMIN(stride + hinc, stride)); |
| 240 | |
| 241 | if (vinc > 0) |
| 242 | cdg_fill_wrapper(0, 0, out, |
| 243 | 0, CDG_FULL_HEIGHT - vinc, in, color, |
| 244 | stride, vinc, stride, roll_over); |
| 245 | else if (vinc < 0) |
| 246 | cdg_fill_wrapper(0, CDG_FULL_HEIGHT + vinc, out, |
| 247 | 0, 0, in, color, |
| 248 | stride, -1 * vinc, stride, roll_over); |
| 249 | |
| 250 | if (hinc > 0) |
| 251 | cdg_fill_wrapper(0, 0, out, |
| 252 | CDG_FULL_WIDTH - hinc, 0, in, color, |
| 253 | hinc, CDG_FULL_HEIGHT, stride, roll_over); |
| 254 | else if (hinc < 0) |
| 255 | cdg_fill_wrapper(CDG_FULL_WIDTH + hinc, 0, out, |
| 256 | 0, 0, in, color, |
| 257 | -1 * hinc, CDG_FULL_HEIGHT, stride, roll_over); |
| 258 | |
| 259 | } |
| 260 | |
| 261 | static int cdg_decode_frame(AVCodecContext *avctx, |
| 262 | void *data, int *got_frame, AVPacket *avpkt) |
| 263 | { |
| 264 | GetByteContext gb; |
| 265 | int buf_size = avpkt->size; |
| 266 | int ret; |
| 267 | uint8_t command, inst; |
| 268 | uint8_t cdg_data[CDG_DATA_SIZE] = {0}; |
| 269 | AVFrame *frame = data; |
| 270 | CDGraphicsContext *cc = avctx->priv_data; |
| 271 | |
| 272 | if (buf_size < CDG_MINIMUM_PKT_SIZE) { |
| 273 | av_log(avctx, AV_LOG_ERROR, "buffer too small for decoder\n"); |
| 274 | return AVERROR(EINVAL); |
| 275 | } |
| 276 | if (buf_size > CDG_HEADER_SIZE + CDG_DATA_SIZE) { |
| 277 | av_log(avctx, AV_LOG_ERROR, "buffer too big for decoder\n"); |
| 278 | return AVERROR(EINVAL); |
| 279 | } |
| 280 | |
| 281 | bytestream2_init(&gb, avpkt->data, avpkt->size); |
| 282 | |
| 283 | if ((ret = ff_reget_buffer(avctx, cc->frame)) < 0) |
| 284 | return ret; |
| 285 | if (!avctx->frame_number) { |
| 286 | memset(cc->frame->data[0], 0, cc->frame->linesize[0] * avctx->height); |
| 287 | memset(cc->frame->data[1], 0, AVPALETTE_SIZE); |
| 288 | } |
| 289 | |
| 290 | command = bytestream2_get_byte(&gb); |
| 291 | inst = bytestream2_get_byte(&gb); |
| 292 | inst &= CDG_MASK; |
| 293 | bytestream2_skip(&gb, 2); |
| 294 | bytestream2_get_buffer(&gb, cdg_data, sizeof(cdg_data)); |
| 295 | |
| 296 | if ((command & CDG_MASK) == CDG_COMMAND) { |
| 297 | switch (inst) { |
| 298 | case CDG_INST_MEMORY_PRESET: |
| 299 | if (!(cdg_data[1] & 0x0F)) |
| 300 | memset(cc->frame->data[0], cdg_data[0] & 0x0F, |
| 301 | cc->frame->linesize[0] * CDG_FULL_HEIGHT); |
| 302 | break; |
| 303 | case CDG_INST_LOAD_PAL_LO: |
| 304 | case CDG_INST_LOAD_PAL_HIGH: |
| 305 | if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) { |
| 306 | av_log(avctx, AV_LOG_ERROR, "buffer too small for loading palette\n"); |
| 307 | return AVERROR(EINVAL); |
| 308 | } |
| 309 | |
| 310 | cdg_load_palette(cc, cdg_data, inst == CDG_INST_LOAD_PAL_LO); |
| 311 | break; |
| 312 | case CDG_INST_BORDER_PRESET: |
| 313 | cdg_border_preset(cc, cdg_data); |
| 314 | break; |
| 315 | case CDG_INST_TILE_BLOCK_XOR: |
| 316 | case CDG_INST_TILE_BLOCK: |
| 317 | if (buf_size - CDG_HEADER_SIZE < CDG_DATA_SIZE) { |
| 318 | av_log(avctx, AV_LOG_ERROR, "buffer too small for drawing tile\n"); |
| 319 | return AVERROR(EINVAL); |
| 320 | } |
| 321 | |
| 322 | ret = cdg_tile_block(cc, cdg_data, inst == CDG_INST_TILE_BLOCK_XOR); |
| 323 | if (ret) { |
| 324 | av_log(avctx, AV_LOG_ERROR, "tile is out of range\n"); |
| 325 | return ret; |
| 326 | } |
| 327 | break; |
| 328 | case CDG_INST_SCROLL_PRESET: |
| 329 | case CDG_INST_SCROLL_COPY: |
| 330 | if (buf_size - CDG_HEADER_SIZE < CDG_MINIMUM_SCROLL_SIZE) { |
| 331 | av_log(avctx, AV_LOG_ERROR, "buffer too small for scrolling\n"); |
| 332 | return AVERROR(EINVAL); |
| 333 | } |
| 334 | |
| 335 | if ((ret = ff_get_buffer(avctx, frame, AV_GET_BUFFER_FLAG_REF)) < 0) |
| 336 | return ret; |
| 337 | |
| 338 | cdg_scroll(cc, cdg_data, frame, inst == CDG_INST_SCROLL_COPY); |
| 339 | av_frame_unref(cc->frame); |
| 340 | ret = av_frame_ref(cc->frame, frame); |
| 341 | if (ret < 0) |
| 342 | return ret; |
| 343 | break; |
| 344 | default: |
| 345 | break; |
| 346 | } |
| 347 | |
| 348 | if (!frame->data[0]) { |
| 349 | ret = av_frame_ref(frame, cc->frame); |
| 350 | if (ret < 0) |
| 351 | return ret; |
| 352 | } |
| 353 | *got_frame = 1; |
| 354 | } else { |
| 355 | *got_frame = 0; |
| 356 | } |
| 357 | |
| 358 | return avpkt->size; |
| 359 | } |
| 360 | |
| 361 | static av_cold int cdg_decode_end(AVCodecContext *avctx) |
| 362 | { |
| 363 | CDGraphicsContext *cc = avctx->priv_data; |
| 364 | |
| 365 | av_frame_free(&cc->frame); |
| 366 | |
| 367 | return 0; |
| 368 | } |
| 369 | |
| 370 | AVCodec ff_cdgraphics_decoder = { |
| 371 | .name = "cdgraphics", |
| 372 | .long_name = NULL_IF_CONFIG_SMALL("CD Graphics video"), |
| 373 | .type = AVMEDIA_TYPE_VIDEO, |
| 374 | .id = AV_CODEC_ID_CDGRAPHICS, |
| 375 | .priv_data_size = sizeof(CDGraphicsContext), |
| 376 | .init = cdg_decode_init, |
| 377 | .close = cdg_decode_end, |
| 378 | .decode = cdg_decode_frame, |
| 379 | .capabilities = CODEC_CAP_DR1, |
| 380 | }; |