1/* 2 * PGS subtitle decoder 3 * Copyright (c) 2009 Stephen Backway 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 * PGS subtitle decoder 25 */ 26 27#include "avcodec.h" 28#include "dsputil.h" 29#include "colorspace.h" 30#include "bytestream.h" 31 32//#define DEBUG_PACKET_CONTENTS 33 34#define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b)) 35 36enum SegmentType { 37 PALETTE_SEGMENT = 0x14, 38 PICTURE_SEGMENT = 0x15, 39 PRESENTATION_SEGMENT = 0x16, 40 WINDOW_SEGMENT = 0x17, 41 DISPLAY_SEGMENT = 0x80, 42}; 43 44typedef struct PGSSubPresentation { 45 int x; 46 int y; 47 int video_w; 48 int video_h; 49 int id_number; 50} PGSSubPresentation; 51 52typedef struct PGSSubPicture { 53 int w; 54 int h; 55 uint8_t *rle; 56 unsigned int rle_buffer_size, rle_data_len; 57} PGSSubPicture; 58 59typedef struct PGSSubContext { 60 PGSSubPresentation presentation; 61 uint32_t clut[256]; 62 PGSSubPicture picture; 63} PGSSubContext; 64 65static av_cold int init_decoder(AVCodecContext *avctx) 66{ 67 avctx->pix_fmt = PIX_FMT_RGB32; 68 69 return 0; 70} 71 72static av_cold int close_decoder(AVCodecContext *avctx) 73{ 74 PGSSubContext *ctx = avctx->priv_data; 75 76 av_freep(&ctx->picture.rle); 77 ctx->picture.rle_buffer_size = 0; 78 79 return 0; 80} 81 82/** 83 * Decodes the RLE data. 84 * 85 * The subtitle is stored as an Run Length Encoded image. 86 * 87 * @param avctx contains the current codec context 88 * @param sub pointer to the processed subtitle data 89 * @param buf pointer to the RLE data to process 90 * @param buf_size size of the RLE data to process 91 */ 92static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub, 93 const uint8_t *buf, unsigned int buf_size) 94{ 95 const uint8_t *rle_bitmap_end; 96 int pixel_count, line_count; 97 98 rle_bitmap_end = buf + buf_size; 99 100 sub->rects[0]->pict.data[0] = av_malloc(sub->rects[0]->w * sub->rects[0]->h); 101 102 if (!sub->rects[0]->pict.data[0]) 103 return -1; 104 105 pixel_count = 0; 106 line_count = 0; 107 108 while (buf < rle_bitmap_end && line_count < sub->rects[0]->h) { 109 uint8_t flags, color; 110 int run; 111 112 color = bytestream_get_byte(&buf); 113 run = 1; 114 115 if (color == 0x00) { 116 flags = bytestream_get_byte(&buf); 117 run = flags & 0x3f; 118 if (flags & 0x40) 119 run = (run << 8) + bytestream_get_byte(&buf); 120 color = flags & 0x80 ? bytestream_get_byte(&buf) : 0; 121 } 122 123 if (run > 0 && pixel_count + run <= sub->rects[0]->w * sub->rects[0]->h) { 124 memset(sub->rects[0]->pict.data[0] + pixel_count, color, run); 125 pixel_count += run; 126 } else if (!run) { 127 /* 128 * New Line. Check if correct pixels decoded, if not display warning 129 * and adjust bitmap pointer to correct new line position. 130 */ 131 if (pixel_count % sub->rects[0]->w > 0) 132 av_log(avctx, AV_LOG_ERROR, "Decoded %d pixels, when line should be %d pixels\n", 133 pixel_count % sub->rects[0]->w, sub->rects[0]->w); 134 line_count++; 135 } 136 } 137 138 dprintf(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, sub->rects[0]->w * sub->rects[0]->h); 139 140 return 0; 141} 142 143/** 144 * Parses the picture segment packet. 145 * 146 * The picture segment contains details on the sequence id, 147 * width, height and Run Length Encoded (RLE) bitmap data. 148 * 149 * @param avctx contains the current codec context 150 * @param buf pointer to the packet to process 151 * @param buf_size size of packet to process 152 * @todo TODO: Enable support for RLE data over multiple packets 153 */ 154static int parse_picture_segment(AVCodecContext *avctx, 155 const uint8_t *buf, int buf_size) 156{ 157 PGSSubContext *ctx = avctx->priv_data; 158 159 uint8_t sequence_desc; 160 unsigned int rle_bitmap_len, width, height; 161 162 /* skip 3 unknown bytes: Object ID (2 bytes), Version Number */ 163 buf += 3; 164 165 /* Read the Sequence Description to determine if start of RLE data or appended to previous RLE */ 166 sequence_desc = bytestream_get_byte(&buf); 167 168 if (!(sequence_desc & 0x80)) { 169 av_log(avctx, AV_LOG_ERROR, "Decoder does not support object data over multiple packets.\n"); 170 return -1; 171 } 172 173 /* Decode rle bitmap length */ 174 rle_bitmap_len = bytestream_get_be24(&buf); 175 176 /* Check to ensure we have enough data for rle_bitmap_length if just a single packet */ 177 if (rle_bitmap_len > buf_size - 7) { 178 av_log(avctx, AV_LOG_ERROR, "Not enough RLE data for specified length of %d.\n", rle_bitmap_len); 179 return -1; 180 } 181 182 ctx->picture.rle_data_len = rle_bitmap_len; 183 184 /* Get bitmap dimensions from data */ 185 width = bytestream_get_be16(&buf); 186 height = bytestream_get_be16(&buf); 187 188 /* Make sure the bitmap is not too large */ 189 if (ctx->presentation.video_w < width || ctx->presentation.video_h < height) { 190 av_log(avctx, AV_LOG_ERROR, "Bitmap dimensions larger then video.\n"); 191 return -1; 192 } 193 194 ctx->picture.w = width; 195 ctx->picture.h = height; 196 197 av_fast_malloc(&ctx->picture.rle, &ctx->picture.rle_buffer_size, rle_bitmap_len); 198 199 if (!ctx->picture.rle) 200 return -1; 201 202 memcpy(ctx->picture.rle, buf, rle_bitmap_len); 203 204 return 0; 205} 206 207/** 208 * Parses the palette segment packet. 209 * 210 * The palette segment contains details of the palette, 211 * a maximum of 256 colors can be defined. 212 * 213 * @param avctx contains the current codec context 214 * @param buf pointer to the packet to process 215 * @param buf_size size of packet to process 216 */ 217static void parse_palette_segment(AVCodecContext *avctx, 218 const uint8_t *buf, int buf_size) 219{ 220 PGSSubContext *ctx = avctx->priv_data; 221 222 const uint8_t *buf_end = buf + buf_size; 223 const uint8_t *cm = ff_cropTbl + MAX_NEG_CROP; 224 int color_id; 225 int y, cb, cr, alpha; 226 int r, g, b, r_add, g_add, b_add; 227 228 /* Skip two null bytes */ 229 buf += 2; 230 231 while (buf < buf_end) { 232 color_id = bytestream_get_byte(&buf); 233 y = bytestream_get_byte(&buf); 234 cb = bytestream_get_byte(&buf); 235 cr = bytestream_get_byte(&buf); 236 alpha = bytestream_get_byte(&buf); 237 238 YUV_TO_RGB1(cb, cr); 239 YUV_TO_RGB2(r, g, b, y); 240 241 dprintf(avctx, "Color %d := (%d,%d,%d,%d)\n", color_id, r, g, b, alpha); 242 243 /* Store color in palette */ 244 ctx->clut[color_id] = RGBA(r,g,b,alpha); 245 } 246} 247 248/** 249 * Parses the presentation segment packet. 250 * 251 * The presentation segment contains details on the video 252 * width, video height, x & y subtitle position. 253 * 254 * @param avctx contains the current codec context 255 * @param buf pointer to the packet to process 256 * @param buf_size size of packet to process 257 * @todo TODO: Implement cropping 258 * @todo TODO: Implement forcing of subtitles 259 * @todo TODO: Blanking of subtitle 260 */ 261static void parse_presentation_segment(AVCodecContext *avctx, 262 const uint8_t *buf, int buf_size) 263{ 264 PGSSubContext *ctx = avctx->priv_data; 265 266 int x, y; 267 uint8_t block; 268 269 ctx->presentation.video_w = bytestream_get_be16(&buf); 270 ctx->presentation.video_h = bytestream_get_be16(&buf); 271 272 dprintf(avctx, "Video Dimensions %dx%d\n", 273 ctx->presentation.video_w, ctx->presentation.video_h); 274 275 /* Skip 1 bytes of unknown, frame rate? */ 276 buf++; 277 278 ctx->presentation.id_number = bytestream_get_be16(&buf); 279 280 /* Next byte is the state. */ 281 block = bytestream_get_byte(&buf);; 282 if (block == 0x80) { 283 /* 284 * Skip 7 bytes of unknown: 285 * palette_update_flag (0x80), 286 * palette_id_to_use, 287 * Object Number (if > 0 determines if more data to process), 288 * object_id_ref (2 bytes), 289 * window_id_ref, 290 * composition_flag (0x80 - object cropped, 0x40 - object forced) 291 */ 292 buf += 7; 293 294 x = bytestream_get_be16(&buf); 295 y = bytestream_get_be16(&buf); 296 297 /* TODO If cropping, cropping_x, cropping_y, cropping_width, cropping_height (all 2 bytes).*/ 298 299 dprintf(avctx, "Subtitle Placement x=%d, y=%d\n", x, y); 300 301 if (x > ctx->presentation.video_w || y > ctx->presentation.video_h) { 302 av_log(avctx, AV_LOG_ERROR, "Subtitle out of video bounds. x = %d, y = %d, video width = %d, video height = %d.\n", 303 x, y, ctx->presentation.video_w, ctx->presentation.video_h); 304 x = 0; y = 0; 305 } 306 307 /* Fill in dimensions */ 308 ctx->presentation.x = x; 309 ctx->presentation.y = y; 310 } else if (block == 0x00) { 311 /* TODO: Blank context as subtitle should not be displayed. 312 * If the subtitle is blanked now the subtitle is not 313 * on screen long enough to read, due to a delay in 314 * initial display timing. 315 */ 316 } 317} 318 319/** 320 * Parses the display segment packet. 321 * 322 * The display segment controls the updating of the display. 323 * 324 * @param avctx contains the current codec context 325 * @param data pointer to the data pertaining the subtitle to display 326 * @param buf pointer to the packet to process 327 * @param buf_size size of packet to process 328 * @todo TODO: Fix start time, relies on correct PTS, currently too late 329 * 330 * @todo TODO: Fix end time, normally cleared by a second display 331 * @todo segment, which is currently ignored as it clears 332 * @todo the subtitle too early. 333 */ 334static int display_end_segment(AVCodecContext *avctx, void *data, 335 const uint8_t *buf, int buf_size) 336{ 337 AVSubtitle *sub = data; 338 PGSSubContext *ctx = avctx->priv_data; 339 340 /* 341 * The end display time is a timeout value and is only reached 342 * if the next subtitle is later then timeout or subtitle has 343 * not been cleared by a subsequent empty display command. 344 */ 345 346 memset(sub, 0, sizeof(*sub)); 347 sub->start_display_time = 0; 348 sub->end_display_time = 20000; 349 sub->format = 0; 350 351 sub->rects = av_mallocz(sizeof(*sub->rects)); 352 sub->rects[0] = av_mallocz(sizeof(*sub->rects[0])); 353 sub->num_rects = 1; 354 355 sub->rects[0]->x = ctx->presentation.x; 356 sub->rects[0]->y = ctx->presentation.y; 357 sub->rects[0]->w = ctx->picture.w; 358 sub->rects[0]->h = ctx->picture.h; 359 sub->rects[0]->type = SUBTITLE_BITMAP; 360 361 /* Process bitmap */ 362 sub->rects[0]->pict.linesize[0] = ctx->picture.w; 363 364 if (ctx->picture.rle) 365 if(decode_rle(avctx, sub, ctx->picture.rle, ctx->picture.rle_data_len) < 0) 366 return 0; 367 368 /* Allocate memory for colors */ 369 sub->rects[0]->nb_colors = 256; 370 sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE); 371 372 memcpy(sub->rects[0]->pict.data[1], ctx->clut, sub->rects[0]->nb_colors * sizeof(uint32_t)); 373 374 return 1; 375} 376 377static int decode(AVCodecContext *avctx, void *data, int *data_size, 378 AVPacket *avpkt) 379{ 380 const uint8_t *buf = avpkt->data; 381 int buf_size = avpkt->size; 382 383 const uint8_t *buf_end; 384 uint8_t segment_type; 385 int segment_length; 386 387#ifdef DEBUG_PACKET_CONTENTS 388 int i; 389 390 av_log(avctx, AV_LOG_INFO, "PGS sub packet:\n"); 391 392 for (i = 0; i < buf_size; i++) { 393 av_log(avctx, AV_LOG_INFO, "%02x ", buf[i]); 394 if (i % 16 == 15) 395 av_log(avctx, AV_LOG_INFO, "\n"); 396 } 397 398 if (i & 15) 399 av_log(avctx, AV_LOG_INFO, "\n"); 400#endif 401 402 *data_size = 0; 403 404 /* Ensure that we have received at a least a segment code and segment length */ 405 if (buf_size < 3) 406 return -1; 407 408 buf_end = buf + buf_size; 409 410 /* Step through buffer to identify segments */ 411 while (buf < buf_end) { 412 segment_type = bytestream_get_byte(&buf); 413 segment_length = bytestream_get_be16(&buf); 414 415 dprintf(avctx, "Segment Length %d, Segment Type %x\n", segment_length, segment_type); 416 417 if (segment_type != DISPLAY_SEGMENT && segment_length > buf_end - buf) 418 break; 419 420 switch (segment_type) { 421 case PALETTE_SEGMENT: 422 parse_palette_segment(avctx, buf, segment_length); 423 break; 424 case PICTURE_SEGMENT: 425 parse_picture_segment(avctx, buf, segment_length); 426 break; 427 case PRESENTATION_SEGMENT: 428 parse_presentation_segment(avctx, buf, segment_length); 429 break; 430 case WINDOW_SEGMENT: 431 /* 432 * Window Segment Structure (No new information provided): 433 * 2 bytes: Unkown, 434 * 2 bytes: X position of subtitle, 435 * 2 bytes: Y position of subtitle, 436 * 2 bytes: Width of subtitle, 437 * 2 bytes: Height of subtitle. 438 */ 439 break; 440 case DISPLAY_SEGMENT: 441 *data_size = display_end_segment(avctx, data, buf, segment_length); 442 break; 443 default: 444 av_log(avctx, AV_LOG_ERROR, "Unknown subtitle segment type 0x%x, length %d\n", 445 segment_type, segment_length); 446 break; 447 } 448 449 buf += segment_length; 450 } 451 452 return buf_size; 453} 454 455AVCodec pgssub_decoder = { 456 "pgssub", 457 AVMEDIA_TYPE_SUBTITLE, 458 CODEC_ID_HDMV_PGS_SUBTITLE, 459 sizeof(PGSSubContext), 460 init_decoder, 461 NULL, 462 close_decoder, 463 decode, 464 .long_name = NULL_IF_CONFIG_SMALL("HDMV Presentation Graphic Stream subtitles"), 465}; 466