libavcodec/pgssubdec.c

   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 libavcodec/pgssubdec.c
  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
  36 enum SegmentType {
  37     PALETTE_SEGMENT      = 0x14,
  38     PICTURE_SEGMENT      = 0x15,
  39     PRESENTATION_SEGMENT = 0x16,
  40     WINDOW_SEGMENT       = 0x17,
  41     DISPLAY_SEGMENT      = 0x80,
  42 };
  43
  44 typedef struct PGSSubPresentation {
  45     int x;
  46     int y;
  47     int video_w;
  48     int video_h;
  49     int id_number;
  50 } PGSSubPresentation;
  51
  52 typedef struct PGSSubPicture {
  53     int          w;
  54     int          h;
  55     uint8_t      *rle;
  56     unsigned int rle_buffer_size, rle_data_len;
  57 } PGSSubPicture;
  58
  59 typedef struct PGSSubContext {
  60     PGSSubPresentation presentation;
  61     uint32_t           clut[256];
  62     PGSSubPicture      picture;
  63 } PGSSubContext;
  64
  65 static av_cold int init_decoder(AVCodecContext *avctx)
  66 {
  67     avctx->pix_fmt     = PIX_FMT_RGB32;
  68
  69     return 0;
  70 }
  71
  72 static 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  */
  92 static 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  */
 154 static 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  */
 217 static 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  */
 261 static 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  */
 334 static 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
 377 static 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
 455 AVCodec pgssub_decoder = {
 456     "pgssub",
 457     CODEC_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 };