pgssubdec.c 14.1 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
/*
 * PGS subtitle decoder
 * Copyright (c) 2009 Stephen Backway
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
23
 * @file
24 25 26 27 28 29
 * PGS subtitle decoder
 */

#include "avcodec.h"
#include "dsputil.h"
#include "bytestream.h"
30
#include "libavutil/colorspace.h"
31
#include "libavutil/imgutils.h"
32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48

//#define DEBUG_PACKET_CONTENTS

#define RGBA(r,g,b,a) (((a) << 24) | ((r) << 16) | ((g) << 8) | (b))

enum SegmentType {
    PALETTE_SEGMENT      = 0x14,
    PICTURE_SEGMENT      = 0x15,
    PRESENTATION_SEGMENT = 0x16,
    WINDOW_SEGMENT       = 0x17,
    DISPLAY_SEGMENT      = 0x80,
};

typedef struct PGSSubPresentation {
    int x;
    int y;
    int id_number;
49
    int object_number;
50 51 52 53 54 55 56
} PGSSubPresentation;

typedef struct PGSSubPicture {
    int          w;
    int          h;
    uint8_t      *rle;
    unsigned int rle_buffer_size, rle_data_len;
57
    unsigned int rle_remaining_len;
58 59 60 61 62 63 64 65 66 67
} PGSSubPicture;

typedef struct PGSSubContext {
    PGSSubPresentation presentation;
    uint32_t           clut[256];
    PGSSubPicture      picture;
} PGSSubContext;

static av_cold int init_decoder(AVCodecContext *avctx)
{
68
    avctx->pix_fmt = PIX_FMT_PAL8;
69 70 71 72 73 74 75 76 77 78 79 80 81 82 83

    return 0;
}

static av_cold int close_decoder(AVCodecContext *avctx)
{
    PGSSubContext *ctx = avctx->priv_data;

    av_freep(&ctx->picture.rle);
    ctx->picture.rle_buffer_size  = 0;

    return 0;
}

/**
84
 * Decode the RLE data.
85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138
 *
 * The subtitle is stored as an Run Length Encoded image.
 *
 * @param avctx contains the current codec context
 * @param sub pointer to the processed subtitle data
 * @param buf pointer to the RLE data to process
 * @param buf_size size of the RLE data to process
 */
static int decode_rle(AVCodecContext *avctx, AVSubtitle *sub,
                      const uint8_t *buf, unsigned int buf_size)
{
    const uint8_t *rle_bitmap_end;
    int pixel_count, line_count;

    rle_bitmap_end = buf + buf_size;

    sub->rects[0]->pict.data[0] = av_malloc(sub->rects[0]->w * sub->rects[0]->h);

    if (!sub->rects[0]->pict.data[0])
        return -1;

    pixel_count = 0;
    line_count  = 0;

    while (buf < rle_bitmap_end && line_count < sub->rects[0]->h) {
        uint8_t flags, color;
        int run;

        color = bytestream_get_byte(&buf);
        run   = 1;

        if (color == 0x00) {
            flags = bytestream_get_byte(&buf);
            run   = flags & 0x3f;
            if (flags & 0x40)
                run = (run << 8) + bytestream_get_byte(&buf);
            color = flags & 0x80 ? bytestream_get_byte(&buf) : 0;
        }

        if (run > 0 && pixel_count + run <= sub->rects[0]->w * sub->rects[0]->h) {
            memset(sub->rects[0]->pict.data[0] + pixel_count, color, run);
            pixel_count += run;
        } else if (!run) {
            /*
             * New Line. Check if correct pixels decoded, if not display warning
             * and adjust bitmap pointer to correct new line position.
             */
            if (pixel_count % sub->rects[0]->w > 0)
                av_log(avctx, AV_LOG_ERROR, "Decoded %d pixels, when line should be %d pixels\n",
                       pixel_count % sub->rects[0]->w, sub->rects[0]->w);
            line_count++;
        }
    }

139 140 141 142 143
    if (pixel_count < sub->rects[0]->w * sub->rects[0]->h) {
        av_log(avctx, AV_LOG_ERROR, "Insufficient RLE data for subtitle\n");
        return -1;
    }

144
    av_dlog(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, sub->rects[0]->w * sub->rects[0]->h);
145 146 147 148 149

    return 0;
}

/**
150
 * Parse the picture segment packet.
151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167
 *
 * The picture segment contains details on the sequence id,
 * width, height and Run Length Encoded (RLE) bitmap data.
 *
 * @param avctx contains the current codec context
 * @param buf pointer to the packet to process
 * @param buf_size size of packet to process
 * @todo TODO: Enable support for RLE data over multiple packets
 */
static int parse_picture_segment(AVCodecContext *avctx,
                                  const uint8_t *buf, int buf_size)
{
    PGSSubContext *ctx = avctx->priv_data;

    uint8_t sequence_desc;
    unsigned int rle_bitmap_len, width, height;

168 169 170 171
    if (buf_size <= 4)
        return -1;
    buf_size -= 4;

172 173 174 175 176 177 178
    /* skip 3 unknown bytes: Object ID (2 bytes), Version Number */
    buf += 3;

    /* Read the Sequence Description to determine if start of RLE data or appended to previous RLE */
    sequence_desc = bytestream_get_byte(&buf);

    if (!(sequence_desc & 0x80)) {
179 180 181
        /* Additional RLE data */
        if (buf_size > ctx->picture.rle_remaining_len)
            return -1;
182

183 184
        memcpy(ctx->picture.rle + ctx->picture.rle_data_len, buf, buf_size);
        ctx->picture.rle_data_len += buf_size;
185
        ctx->picture.rle_remaining_len -= buf_size;
186

187
        return 0;
188 189
    }

190 191 192 193 194 195
    if (buf_size <= 7)
        return -1;
    buf_size -= 7;

    /* Decode rle bitmap length, stored size includes width/height data */
    rle_bitmap_len = bytestream_get_be24(&buf) - 2*2;
196 197 198 199 200 201

    /* Get bitmap dimensions from data */
    width  = bytestream_get_be16(&buf);
    height = bytestream_get_be16(&buf);

    /* Make sure the bitmap is not too large */
202
    if (avctx->width < width || avctx->height < height) {
203 204 205 206 207 208 209 210 211 212 213 214
        av_log(avctx, AV_LOG_ERROR, "Bitmap dimensions larger then video.\n");
        return -1;
    }

    ctx->picture.w = width;
    ctx->picture.h = height;

    av_fast_malloc(&ctx->picture.rle, &ctx->picture.rle_buffer_size, rle_bitmap_len);

    if (!ctx->picture.rle)
        return -1;

215 216 217
    memcpy(ctx->picture.rle, buf, buf_size);
    ctx->picture.rle_data_len = buf_size;
    ctx->picture.rle_remaining_len = rle_bitmap_len - buf_size;
218 219 220 221 222

    return 0;
}

/**
223
 * Parse the palette segment packet.
224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249
 *
 * The palette segment contains details of the palette,
 * a maximum of 256 colors can be defined.
 *
 * @param avctx contains the current codec context
 * @param buf pointer to the packet to process
 * @param buf_size size of packet to process
 */
static void parse_palette_segment(AVCodecContext *avctx,
                                  const uint8_t *buf, int buf_size)
{
    PGSSubContext *ctx = avctx->priv_data;

    const uint8_t *buf_end = buf + buf_size;
    const uint8_t *cm      = ff_cropTbl + MAX_NEG_CROP;
    int color_id;
    int y, cb, cr, alpha;
    int r, g, b, r_add, g_add, b_add;

    /* Skip two null bytes */
    buf += 2;

    while (buf < buf_end) {
        color_id  = bytestream_get_byte(&buf);
        y         = bytestream_get_byte(&buf);
        cr        = bytestream_get_byte(&buf);
250
        cb        = bytestream_get_byte(&buf);
251 252 253 254 255
        alpha     = bytestream_get_byte(&buf);

        YUV_TO_RGB1(cb, cr);
        YUV_TO_RGB2(r, g, b, y);

256
        av_dlog(avctx, "Color %d := (%d,%d,%d,%d)\n", color_id, r, g, b, alpha);
257 258 259 260 261 262 263

        /* Store color in palette */
        ctx->clut[color_id] = RGBA(r,g,b,alpha);
    }
}

/**
264
 * Parse the presentation segment packet.
265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281
 *
 * The presentation segment contains details on the video
 * width, video height, x & y subtitle position.
 *
 * @param avctx contains the current codec context
 * @param buf pointer to the packet to process
 * @param buf_size size of packet to process
 * @todo TODO: Implement cropping
 * @todo TODO: Implement forcing of subtitles
 */
static void parse_presentation_segment(AVCodecContext *avctx,
                                       const uint8_t *buf, int buf_size)
{
    PGSSubContext *ctx = avctx->priv_data;

    int x, y;

282 283
    int w = bytestream_get_be16(&buf);
    int h = bytestream_get_be16(&buf);
284

285
    av_dlog(avctx, "Video Dimensions %dx%d\n",
286
            w, h);
287
    if (av_image_check_size(w, h, 0, avctx) >= 0)
288
        avcodec_set_dimensions(avctx, w, h);
289 290 291 292 293 294

    /* Skip 1 bytes of unknown, frame rate? */
    buf++;

    ctx->presentation.id_number = bytestream_get_be16(&buf);

Reimar Döffinger's avatar
Reimar Döffinger committed
295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319
    /*
     * Skip 3 bytes of unknown:
     *     state
     *     palette_update_flag (0x80),
     *     palette_id_to_use,
     */
    buf += 3;

    ctx->presentation.object_number = bytestream_get_byte(&buf);
    if (!ctx->presentation.object_number)
        return;

    /*
     * Skip 4 bytes of unknown:
     *     object_id_ref (2 bytes),
     *     window_id_ref,
     *     composition_flag (0x80 - object cropped, 0x40 - object forced)
     */
    buf += 4;

    x = bytestream_get_be16(&buf);
    y = bytestream_get_be16(&buf);

    /* TODO If cropping, cropping_x, cropping_y, cropping_width, cropping_height (all 2 bytes).*/

320
    av_dlog(avctx, "Subtitle Placement x=%d, y=%d\n", x, y);
Reimar Döffinger's avatar
Reimar Döffinger committed
321 322 323 324 325 326

    if (x > avctx->width || y > avctx->height) {
        av_log(avctx, AV_LOG_ERROR, "Subtitle out of video bounds. x = %d, y = %d, video width = %d, video height = %d.\n",
               x, y, avctx->width, avctx->height);
        x = 0; y = 0;
    }
327

Reimar Döffinger's avatar
Reimar Döffinger committed
328 329 330
    /* Fill in dimensions */
    ctx->presentation.x = x;
    ctx->presentation.y = y;
331 332 333
}

/**
334
 * Parse the display segment packet.
335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359
 *
 * The display segment controls the updating of the display.
 *
 * @param avctx contains the current codec context
 * @param data pointer to the data pertaining the subtitle to display
 * @param buf pointer to the packet to process
 * @param buf_size size of packet to process
 * @todo TODO: Fix start time, relies on correct PTS, currently too late
 *
 * @todo TODO: Fix end time, normally cleared by a second display
 * @todo       segment, which is currently ignored as it clears
 * @todo       the subtitle too early.
 */
static int display_end_segment(AVCodecContext *avctx, void *data,
                               const uint8_t *buf, int buf_size)
{
    AVSubtitle    *sub = data;
    PGSSubContext *ctx = avctx->priv_data;

    /*
     *      The end display time is a timeout value and is only reached
     *      if the next subtitle is later then timeout or subtitle has
     *      not been cleared by a subsequent empty display command.
     */

360 361 362 363
    // Blank if last object_number was 0.
    // Note that this may be wrong for more complex subtitles.
    if (!ctx->presentation.object_number)
        return 1;
364 365 366 367
    sub->start_display_time = 0;
    sub->end_display_time   = 20000;
    sub->format             = 0;

Reimar Döffinger's avatar
Reimar Döffinger committed
368 369 370
    sub->rects     = av_mallocz(sizeof(*sub->rects));
    sub->rects[0]  = av_mallocz(sizeof(*sub->rects[0]));
    sub->num_rects = 1;
371 372 373 374 375 376 377 378 379 380

    sub->rects[0]->x    = ctx->presentation.x;
    sub->rects[0]->y    = ctx->presentation.y;
    sub->rects[0]->w    = ctx->picture.w;
    sub->rects[0]->h    = ctx->picture.h;
    sub->rects[0]->type = SUBTITLE_BITMAP;

    /* Process bitmap */
    sub->rects[0]->pict.linesize[0] = ctx->picture.w;

381 382 383 384
    if (ctx->picture.rle) {
        if (ctx->picture.rle_remaining_len)
            av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n",
                   ctx->picture.rle_data_len, ctx->picture.rle_remaining_len);
385 386
        if(decode_rle(avctx, sub, ctx->picture.rle, ctx->picture.rle_data_len) < 0)
            return 0;
387
    }
388 389
    /* Allocate memory for colors */
    sub->rects[0]->nb_colors    = 256;
390
    sub->rects[0]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);
391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434

    memcpy(sub->rects[0]->pict.data[1], ctx->clut, sub->rects[0]->nb_colors * sizeof(uint32_t));

    return 1;
}

static int decode(AVCodecContext *avctx, void *data, int *data_size,
                  AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size       = avpkt->size;

    const uint8_t *buf_end;
    uint8_t       segment_type;
    int           segment_length;

#ifdef DEBUG_PACKET_CONTENTS
    int i;

    av_log(avctx, AV_LOG_INFO, "PGS sub packet:\n");

    for (i = 0; i < buf_size; i++) {
        av_log(avctx, AV_LOG_INFO, "%02x ", buf[i]);
        if (i % 16 == 15)
            av_log(avctx, AV_LOG_INFO, "\n");
    }

    if (i & 15)
        av_log(avctx, AV_LOG_INFO, "\n");
#endif

    *data_size = 0;

    /* Ensure that we have received at a least a segment code and segment length */
    if (buf_size < 3)
        return -1;

    buf_end = buf + buf_size;

    /* Step through buffer to identify segments */
    while (buf < buf_end) {
        segment_type   = bytestream_get_byte(&buf);
        segment_length = bytestream_get_be16(&buf);

435
        av_dlog(avctx, "Segment Length %d, Segment Type %x\n", segment_length, segment_type);
436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474

        if (segment_type != DISPLAY_SEGMENT && segment_length > buf_end - buf)
            break;

        switch (segment_type) {
        case PALETTE_SEGMENT:
            parse_palette_segment(avctx, buf, segment_length);
            break;
        case PICTURE_SEGMENT:
            parse_picture_segment(avctx, buf, segment_length);
            break;
        case PRESENTATION_SEGMENT:
            parse_presentation_segment(avctx, buf, segment_length);
            break;
        case WINDOW_SEGMENT:
            /*
             * Window Segment Structure (No new information provided):
             *     2 bytes: Unkown,
             *     2 bytes: X position of subtitle,
             *     2 bytes: Y position of subtitle,
             *     2 bytes: Width of subtitle,
             *     2 bytes: Height of subtitle.
             */
            break;
        case DISPLAY_SEGMENT:
            *data_size = display_end_segment(avctx, data, buf, segment_length);
            break;
        default:
            av_log(avctx, AV_LOG_ERROR, "Unknown subtitle segment type 0x%x, length %d\n",
                   segment_type, segment_length);
            break;
        }

        buf += segment_length;
    }

    return buf_size;
}

475
AVCodec ff_pgssub_decoder = {
476
    "pgssub",
477
    AVMEDIA_TYPE_SUBTITLE,
478 479 480 481 482 483 484 485
    CODEC_ID_HDMV_PGS_SUBTITLE,
    sizeof(PGSSubContext),
    init_decoder,
    NULL,
    close_decoder,
    decode,
    .long_name = NULL_IF_CONFIG_SMALL("HDMV Presentation Graphic Stream subtitles"),
};