aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/pgssubdec.c
blob: d0d4dd6aff0bebd29ec77986ebdf4642dec49fa6 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
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
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
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
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
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
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
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
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
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
435
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
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
/*
 * 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
 */

/**
 * @file
 * PGS subtitle decoder
 */

#include "avcodec.h"
#include "dsputil.h"
#include "bytestream.h"
#include "libavutil/colorspace.h"
#include "libavutil/imgutils.h"
#include "libavutil/opt.h"

#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 PGSSubPictureReference {
    int x;
    int y;
    int picture_id;
    int composition;
} PGSSubPictureReference;

typedef struct PGSSubPresentation {
    int                    id_number;
    int                    object_count;
    PGSSubPictureReference *objects;
} PGSSubPresentation;

typedef struct PGSSubPicture {
    int          w;
    int          h;
    uint8_t      *rle;
    unsigned int rle_buffer_size, rle_data_len;
    unsigned int rle_remaining_len;
} PGSSubPicture;

typedef struct PGSSubContext {
    AVClass *class;
    PGSSubPresentation presentation;
    uint32_t           clut[256];
    PGSSubPicture      pictures[UINT16_MAX];
    int64_t            pts;
    int forced_subs_only;
} PGSSubContext;

static av_cold int init_decoder(AVCodecContext *avctx)
{
    avctx->pix_fmt     = AV_PIX_FMT_PAL8;

    return 0;
}

static av_cold int close_decoder(AVCodecContext *avctx)
{
    uint16_t picture;

    PGSSubContext *ctx = avctx->priv_data;

    av_freep(&ctx->presentation.objects);
    ctx->presentation.object_count = 0;

    for (picture = 0; picture < UINT16_MAX; ++picture) {
        av_freep(&ctx->pictures[picture].rle);
        ctx->pictures[picture].rle_buffer_size = 0;
    }

    return 0;
}

/**
 * Decode the RLE data.
 *
 * 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, int rect,
                      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[rect]->pict.data[0] = av_malloc(sub->rects[rect]->w * sub->rects[rect]->h);

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

    pixel_count = 0;
    line_count  = 0;

    while (buf < rle_bitmap_end && line_count < sub->rects[rect]->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[rect]->w * sub->rects[rect]->h) {
            memset(sub->rects[rect]->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[rect]->w > 0)
                av_log(avctx, AV_LOG_ERROR, "Decoded %d pixels, when line should be %d pixels\n",
                       pixel_count % sub->rects[rect]->w, sub->rects[rect]->w);
            line_count++;
        }
    }

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

    av_dlog(avctx, "Pixel Count = %d, Area = %d\n", pixel_count, sub->rects[rect]->w * sub->rects[rect]->h);

    return 0;
}

/**
 * Parse the picture segment packet.
 *
 * 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;
    uint16_t picture_id;

    if (buf_size <= 4)
        return -1;
    buf_size -= 4;

    picture_id = bytestream_get_be16(&buf);

    /* skip 1 unknown byte: Version Number */
    buf++;

    /* 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)) {
        /* Additional RLE data */
        if (buf_size > ctx->pictures[picture_id].rle_remaining_len)
            return -1;

        memcpy(ctx->pictures[picture_id].rle + ctx->pictures[picture_id].rle_data_len, buf, buf_size);
        ctx->pictures[picture_id].rle_data_len += buf_size;
        ctx->pictures[picture_id].rle_remaining_len -= buf_size;

        return 0;
    }

    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;

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

    /* Make sure the bitmap is not too large */
    if (avctx->width < width || avctx->height < height) {
        av_log(avctx, AV_LOG_ERROR, "Bitmap dimensions larger than video.\n");
        return -1;
    }

    ctx->pictures[picture_id].w = width;
    ctx->pictures[picture_id].h = height;

    av_fast_malloc(&ctx->pictures[picture_id].rle, &ctx->pictures[picture_id].rle_buffer_size, rle_bitmap_len);

    if (!ctx->pictures[picture_id].rle)
        return -1;

    memcpy(ctx->pictures[picture_id].rle, buf, buf_size);
    ctx->pictures[picture_id].rle_data_len      = buf_size;
    ctx->pictures[picture_id].rle_remaining_len = rle_bitmap_len - buf_size;

    return 0;
}

/**
 * Parse the palette segment packet.
 *
 * 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);
        cb        = bytestream_get_byte(&buf);
        alpha     = bytestream_get_byte(&buf);

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

        av_dlog(avctx, "Color %d := (%d,%d,%d,%d)\n", color_id, r, g, b, alpha);

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

/**
 * Parse the presentation segment packet.
 *
 * 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
 */
static void parse_presentation_segment(AVCodecContext *avctx,
                                       const uint8_t *buf, int buf_size)
{
    PGSSubContext *ctx = avctx->priv_data;

    int w = bytestream_get_be16(&buf);
    int h = bytestream_get_be16(&buf);

    uint16_t object_index;

    av_dlog(avctx, "Video Dimensions %dx%d\n",
            w, h);
    if (av_image_check_size(w, h, 0, avctx) >= 0)
        avcodec_set_dimensions(avctx, w, h);

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

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

    /*
     * Skip 3 bytes of unknown:
     *     state
     *     palette_update_flag (0x80),
     *     palette_id_to_use,
     */
    buf += 3;

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

    /* Verify that enough bytes are remaining for all of the objects. */
    buf_size -= 11;
    if (buf_size < ctx->presentation.object_count * 8) {
        ctx->presentation.object_count = 0;
        return;
    }

    av_freep(&ctx->presentation.objects);
    ctx->presentation.objects = av_malloc(sizeof(PGSSubPictureReference) * ctx->presentation.object_count);
    if (!ctx->presentation.objects) {
        ctx->presentation.object_count = 0;
        return;
    }

    for (object_index = 0; object_index < ctx->presentation.object_count; ++object_index) {
        PGSSubPictureReference *reference = &ctx->presentation.objects[object_index];
        reference->picture_id             = bytestream_get_be16(&buf);

        /* Skip window_id_ref */
        buf++;
        /* composition_flag (0x80 - object cropped, 0x40 - object forced) */
        reference->composition = bytestream_get_byte(&buf);

        reference->x = bytestream_get_be16(&buf);
        reference->y = bytestream_get_be16(&buf);

        /* TODO If cropping, cropping_x, cropping_y, cropping_width, cropping_height (all 2 bytes).*/
        av_dlog(avctx, "Subtitle Placement ID=%d, x=%d, y=%d\n", reference->picture_id, reference->x, reference->y);

        if (reference->x > avctx->width || reference->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",
                   reference->x, reference->y, avctx->width, avctx->height);
            reference->x = 0;
            reference->y = 0;
        }
    }
}

/**
 * Parse the display segment packet.
 *
 * 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;
    int64_t pts;

    uint16_t rect;

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

    pts = ctx->pts != AV_NOPTS_VALUE ? ctx->pts : sub->pts;
    memset(sub, 0, sizeof(*sub));
    sub->pts = pts;
    ctx->pts = AV_NOPTS_VALUE;

    // Blank if last object_count was 0.
    if (!ctx->presentation.object_count)
        return 1;

    sub->start_display_time = 0;
    sub->end_display_time   = 20000;
    sub->format             = 0;

    sub->num_rects = ctx->presentation.object_count;
    sub->rects     = av_mallocz(sizeof(*sub->rects) * sub->num_rects);

    for (rect = 0; rect < sub->num_rects; ++rect) {
        uint16_t picture_id    = ctx->presentation.objects[rect].picture_id;
        sub->rects[rect]       = av_mallocz(sizeof(*sub->rects[rect]));
        sub->rects[rect]->x    = ctx->presentation.objects[rect].x;
        sub->rects[rect]->y    = ctx->presentation.objects[rect].y;
        sub->rects[rect]->w    = ctx->pictures[picture_id].w;
        sub->rects[rect]->h    = ctx->pictures[picture_id].h;
        sub->rects[rect]->type = SUBTITLE_BITMAP;

        /* Process bitmap */
        sub->rects[rect]->pict.linesize[0] = ctx->pictures[picture_id].w;
        if (ctx->pictures[picture_id].rle) {
            if (ctx->pictures[picture_id].rle_remaining_len)
                av_log(avctx, AV_LOG_ERROR, "RLE data length %u is %u bytes shorter than expected\n",
                       ctx->pictures[picture_id].rle_data_len, ctx->pictures[picture_id].rle_remaining_len);
            if (decode_rle(avctx, sub, rect, ctx->pictures[picture_id].rle, ctx->pictures[picture_id].rle_data_len) < 0)
                return 0;
        }

        /* Allocate memory for colors */
        sub->rects[rect]->nb_colors    = 256;
        sub->rects[rect]->pict.data[1] = av_mallocz(AVPALETTE_SIZE);

        /* Copy the forced flag */
        sub->rects[rect]->forced = (ctx->presentation.objects[rect].composition & 0x40) != 0;

        if (!ctx->forced_subs_only || ctx->presentation.objects[rect].composition & 0x40)
        memcpy(sub->rects[rect]->pict.data[1], ctx->clut, sub->rects[rect]->nb_colors * sizeof(uint32_t));
    }

    return 1;
}

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

    const uint8_t *buf_end;
    uint8_t       segment_type;
    int           segment_length;
    int i;

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

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

    if (i & 15)
        av_dlog(avctx, "\n");

    *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);

        av_dlog(avctx, "Segment Length %d, Segment Type %x\n", segment_length, segment_type);

        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);
            ctx->pts = sub->pts;
            break;
        case WINDOW_SEGMENT:
            /*
             * Window Segment Structure (No new information provided):
             *     2 bytes: Unknown,
             *     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;
}

#define OFFSET(x) offsetof(PGSSubContext, x)
#define SD AV_OPT_FLAG_SUBTITLE_PARAM | AV_OPT_FLAG_DECODING_PARAM
static const AVOption options[] = {
    {"forced_subs_only", "Only show forced subtitles", OFFSET(forced_subs_only), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 1, SD},
    { NULL },
};

static const AVClass pgsdec_class = {
    .class_name = "PGS subtitle decoder",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
};

AVCodec ff_pgssub_decoder = {
    .name           = "pgssub",
    .type           = AVMEDIA_TYPE_SUBTITLE,
    .id             = AV_CODEC_ID_HDMV_PGS_SUBTITLE,
    .priv_data_size = sizeof(PGSSubContext),
    .init           = init_decoder,
    .close          = close_decoder,
    .decode         = decode,
    .long_name      = NULL_IF_CONFIG_SMALL("HDMV Presentation Graphic Stream subtitles"),
    .priv_class     = &pgsdec_class,
};