aboutsummaryrefslogtreecommitdiffstats
path: root/src/sls.cpp
blob: 28b0997ad38efc80ed327c464876935c1e6ae0c6 (plain)
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
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
/*
    Copyright (C) 2014 CSP Innovazione nelle ICT s.c.a r.l. (http://rd.csp.it/)

    Copyright (C) 2014, 2015 Matthias P. Braendli (http://opendigitalradio.org)

    Copyright (C) 2015, 2016, 2017 Stefan Pöschel (http://opendigitalradio.org)

    This program is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    This program 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 General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/
/*!
    \file sls.cpp
    \brief Slideshow related code

    \author Sergio Sagliocco <sergio.sagliocco@csp.it>
    \author Matthias P. Braendli <matthias@mpb.li>
    \author Stefan Pöschel <odr@basicmaster.de>
*/

#include "sls.h"


// --- History -----------------------------------------------------------------
const size_t History::MAXHISTORYLEN   =    50; // How many slides to keep in history


int History::find(const fingerprint_t& fp) const
{
    size_t i;
    for (i = 0; i < m_database.size(); i++) {
        if (m_database[i] == fp) {
            // return the id of fingerprint found
            return m_database[i].fidx;
        }
    }

    // return -1 when the database doesn't contain this fingerprint
    return -1;
}


void History::add(fingerprint_t& fp)
{
    m_database.push_back(fp);

    if (m_database.size() > m_hist_size) {
        m_database.pop_front();
    }
}


void History::disp_database()
{
    size_t id;
    printf("HISTORY DATABASE:\n");
    if (m_database.empty()) {
        printf(" empty\n");
    }
    else {
        for (id = 0; id < m_database.size(); id++) {
            printf(" id %4zu: ", id);
            m_database[id].disp();
        }
    }
    printf("-----------------\n");
}


int History::get_fidx(const char* filepath)
{
    fingerprint_t fp;

    fp.load_from_file(filepath);

    int idx = find(fp);

    if (idx < 0) {
        idx = m_last_given_fidx++;
        fp.fidx = idx;

        if (m_last_given_fidx > SLSManager::MAXSLIDEID) {
            m_last_given_fidx = 0;
        }

        add(fp);
    }

    return idx;
}


// --- MOTHeader -----------------------------------------------------------------
MOTHeader::MOTHeader(size_t body_size, int content_type, int content_subtype)
: header_size(0), data(uint8_vector_t(7, 0x00)) {
    // init header core

    // body size
    data[0] = (body_size >> 20) & 0xFF;
    data[1] = (body_size >> 12) & 0xFF;
    data[2] = (body_size >>  4) & 0xFF;
    data[3] = (body_size <<  4) & 0xF0;

    // header size
    IncrementHeaderSize(data.size());

    // content type
    data[5] |= (content_type << 1) & 0x7E;

    // content subtype
    data[5] |= (content_subtype >> 8) & 0x01;
    data[6] |=  content_subtype       & 0xFF;
}


void MOTHeader::IncrementHeaderSize(size_t size) {
    header_size += size;

    data[3] &= 0xF0;
    data[3] |= (header_size >> 9) & 0x0F;

    data[4]  = (header_size >> 1) & 0xFF;

    data[5] &= 0x7F;
    data[5] |= (header_size << 7) & 0x80;
}


void MOTHeader::AddExtensionFixedSize(int pli, int param_id, const uint8_t* data_field, size_t data_field_len) {
    AddParamHeader(pli, param_id);

    for (size_t i = 0; i < data_field_len; i++)
        data.push_back(data_field[i]);

    IncrementHeaderSize(1 + data_field_len);
}


void MOTHeader::AddExtensionVarSize(int param_id, const uint8_t* data_field, size_t data_field_len) {
    AddParamHeader(0b11, param_id);

    // longer field lens use 15 instead of 7 bits
    bool ext = data_field_len > 127;
    if (ext) {
        data.push_back(0x80 | ((data_field_len >> 8) & 0x7F));
        data.push_back(data_field_len & 0xFF);
    } else {
        data.push_back(data_field_len & 0x7F);
    }

    for (size_t i = 0; i < data_field_len; i++)
        data.push_back(data_field[i]);

    IncrementHeaderSize(1 + (ext ? 2 : 1) + data_field_len);
}


void MOTHeader::AddExtension(int param_id, const uint8_t* data_field, size_t data_field_len) {
    int pli;

    switch(data_field_len) {
    case 0:
        pli = 0b00;
        break;
    case 1:
        pli = 0b01;
        break;
    case 4:
        pli = 0b10;
        break;
    default:
        pli = 0b11;
        break;
    }

    if (pli == 0b11)
        AddExtensionVarSize(param_id, data_field, data_field_len);
    else
        AddExtensionFixedSize(pli, param_id, data_field, data_field_len);
}


// --- SLSManager -----------------------------------------------------------------
const size_t SLSManager::MAXSEGLEN       =  8189; // Bytes (EN 301 234 v2.1.1, ch. 5.1.1)
const size_t SLSManager::MAXSLIDESIZE    = 51200; // Bytes (TS 101 499 v3.1.1, ch. 9.1.2)
const int    SLSManager::MAXSLIDEID      =  9999; // Roll-over value for fidx
const int    SLSManager::MINQUALITY      =    40; // Do not allow the image compressor to go below JPEG quality 40
const std::string SLSManager::SLS_PARAMS_SUFFIX = ".sls_params";


void SLSManager::warnOnSmallerImage(size_t height, size_t width, const std::string& fname) {
    if (height < 240 || width < 320)
        fprintf(stderr, "ODR-PadEnc Warning: Image '%s' smaller than recommended size (%zu x %zu < 320 x 240 px)\n", fname.c_str(), width, height);
}


/*! Scales the image down if needed,
 * so that it is 320x240 pixels.
 * Automatically reduces the quality to make sure the
 * blobsize is not too large.
 *
 * \return the blobsize
 */
#if HAVE_MAGICKWAND
size_t SLSManager::resizeImage(MagickWand* m_wand, unsigned char** blob, const std::string& fname, bool* jfif_not_png)
{
    unsigned char* blob_png;
    unsigned char* blob_jpg;
    size_t blobsize_png;
    size_t blobsize_jpg;

    size_t height = MagickGetImageHeight(m_wand);
    size_t width  = MagickGetImageWidth(m_wand);

    while (height > 240 || width > 320) {
        if (height/240.0 > width/320.0) {
            width = width * 240.0 / height;
            height = 240;
        }
        else {
            height = height * 320.0 / width;
            width = 320;
        }
        MagickResizeImage(m_wand, width, height, LanczosFilter, 1);
    }

    height = MagickGetImageHeight(m_wand);
    width  = MagickGetImageWidth(m_wand);

    // try PNG (zlib level 9 / possibly adaptive filtering)
    MagickSetImageFormat(m_wand, "png");
    MagickSetImageCompressionQuality(m_wand, 95);
    blob_png = MagickGetImageBlob(m_wand, &blobsize_png);

    // try JPG
    MagickSetImageFormat(m_wand, "jpg");

    blob_jpg = NULL;
    int quality_jpg = 100;
    do {
        free(blob_jpg);
        quality_jpg -= 5;

        MagickSetImageCompressionQuality(m_wand, quality_jpg);
        blob_jpg = MagickGetImageBlob(m_wand, &blobsize_jpg);
    } while (blobsize_jpg > MAXSLIDESIZE && quality_jpg > MINQUALITY);


    // check for max size
    if (blobsize_png > MAXSLIDESIZE && blobsize_jpg > MAXSLIDESIZE) {
        fprintf(stderr, "ODR-PadEnc: Image Size too large after compression: %zu bytes (PNG), %zu bytes (JPEG)\n",
                blobsize_png, blobsize_jpg);
        free(blob_png);
        free(blob_jpg);
        return 0;
    }

    // choose the smaller one (at least one does not exceed the max size)
    *jfif_not_png = blobsize_jpg < blobsize_png;

    if (verbose) {
        if (*jfif_not_png)
            fprintf(stderr, "ODR-PadEnc resized image to %zu x %zu. Size after compression %zu bytes (JPEG, q=%d; PNG was %zu bytes)\n",
                    width, height, blobsize_jpg, quality_jpg, blobsize_png);
        else
            fprintf(stderr, "ODR-PadEnc resized image to %zu x %zu. Size after compression %zu bytes (PNG; JPEG was %zu bytes)\n",
                    width, height, blobsize_png, blobsize_jpg);
    }

    // warn if resized image smaller than default dimension
    warnOnSmallerImage(height, width, fname);

    free(*jfif_not_png ? blob_png : blob_jpg);
    *blob = *jfif_not_png ? blob_jpg : blob_png;
    return *jfif_not_png ? blobsize_jpg : blobsize_png;
}
#endif


int SLSManager::encodeFile(const std::string& fname, int fidx, bool raw_slides)
{
    int ret = 0;
    int nseg, lastseglen, i, last, curseglen;
#if HAVE_MAGICKWAND
    MagickWand *m_wand = NULL;
    MagickBooleanType err;
#endif
    size_t blobsize, height, width;
    bool jpeg_progr;
    unsigned char *blob = NULL;
    unsigned char *curseg = NULL;
    MSCDG msc;
    DATA_GROUP* dgli;
    DATA_GROUP* mscdg;

    size_t orig_quality;
    char*  orig_format = NULL;
    /*! We handle JPEG differently, because we want to avoid recompressing the
     * image if it is suitable as is
     */
    bool orig_is_jpeg = false;

    /*! If the original is a PNG, we transmit it as is, if the resolution is correct
     * and the file is not too large. Otherwise it gets resized and sent as JPEG.
     */
    bool orig_is_png = false;

    /*! By default, we do resize the image to 320x240, with a quality such that
     * the blobsize is at most MAXSLIDESIZE.
     *
     * For JPEG input files that are already at the right resolution and at the
     * right blobsize, we disable this to avoid quality loss due to recompression
     *
     * As device support of this feature is optional, we furthermore require JPEG input
     * files to not have progressive coding.
     */
    bool resize_required = true;

    bool jfif_not_png = true;

    if (!raw_slides) {
#if HAVE_MAGICKWAND

        m_wand = NewMagickWand();

        err = MagickReadImage(m_wand, fname.c_str());
        if (err == MagickFalse) {
            fprintf(stderr, "ODR-PadEnc Error: Unable to load image '%s'\n",
                    fname.c_str());

            goto encodefile_out;
        }

        height       = MagickGetImageHeight(m_wand);
        width        = MagickGetImageWidth(m_wand);
        orig_format  = MagickGetImageFormat(m_wand);
        jpeg_progr   = MagickGetImageInterlaceScheme(m_wand) == JPEGInterlace;

        // By default assume that the image has full quality and can be reduced
        orig_quality = 100;

        // strip unneeded information (profiles, meta data)
        MagickStripImage(m_wand);

        if (orig_format) {
            if (strcmp(orig_format, "JPEG") == 0) {
                orig_quality = MagickGetImageCompressionQuality(m_wand);
                orig_is_jpeg = true;

                if (verbose) {
                    fprintf(stderr, "ODR-PadEnc image: '%s' (id=%d)."
                            " Original size: %zu x %zu. (%s, q=%zu, progr=%s)\n",
                            fname.c_str(), fidx, width, height, orig_format, orig_quality, jpeg_progr ? "y" : "n");
                }
            }
            else if (strcmp(orig_format, "PNG") == 0) {
                orig_is_png = true;
                jfif_not_png = false;

                if (verbose) {
                    fprintf(stderr, "ODR-PadEnc image: '%s' (id=%d)."
                            " Original size: %zu x %zu. (%s)\n",
                            fname.c_str(), fidx, width, height, orig_format);
                }
            }
            else if (verbose) {
                fprintf(stderr, "ODR-PadEnc image: '%s' (id=%d)."
                        " Original size: %zu x %zu. (%s)\n",
                        fname.c_str(), fidx, width, height, orig_format);
            }

            free(orig_format);
        }
        else {
            fprintf(stderr, "ODR-PadEnc Warning: Unable to detect image format of '%s'\n",
                    fname.c_str());

            fprintf(stderr, "ODR-PadEnc image: '%s' (id=%d).  Original size: %zu x %zu.\n",
                    fname.c_str(), fidx, width, height);
        }

        if ((orig_is_jpeg || orig_is_png) && height <= 240 && width <= 320 && not jpeg_progr) {
            // Don't recompress the image and check if the blobsize is suitable
            blob = MagickGetImageBlob(m_wand, &blobsize);

            if (blobsize <= MAXSLIDESIZE) {
                if (verbose) {
                    fprintf(stderr, "ODR-PadEnc image: '%s' (id=%d).  No resize needed: %zu Bytes\n",
                            fname.c_str(), fidx, blobsize);
                }
                resize_required = false;
            }
        }

        if (resize_required) {
            blobsize = resizeImage(m_wand, &blob, fname, &jfif_not_png);
        }
        else {
            // warn if unresized image smaller than default dimension
            warnOnSmallerImage(height, width, fname);
        }

#else
        fprintf(stderr, "ODR-PadEnc has not been compiled with MagickWand, only RAW slides are supported!\n");
        ret = -1;
        goto encodefile_out;
#endif
    }
    else { // Use RAW data, it might not even be a jpg !
        // read file
        FILE* pFile = fopen(fname.c_str(), "rb");
        if (pFile == NULL) {
            fprintf(stderr, "ODR-PadEnc Error: Unable to load file '%s'\n",
                    fname.c_str());
            goto encodefile_out;
        }

        // obtain file size:
        fseek(pFile, 0, SEEK_END);
        blobsize = ftell(pFile);
        rewind(pFile);

        if (verbose) {
            fprintf(stderr, "ODR-PadEnc image: '%s' (id=%d). Raw file: %zu Bytes\n",
                    fname.c_str(), fidx, blobsize);
        }

        if (blobsize > MAXSLIDESIZE) {
            fprintf(stderr, "ODR-PadEnc Warning: blob in raw-slide '%s' too large\n",
                    fname.c_str());
        }

        // allocate memory to contain the whole file:
        blob = (unsigned char*)malloc(sizeof(char) * blobsize);
        if (blob == NULL) {
            fprintf(stderr, "ODR-PadEnc Error: Memory allocation error\n");
            goto encodefile_out;
        }

        // copy the file into the buffer:
        if (fread(blob, blobsize, 1, pFile) != 1) {
            fprintf(stderr, "ODR-PadEnc Error: Could not read file\n");
            goto encodefile_out;
        }

        size_t last_dot = fname.rfind(".");

        // default:
        jfif_not_png = true; // This is how we did it in the past.
                             // It's wrong anyway, so we're at least compatible

        if (last_dot != std::string::npos) {
            std::string file_extension = fname.substr(last_dot, std::string::npos);

            std::transform(file_extension.begin(), file_extension.end(), file_extension.begin(), ::tolower);

            if (file_extension == ".png") {
                jfif_not_png = false;
            }
        }

        if (pFile != NULL) {
            fclose(pFile);
        }
    }

    if (blobsize) {
        nseg = blobsize / MAXSEGLEN;
        lastseglen = blobsize % MAXSEGLEN;
        if (lastseglen != 0) {
            nseg++;
        }

        uint8_vector_t mothdr = createMotHeader(blobsize, fidx, jfif_not_png, fname + SLS_PARAMS_SUFFIX);
        // Create the MSC Data Group C-Structure
        createMscDG(&msc, 3, &cindex_header, 0, 1, fidx, &mothdr[0], mothdr.size());
        // Generate the MSC DG frame (Figure 9 en 300 401)
        mscdg = packMscDG(&msc);
        dgli = PADPacketizer::CreateDataGroupLengthIndicator(mscdg->data.size());

        pad_packetizer->AddDG(dgli, false);
        pad_packetizer->AddDG(mscdg, false);

        for (i = 0; i < nseg; i++) {
            curseg = blob + i * MAXSEGLEN;
            if (i == nseg-1) {
                curseglen = lastseglen;
                last = 1;
            }
            else {
                curseglen = MAXSEGLEN;
                last = 0;
            }

            createMscDG(&msc, 4, &cindex_body, i, last, fidx, curseg, curseglen);
            mscdg = packMscDG(&msc);
            dgli = PADPacketizer::CreateDataGroupLengthIndicator(mscdg->data.size());

            pad_packetizer->AddDG(dgli, false);
            pad_packetizer->AddDG(mscdg, false);
        }

        ret = 1;
    }

encodefile_out:
#if HAVE_MAGICKWAND
    if (m_wand) {
        m_wand = DestroyMagickWand(m_wand);
    }
#endif

    if (blob) {
        free(blob);
    }
    return ret;
}


bool SLSManager::parse_sls_param_id(const std::string &key, const std::string &value, uint8_t &target) {
    int value_int = atoi(value.c_str());
    if (value_int >= 0x00 && value_int <= 0xFF) {
        target = value_int;
        return true;
    }
    fprintf(stderr, "ODR-PadEnc Warning: SLS parameter '%s' %d out of range - ignored\n", key.c_str(), value_int);
    return false;
}


bool SLSManager::check_sls_param_len(const std::string &key, size_t len, size_t len_max) {
    if (len <= len_max)
        return true;
    fprintf(stderr, "ODR-PadEnc Warning: SLS parameter '%s' exceeds its maximum length (%zu > %zu) - ignored\n", key.c_str(), len, len_max);
    return false;
}


void SLSManager::process_mot_params_file(MOTHeader& header, const std::string &params_fname) {
    std::ifstream params_fstream(params_fname);
    if (!params_fstream.is_open())
        return;

    std::string line;
    while (std::getline(params_fstream, line)) {
        // ignore empty lines and comments
        if (line.empty() || line[0] == '#')
            continue;

        // parse key/value pair
        size_t separator_pos = line.find('=');
        if (separator_pos == std::string::npos) {
            fprintf(stderr, "ODR-PadEnc Warning: SLS parameter line '%s' without separator - ignored\n", line.c_str());
            continue;
        }
        std::string key = line.substr(0, separator_pos);
        std::string value = line.substr(separator_pos + 1);
#ifdef DEBUG
        fprintf(stderr, "process_mot_params_file: key: '%s', value: '%s'\n", key.c_str(), value.c_str());
#endif

        if (key == "CategoryID/SlideID") {
            // split value
            std::vector<std::string> params = split_string(value, ' ');
            if (params.size() != 2) {
                fprintf(stderr, "ODR-PadEnc Warning: SLS parameter CategoryID/SlideID value '%s' does not have two parts - ignored\n", value.c_str());
                continue;
            }

            uint8_t id_param[2];
            if (parse_sls_param_id("CategoryID", params[0], id_param[0]) &
                parse_sls_param_id("SlideID", params[1], id_param[1])) {
                header.AddExtension(0x25, id_param, sizeof(id_param));
                if (verbose)
                    fprintf(stderr, "ODR-PadEnc SLS parameter: CategoryID = %d / SlideID = %d\n", id_param[0], id_param[1]);
            }
            continue;
        }
        if (key == "CategoryTitle") {
            if(!check_sls_param_len("CategoryTitle", value.length(), 128))
                continue;

            header.AddExtension(0x26, (uint8_t*) value.c_str(), value.length());
            if (verbose)
                fprintf(stderr, "ODR-PadEnc SLS parameter: CategoryTitle = '%s'\n", value.c_str());
            continue;
        }
        if (key == "ClickThroughURL") {
            if(!check_sls_param_len("ClickThroughURL", value.length(), 512))
                continue;

            header.AddExtension(0x27, (uint8_t*) value.c_str(), value.length());
            if (verbose)
                fprintf(stderr, "ODR-PadEnc SLS parameter: ClickThroughURL = '%s'\n", value.c_str());
            continue;
        }
        if (key == "AlternativeLocationURL") {
            if(!check_sls_param_len("AlternativeLocationURL", value.length(), 512))
                continue;

            header.AddExtension(0x28, (uint8_t*) value.c_str(), value.length());
            if (verbose)
                fprintf(stderr, "ODR-PadEnc SLS parameter: AlternativeLocationURL = '%s'\n", value.c_str());
            continue;
        }

        fprintf(stderr, "ODR-PadEnc Warning: SLS parameter '%s' unknown - ignored\n", key.c_str());
    }
}


uint8_vector_t SLSManager::createMotHeader(size_t blobsize, int fidx, bool jfif_not_png, const std::string &params_fname)
{
    // prepare ContentName
    uint8_t cntemp[10];     // = 1 + 8 + 1 = charset + name + terminator
    cntemp[0] = (uint8_t) DABCharset::COMPLETE_EBU_LATIN << 4;
    snprintf((char*) (cntemp + 1), sizeof(cntemp) - 1, "%04d.%s", fidx, jfif_not_png ? "jpg" : "png");

    // MOT header - content type: image, content subtype: JFIF / PNG
    MOTHeader header(blobsize, 0x02, jfif_not_png ? 0x001 : 0x003);

    // TriggerTime: NOW
    uint8_t triggertime_now[4] = {0x00};
    header.AddExtension(0x05, triggertime_now, sizeof(triggertime_now));

    // ContentName: XXXX.jpg / XXXX.png
    header.AddExtension(0x0C, cntemp, sizeof(cntemp) - 1);   // omit terminator

    // process params file if present
    process_mot_params_file(header, params_fname);

    if (verbose)
        fprintf(stderr, "ODR-PadEnc writing image as '%s'\n", cntemp + 1);

    return header.GetData();
}


void SLSManager::createMscDG(MSCDG* msc, unsigned short int dgtype,
        int *cindex, unsigned short int segnum, unsigned short int lastseg,
        unsigned short int tid, unsigned char* data,
        unsigned short int datalen)
{
    msc->extflag = 0;
    msc->crcflag = 1;
    msc->segflag = 1;
    msc->accflag = 1;
    msc->dgtype = dgtype;
    msc->cindex = *cindex;
    msc->rindex = 0;
    msc->last = lastseg;
    msc->segnum = segnum;
    msc->rfa = 0;
    msc->tidflag = 1;
    msc->lenid = 2;
    msc->tid = tid;
    msc->segdata = data;
    msc->rcount = 0;
    msc->seglen = datalen;

    *cindex = (*cindex + 1) % 16;   // increment continuity index
}


DATA_GROUP* SLSManager::packMscDG(MSCDG* msc)
{
    DATA_GROUP* dg = new DATA_GROUP(9 + msc->seglen, 12, 13);
    uint8_vector_t &b = dg->data;

    // headers
    b[0] = (msc->extflag<<7) | (msc->crcflag<<6) | (msc->segflag<<5) |
           (msc->accflag<<4) | msc->dgtype;

    b[1] = (msc->cindex<<4) | msc->rindex;
    b[2] = (msc->last<<7) | ((msc->segnum & 0x7F00) >> 8);
    b[3] =  msc->segnum & 0x00FF;
    b[4] = 0;
    b[4] = (msc->rfa << 5) | (msc->tidflag << 4) | msc->lenid;
    b[5] = (msc->tid & 0xFF00) >> 8;
    b[6] =  msc->tid & 0x00FF;
    b[7] = (msc->rcount << 5) | ((msc->seglen & 0x1F00)>>8);
    b[8] =  msc->seglen & 0x00FF;

    // data field
    memcpy(&b[9], msc->segdata, msc->seglen);

    // CRC
    dg->AppendCRC();

    return dg;
}