summaryrefslogtreecommitdiff
path: root/libavcodec/truemotion1.c
blob: 97330d1bb41ee109f15dc4578de5d99b995e1333 (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
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
/*
 * Duck TrueMotion 1.0 Decoder
 * Copyright (C) 2003 Alex Beregszaszi & Mike Melanson
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

/**
 * @file
 * Duck TrueMotion v1 Video Decoder by
 * Alex Beregszaszi and
 * Mike Melanson (melanson@pcisys.net)
 *
 * The TrueMotion v1 decoder presently only decodes 16-bit TM1 data and
 * outputs RGB555 (or RGB565) data. 24-bit TM1 data is not supported yet.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#include "avcodec.h"
#include "dsputil.h"
#include "libavutil/imgutils.h"

#include "truemotion1data.h"

typedef struct TrueMotion1Context {
    AVCodecContext *avctx;
    AVFrame frame;

    const uint8_t *buf;
    int size;

    const uint8_t *mb_change_bits;
    int mb_change_bits_row_size;
    const uint8_t *index_stream;
    int index_stream_size;

    int flags;
    int x, y, w, h;

    uint32_t y_predictor_table[1024];
    uint32_t c_predictor_table[1024];
    uint32_t fat_y_predictor_table[1024];
    uint32_t fat_c_predictor_table[1024];

    int compression;
    int block_type;
    int block_width;
    int block_height;

    int16_t ydt[8];
    int16_t cdt[8];
    int16_t fat_ydt[8];
    int16_t fat_cdt[8];

    int last_deltaset, last_vectable;

    unsigned int *vert_pred;
    int vert_pred_size;

} TrueMotion1Context;

#define FLAG_SPRITE         32
#define FLAG_KEYFRAME       16
#define FLAG_INTERFRAME      8
#define FLAG_INTERPOLATED    4

struct frame_header {
    uint8_t header_size;
    uint8_t compression;
    uint8_t deltaset;
    uint8_t vectable;
    uint16_t ysize;
    uint16_t xsize;
    uint16_t checksum;
    uint8_t version;
    uint8_t header_type;
    uint8_t flags;
    uint8_t control;
    uint16_t xoffset;
    uint16_t yoffset;
    uint16_t width;
    uint16_t height;
};

#define ALGO_NOP        0
#define ALGO_RGB16V     1
#define ALGO_RGB16H     2
#define ALGO_RGB24H     3

/* these are the various block sizes that can occupy a 4x4 block */
#define BLOCK_2x2  0
#define BLOCK_2x4  1
#define BLOCK_4x2  2
#define BLOCK_4x4  3

typedef struct comp_types {
    int algorithm;
    int block_width; // vres
    int block_height; // hres
    int block_type;
} comp_types;

/* { valid for metatype }, algorithm, num of deltas, vert res, horiz res */
static const comp_types compression_types[17] = {
    { ALGO_NOP,    0, 0, 0 },

    { ALGO_RGB16V, 4, 4, BLOCK_4x4 },
    { ALGO_RGB16H, 4, 4, BLOCK_4x4 },
    { ALGO_RGB16V, 4, 2, BLOCK_4x2 },
    { ALGO_RGB16H, 4, 2, BLOCK_4x2 },

    { ALGO_RGB16V, 2, 4, BLOCK_2x4 },
    { ALGO_RGB16H, 2, 4, BLOCK_2x4 },
    { ALGO_RGB16V, 2, 2, BLOCK_2x2 },
    { ALGO_RGB16H, 2, 2, BLOCK_2x2 },

    { ALGO_NOP,    4, 4, BLOCK_4x4 },
    { ALGO_RGB24H, 4, 4, BLOCK_4x4 },
    { ALGO_NOP,    4, 2, BLOCK_4x2 },
    { ALGO_RGB24H, 4, 2, BLOCK_4x2 },

    { ALGO_NOP,    2, 4, BLOCK_2x4 },
    { ALGO_RGB24H, 2, 4, BLOCK_2x4 },
    { ALGO_NOP,    2, 2, BLOCK_2x2 },
    { ALGO_RGB24H, 2, 2, BLOCK_2x2 }
};

static void select_delta_tables(TrueMotion1Context *s, int delta_table_index)
{
    int i;

    if (delta_table_index > 3)
        return;

    memcpy(s->ydt, ydts[delta_table_index], 8 * sizeof(int16_t));
    memcpy(s->cdt, cdts[delta_table_index], 8 * sizeof(int16_t));
    memcpy(s->fat_ydt, fat_ydts[delta_table_index], 8 * sizeof(int16_t));
    memcpy(s->fat_cdt, fat_cdts[delta_table_index], 8 * sizeof(int16_t));

    /* Y skinny deltas need to be halved for some reason; maybe the
     * skinny Y deltas should be modified */
    for (i = 0; i < 8; i++)
    {
        /* drop the lsb before dividing by 2-- net effect: round down
         * when dividing a negative number (e.g., -3/2 = -2, not -1) */
        s->ydt[i] &= 0xFFFE;
        s->ydt[i] /= 2;
    }
}

#if HAVE_BIGENDIAN
static int make_ydt15_entry(int p2, int p1, int16_t *ydt)
#else
static int make_ydt15_entry(int p1, int p2, int16_t *ydt)
#endif
{
    int lo, hi;

    lo = ydt[p1];
    lo += (lo << 5) + (lo << 10);
    hi = ydt[p2];
    hi += (hi << 5) + (hi << 10);
    return (lo + (hi << 16)) << 1;
}

static int make_cdt15_entry(int p1, int p2, int16_t *cdt)
{
    int r, b, lo;

    b = cdt[p2];
    r = cdt[p1] << 10;
    lo = b + r;
    return (lo + (lo << 16)) << 1;
}

#if HAVE_BIGENDIAN
static int make_ydt16_entry(int p2, int p1, int16_t *ydt)
#else
static int make_ydt16_entry(int p1, int p2, int16_t *ydt)
#endif
{
    int lo, hi;

    lo = ydt[p1];
    lo += (lo << 6) + (lo << 11);
    hi = ydt[p2];
    hi += (hi << 6) + (hi << 11);
    return (lo + (hi << 16)) << 1;
}

static int make_cdt16_entry(int p1, int p2, int16_t *cdt)
{
    int r, b, lo;

    b = cdt[p2];
    r = cdt[p1] << 11;
    lo = b + r;
    return (lo + (lo << 16)) << 1;
}

static int make_ydt24_entry(int p1, int p2, int16_t *ydt)
{
    int lo, hi;

    lo = ydt[p1];
    hi = ydt[p2];
    return (lo + (hi << 8) + (hi << 16)) << 1;
}

static int make_cdt24_entry(int p1, int p2, int16_t *cdt)
{
    int r, b;

    b = cdt[p2];
    r = cdt[p1]<<16;
    return (b+r) << 1;
}

static void gen_vector_table15(TrueMotion1Context *s, const uint8_t *sel_vector_table)
{
    int len, i, j;
    unsigned char delta_pair;

    for (i = 0; i < 1024; i += 4)
    {
        len = *sel_vector_table++ / 2;
        for (j = 0; j < len; j++)
        {
            delta_pair = *sel_vector_table++;
            s->y_predictor_table[i+j] = 0xfffffffe &
                make_ydt15_entry(delta_pair >> 4, delta_pair & 0xf, s->ydt);
            s->c_predictor_table[i+j] = 0xfffffffe &
                make_cdt15_entry(delta_pair >> 4, delta_pair & 0xf, s->cdt);
        }
        s->y_predictor_table[i+(j-1)] |= 1;
        s->c_predictor_table[i+(j-1)] |= 1;
    }
}

static void gen_vector_table16(TrueMotion1Context *s, const uint8_t *sel_vector_table)
{
    int len, i, j;
    unsigned char delta_pair;

    for (i = 0; i < 1024; i += 4)
    {
        len = *sel_vector_table++ / 2;
        for (j = 0; j < len; j++)
        {
            delta_pair = *sel_vector_table++;
            s->y_predictor_table[i+j] = 0xfffffffe &
                make_ydt16_entry(delta_pair >> 4, delta_pair & 0xf, s->ydt);
            s->c_predictor_table[i+j] = 0xfffffffe &
                make_cdt16_entry(delta_pair >> 4, delta_pair & 0xf, s->cdt);
        }
        s->y_predictor_table[i+(j-1)] |= 1;
        s->c_predictor_table[i+(j-1)] |= 1;
    }
}

static void gen_vector_table24(TrueMotion1Context *s, const uint8_t *sel_vector_table)
{
    int len, i, j;
    unsigned char delta_pair;

    for (i = 0; i < 1024; i += 4)
    {
        len = *sel_vector_table++ / 2;
        for (j = 0; j < len; j++)
        {
            delta_pair = *sel_vector_table++;
            s->y_predictor_table[i+j] = 0xfffffffe &
                make_ydt24_entry(delta_pair >> 4, delta_pair & 0xf, s->ydt);
            s->c_predictor_table[i+j] = 0xfffffffe &
                make_cdt24_entry(delta_pair >> 4, delta_pair & 0xf, s->cdt);
            s->fat_y_predictor_table[i+j] = 0xfffffffe &
                make_ydt24_entry(delta_pair >> 4, delta_pair & 0xf, s->fat_ydt);
            s->fat_c_predictor_table[i+j] = 0xfffffffe &
                make_cdt24_entry(delta_pair >> 4, delta_pair & 0xf, s->fat_cdt);
        }
        s->y_predictor_table[i+(j-1)] |= 1;
        s->c_predictor_table[i+(j-1)] |= 1;
        s->fat_y_predictor_table[i+(j-1)] |= 1;
        s->fat_c_predictor_table[i+(j-1)] |= 1;
    }
}

/* Returns the number of bytes consumed from the bytestream. Returns -1 if
 * there was an error while decoding the header */
static int truemotion1_decode_header(TrueMotion1Context *s)
{
    int i;
    int width_shift = 0;
    int new_pix_fmt;
    struct frame_header header;
    uint8_t header_buffer[128];  /* logical maximum size of the header */
    const uint8_t *sel_vector_table;

    header.header_size = ((s->buf[0] >> 5) | (s->buf[0] << 3)) & 0x7f;
    if (s->buf[0] < 0x10)
    {
        av_log(s->avctx, AV_LOG_ERROR, "invalid header size (%d)\n", s->buf[0]);
        return -1;
    }

    /* unscramble the header bytes with a XOR operation */
    memset(header_buffer, 0, 128);
    for (i = 1; i < header.header_size; i++)
        header_buffer[i - 1] = s->buf[i] ^ s->buf[i + 1];

    header.compression = header_buffer[0];
    header.deltaset = header_buffer[1];
    header.vectable = header_buffer[2];
    header.ysize = AV_RL16(&header_buffer[3]);
    header.xsize = AV_RL16(&header_buffer[5]);
    header.checksum = AV_RL16(&header_buffer[7]);
    header.version = header_buffer[9];
    header.header_type = header_buffer[10];
    header.flags = header_buffer[11];
    header.control = header_buffer[12];

    /* Version 2 */
    if (header.version >= 2)
    {
        if (header.header_type > 3)
        {
            av_log(s->avctx, AV_LOG_ERROR, "invalid header type (%d)\n", header.header_type);
            return -1;
        } else if ((header.header_type == 2) || (header.header_type == 3)) {
            s->flags = header.flags;
            if (!(s->flags & FLAG_INTERFRAME))
                s->flags |= FLAG_KEYFRAME;
        } else
            s->flags = FLAG_KEYFRAME;
    } else /* Version 1 */
        s->flags = FLAG_KEYFRAME;

    if (s->flags & FLAG_SPRITE) {
        av_log_ask_for_sample(s->avctx, "SPRITE frame found.\n");
        /* FIXME header.width, height, xoffset and yoffset aren't initialized */
#if 0
        s->w = header.width;
        s->h = header.height;
        s->x = header.xoffset;
        s->y = header.yoffset;
#else
        return -1;
#endif
    } else {
        s->w = header.xsize;
        s->h = header.ysize;
        if (header.header_type < 2) {
            if ((s->w < 213) && (s->h >= 176))
            {
                s->flags |= FLAG_INTERPOLATED;
                av_log_ask_for_sample(s->avctx, "INTERPOLATION selected.\n");
            }
        }
    }

    if (header.compression >= 17) {
        av_log(s->avctx, AV_LOG_ERROR, "invalid compression type (%d)\n", header.compression);
        return -1;
    }

    if ((header.deltaset != s->last_deltaset) ||
        (header.vectable != s->last_vectable))
        select_delta_tables(s, header.deltaset);

    if ((header.compression & 1) && header.header_type)
        sel_vector_table = pc_tbl2;
    else {
        if (header.vectable > 0 && header.vectable < 4)
            sel_vector_table = tables[header.vectable - 1];
        else {
            av_log(s->avctx, AV_LOG_ERROR, "invalid vector table id (%d)\n", header.vectable);
            return -1;
        }
    }

    if (compression_types[header.compression].algorithm == ALGO_RGB24H) {
        new_pix_fmt = PIX_FMT_RGB32;
        width_shift = 1;
    } else
        new_pix_fmt = PIX_FMT_RGB555; // RGB565 is supported as well

    s->w >>= width_shift;
    if (av_image_check_size(s->w, s->h, 0, s->avctx) < 0)
        return -1;

    if (s->w != s->avctx->width || s->h != s->avctx->height ||
        new_pix_fmt != s->avctx->pix_fmt) {
        if (s->frame.data[0])
            s->avctx->release_buffer(s->avctx, &s->frame);
        s->avctx->sample_aspect_ratio = (AVRational){ 1 << width_shift, 1 };
        s->avctx->pix_fmt = new_pix_fmt;
        avcodec_set_dimensions(s->avctx, s->w, s->h);
        av_fast_malloc(&s->vert_pred, &s->vert_pred_size, s->avctx->width * sizeof(unsigned int));
    }

    /* There is 1 change bit per 4 pixels, so each change byte represents
     * 32 pixels; divide width by 4 to obtain the number of change bits and
     * then round up to the nearest byte. */
    s->mb_change_bits_row_size = ((s->avctx->width >> (2 - width_shift)) + 7) >> 3;

    if ((header.deltaset != s->last_deltaset) || (header.vectable != s->last_vectable))
    {
        if (compression_types[header.compression].algorithm == ALGO_RGB24H)
            gen_vector_table24(s, sel_vector_table);
        else
        if (s->avctx->pix_fmt == PIX_FMT_RGB555)
            gen_vector_table15(s, sel_vector_table);
        else
            gen_vector_table16(s, sel_vector_table);
    }

    /* set up pointers to the other key data chunks */
    s->mb_change_bits = s->buf + header.header_size;
    if (s->flags & FLAG_KEYFRAME) {
        /* no change bits specified for a keyframe; only index bytes */
        s->index_stream = s->mb_change_bits;
    } else {
        /* one change bit per 4x4 block */
        s->index_stream = s->mb_change_bits +
            (s->mb_change_bits_row_size * (s->avctx->height >> 2));
    }
    s->index_stream_size = s->size - (s->index_stream - s->buf);

    s->last_deltaset = header.deltaset;
    s->last_vectable = header.vectable;
    s->compression = header.compression;
    s->block_width = compression_types[header.compression].block_width;
    s->block_height = compression_types[header.compression].block_height;
    s->block_type = compression_types[header.compression].block_type;

    if (s->avctx->debug & FF_DEBUG_PICT_INFO)
        av_log(s->avctx, AV_LOG_INFO, "tables: %d / %d c:%d %dx%d t:%d %s%s%s%s\n",
            s->last_deltaset, s->last_vectable, s->compression, s->block_width,
            s->block_height, s->block_type,
            s->flags & FLAG_KEYFRAME ? " KEY" : "",
            s->flags & FLAG_INTERFRAME ? " INTER" : "",
            s->flags & FLAG_SPRITE ? " SPRITE" : "",
            s->flags & FLAG_INTERPOLATED ? " INTERPOL" : "");

    return header.header_size;
}

static av_cold int truemotion1_decode_init(AVCodecContext *avctx)
{
    TrueMotion1Context *s = avctx->priv_data;

    s->avctx = avctx;

    // FIXME: it may change ?
//    if (avctx->bits_per_sample == 24)
//        avctx->pix_fmt = PIX_FMT_RGB24;
//    else
//        avctx->pix_fmt = PIX_FMT_RGB555;

    s->frame.data[0] = NULL;

    /* there is a vertical predictor for each pixel in a line; each vertical
     * predictor is 0 to start with */
    av_fast_malloc(&s->vert_pred, &s->vert_pred_size, s->avctx->width * sizeof(unsigned int));

    return 0;
}

/*
Block decoding order:

dxi: Y-Y
dxic: Y-C-Y
dxic2: Y-C-Y-C

hres,vres,i,i%vres (0 < i < 4)
2x2 0: 0 dxic2
2x2 1: 1 dxi
2x2 2: 0 dxic2
2x2 3: 1 dxi
2x4 0: 0 dxic2
2x4 1: 1 dxi
2x4 2: 2 dxi
2x4 3: 3 dxi
4x2 0: 0 dxic
4x2 1: 1 dxi
4x2 2: 0 dxic
4x2 3: 1 dxi
4x4 0: 0 dxic
4x4 1: 1 dxi
4x4 2: 2 dxi
4x4 3: 3 dxi
*/

#define GET_NEXT_INDEX() \
{\
    if (index_stream_index >= s->index_stream_size) { \
        av_log(s->avctx, AV_LOG_INFO, " help! truemotion1 decoder went out of bounds\n"); \
        return; \
    } \
    index = s->index_stream[index_stream_index++] * 4; \
}

#define APPLY_C_PREDICTOR() \
    predictor_pair = s->c_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->c_predictor_table[index]; \
            horiz_pred += ((predictor_pair >> 1) * 5); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;

#define APPLY_C_PREDICTOR_24() \
    predictor_pair = s->c_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->fat_c_predictor_table[index]; \
            horiz_pred += (predictor_pair >> 1); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;


#define APPLY_Y_PREDICTOR() \
    predictor_pair = s->y_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->y_predictor_table[index]; \
            horiz_pred += ((predictor_pair >> 1) * 5); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;

#define APPLY_Y_PREDICTOR_24() \
    predictor_pair = s->y_predictor_table[index]; \
    horiz_pred += (predictor_pair >> 1); \
    if (predictor_pair & 1) { \
        GET_NEXT_INDEX() \
        if (!index) { \
            GET_NEXT_INDEX() \
            predictor_pair = s->fat_y_predictor_table[index]; \
            horiz_pred += (predictor_pair >> 1); \
            if (predictor_pair & 1) \
                GET_NEXT_INDEX() \
            else \
                index++; \
        } \
    } else \
        index++;

#define OUTPUT_PIXEL_PAIR() \
    *current_pixel_pair = *vert_pred + horiz_pred; \
    *vert_pred++ = *current_pixel_pair++;

static void truemotion1_decode_16bit(TrueMotion1Context *s)
{
    int y;
    int pixels_left;  /* remaining pixels on this line */
    unsigned int predictor_pair;
    unsigned int horiz_pred;
    unsigned int *vert_pred;
    unsigned int *current_pixel_pair;
    unsigned char *current_line = s->frame.data[0];
    int keyframe = s->flags & FLAG_KEYFRAME;

    /* these variables are for managing the stream of macroblock change bits */
    const unsigned char *mb_change_bits = s->mb_change_bits;
    unsigned char mb_change_byte;
    unsigned char mb_change_byte_mask;
    int mb_change_index;

    /* these variables are for managing the main index stream */
    int index_stream_index = 0;  /* yes, the index into the index stream */
    int index;

    /* clean out the line buffer */
    memset(s->vert_pred, 0, s->avctx->width * sizeof(unsigned int));

    GET_NEXT_INDEX();

    for (y = 0; y < s->avctx->height; y++) {

        /* re-init variables for the next line iteration */
        horiz_pred = 0;
        current_pixel_pair = (unsigned int *)current_line;
        vert_pred = s->vert_pred;
        mb_change_index = 0;
        mb_change_byte = mb_change_bits[mb_change_index++];
        mb_change_byte_mask = 0x01;
        pixels_left = s->avctx->width;

        while (pixels_left > 0) {

            if (keyframe || ((mb_change_byte & mb_change_byte_mask) == 0)) {

                switch (y & 3) {
                case 0:
                    /* if macroblock width is 2, apply C-Y-C-Y; else
                     * apply C-Y-Y */
                    if (s->block_width == 2) {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;

                case 1:
                case 3:
                    /* always apply 2 Y predictors on these iterations */
                    APPLY_Y_PREDICTOR();
                    OUTPUT_PIXEL_PAIR();
                    APPLY_Y_PREDICTOR();
                    OUTPUT_PIXEL_PAIR();
                    break;

                case 2:
                    /* this iteration might be C-Y-C-Y, Y-Y, or C-Y-Y
                     * depending on the macroblock type */
                    if (s->block_type == BLOCK_2x2) {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    } else if (s->block_type == BLOCK_4x2) {
                        APPLY_C_PREDICTOR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;
                }

            } else {

                /* skip (copy) four pixels, but reassign the horizontal
                 * predictor */
                *vert_pred++ = *current_pixel_pair++;
                horiz_pred = *current_pixel_pair - *vert_pred;
                *vert_pred++ = *current_pixel_pair++;

            }

            if (!keyframe) {
                mb_change_byte_mask <<= 1;

                /* next byte */
                if (!mb_change_byte_mask) {
                    mb_change_byte = mb_change_bits[mb_change_index++];
                    mb_change_byte_mask = 0x01;
                }
            }

            pixels_left -= 4;
        }

        /* next change row */
        if (((y + 1) & 3) == 0)
            mb_change_bits += s->mb_change_bits_row_size;

        current_line += s->frame.linesize[0];
    }
}

static void truemotion1_decode_24bit(TrueMotion1Context *s)
{
    int y;
    int pixels_left;  /* remaining pixels on this line */
    unsigned int predictor_pair;
    unsigned int horiz_pred;
    unsigned int *vert_pred;
    unsigned int *current_pixel_pair;
    unsigned char *current_line = s->frame.data[0];
    int keyframe = s->flags & FLAG_KEYFRAME;

    /* these variables are for managing the stream of macroblock change bits */
    const unsigned char *mb_change_bits = s->mb_change_bits;
    unsigned char mb_change_byte;
    unsigned char mb_change_byte_mask;
    int mb_change_index;

    /* these variables are for managing the main index stream */
    int index_stream_index = 0;  /* yes, the index into the index stream */
    int index;

    /* clean out the line buffer */
    memset(s->vert_pred, 0, s->avctx->width * sizeof(unsigned int));

    GET_NEXT_INDEX();

    for (y = 0; y < s->avctx->height; y++) {

        /* re-init variables for the next line iteration */
        horiz_pred = 0;
        current_pixel_pair = (unsigned int *)current_line;
        vert_pred = s->vert_pred;
        mb_change_index = 0;
        mb_change_byte = mb_change_bits[mb_change_index++];
        mb_change_byte_mask = 0x01;
        pixels_left = s->avctx->width;

        while (pixels_left > 0) {

            if (keyframe || ((mb_change_byte & mb_change_byte_mask) == 0)) {

                switch (y & 3) {
                case 0:
                    /* if macroblock width is 2, apply C-Y-C-Y; else
                     * apply C-Y-Y */
                    if (s->block_width == 2) {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;

                case 1:
                case 3:
                    /* always apply 2 Y predictors on these iterations */
                    APPLY_Y_PREDICTOR_24();
                    OUTPUT_PIXEL_PAIR();
                    APPLY_Y_PREDICTOR_24();
                    OUTPUT_PIXEL_PAIR();
                    break;

                case 2:
                    /* this iteration might be C-Y-C-Y, Y-Y, or C-Y-Y
                     * depending on the macroblock type */
                    if (s->block_type == BLOCK_2x2) {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    } else if (s->block_type == BLOCK_4x2) {
                        APPLY_C_PREDICTOR_24();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    } else {
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                        APPLY_Y_PREDICTOR_24();
                        OUTPUT_PIXEL_PAIR();
                    }
                    break;
                }

            } else {

                /* skip (copy) four pixels, but reassign the horizontal
                 * predictor */
                *vert_pred++ = *current_pixel_pair++;
                horiz_pred = *current_pixel_pair - *vert_pred;
                *vert_pred++ = *current_pixel_pair++;

            }

            if (!keyframe) {
                mb_change_byte_mask <<= 1;

                /* next byte */
                if (!mb_change_byte_mask) {
                    mb_change_byte = mb_change_bits[mb_change_index++];
                    mb_change_byte_mask = 0x01;
                }
            }

            pixels_left -= 2;
        }

        /* next change row */
        if (((y + 1) & 3) == 0)
            mb_change_bits += s->mb_change_bits_row_size;

        current_line += s->frame.linesize[0];
    }
}


static int truemotion1_decode_frame(AVCodecContext *avctx,
                                    void *data, int *data_size,
                                    AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    TrueMotion1Context *s = avctx->priv_data;

    s->buf = buf;
    s->size = buf_size;

    if (truemotion1_decode_header(s) == -1)
        return -1;

    s->frame.reference = 1;
    s->frame.buffer_hints = FF_BUFFER_HINTS_VALID |
        FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
    if (avctx->reget_buffer(avctx, &s->frame) < 0) {
        av_log(s->avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    if (compression_types[s->compression].algorithm == ALGO_RGB24H) {
        truemotion1_decode_24bit(s);
    } else if (compression_types[s->compression].algorithm != ALGO_NOP) {
        truemotion1_decode_16bit(s);
    }

    *data_size = sizeof(AVFrame);
    *(AVFrame*)data = s->frame;

    /* report that the buffer was completely consumed */
    return buf_size;
}

static av_cold int truemotion1_decode_end(AVCodecContext *avctx)
{
    TrueMotion1Context *s = avctx->priv_data;

    if (s->frame.data[0])
        avctx->release_buffer(avctx, &s->frame);

    av_free(s->vert_pred);

    return 0;
}

AVCodec ff_truemotion1_decoder = {
    "truemotion1",
    AVMEDIA_TYPE_VIDEO,
    CODEC_ID_TRUEMOTION1,
    sizeof(TrueMotion1Context),
    truemotion1_decode_init,
    NULL,
    truemotion1_decode_end,
    truemotion1_decode_frame,
    CODEC_CAP_DR1,
    .long_name = NULL_IF_CONFIG_SMALL("Duck TrueMotion 1.0"),
};