aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/truemotion2.c
blob: f29db593f9cdf767ed586e216cff4658a9c8522e (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
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
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
/*
 * Duck/ON2 TrueMotion 2 Decoder
 * Copyright (c) 2005 Konstantin Shishkov
 *
 * 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
 * Duck TrueMotion2 decoder.
 */

#include <inttypes.h>

#include "avcodec.h"
#include "bswapdsp.h"
#include "bytestream.h"
#include "get_bits.h"
#include "internal.h"

#define TM2_ESCAPE 0x80000000
#define TM2_DELTAS 64

/* Huffman-coded streams of different types of blocks */
enum TM2_STREAMS {
    TM2_C_HI = 0,
    TM2_C_LO,
    TM2_L_HI,
    TM2_L_LO,
    TM2_UPD,
    TM2_MOT,
    TM2_TYPE,
    TM2_NUM_STREAMS
};

/* Block types */
enum TM2_BLOCKS {
    TM2_HI_RES = 0,
    TM2_MED_RES,
    TM2_LOW_RES,
    TM2_NULL_RES,
    TM2_UPDATE,
    TM2_STILL,
    TM2_MOTION
};

typedef struct TM2Context {
    AVCodecContext *avctx;
    AVFrame *pic;

    GetBitContext gb;
    int error;
    BswapDSPContext bdsp;

    uint8_t *buffer;
    int buffer_size;

    /* TM2 streams */
    int *tokens[TM2_NUM_STREAMS];
    int tok_lens[TM2_NUM_STREAMS];
    int tok_ptrs[TM2_NUM_STREAMS];
    int deltas[TM2_NUM_STREAMS][TM2_DELTAS];
    /* for blocks decoding */
    int D[4];
    int CD[4];
    int *last;
    int *clast;

    /* data for current and previous frame */
    int *Y_base, *UV_base;
    int *Y1, *U1, *V1, *Y2, *U2, *V2;
    int y_stride, uv_stride;
    int cur;
} TM2Context;

/**
* Huffman codes for each of streams
*/
typedef struct TM2Codes {
    VLC vlc; ///< table for FFmpeg bitstream reader
    int bits;
    int *recode; ///< table for converting from code indexes to values
    int length;
} TM2Codes;

/**
* structure for gathering Huffman codes information
*/
typedef struct TM2Huff {
    int val_bits; ///< length of literal
    int max_bits; ///< maximum length of code
    int min_bits; ///< minimum length of code
    int nodes; ///< total number of nodes in tree
    int num; ///< current number filled
    int max_num; ///< total number of codes
    int *nums; ///< literals
    uint8_t *lens; ///< codelengths
} TM2Huff;

/**
 *
 * @returns the length of the longest code or an AVERROR code
 */
static int tm2_read_tree(TM2Context *ctx, int length, TM2Huff *huff)
{
    int ret, ret2;
    if (length > huff->max_bits) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Tree exceeded its given depth (%i)\n",
               huff->max_bits);
        return AVERROR_INVALIDDATA;
    }

    if (!get_bits1(&ctx->gb)) { /* literal */
        if (length == 0) {
            length = 1;
        }
        if (huff->num >= huff->max_num) {
            av_log(ctx->avctx, AV_LOG_DEBUG, "Too many literals\n");
            return AVERROR_INVALIDDATA;
        }
        huff->nums[huff->num] = get_bits_long(&ctx->gb, huff->val_bits);
        huff->lens[huff->num] = length;
        huff->num++;
        return length;
    } else { /* non-terminal node */
        if ((ret2 = tm2_read_tree(ctx, length + 1, huff)) < 0)
            return ret2;
        if ((ret = tm2_read_tree(ctx, length + 1, huff)) < 0)
            return ret;
    }
    return FFMAX(ret, ret2);
}

static int tm2_build_huff_table(TM2Context *ctx, TM2Codes *code)
{
    TM2Huff huff;
    int res = 0;

    huff.val_bits = get_bits(&ctx->gb, 5);
    huff.max_bits = get_bits(&ctx->gb, 5);
    huff.min_bits = get_bits(&ctx->gb, 5);
    huff.nodes    = get_bits(&ctx->gb, 17);
    huff.num      = 0;

    /* check for correct codes parameters */
    if ((huff.val_bits < 1) || (huff.val_bits > 32) ||
        (huff.max_bits < 0) || (huff.max_bits > 25)) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect tree parameters - literal "
               "length: %i, max code length: %i\n", huff.val_bits, huff.max_bits);
        return AVERROR_INVALIDDATA;
    }
    if ((huff.nodes <= 0) || (huff.nodes > 0x10000)) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect number of Huffman tree "
               "nodes: %i\n", huff.nodes);
        return AVERROR_INVALIDDATA;
    }
    /* one-node tree */
    if (huff.max_bits == 0)
        huff.max_bits = 1;

    /* allocate space for codes - it is exactly ceil(nodes / 2) entries */
    huff.max_num = (huff.nodes + 1) >> 1;
    huff.nums    = av_calloc(huff.max_num, sizeof(int));
    huff.lens    = av_mallocz(huff.max_num);

    if (!huff.nums || !huff.lens) {
        res = AVERROR(ENOMEM);
        goto out;
    }

    res = tm2_read_tree(ctx, 0, &huff);

    if (res >= 0 && res != huff.max_bits) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Got less bits than expected: %i of %i\n",
               res, huff.max_bits);
        res = AVERROR_INVALIDDATA;
    }
    if (huff.num != huff.max_num) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Got less codes than expected: %i of %i\n",
               huff.num, huff.max_num);
        res = AVERROR_INVALIDDATA;
    }

    /* convert codes to vlc_table */
    if (res >= 0) {
        res = ff_init_vlc_from_lengths(&code->vlc, huff.max_bits, huff.max_num,
                                       huff.lens, sizeof(huff.lens[0]),
                                       NULL, 0, 0, 0, 0, ctx->avctx);
        if (res < 0)
            av_log(ctx->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
        else {
            code->bits = huff.max_bits;
            code->length = huff.max_num;
            code->recode = huff.nums;
            huff.nums = NULL;
        }
    }

out:
    /* free allocated memory */
    av_free(huff.nums);
    av_free(huff.lens);

    return res;
}

static void tm2_free_codes(TM2Codes *code)
{
    av_free(code->recode);
    if (code->vlc.table)
        ff_free_vlc(&code->vlc);
}

static inline int tm2_get_token(GetBitContext *gb, TM2Codes *code)
{
    int val;
    val = get_vlc2(gb, code->vlc.table, code->bits, 1);
    if(val<0)
        return -1;
    return code->recode[val];
}

#define TM2_OLD_HEADER_MAGIC 0x00000100
#define TM2_NEW_HEADER_MAGIC 0x00000101

static inline int tm2_read_header(TM2Context *ctx, const uint8_t *buf)
{
    uint32_t magic = AV_RL32(buf);

    switch (magic) {
    case TM2_OLD_HEADER_MAGIC:
        avpriv_request_sample(ctx->avctx, "Old TM2 header");
        return 0;
    case TM2_NEW_HEADER_MAGIC:
        return 0;
    default:
        av_log(ctx->avctx, AV_LOG_ERROR, "Not a TM2 header: 0x%08"PRIX32"\n",
               magic);
        return AVERROR_INVALIDDATA;
    }
}

static int tm2_read_deltas(TM2Context *ctx, int stream_id)
{
    int d, mb;
    int i, v;

    d  = get_bits(&ctx->gb, 9);
    mb = get_bits(&ctx->gb, 5);

    av_assert2(mb < 32);
    if ((d < 1) || (d > TM2_DELTAS) || (mb < 1)) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect delta table: %i deltas x %i bits\n", d, mb);
        return AVERROR_INVALIDDATA;
    }

    for (i = 0; i < d; i++) {
        v = get_bits_long(&ctx->gb, mb);
        if (v & (1 << (mb - 1)))
            ctx->deltas[stream_id][i] = v - (1U << mb);
        else
            ctx->deltas[stream_id][i] = v;
    }
    for (; i < TM2_DELTAS; i++)
        ctx->deltas[stream_id][i] = 0;

    return 0;
}

static int tm2_read_stream(TM2Context *ctx, const uint8_t *buf, int stream_id, int buf_size)
{
    int i, ret;
    int skip = 0;
    int len, toks, pos;
    TM2Codes codes;
    GetByteContext gb;

    if (buf_size < 4) {
        av_log(ctx->avctx, AV_LOG_ERROR, "not enough space for len left\n");
        return AVERROR_INVALIDDATA;
    }

    /* get stream length in dwords */
    bytestream2_init(&gb, buf, buf_size);
    len  = bytestream2_get_be32(&gb);

    if (len == 0)
        return 4;

    if (len >= INT_MAX / 4 - 1 || len < 0 || len * 4 + 4 > buf_size) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Error, invalid stream size.\n");
        return AVERROR_INVALIDDATA;
    }
    skip = len * 4 + 4;

    toks = bytestream2_get_be32(&gb);
    if (toks & 1) {
        len = bytestream2_get_be32(&gb);
        if (len == TM2_ESCAPE) {
            len = bytestream2_get_be32(&gb);
        }
        if (len > 0) {
            pos = bytestream2_tell(&gb);
            if (skip <= pos)
                return AVERROR_INVALIDDATA;
            init_get_bits(&ctx->gb, buf + pos, (skip - pos) * 8);
            if ((ret = tm2_read_deltas(ctx, stream_id)) < 0)
                return ret;
            bytestream2_skip(&gb, ((get_bits_count(&ctx->gb) + 31) >> 5) << 2);
        }
    }
    /* skip unused fields */
    len = bytestream2_get_be32(&gb);
    if (len == TM2_ESCAPE) { /* some unknown length - could be escaped too */
        bytestream2_skip(&gb, 8); /* unused by decoder */
    } else {
        bytestream2_skip(&gb, 4); /* unused by decoder */
    }

    pos = bytestream2_tell(&gb);
    if (skip <= pos)
        return AVERROR_INVALIDDATA;
    init_get_bits(&ctx->gb, buf + pos, (skip - pos) * 8);
    if ((ret = tm2_build_huff_table(ctx, &codes)) < 0)
        return ret;
    bytestream2_skip(&gb, ((get_bits_count(&ctx->gb) + 31) >> 5) << 2);

    toks >>= 1;
    /* check if we have sane number of tokens */
    if ((toks < 0) || (toks > 0xFFFFFF)) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect number of tokens: %i\n", toks);
        ret = AVERROR_INVALIDDATA;
        goto end;
    }
    ret = av_reallocp_array(&ctx->tokens[stream_id], toks, sizeof(int));
    if (ret < 0) {
        ctx->tok_lens[stream_id] = 0;
        goto end;
    }
    ctx->tok_lens[stream_id] = toks;
    len = bytestream2_get_be32(&gb);
    if (len > 0) {
        pos = bytestream2_tell(&gb);
        if (skip <= pos) {
            ret = AVERROR_INVALIDDATA;
            goto end;
        }
        init_get_bits(&ctx->gb, buf + pos, (skip - pos) * 8);
        for (i = 0; i < toks; i++) {
            if (get_bits_left(&ctx->gb) <= 0) {
                av_log(ctx->avctx, AV_LOG_ERROR, "Incorrect number of tokens: %i\n", toks);
                ret = AVERROR_INVALIDDATA;
                goto end;
            }
            ctx->tokens[stream_id][i] = tm2_get_token(&ctx->gb, &codes);
            if (stream_id <= TM2_MOT && ctx->tokens[stream_id][i] >= TM2_DELTAS || ctx->tokens[stream_id][i]<0) {
                av_log(ctx->avctx, AV_LOG_ERROR, "Invalid delta token index %d for type %d, n=%d\n",
                       ctx->tokens[stream_id][i], stream_id, i);
                ret = AVERROR_INVALIDDATA;
                goto end;
            }
        }
    } else {
        if (len < 0) {
            ret = AVERROR_INVALIDDATA;
            goto end;
        }
        for (i = 0; i < toks; i++) {
            ctx->tokens[stream_id][i] = codes.recode[0];
            if (stream_id <= TM2_MOT && ctx->tokens[stream_id][i] >= TM2_DELTAS) {
                av_log(ctx->avctx, AV_LOG_ERROR, "Invalid delta token index %d for type %d, n=%d\n",
                       ctx->tokens[stream_id][i], stream_id, i);
                ret = AVERROR_INVALIDDATA;
                goto end;
            }
        }
    }

    ret = skip;

end:
    tm2_free_codes(&codes);
    return ret;
}

static inline int GET_TOK(TM2Context *ctx,int type)
{
    if (ctx->tok_ptrs[type] >= ctx->tok_lens[type]) {
        av_log(ctx->avctx, AV_LOG_ERROR, "Read token from stream %i out of bounds (%i>=%i)\n", type, ctx->tok_ptrs[type], ctx->tok_lens[type]);
        ctx->error = 1;
        return 0;
    }
    if (type <= TM2_MOT) {
        if (ctx->tokens[type][ctx->tok_ptrs[type]] >= TM2_DELTAS) {
            av_log(ctx->avctx, AV_LOG_ERROR, "token %d is too large\n", ctx->tokens[type][ctx->tok_ptrs[type]]);
            return 0;
        }
        return ctx->deltas[type][ctx->tokens[type][ctx->tok_ptrs[type]++]];
    }
    return ctx->tokens[type][ctx->tok_ptrs[type]++];
}

/* blocks decoding routines */

/* common Y, U, V pointers initialisation */
#define TM2_INIT_POINTERS() \
    int *last, *clast; \
    int *Y, *U, *V;\
    int Ystride, Ustride, Vstride;\
\
    Ystride = ctx->y_stride;\
    Vstride = ctx->uv_stride;\
    Ustride = ctx->uv_stride;\
    Y = (ctx->cur?ctx->Y2:ctx->Y1) + by * 4 * Ystride + bx * 4;\
    V = (ctx->cur?ctx->V2:ctx->V1) + by * 2 * Vstride + bx * 2;\
    U = (ctx->cur?ctx->U2:ctx->U1) + by * 2 * Ustride + bx * 2;\
    last = ctx->last + bx * 4;\
    clast = ctx->clast + bx * 4;

#define TM2_INIT_POINTERS_2() \
    unsigned *Yo, *Uo, *Vo;\
    int oYstride, oUstride, oVstride;\
\
    TM2_INIT_POINTERS();\
    oYstride = Ystride;\
    oVstride = Vstride;\
    oUstride = Ustride;\
    Yo = (ctx->cur?ctx->Y1:ctx->Y2) + by * 4 * oYstride + bx * 4;\
    Vo = (ctx->cur?ctx->V1:ctx->V2) + by * 2 * oVstride + bx * 2;\
    Uo = (ctx->cur?ctx->U1:ctx->U2) + by * 2 * oUstride + bx * 2;

/* recalculate last and delta values for next blocks */
#define TM2_RECALC_BLOCK(CHR, stride, last, CD) {\
    CD[0] = (unsigned)CHR[         1] - (unsigned)last[1];\
    CD[1] = (unsigned)CHR[stride + 1] - (unsigned) CHR[1];\
    last[0] = (int)CHR[stride + 0];\
    last[1] = (int)CHR[stride + 1];}

/* common operations - add deltas to 4x4 block of luma or 2x2 blocks of chroma */
static inline void tm2_apply_deltas(TM2Context *ctx, int* Y, int stride, int *deltas, int *last)
{
    unsigned ct, d;
    int i, j;

    for (j = 0; j < 4; j++){
        ct = ctx->D[j];
        for (i = 0; i < 4; i++){
            d        = deltas[i + j * 4];
            ct      += d;
            last[i] += ct;
            Y[i]     = av_clip_uint8(last[i]);
        }
        Y        += stride;
        ctx->D[j] = ct;
    }
}

static inline void tm2_high_chroma(int *data, int stride, int *last, unsigned *CD, int *deltas)
{
    int i, j;
    for (j = 0; j < 2; j++) {
        for (i = 0; i < 2; i++)  {
            CD[j]   += deltas[i + j * 2];
            last[i] += CD[j];
            data[i]  = last[i];
        }
        data += stride;
    }
}

static inline void tm2_low_chroma(int *data, int stride, int *clast, unsigned *CD, int *deltas, int bx)
{
    int t;
    int l;
    int prev;

    if (bx > 0)
        prev = clast[-3];
    else
        prev = 0;
    t        = (int)(CD[0] + CD[1]) >> 1;
    l        = (int)(prev - CD[0] - CD[1] + clast[1]) >> 1;
    CD[1]    = CD[0] + CD[1] - t;
    CD[0]    = t;
    clast[0] = l;

    tm2_high_chroma(data, stride, clast, CD, deltas);
}

static inline void tm2_hi_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i;
    int deltas[16];
    TM2_INIT_POINTERS();

    /* hi-res chroma */
    for (i = 0; i < 4; i++) {
        deltas[i]     = GET_TOK(ctx, TM2_C_HI);
        deltas[i + 4] = GET_TOK(ctx, TM2_C_HI);
    }
    tm2_high_chroma(U, Ustride, clast,     ctx->CD,     deltas);
    tm2_high_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas + 4);

    /* hi-res luma */
    for (i = 0; i < 16; i++)
        deltas[i] = GET_TOK(ctx, TM2_L_HI);

    tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
}

static inline void tm2_med_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i;
    int deltas[16];
    TM2_INIT_POINTERS();

    /* low-res chroma */
    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);

    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);

    /* hi-res luma */
    for (i = 0; i < 16; i++)
        deltas[i] = GET_TOK(ctx, TM2_L_HI);

    tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
}

static inline void tm2_low_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i;
    int t1, t2;
    int deltas[16];
    TM2_INIT_POINTERS();

    /* low-res chroma */
    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);

    deltas[0] = GET_TOK(ctx, TM2_C_LO);
    deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);

    /* low-res luma */
    for (i = 0; i < 16; i++)
        deltas[i] = 0;

    deltas[ 0] = GET_TOK(ctx, TM2_L_LO);
    deltas[ 2] = GET_TOK(ctx, TM2_L_LO);
    deltas[ 8] = GET_TOK(ctx, TM2_L_LO);
    deltas[10] = GET_TOK(ctx, TM2_L_LO);

    if (bx > 0)
        last[0] = (int)((unsigned)last[-1] - ctx->D[0] - ctx->D[1] - ctx->D[2] - ctx->D[3] + last[1]) >> 1;
    else
        last[0] = (int)((unsigned)last[1]  - ctx->D[0] - ctx->D[1] - ctx->D[2] - ctx->D[3])>> 1;
    last[2] = (int)((unsigned)last[1] + last[3]) >> 1;

    t1 = ctx->D[0] + (unsigned)ctx->D[1];
    ctx->D[0] = t1 >> 1;
    ctx->D[1] = t1 - (t1 >> 1);
    t2 = ctx->D[2] + (unsigned)ctx->D[3];
    ctx->D[2] = t2 >> 1;
    ctx->D[3] = t2 - (t2 >> 1);

    tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
}

static inline void tm2_null_res_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i;
    int ct;
    unsigned left, right;
    int diff;
    int deltas[16];
    TM2_INIT_POINTERS();

    /* null chroma */
    deltas[0] = deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(U, Ustride, clast, ctx->CD, deltas, bx);

    deltas[0] = deltas[1] = deltas[2] = deltas[3] = 0;
    tm2_low_chroma(V, Vstride, clast + 2, ctx->CD + 2, deltas, bx);

    /* null luma */
    for (i = 0; i < 16; i++)
        deltas[i] = 0;

    ct = (unsigned)ctx->D[0] + ctx->D[1] + ctx->D[2] + ctx->D[3];

    if (bx > 0)
        left = last[-1] - (unsigned)ct;
    else
        left = 0;

    right   = last[3];
    diff    = right - left;
    last[0] = left + (diff >> 2);
    last[1] = left + (diff >> 1);
    last[2] = right - (diff >> 2);
    last[3] = right;
    {
        unsigned tp = left;

        ctx->D[0] = (tp + (ct >> 2)) - left;
        left     += ctx->D[0];
        ctx->D[1] = (tp + (ct >> 1)) - left;
        left     += ctx->D[1];
        ctx->D[2] = ((tp + ct) - (ct >> 2)) - left;
        left     += ctx->D[2];
        ctx->D[3] = (tp + ct) - left;
    }
    tm2_apply_deltas(ctx, Y, Ystride, deltas, last);
}

static inline void tm2_still_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i, j;
    TM2_INIT_POINTERS_2();

    /* update chroma */
    for (j = 0; j < 2; j++) {
        for (i = 0; i < 2; i++){
            U[i] = Uo[i];
            V[i] = Vo[i];
        }
        U  += Ustride; V += Vstride;
        Uo += oUstride; Vo += oVstride;
    }
    U -= Ustride * 2;
    V -= Vstride * 2;
    TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
    TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));

    /* update deltas */
    ctx->D[0] = Yo[3] - last[3];
    ctx->D[1] = Yo[3 + oYstride] - Yo[3];
    ctx->D[2] = Yo[3 + oYstride * 2] - Yo[3 + oYstride];
    ctx->D[3] = Yo[3 + oYstride * 3] - Yo[3 + oYstride * 2];

    for (j = 0; j < 4; j++) {
        for (i = 0; i < 4; i++) {
            Y[i]    = Yo[i];
            last[i] = Yo[i];
        }
        Y  += Ystride;
        Yo += oYstride;
    }
}

static inline void tm2_update_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i, j;
    unsigned d;
    TM2_INIT_POINTERS_2();

    /* update chroma */
    for (j = 0; j < 2; j++) {
        for (i = 0; i < 2; i++) {
            U[i] = Uo[i] + GET_TOK(ctx, TM2_UPD);
            V[i] = Vo[i] + GET_TOK(ctx, TM2_UPD);
        }
        U  += Ustride;
        V  += Vstride;
        Uo += oUstride;
        Vo += oVstride;
    }
    U -= Ustride * 2;
    V -= Vstride * 2;
    TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
    TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));

    /* update deltas */
    ctx->D[0] = Yo[3] - last[3];
    ctx->D[1] = Yo[3 + oYstride] - Yo[3];
    ctx->D[2] = Yo[3 + oYstride * 2] - Yo[3 + oYstride];
    ctx->D[3] = Yo[3 + oYstride * 3] - Yo[3 + oYstride * 2];

    for (j = 0; j < 4; j++) {
        d = last[3];
        for (i = 0; i < 4; i++) {
            Y[i]    = Yo[i] + (unsigned)GET_TOK(ctx, TM2_UPD);
            last[i] = Y[i];
        }
        ctx->D[j] = last[3] - d;
        Y  += Ystride;
        Yo += oYstride;
    }
}

static inline void tm2_motion_block(TM2Context *ctx, AVFrame *pic, int bx, int by)
{
    int i, j;
    int mx, my;
    TM2_INIT_POINTERS_2();

    mx = GET_TOK(ctx, TM2_MOT);
    my = GET_TOK(ctx, TM2_MOT);
    mx = av_clip(mx, -(bx * 4 + 4), ctx->avctx->width  - bx * 4);
    my = av_clip(my, -(by * 4 + 4), ctx->avctx->height - by * 4);

    if (4*bx+mx<0 || 4*by+my<0 || 4*bx+mx+4 > ctx->avctx->width || 4*by+my+4 > ctx->avctx->height) {
        av_log(ctx->avctx, AV_LOG_ERROR, "MV out of picture\n");
        return;
    }

    Yo += my * oYstride + mx;
    Uo += (my >> 1) * oUstride + (mx >> 1);
    Vo += (my >> 1) * oVstride + (mx >> 1);

    /* copy chroma */
    for (j = 0; j < 2; j++) {
        for (i = 0; i < 2; i++) {
            U[i] = Uo[i];
            V[i] = Vo[i];
        }
        U  += Ustride;
        V  += Vstride;
        Uo += oUstride;
        Vo += oVstride;
    }
    U -= Ustride * 2;
    V -= Vstride * 2;
    TM2_RECALC_BLOCK(U, Ustride, clast, ctx->CD);
    TM2_RECALC_BLOCK(V, Vstride, (clast + 2), (ctx->CD + 2));

    /* copy luma */
    for (j = 0; j < 4; j++) {
        for (i = 0; i < 4; i++) {
            Y[i] = Yo[i];
        }
        Y  += Ystride;
        Yo += oYstride;
    }
    /* calculate deltas */
    Y -= Ystride * 4;
    ctx->D[0] = (unsigned)Y[3] - last[3];
    ctx->D[1] = (unsigned)Y[3 + Ystride] - Y[3];
    ctx->D[2] = (unsigned)Y[3 + Ystride * 2] - Y[3 + Ystride];
    ctx->D[3] = (unsigned)Y[3 + Ystride * 3] - Y[3 + Ystride * 2];
    for (i = 0; i < 4; i++)
        last[i] = Y[i + Ystride * 3];
}

static int tm2_decode_blocks(TM2Context *ctx, AVFrame *p)
{
    int i, j;
    int w = ctx->avctx->width, h = ctx->avctx->height, bw = w >> 2, bh = h >> 2, cw = w >> 1;
    int type;
    int keyframe = 1;
    int *Y, *U, *V;
    uint8_t *dst;

    for (i = 0; i < TM2_NUM_STREAMS; i++)
        ctx->tok_ptrs[i] = 0;

    if (ctx->tok_lens[TM2_TYPE]<bw*bh) {
        av_log(ctx->avctx,AV_LOG_ERROR,"Got %i tokens for %i blocks\n",ctx->tok_lens[TM2_TYPE],bw*bh);
        return AVERROR_INVALIDDATA;
    }

    memset(ctx->last, 0, 4 * bw * sizeof(int));
    memset(ctx->clast, 0, 4 * bw * sizeof(int));

    for (j = 0; j < bh; j++) {
        memset(ctx->D, 0, 4 * sizeof(int));
        memset(ctx->CD, 0, 4 * sizeof(int));
        for (i = 0; i < bw; i++) {
            type = GET_TOK(ctx, TM2_TYPE);
            switch(type) {
            case TM2_HI_RES:
                tm2_hi_res_block(ctx, p, i, j);
                break;
            case TM2_MED_RES:
                tm2_med_res_block(ctx, p, i, j);
                break;
            case TM2_LOW_RES:
                tm2_low_res_block(ctx, p, i, j);
                break;
            case TM2_NULL_RES:
                tm2_null_res_block(ctx, p, i, j);
                break;
            case TM2_UPDATE:
                tm2_update_block(ctx, p, i, j);
                keyframe = 0;
                break;
            case TM2_STILL:
                tm2_still_block(ctx, p, i, j);
                keyframe = 0;
                break;
            case TM2_MOTION:
                tm2_motion_block(ctx, p, i, j);
                keyframe = 0;
                break;
            default:
                av_log(ctx->avctx, AV_LOG_ERROR, "Skipping unknown block type %i\n", type);
            }
            if (ctx->error)
                return AVERROR_INVALIDDATA;
        }
    }

    /* copy data from our buffer to AVFrame */
    Y = (ctx->cur?ctx->Y2:ctx->Y1);
    U = (ctx->cur?ctx->U2:ctx->U1);
    V = (ctx->cur?ctx->V2:ctx->V1);
    dst = p->data[0];
    for (j = 0; j < h; j++) {
        for (i = 0; i < w; i++) {
            unsigned y = Y[i], u = U[i >> 1], v = V[i >> 1];
            dst[3*i+0] = av_clip_uint8(y + v);
            dst[3*i+1] = av_clip_uint8(y);
            dst[3*i+2] = av_clip_uint8(y + u);
        }

        /* horizontal edge extension */
        Y[-4]    = Y[-3]    = Y[-2]    = Y[-1] = Y[0];
        Y[w + 3] = Y[w + 2] = Y[w + 1] = Y[w]  = Y[w - 1];

        /* vertical edge extension */
        if (j == 0) {
            memcpy(Y - 4 - 1 * ctx->y_stride, Y - 4, ctx->y_stride);
            memcpy(Y - 4 - 2 * ctx->y_stride, Y - 4, ctx->y_stride);
            memcpy(Y - 4 - 3 * ctx->y_stride, Y - 4, ctx->y_stride);
            memcpy(Y - 4 - 4 * ctx->y_stride, Y - 4, ctx->y_stride);
        } else if (j == h - 1) {
            memcpy(Y - 4 + 1 * ctx->y_stride, Y - 4, ctx->y_stride);
            memcpy(Y - 4 + 2 * ctx->y_stride, Y - 4, ctx->y_stride);
            memcpy(Y - 4 + 3 * ctx->y_stride, Y - 4, ctx->y_stride);
            memcpy(Y - 4 + 4 * ctx->y_stride, Y - 4, ctx->y_stride);
        }

        Y += ctx->y_stride;
        if (j & 1) {
            /* horizontal edge extension */
            U[-2]     = U[-1] = U[0];
            V[-2]     = V[-1] = V[0];
            U[cw + 1] = U[cw] = U[cw - 1];
            V[cw + 1] = V[cw] = V[cw - 1];

            /* vertical edge extension */
            if (j == 1) {
                memcpy(U - 2 - 1 * ctx->uv_stride, U - 2, ctx->uv_stride);
                memcpy(V - 2 - 1 * ctx->uv_stride, V - 2, ctx->uv_stride);
                memcpy(U - 2 - 2 * ctx->uv_stride, U - 2, ctx->uv_stride);
                memcpy(V - 2 - 2 * ctx->uv_stride, V - 2, ctx->uv_stride);
            } else if (j == h - 1) {
                memcpy(U - 2 + 1 * ctx->uv_stride, U - 2, ctx->uv_stride);
                memcpy(V - 2 + 1 * ctx->uv_stride, V - 2, ctx->uv_stride);
                memcpy(U - 2 + 2 * ctx->uv_stride, U - 2, ctx->uv_stride);
                memcpy(V - 2 + 2 * ctx->uv_stride, V - 2, ctx->uv_stride);
            }

            U += ctx->uv_stride;
            V += ctx->uv_stride;
        }
        dst += p->linesize[0];
    }

    return keyframe;
}

static const int tm2_stream_order[TM2_NUM_STREAMS] = {
    TM2_C_HI, TM2_C_LO, TM2_L_HI, TM2_L_LO, TM2_UPD, TM2_MOT, TM2_TYPE
};

#define TM2_HEADER_SIZE 40

static int decode_frame(AVCodecContext *avctx,
                        void *data, int *got_frame,
                        AVPacket *avpkt)
{
    TM2Context * const l = avctx->priv_data;
    const uint8_t *buf   = avpkt->data;
    int buf_size         = avpkt->size & ~3;
    AVFrame * const p    = l->pic;
    int offset           = TM2_HEADER_SIZE;
    int i, t, ret;

    l->error = 0;

    av_fast_padded_malloc(&l->buffer, &l->buffer_size, buf_size);
    if (!l->buffer) {
        av_log(avctx, AV_LOG_ERROR, "Cannot allocate temporary buffer\n");
        return AVERROR(ENOMEM);
    }

    if ((ret = ff_reget_buffer(avctx, p, 0)) < 0)
        return ret;

    l->bdsp.bswap_buf((uint32_t *) l->buffer, (const uint32_t *) buf,
                      buf_size >> 2);

    if ((ret = tm2_read_header(l, l->buffer)) < 0) {
        return ret;
    }

    for (i = 0; i < TM2_NUM_STREAMS; i++) {
        if (offset >= buf_size) {
            av_log(avctx, AV_LOG_ERROR, "no space for tm2_read_stream\n");
            return AVERROR_INVALIDDATA;
        }

        t = tm2_read_stream(l, l->buffer + offset, tm2_stream_order[i],
                            buf_size - offset);
        if (t < 0) {
            int j = tm2_stream_order[i];
            if (l->tok_lens[j])
                memset(l->tokens[j], 0, sizeof(**l->tokens) * l->tok_lens[j]);
            return t;
        }
        offset += t;
    }
    p->key_frame = tm2_decode_blocks(l, p);
    if (p->key_frame)
        p->pict_type = AV_PICTURE_TYPE_I;
    else
        p->pict_type = AV_PICTURE_TYPE_P;

    l->cur = !l->cur;
    *got_frame      = 1;
    ret = av_frame_ref(data, l->pic);

    return (ret < 0) ? ret : buf_size;
}

static av_cold int decode_init(AVCodecContext *avctx)
{
    TM2Context * const l = avctx->priv_data;
    int w = avctx->width, h = avctx->height;

    if ((avctx->width & 3) || (avctx->height & 3)) {
        av_log(avctx, AV_LOG_ERROR, "Width and height must be multiple of 4\n");
        return AVERROR(EINVAL);
    }

    l->avctx       = avctx;
    avctx->pix_fmt = AV_PIX_FMT_BGR24;

    l->pic = av_frame_alloc();
    if (!l->pic)
        return AVERROR(ENOMEM);

    ff_bswapdsp_init(&l->bdsp);

    l->last  = av_malloc_array(w, 2 * sizeof(*l->last));
    if (!l->last)
        return AVERROR(ENOMEM);
    l->clast = l->last + w;

    w += 8;
    h += 8;
    l->Y_base = av_calloc(w * h, 2 * sizeof(*l->Y_base));
    if (!l->Y_base)
        return AVERROR(ENOMEM);
    l->y_stride = w;
    l->Y1 = l->Y_base + l->y_stride * 4 + 4;
    l->Y2 = l->Y1 + w * h;
    w = (w + 1) >> 1;
    h = (h + 1) >> 1;
    l->UV_base = av_calloc(w * h, 4 * sizeof(*l->UV_base));
    if (!l->UV_base)
        return AVERROR(ENOMEM);
    l->uv_stride = w;
    l->U1 = l->UV_base + l->uv_stride * 2 + 2;
    l->U2 = l->U1 + w * h;
    l->V1 = l->U2 + w * h;
    l->V2 = l->V1 + w * h;

    return 0;
}

static av_cold int decode_end(AVCodecContext *avctx)
{
    TM2Context * const l = avctx->priv_data;
    int i;

    av_freep(&l->last);
    for (i = 0; i < TM2_NUM_STREAMS; i++)
        av_freep(&l->tokens[i]);

    av_freep(&l->Y_base);
    av_freep(&l->UV_base);
    av_freep(&l->buffer);
    l->buffer_size = 0;

    av_frame_free(&l->pic);

    return 0;
}

const AVCodec ff_truemotion2_decoder = {
    .name           = "truemotion2",
    .long_name      = NULL_IF_CONFIG_SMALL("Duck TrueMotion 2.0"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_TRUEMOTION2,
    .priv_data_size = sizeof(TM2Context),
    .init           = decode_init,
    .close          = decode_end,
    .decode         = decode_frame,
    .capabilities   = AV_CODEC_CAP_DR1,
    .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP | FF_CODEC_CAP_INIT_THREADSAFE,
};