aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/indeo4.c
blob: 3c749a9b8b6deda181167d28cf90f8c852cda6fc (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
/*
 * Indeo Video Interactive v4 compatible decoder
 * Copyright (c) 2009-2011 Maxim Poliakovski
 *
 * 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
 * Indeo Video Interactive version 4 decoder
 *
 * Indeo 4 data is usually transported within .avi or .mov files.
 * Known FOURCCs: 'IV41'
 */

#define BITSTREAM_READER_LE
#include "avcodec.h"
#include "get_bits.h"
#include "ivi_dsp.h"
#include "ivi_common.h"
#include "indeo4data.h"

/**
 *  Indeo 4 frame types.
 */
enum {
    FRAMETYPE_INTRA       = 0,
    FRAMETYPE_INTRA1      = 1,  ///< intra frame with slightly different bitstream coding
    FRAMETYPE_INTER       = 2,  ///< non-droppable P-frame
    FRAMETYPE_BIDIR       = 3,  ///< bidirectional frame
    FRAMETYPE_INTER_NOREF = 4,  ///< droppable P-frame
    FRAMETYPE_NULL_FIRST  = 5,  ///< empty frame with no data
    FRAMETYPE_NULL_LAST   = 6   ///< empty frame with no data
};

#define IVI4_PIC_SIZE_ESC   7


static const struct {
    InvTransformPtr *inv_trans;
    DCTransformPtr  *dc_trans;
    int             is_2d_trans;
} transforms[18] = {
    { ff_ivi_inverse_haar_8x8,  ff_ivi_dc_haar_2d,       1 },
    { ff_ivi_row_haar8,         ff_ivi_dc_haar_2d,       0 },
    { ff_ivi_col_haar8,         ff_ivi_dc_haar_2d,       0 },
    { ff_ivi_put_pixels_8x8,    ff_ivi_put_dc_pixel_8x8, 1 },
    { ff_ivi_inverse_slant_8x8, ff_ivi_dc_slant_2d,      1 },
    { ff_ivi_row_slant8,        ff_ivi_dc_row_slant,     1 },
    { ff_ivi_col_slant8,        ff_ivi_dc_col_slant,     1 },
    { NULL, NULL, 0 }, /* inverse DCT 8x8 */
    { NULL, NULL, 0 }, /* inverse DCT 8x1 */
    { NULL, NULL, 0 }, /* inverse DCT 1x8 */
    { ff_ivi_inverse_haar_4x4,  ff_ivi_dc_haar_2d,       1 },
    { ff_ivi_inverse_slant_4x4, ff_ivi_dc_slant_2d,      1 },
    { NULL, NULL, 0 }, /* no transform 4x4 */
    { ff_ivi_row_haar4,         ff_ivi_dc_haar_2d,       0 },
    { ff_ivi_col_haar4,         ff_ivi_dc_haar_2d,       0 },
    { ff_ivi_row_slant4,        ff_ivi_dc_row_slant,     0 },
    { ff_ivi_col_slant4,        ff_ivi_dc_col_slant,     0 },
    { NULL, NULL, 0 }, /* inverse DCT 4x4 */
};

/**
 *  Decode subdivision of a plane.
 *  This is a simplified version that checks for two supported subdivisions:
 *  - 1 wavelet band  per plane, size factor 1:1, code pattern: 3
 *  - 4 wavelet bands per plane, size factor 1:4, code pattern: 2,3,3,3,3
 *  Anything else is either unsupported or corrupt.
 *
 *  @param[in,out] gb    the GetBit context
 *  @return        number of wavelet bands or 0 on error
 */
static int decode_plane_subdivision(GetBitContext *gb)
{
    int i;

    switch (get_bits(gb, 2)) {
    case 3:
        return 1;
    case 2:
        for (i = 0; i < 4; i++)
            if (get_bits(gb, 2) != 3)
                return 0;
        return 4;
    default:
        return 0;
    }
}

static inline int scale_tile_size(int def_size, int size_factor)
{
    return size_factor == 15 ? def_size : (size_factor + 1) << 5;
}

/**
 *  Decode Indeo 4 picture header.
 *
 *  @param[in,out] ctx       pointer to the decoder context
 *  @param[in]     avctx     pointer to the AVCodecContext
 *  @return        result code: 0 = OK, negative number = error
 */
static int decode_pic_hdr(IVI45DecContext *ctx, AVCodecContext *avctx)
{
    int             pic_size_indx, i, p;
    IVIPicConfig    pic_conf;

    if (get_bits(&ctx->gb, 18) != 0x3FFF8) {
        av_log(avctx, AV_LOG_ERROR, "Invalid picture start code!\n");
        return AVERROR_INVALIDDATA;
    }

    ctx->prev_frame_type = ctx->frame_type;
    ctx->frame_type      = get_bits(&ctx->gb, 3);
    if (ctx->frame_type == 7) {
        av_log(avctx, AV_LOG_ERROR, "Invalid frame type: %d\n", ctx->frame_type);
        return AVERROR_INVALIDDATA;
    }

#if IVI4_STREAM_ANALYSER
    if (ctx->frame_type == FRAMETYPE_BIDIR)
        ctx->has_b_frames = 1;
#endif

    ctx->transp_status = get_bits1(&ctx->gb);
#if IVI4_STREAM_ANALYSER
    if (ctx->transp_status) {
        ctx->has_transp = 1;
    }
#endif

    /* unknown bit: Mac decoder ignores this bit, XANIM returns error */
    if (get_bits1(&ctx->gb)) {
        av_log(avctx, AV_LOG_ERROR, "Sync bit is set!\n");
        return AVERROR_INVALIDDATA;
    }

    ctx->data_size = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 24) : 0;

    /* null frames don't contain anything else so we just return */
    if (ctx->frame_type >= FRAMETYPE_NULL_FIRST) {
        av_dlog(avctx, "Null frame encountered!\n");
        return 0;
    }

    /* Check key lock status. If enabled - ignore lock word.         */
    /* Usually we have to prompt the user for the password, but      */
    /* we don't do that because Indeo 4 videos can be decoded anyway */
    if (get_bits1(&ctx->gb)) {
        skip_bits_long(&ctx->gb, 32);
        av_dlog(avctx, "Password-protected clip!\n");
    }

    pic_size_indx = get_bits(&ctx->gb, 3);
    if (pic_size_indx == IVI4_PIC_SIZE_ESC) {
        pic_conf.pic_height = get_bits(&ctx->gb, 16);
        pic_conf.pic_width  = get_bits(&ctx->gb, 16);
    } else {
        pic_conf.pic_height = ivi4_common_pic_sizes[pic_size_indx * 2 + 1];
        pic_conf.pic_width  = ivi4_common_pic_sizes[pic_size_indx * 2    ];
    }

    /* Decode tile dimensions. */
    if (get_bits1(&ctx->gb)) {
        pic_conf.tile_height = scale_tile_size(pic_conf.pic_height, get_bits(&ctx->gb, 4));
        pic_conf.tile_width  = scale_tile_size(pic_conf.pic_width,  get_bits(&ctx->gb, 4));
#if IVI4_STREAM_ANALYSER
        ctx->uses_tiling = 1;
#endif
    } else {
        pic_conf.tile_height = pic_conf.pic_height;
        pic_conf.tile_width  = pic_conf.pic_width;
    }

    /* Decode chroma subsampling. We support only 4:4 aka YVU9. */
    if (get_bits(&ctx->gb, 2)) {
        av_log(avctx, AV_LOG_ERROR, "Only YVU9 picture format is supported!\n");
        return AVERROR_INVALIDDATA;
    }
    pic_conf.chroma_height = (pic_conf.pic_height + 3) >> 2;
    pic_conf.chroma_width  = (pic_conf.pic_width  + 3) >> 2;

    /* decode subdivision of the planes */
    pic_conf.luma_bands = decode_plane_subdivision(&ctx->gb);
    if (pic_conf.luma_bands)
        pic_conf.chroma_bands = decode_plane_subdivision(&ctx->gb);
    ctx->is_scalable = pic_conf.luma_bands != 1 || pic_conf.chroma_bands != 1;
    if (ctx->is_scalable && (pic_conf.luma_bands != 4 || pic_conf.chroma_bands != 1)) {
        av_log(avctx, AV_LOG_ERROR, "Scalability: unsupported subdivision! Luma bands: %d, chroma bands: %d\n",
               pic_conf.luma_bands, pic_conf.chroma_bands);
        return AVERROR_INVALIDDATA;
    }

    /* check if picture layout was changed and reallocate buffers */
    if (ivi_pic_config_cmp(&pic_conf, &ctx->pic_conf)) {
        if (ff_ivi_init_planes(ctx->planes, &pic_conf)) {
            av_log(avctx, AV_LOG_ERROR, "Couldn't reallocate color planes!\n");
            ctx->pic_conf.luma_bands = 0;
            return AVERROR(ENOMEM);
        }

        ctx->pic_conf = pic_conf;

        /* set default macroblock/block dimensions */
        for (p = 0; p <= 2; p++) {
            for (i = 0; i < (!p ? pic_conf.luma_bands : pic_conf.chroma_bands); i++) {
                ctx->planes[p].bands[i].mb_size  = !p ? (!ctx->is_scalable ? 16 : 8) : 4;
                ctx->planes[p].bands[i].blk_size = !p ? 8 : 4;
            }
        }

        if (ff_ivi_init_tiles(ctx->planes, ctx->pic_conf.tile_width,
                              ctx->pic_conf.tile_height)) {
            av_log(avctx, AV_LOG_ERROR,
                   "Couldn't reallocate internal structures!\n");
            return AVERROR(ENOMEM);
        }
    }

    ctx->frame_num = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 20) : 0;

    /* skip decTimeEst field if present */
    if (get_bits1(&ctx->gb))
        skip_bits(&ctx->gb, 8);

    /* decode macroblock and block huffman codebooks */
    if (ff_ivi_dec_huff_desc(&ctx->gb, get_bits1(&ctx->gb), IVI_MB_HUFF,  &ctx->mb_vlc,  avctx) ||
        ff_ivi_dec_huff_desc(&ctx->gb, get_bits1(&ctx->gb), IVI_BLK_HUFF, &ctx->blk_vlc, avctx))
        return AVERROR_INVALIDDATA;

    ctx->rvmap_sel = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 3) : 8;

    ctx->in_imf = get_bits1(&ctx->gb);
    ctx->in_q   = get_bits1(&ctx->gb);

    ctx->pic_glob_quant = get_bits(&ctx->gb, 5);

    /* TODO: ignore this parameter if unused */
    ctx->unknown1 = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 3) : 0;

    ctx->checksum = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 16) : 0;

    /* skip picture header extension if any */
    while (get_bits1(&ctx->gb)) {
        av_dlog(avctx, "Pic hdr extension encountered!\n");
        skip_bits(&ctx->gb, 8);
    }

    if (get_bits1(&ctx->gb)) {
        av_log(avctx, AV_LOG_ERROR, "Bad blocks bits encountered!\n");
    }

    align_get_bits(&ctx->gb);

    return 0;
}


/**
 *  Decode Indeo 4 band header.
 *
 *  @param[in,out] ctx       pointer to the decoder context
 *  @param[in,out] band      pointer to the band descriptor
 *  @param[in]     avctx     pointer to the AVCodecContext
 *  @return        result code: 0 = OK, negative number = error
 */
static int decode_band_hdr(IVI45DecContext *ctx, IVIBandDesc *band,
                           AVCodecContext *avctx)
{
    int plane, band_num, indx, transform_id, scan_indx;
    int i;

    plane    = get_bits(&ctx->gb, 2);
    band_num = get_bits(&ctx->gb, 4);
    if (band->plane != plane || band->band_num != band_num) {
        av_log(avctx, AV_LOG_ERROR, "Invalid band header sequence!\n");
        return AVERROR_INVALIDDATA;
    }

    band->is_empty = get_bits1(&ctx->gb);
    if (!band->is_empty) {
        int old_blk_size = band->blk_size;
        /* skip header size
         * If header size is not given, header size is 4 bytes. */
        if (get_bits1(&ctx->gb))
            skip_bits(&ctx->gb, 16);

        band->is_halfpel = get_bits(&ctx->gb, 2);
        if (band->is_halfpel >= 2) {
            av_log(avctx, AV_LOG_ERROR, "Invalid/unsupported mv resolution: %d!\n",
                   band->is_halfpel);
            return AVERROR_INVALIDDATA;
        }
#if IVI4_STREAM_ANALYSER
        if (!band->is_halfpel)
            ctx->uses_fullpel = 1;
#endif

        band->checksum_present = get_bits1(&ctx->gb);
        if (band->checksum_present)
            band->checksum = get_bits(&ctx->gb, 16);

        indx = get_bits(&ctx->gb, 2);
        if (indx == 3) {
            av_log(avctx, AV_LOG_ERROR, "Invalid block size!\n");
            return AVERROR_INVALIDDATA;
        }
        band->mb_size  = 16 >> indx;
        band->blk_size = 8 >> (indx >> 1);

        band->inherit_mv     = get_bits1(&ctx->gb);
        band->inherit_qdelta = get_bits1(&ctx->gb);

        band->glob_quant = get_bits(&ctx->gb, 5);

        if (!get_bits1(&ctx->gb) || ctx->frame_type == FRAMETYPE_INTRA) {
            transform_id = get_bits(&ctx->gb, 5);
            if (transform_id >= FF_ARRAY_ELEMS(transforms) ||
                !transforms[transform_id].inv_trans) {
                avpriv_request_sample(avctx, "Transform %d", transform_id);
                return AVERROR_PATCHWELCOME;
            }
            if ((transform_id >= 7 && transform_id <= 9) ||
                 transform_id == 17) {
                avpriv_request_sample(avctx, "DCT transform");
                return AVERROR_PATCHWELCOME;
            }

#if IVI4_STREAM_ANALYSER
            if ((transform_id >= 0 && transform_id <= 2) || transform_id == 10)
                ctx->uses_haar = 1;
#endif

            band->inv_transform = transforms[transform_id].inv_trans;
            band->dc_transform  = transforms[transform_id].dc_trans;
            band->is_2d_trans   = transforms[transform_id].is_2d_trans;
            if (transform_id < 10)
                band->transform_size = 8;
            else
                band->transform_size = 4;

            if (band->blk_size != band->transform_size)
                return AVERROR_INVALIDDATA;

            scan_indx = get_bits(&ctx->gb, 4);
            if (scan_indx == 15) {
                av_log(avctx, AV_LOG_ERROR, "Custom scan pattern encountered!\n");
                return AVERROR_INVALIDDATA;
            }
            if (scan_indx > 4 && scan_indx < 10) {
                if (band->blk_size != 4)
                    return AVERROR_INVALIDDATA;
            } else if (band->blk_size != 8)
                return AVERROR_INVALIDDATA;

            band->scan = scan_index_to_tab[scan_indx];

            band->quant_mat = get_bits(&ctx->gb, 5);
            if (band->quant_mat == 31) {
                av_log(avctx, AV_LOG_ERROR, "Custom quant matrix encountered!\n");
                return AVERROR_INVALIDDATA;
            }
            if (band->quant_mat >= FF_ARRAY_ELEMS(quant_index_to_tab)) {
                avpriv_request_sample(avctx, "Quantization matrix %d",
                                      band->quant_mat);
                return AVERROR_INVALIDDATA;
            }
        } else {
            if (old_blk_size != band->blk_size) {
                av_log(avctx, AV_LOG_ERROR,
                       "The band block size does not match the configuration "
                       "inherited\n");
                return AVERROR_INVALIDDATA;
            }
        }

        /* decode block huffman codebook */
        if (!get_bits1(&ctx->gb))
            band->blk_vlc.tab = ctx->blk_vlc.tab;
        else
            if (ff_ivi_dec_huff_desc(&ctx->gb, 1, IVI_BLK_HUFF,
                                     &band->blk_vlc, avctx))
                return AVERROR_INVALIDDATA;

        /* select appropriate rvmap table for this band */
        band->rvmap_sel = get_bits1(&ctx->gb) ? get_bits(&ctx->gb, 3) : 8;

        /* decode rvmap probability corrections if any */
        band->num_corr = 0; /* there is no corrections */
        if (get_bits1(&ctx->gb)) {
            band->num_corr = get_bits(&ctx->gb, 8); /* get number of correction pairs */
            if (band->num_corr > 61) {
                av_log(avctx, AV_LOG_ERROR, "Too many corrections: %d\n",
                       band->num_corr);
                return AVERROR_INVALIDDATA;
            }

            /* read correction pairs */
            for (i = 0; i < band->num_corr * 2; i++)
                band->corr[i] = get_bits(&ctx->gb, 8);
        }
    }

    if (band->blk_size == 8) {
        band->intra_base = &ivi4_quant_8x8_intra[quant_index_to_tab[band->quant_mat]][0];
        band->inter_base = &ivi4_quant_8x8_inter[quant_index_to_tab[band->quant_mat]][0];
    } else {
        band->intra_base = &ivi4_quant_4x4_intra[quant_index_to_tab[band->quant_mat]][0];
        band->inter_base = &ivi4_quant_4x4_inter[quant_index_to_tab[band->quant_mat]][0];
    }

    /* Indeo 4 doesn't use scale tables */
    band->intra_scale = NULL;
    band->inter_scale = NULL;

    align_get_bits(&ctx->gb);

    return 0;
}


/**
 *  Decode information (block type, cbp, quant delta, motion vector)
 *  for all macroblocks in the current tile.
 *
 *  @param[in,out] ctx       pointer to the decoder context
 *  @param[in,out] band      pointer to the band descriptor
 *  @param[in,out] tile      pointer to the tile descriptor
 *  @param[in]     avctx     pointer to the AVCodecContext
 *  @return        result code: 0 = OK, negative number = error
 */
static int decode_mb_info(IVI45DecContext *ctx, IVIBandDesc *band,
                          IVITile *tile, AVCodecContext *avctx)
{
    int         x, y, mv_x, mv_y, mv_delta, offs, mb_offset, blks_per_mb,
                mv_scale, mb_type_bits;
    IVIMbInfo   *mb, *ref_mb;
    int         row_offset = band->mb_size * band->pitch;

    mb     = tile->mbs;
    ref_mb = tile->ref_mbs;
    offs   = tile->ypos * band->pitch + tile->xpos;

    blks_per_mb  = band->mb_size   != band->blk_size  ? 4 : 1;
    mb_type_bits = ctx->frame_type == FRAMETYPE_BIDIR ? 2 : 1;

    /* scale factor for motion vectors */
    mv_scale = (ctx->planes[0].bands[0].mb_size >> 3) - (band->mb_size >> 3);
    mv_x = mv_y = 0;

    for (y = tile->ypos; y < tile->ypos + tile->height; y += band->mb_size) {
        mb_offset = offs;

        for (x = tile->xpos; x < tile->xpos + tile->width; x += band->mb_size) {
            mb->xpos     = x;
            mb->ypos     = y;
            mb->buf_offs = mb_offset;

            if (get_bits1(&ctx->gb)) {
                if (ctx->frame_type == FRAMETYPE_INTRA) {
                    av_log(avctx, AV_LOG_ERROR, "Empty macroblock in an INTRA picture!\n");
                    return AVERROR_INVALIDDATA;
                }
                mb->type = 1; /* empty macroblocks are always INTER */
                mb->cbp  = 0; /* all blocks are empty */

                mb->q_delta = 0;
                if (!band->plane && !band->band_num && ctx->in_q) {
                    mb->q_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                           IVI_VLC_BITS, 1);
                    mb->q_delta = IVI_TOSIGNED(mb->q_delta);
                }

                mb->mv_x = mb->mv_y = 0; /* no motion vector coded */
                if (band->inherit_mv && ref_mb) {
                    /* motion vector inheritance */
                    if (mv_scale) {
                        mb->mv_x = ivi_scale_mv(ref_mb->mv_x, mv_scale);
                        mb->mv_y = ivi_scale_mv(ref_mb->mv_y, mv_scale);
                    } else {
                        mb->mv_x = ref_mb->mv_x;
                        mb->mv_y = ref_mb->mv_y;
                    }
                }
            } else {
                if (band->inherit_mv) {
                    /* copy mb_type from corresponding reference mb */
                    if (!ref_mb)
                        return AVERROR_INVALIDDATA;
                    mb->type = ref_mb->type;
                } else if (ctx->frame_type == FRAMETYPE_INTRA ||
                           ctx->frame_type == FRAMETYPE_INTRA1) {
                    mb->type = 0; /* mb_type is always INTRA for intra-frames */
                } else {
                    mb->type = get_bits(&ctx->gb, mb_type_bits);
                }

                mb->cbp = get_bits(&ctx->gb, blks_per_mb);

                mb->q_delta = 0;
                if (band->inherit_qdelta) {
                    if (ref_mb) mb->q_delta = ref_mb->q_delta;
                } else if (mb->cbp || (!band->plane && !band->band_num &&
                           ctx->in_q)) {
                    mb->q_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                           IVI_VLC_BITS, 1);
                    mb->q_delta = IVI_TOSIGNED(mb->q_delta);
                }

                if (!mb->type) {
                    mb->mv_x = mb->mv_y = 0; /* there is no motion vector in intra-macroblocks */
                } else {
                    if (band->inherit_mv) {
                        if (ref_mb)
                            /* motion vector inheritance */
                            if (mv_scale) {
                                mb->mv_x = ivi_scale_mv(ref_mb->mv_x, mv_scale);
                                mb->mv_y = ivi_scale_mv(ref_mb->mv_y, mv_scale);
                            } else {
                                mb->mv_x = ref_mb->mv_x;
                                mb->mv_y = ref_mb->mv_y;
                            }
                    } else {
                        /* decode motion vector deltas */
                        mv_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                            IVI_VLC_BITS, 1);
                        mv_y += IVI_TOSIGNED(mv_delta);
                        mv_delta = get_vlc2(&ctx->gb, ctx->mb_vlc.tab->table,
                                            IVI_VLC_BITS, 1);
                        mv_x += IVI_TOSIGNED(mv_delta);
                        mb->mv_x = mv_x;
                        mb->mv_y = mv_y;
                    }
                }
            }

            mb++;
            if (ref_mb)
                ref_mb++;
            mb_offset += band->mb_size;
        }

        offs += row_offset;
    }

    align_get_bits(&ctx->gb);

    return 0;
}


/**
 *  Rearrange decoding and reference buffers.
 *
 *  @param[in,out] ctx       pointer to the decoder context
 */
static void switch_buffers(IVI45DecContext *ctx)
{
    switch (ctx->prev_frame_type) {
    case FRAMETYPE_INTRA:
    case FRAMETYPE_INTRA1:
    case FRAMETYPE_INTER:
        ctx->buf_switch ^= 1;
        ctx->dst_buf     = ctx->buf_switch;
        ctx->ref_buf     = ctx->buf_switch ^ 1;
        break;
    case FRAMETYPE_INTER_NOREF:
        break;
    }

    switch (ctx->frame_type) {
    case FRAMETYPE_INTRA:
    case FRAMETYPE_INTRA1:
        ctx->buf_switch = 0;
        /* FALLTHROUGH */
    case FRAMETYPE_INTER:
        ctx->dst_buf = ctx->buf_switch;
        ctx->ref_buf = ctx->buf_switch ^ 1;
        break;
    case FRAMETYPE_INTER_NOREF:
    case FRAMETYPE_NULL_FIRST:
    case FRAMETYPE_NULL_LAST:
        break;
    }
}


static int is_nonnull_frame(IVI45DecContext *ctx)
{
    return ctx->frame_type < FRAMETYPE_NULL_FIRST;
}


static av_cold int decode_init(AVCodecContext *avctx)
{
    IVI45DecContext *ctx = avctx->priv_data;

    ff_ivi_init_static_vlc();

    /* copy rvmap tables in our context so we can apply changes to them */
    memcpy(ctx->rvmap_tabs, ff_ivi_rvmap_tabs, sizeof(ff_ivi_rvmap_tabs));

    /* Force allocation of the internal buffers */
    /* during picture header decoding.          */
    ctx->pic_conf.pic_width  = 0;
    ctx->pic_conf.pic_height = 0;

    avctx->pix_fmt = AV_PIX_FMT_YUV410P;

    ctx->decode_pic_hdr   = decode_pic_hdr;
    ctx->decode_band_hdr  = decode_band_hdr;
    ctx->decode_mb_info   = decode_mb_info;
    ctx->switch_buffers   = switch_buffers;
    ctx->is_nonnull_frame = is_nonnull_frame;

    return 0;
}


AVCodec ff_indeo4_decoder = {
    .name           = "indeo4",
    .long_name      = NULL_IF_CONFIG_SMALL("Intel Indeo Video Interactive 4"),
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = AV_CODEC_ID_INDEO4,
    .priv_data_size = sizeof(IVI45DecContext),
    .init           = decode_init,
    .close          = ff_ivi_decode_close,
    .decode         = ff_ivi_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
};