summaryrefslogtreecommitdiffstats
path: root/libavcodec/smc.c
blob: 86f4282d54bed77afd918e7cf9d7c22ac93e8fa0 (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
/*
 * Quicktime Graphics (SMC) Video Decoder
 * Copyright (C) 2003 the ffmpeg project
 *
 * 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
 * QT SMC Video Decoder by Mike Melanson (melanson@pcisys.net)
 * For more information about the SMC format, visit:
 *   http://www.pcisys.net/~melanson/codecs/
 *
 * The SMC decoder outputs PAL8 colorspace data.
 */

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

#include "libavutil/intreadwrite.h"
#include "avcodec.h"

#define CPAIR 2
#define CQUAD 4
#define COCTET 8

#define COLORS_PER_TABLE 256

typedef struct SmcContext {

    AVCodecContext *avctx;
    AVFrame frame;

    const unsigned char *buf;
    int size;

    /* SMC color tables */
    unsigned char color_pairs[COLORS_PER_TABLE * CPAIR];
    unsigned char color_quads[COLORS_PER_TABLE * CQUAD];
    unsigned char color_octets[COLORS_PER_TABLE * COCTET];

    uint32_t pal[256];
} SmcContext;

#define GET_BLOCK_COUNT() \
  (opcode & 0x10) ? (1 + s->buf[stream_ptr++]) : 1 + (opcode & 0x0F);

#define ADVANCE_BLOCK() \
{ \
    pixel_ptr += 4; \
    if (pixel_ptr >= width) \
    { \
        pixel_ptr = 0; \
        row_ptr += stride * 4; \
    } \
    total_blocks--; \
    if (total_blocks < 0) \
    { \
        av_log(s->avctx, AV_LOG_INFO, "warning: block counter just went negative (this should not happen)\n"); \
        return; \
    } \
}

static void smc_decode_stream(SmcContext *s)
{
    int width = s->avctx->width;
    int height = s->avctx->height;
    int stride = s->frame.linesize[0];
    int i;
    int stream_ptr = 0;
    int chunk_size;
    unsigned char opcode;
    int n_blocks;
    unsigned int color_flags;
    unsigned int color_flags_a;
    unsigned int color_flags_b;
    unsigned int flag_mask;

    unsigned char *pixels = s->frame.data[0];

    int image_size = height * s->frame.linesize[0];
    int row_ptr = 0;
    int pixel_ptr = 0;
    int pixel_x, pixel_y;
    int row_inc = stride - 4;
    int block_ptr;
    int prev_block_ptr;
    int prev_block_ptr1, prev_block_ptr2;
    int prev_block_flag;
    int total_blocks;
    int color_table_index;  /* indexes to color pair, quad, or octet tables */
    int pixel;

    int color_pair_index = 0;
    int color_quad_index = 0;
    int color_octet_index = 0;

    /* make the palette available */
    memcpy(s->frame.data[1], s->pal, AVPALETTE_SIZE);

    chunk_size = AV_RB32(&s->buf[stream_ptr]) & 0x00FFFFFF;
    stream_ptr += 4;
    if (chunk_size != s->size)
        av_log(s->avctx, AV_LOG_INFO, "warning: MOV chunk size != encoded chunk size (%d != %d); using MOV chunk size\n",
            chunk_size, s->size);

    chunk_size = s->size;
    total_blocks = ((s->avctx->width + 3) / 4) * ((s->avctx->height + 3) / 4);

    /* traverse through the blocks */
    while (total_blocks) {
        /* sanity checks */
        /* make sure stream ptr hasn't gone out of bounds */
        if (stream_ptr > chunk_size) {
            av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (stream ptr = %d, chunk size = %d)\n",
                stream_ptr, chunk_size);
            return;
        }
        /* make sure the row pointer hasn't gone wild */
        if (row_ptr >= image_size) {
            av_log(s->avctx, AV_LOG_INFO, "SMC decoder just went out of bounds (row ptr = %d, height = %d)\n",
                row_ptr, image_size);
            return;
        }

        opcode = s->buf[stream_ptr++];
        switch (opcode & 0xF0) {
        /* skip n blocks */
        case 0x00:
        case 0x10:
            n_blocks = GET_BLOCK_COUNT();
            while (n_blocks--) {
                ADVANCE_BLOCK();
            }
            break;

        /* repeat last block n times */
        case 0x20:
        case 0x30:
            n_blocks = GET_BLOCK_COUNT();

            /* sanity check */
            if ((row_ptr == 0) && (pixel_ptr == 0)) {
                av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but no blocks rendered yet\n",
                    opcode & 0xF0);
                break;
            }

            /* figure out where the previous block started */
            if (pixel_ptr == 0)
                prev_block_ptr1 =
                    (row_ptr - s->avctx->width * 4) + s->avctx->width - 4;
            else
                prev_block_ptr1 = row_ptr + pixel_ptr - 4;

            while (n_blocks--) {
                block_ptr = row_ptr + pixel_ptr;
                prev_block_ptr = prev_block_ptr1;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
                        pixels[block_ptr++] = pixels[prev_block_ptr++];
                    }
                    block_ptr += row_inc;
                    prev_block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* repeat previous pair of blocks n times */
        case 0x40:
        case 0x50:
            n_blocks = GET_BLOCK_COUNT();
            n_blocks *= 2;

            /* sanity check */
            if ((row_ptr == 0) && (pixel_ptr < 2 * 4)) {
                av_log(s->avctx, AV_LOG_INFO, "encountered repeat block opcode (%02X) but not enough blocks rendered yet\n",
                    opcode & 0xF0);
                break;
            }

            /* figure out where the previous 2 blocks started */
            if (pixel_ptr == 0)
                prev_block_ptr1 = (row_ptr - s->avctx->width * 4) +
                    s->avctx->width - 4 * 2;
            else if (pixel_ptr == 4)
                prev_block_ptr1 = (row_ptr - s->avctx->width * 4) + row_inc;
            else
                prev_block_ptr1 = row_ptr + pixel_ptr - 4 * 2;

            if (pixel_ptr == 0)
                prev_block_ptr2 = (row_ptr - s->avctx->width * 4) + row_inc;
            else
                prev_block_ptr2 = row_ptr + pixel_ptr - 4;

            prev_block_flag = 0;
            while (n_blocks--) {
                block_ptr = row_ptr + pixel_ptr;
                if (prev_block_flag)
                    prev_block_ptr = prev_block_ptr2;
                else
                    prev_block_ptr = prev_block_ptr1;
                prev_block_flag = !prev_block_flag;

                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
                        pixels[block_ptr++] = pixels[prev_block_ptr++];
                    }
                    block_ptr += row_inc;
                    prev_block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* 1-color block encoding */
        case 0x60:
        case 0x70:
            n_blocks = GET_BLOCK_COUNT();
            pixel = s->buf[stream_ptr++];

            while (n_blocks--) {
                block_ptr = row_ptr + pixel_ptr;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
                        pixels[block_ptr++] = pixel;
                    }
                    block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* 2-color block encoding */
        case 0x80:
        case 0x90:
            n_blocks = (opcode & 0x0F) + 1;

            /* figure out which color pair to use to paint the 2-color block */
            if ((opcode & 0xF0) == 0x80) {
                /* fetch the next 2 colors from bytestream and store in next
                 * available entry in the color pair table */
                for (i = 0; i < CPAIR; i++) {
                    pixel = s->buf[stream_ptr++];
                    color_table_index = CPAIR * color_pair_index + i;
                    s->color_pairs[color_table_index] = pixel;
                }
                /* this is the base index to use for this block */
                color_table_index = CPAIR * color_pair_index;
                color_pair_index++;
                /* wraparound */
                if (color_pair_index == COLORS_PER_TABLE)
                    color_pair_index = 0;
            } else
                color_table_index = CPAIR * s->buf[stream_ptr++];

            while (n_blocks--) {
                color_flags = AV_RB16(&s->buf[stream_ptr]);
                stream_ptr += 2;
                flag_mask = 0x8000;
                block_ptr = row_ptr + pixel_ptr;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
                        if (color_flags & flag_mask)
                            pixel = color_table_index + 1;
                        else
                            pixel = color_table_index;
                        flag_mask >>= 1;
                        pixels[block_ptr++] = s->color_pairs[pixel];
                    }
                    block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* 4-color block encoding */
        case 0xA0:
        case 0xB0:
            n_blocks = (opcode & 0x0F) + 1;

            /* figure out which color quad to use to paint the 4-color block */
            if ((opcode & 0xF0) == 0xA0) {
                /* fetch the next 4 colors from bytestream and store in next
                 * available entry in the color quad table */
                for (i = 0; i < CQUAD; i++) {
                    pixel = s->buf[stream_ptr++];
                    color_table_index = CQUAD * color_quad_index + i;
                    s->color_quads[color_table_index] = pixel;
                }
                /* this is the base index to use for this block */
                color_table_index = CQUAD * color_quad_index;
                color_quad_index++;
                /* wraparound */
                if (color_quad_index == COLORS_PER_TABLE)
                    color_quad_index = 0;
            } else
                color_table_index = CQUAD * s->buf[stream_ptr++];

            while (n_blocks--) {
                color_flags = AV_RB32(&s->buf[stream_ptr]);
                stream_ptr += 4;
                /* flag mask actually acts as a bit shift count here */
                flag_mask = 30;
                block_ptr = row_ptr + pixel_ptr;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
                        pixel = color_table_index +
                            ((color_flags >> flag_mask) & 0x03);
                        flag_mask -= 2;
                        pixels[block_ptr++] = s->color_quads[pixel];
                    }
                    block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* 8-color block encoding */
        case 0xC0:
        case 0xD0:
            n_blocks = (opcode & 0x0F) + 1;

            /* figure out which color octet to use to paint the 8-color block */
            if ((opcode & 0xF0) == 0xC0) {
                /* fetch the next 8 colors from bytestream and store in next
                 * available entry in the color octet table */
                for (i = 0; i < COCTET; i++) {
                    pixel = s->buf[stream_ptr++];
                    color_table_index = COCTET * color_octet_index + i;
                    s->color_octets[color_table_index] = pixel;
                }
                /* this is the base index to use for this block */
                color_table_index = COCTET * color_octet_index;
                color_octet_index++;
                /* wraparound */
                if (color_octet_index == COLORS_PER_TABLE)
                    color_octet_index = 0;
            } else
                color_table_index = COCTET * s->buf[stream_ptr++];

            while (n_blocks--) {
                /*
                  For this input of 6 hex bytes:
                    01 23 45 67 89 AB
                  Mangle it to this output:
                    flags_a = xx012456, flags_b = xx89A37B
                */
                /* build the color flags */
                color_flags_a =
                    ((AV_RB16(s->buf + stream_ptr    ) & 0xFFF0) << 8) |
                     (AV_RB16(s->buf + stream_ptr + 2) >> 4);
                color_flags_b =
                    ((AV_RB16(s->buf + stream_ptr + 4) & 0xFFF0) << 8) |
                    ((s->buf[stream_ptr + 1] & 0x0F) << 8) |
                    ((s->buf[stream_ptr + 3] & 0x0F) << 4) |
                    (s->buf[stream_ptr + 5] & 0x0F);
                stream_ptr += 6;

                color_flags = color_flags_a;
                /* flag mask actually acts as a bit shift count here */
                flag_mask = 21;
                block_ptr = row_ptr + pixel_ptr;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    /* reload flags at third row (iteration pixel_y == 2) */
                    if (pixel_y == 2) {
                        color_flags = color_flags_b;
                        flag_mask = 21;
                    }
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
                        pixel = color_table_index +
                            ((color_flags >> flag_mask) & 0x07);
                        flag_mask -= 3;
                        pixels[block_ptr++] = s->color_octets[pixel];
                    }
                    block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        /* 16-color block encoding (every pixel is a different color) */
        case 0xE0:
            n_blocks = (opcode & 0x0F) + 1;

            while (n_blocks--) {
                block_ptr = row_ptr + pixel_ptr;
                for (pixel_y = 0; pixel_y < 4; pixel_y++) {
                    for (pixel_x = 0; pixel_x < 4; pixel_x++) {
                        pixels[block_ptr++] = s->buf[stream_ptr++];
                    }
                    block_ptr += row_inc;
                }
                ADVANCE_BLOCK();
            }
            break;

        case 0xF0:
            av_log(s->avctx, AV_LOG_INFO, "0xF0 opcode seen in SMC chunk (contact the developers)\n");
            break;
        }
    }
}

static av_cold int smc_decode_init(AVCodecContext *avctx)
{
    SmcContext *s = avctx->priv_data;

    s->avctx = avctx;
    avctx->pix_fmt = PIX_FMT_PAL8;

    avcodec_get_frame_defaults(&s->frame);
    s->frame.data[0] = NULL;

    return 0;
}

static int smc_decode_frame(AVCodecContext *avctx,
                             void *data, int *data_size,
                             AVPacket *avpkt)
{
    const uint8_t *buf = avpkt->data;
    int buf_size = avpkt->size;
    SmcContext *s = avctx->priv_data;
    const uint8_t *pal = av_packet_get_side_data(avpkt, AV_PKT_DATA_PALETTE, NULL);

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

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

    if (pal) {
        s->frame.palette_has_changed = 1;
        memcpy(s->pal, pal, AVPALETTE_SIZE);
    }

    smc_decode_stream(s);

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

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

static av_cold int smc_decode_end(AVCodecContext *avctx)
{
    SmcContext *s = avctx->priv_data;

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

    return 0;
}

AVCodec ff_smc_decoder = {
    .name           = "smc",
    .type           = AVMEDIA_TYPE_VIDEO,
    .id             = CODEC_ID_SMC,
    .priv_data_size = sizeof(SmcContext),
    .init           = smc_decode_init,
    .close          = smc_decode_end,
    .decode         = smc_decode_frame,
    .capabilities   = CODEC_CAP_DR1,
    .long_name = NULL_IF_CONFIG_SMALL("QuickTime Graphics (SMC)"),
};
OpenPOWER on IntegriCloud