aboutsummaryrefslogtreecommitdiffstats
path: root/libavcodec/mimic.c
blob: 6fa8534eb28717e8c40e4cbb3d73559a0a73e039 (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
/*
 * Copyright (C) 2005  Ole Andr� Vadla Ravn�s <oleavr@gmail.com>
 * Copyright (C) 2008  Ramiro Polla <ramiro@lisha.ufsc.br>
 *
 * 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
 */

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

#include "avcodec.h"
#include "bitstream.h"
#include "dsputil.h"

#define MIMIC_HEADER_SIZE   20

typedef struct {
    AVCodecContext *avctx;

    int             num_vblocks[3];
    int             num_hblocks[3];

    uint8_t        *swap_buf;
    int             swap_buf_size;

    int             cur_index;
    int             prev_index;

    AVFrame         buf_ptrs    [16];
    AVPicture       flipped_ptrs[16];

    DECLARE_ALIGNED_16(DCTELEM, dct_block[64]);

    GetBitContext   gb;
    ScanTable       scantable;
    DSPContext      dsp;
    VLC             vlc1;
} MimicContext;

static const uint32_t huffcodes[] = {
    0x0000000a, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
    0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000,
    0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x00000000, 0x0000000b,
    0x0000001b, 0x00000038, 0x00000078, 0x00000079, 0x0000007a, 0x000000f9,
    0x000000fa, 0x000003fb, 0x000007f8, 0x000007f9, 0x000007fa, 0x000007fb,
    0x00000ff8, 0x00000ff9, 0x00000001, 0x00000039, 0x0000007b, 0x000000fb,
    0x000001f8, 0x000001f9, 0x00000ffa, 0x00000ffb, 0x00001ff8, 0x00001ff9,
    0x00001ffa, 0x00001ffb, 0x00003ff8, 0x00003ff9, 0x00003ffa, 0x00000000,
    0x00000004, 0x0000003a, 0x000001fa, 0x00003ffb, 0x00007ff8, 0x00007ff9,
    0x00007ffa, 0x00007ffb, 0x0000fff8, 0x0000fff9, 0x0000fffa, 0x0000fffb,
    0x0001fff8, 0x0001fff9, 0x0001fffa, 0x00000000, 0x0000000c, 0x000000f8,
    0x000001fb, 0x0001fffb, 0x0003fff8, 0x0003fff9, 0x0003fffa, 0x0003fffb,
    0x0007fff8, 0x0007fff9, 0x0007fffa, 0x0007fffb, 0x000ffff8, 0x000ffff9,
    0x000ffffa, 0x00000000, 0x0000001a, 0x000003f8, 0x000ffffb, 0x001ffff8,
    0x001ffff9, 0x001ffffa, 0x001ffffb, 0x003ffff8, 0x003ffff9, 0x003ffffa,
    0x003ffffb, 0x007ffff8, 0x007ffff9, 0x007ffffa, 0x007ffffb, 0x00000000,
    0x0000003b, 0x000003f9, 0x00fffff8, 0x00fffff9, 0x00fffffa, 0x00fffffb,
    0x01fffff8, 0x01fffff9, 0x01fffffa, 0x01fffffb, 0x03fffff8, 0x03fffff9,
    0x03fffffa, 0x03fffffb, 0x07fffff8, 0x00000000, 0x000003fa, 0x07fffff9,
    0x07fffffa, 0x07fffffb, 0x0ffffff8, 0x0ffffff9, 0x0ffffffa, 0x0ffffffb,
    0x1ffffff8, 0x1ffffff9, 0x1ffffffa, 0x1ffffffb, 0x3ffffff8, 0x3ffffff9,
    0x3ffffffa,
};

static const uint8_t huffbits[] = {
     4,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,  0,
     0,  0,  0,  0,  2,  4,  5,  6,  7,  7,  7,  8,
     8, 10, 11, 11, 11, 11, 12, 12,  2,  6,  7,  8,
     9,  9, 12, 12, 13, 13, 13, 13, 14, 14, 14,  0,
     3,  6,  9, 14, 15, 15, 15, 15, 16, 16, 16, 16,
    17, 17, 17,  0,  4,  8,  9, 17, 18, 18, 18, 18,
    19, 19, 19, 19, 20, 20, 20,  0,  5, 10, 20, 21,
    21, 21, 21, 22, 22, 22, 22, 23, 23, 23, 23,  0,
     6, 10, 24, 24, 24, 24, 25, 25, 25, 25, 26, 26,
    26, 26, 27,  0, 10, 27, 27, 27, 28, 28, 28, 28,
    29, 29, 29, 29, 30, 30, 30,
};

static const uint8_t col_zag[64] = {
     0,  8,  1,  2,  9, 16, 24, 17,
    10,  3,  4, 11, 18, 25, 32, 40,
    33, 26, 19, 12,  5,  6, 13, 20,
    27, 34, 41, 48, 56, 49, 42, 35,
    28, 21, 14,  7, 15, 22, 29, 36,
    43, 50, 57, 58, 51, 44, 37, 30,
    23, 31, 38, 45, 52, 59, 39, 46,
    53, 60, 61, 54, 47, 55, 62, 63
};

static av_cold int mimic_decode_init(AVCodecContext *avctx)
{
    MimicContext *ctx = avctx->priv_data;

    ctx->prev_index = 0;
    ctx->cur_index = 15;

    if(init_vlc(&ctx->vlc1, 8, sizeof(huffbits)/sizeof(huffbits[0]),
                 huffbits, 1, 1, huffcodes, 4, 4, 0)) {
        av_log(avctx, AV_LOG_ERROR, "error initializing vlc table\n");
        return -1;
    }
    dsputil_init(&ctx->dsp, avctx);
    ff_init_scantable(ctx->dsp.idct_permutation, &ctx->scantable, col_zag);

    return 0;
}

const static int8_t vlcdec_lookup[9][64] = {
    {    0, },
    {   -1,   1, },
    {   -3,   3,   -2,   2, },
    {   -7,   7,   -6,   6,   -5,   5,   -4,   4, },
    {  -15,  15,  -14,  14,  -13,  13,  -12,  12,
       -11,  11,  -10,  10,   -9,   9,   -8,   8, },
    {  -31,  31,  -30,  30,  -29,  29,  -28,  28,
       -27,  27,  -26,  26,  -25,  25,  -24,  24,
       -23,  23,  -22,  22,  -21,  21,  -20,  20,
       -19,  19,  -18,  18,  -17,  17,  -16,  16, },
    {  -63,  63,  -62,  62,  -61,  61,  -60,  60,
       -59,  59,  -58,  58,  -57,  57,  -56,  56,
       -55,  55,  -54,  54,  -53,  53,  -52,  52,
       -51,  51,  -50,  50,  -49,  49,  -48,  48,
       -47,  47,  -46,  46,  -45,  45,  -44,  44,
       -43,  43,  -42,  42,  -41,  41,  -40,  40,
       -39,  39,  -38,  38,  -37,  37,  -36,  36,
       -35,  35,  -34,  34,  -33,  33,  -32,  32, },
    { -127, 127, -126, 126, -125, 125, -124, 124,
      -123, 123, -122, 122, -121, 121, -120, 120,
      -119, 119, -118, 118, -117, 117, -116, 116,
      -115, 115, -114, 114, -113, 113, -112, 112,
      -111, 111, -110, 110, -109, 109, -108, 108,
      -107, 107, -106, 106, -105, 105, -104, 104,
      -103, 103, -102, 102, -101, 101, -100, 100,
       -99,  99,  -98,  98,  -97,  97,  -96,  96, },
    {  -95,  95,  -94,  94,  -93,  93,  -92,  92,
       -91,  91,  -90,  90,  -89,  89,  -88,  88,
       -87,  87,  -86,  86,  -85,  85,  -84,  84,
       -83,  83,  -82,  82,  -81,  81,  -80,  80,
       -79,  79,  -78,  78,  -77,  77,  -76,  76,
       -75,  75,  -74,  74,  -73,  73,  -72,  72,
       -71,  71,  -70,  70,  -69,  69,  -68,  68,
       -67,  67,  -66,  66,  -65,  65,  -64,  64, },
};

static int vlc_decode_block(MimicContext *ctx, DCTELEM *block, int num_coeffs,
                            int qscale)
{
    unsigned int pos;

    memset(block, 0, 64 * sizeof(DCTELEM));

    block[0] = get_bits(&ctx->gb, 8) << 3;

    for(pos = 1; pos < num_coeffs; pos++) {
        uint32_t vlc, num_bits;
        int value;
        int coeff;

        vlc = get_vlc2(&ctx->gb, ctx->vlc1.table, ctx->vlc1.bits, 4);
        if(!vlc) /* end-of-block code */
            return 1;
        if(vlc == -1)
            return 0;

        /* pos_add and num_bits are coded in the vlc code */
        pos +=     vlc&15; // pos_add
        num_bits = vlc>>4; // num_bits

        if(pos >= 64)
            return 0;

        value = get_bits(&ctx->gb, num_bits);

        /* FFmpeg's IDCT behaves somewhat different from the original code, so
         * a factor of 4 was added to the input */

        coeff = vlcdec_lookup[num_bits][value];
        if(pos<3)
            coeff <<= 4;
        else /* TODO Use >> 10 instead of / 1001 */
            coeff = (coeff * qscale) / 1001;

        block[ctx->scantable.permutated[pos]] = coeff;
    }

    return 1;
}

static int decode(MimicContext *ctx, int quality, int num_coeffs,
                  int is_iframe)
{
    int y, x, plane;

    for(plane = 0; plane < 3; plane++) {
        const int is_chroma = !!plane;
        const int qscale = av_clip(10000-quality,is_chroma?1000:2000,10000)<<2;
        const int stride = ctx->flipped_ptrs[ctx->cur_index].linesize[plane];
        const uint8_t *src = ctx->flipped_ptrs[ctx->prev_index].data[plane];
        uint8_t       *dst = ctx->flipped_ptrs[ctx->cur_index ].data[plane];

        for(y = 0 ; y < ctx->num_vblocks[plane] ; y++) {
            for(x = 0; x < ctx->num_hblocks[plane]; x++) {

                /* Check for a change condition in the current block.
                 * - iframes always change.
                 * - Luma plane changes on get_bits1 == 0
                 * - Chroma planes change on get_bits1 == 1 */
                if(is_iframe || get_bits1(&ctx->gb) == is_chroma) {

                    /* Luma planes may use a backreference from the 15 last
                     * frames preceding the previous. (get_bits1 == 1)
                     * Chroma planes don't use backreferences. */
                    if(is_chroma || is_iframe || !get_bits1(&ctx->gb)) {

                        if(!vlc_decode_block(ctx, ctx->dct_block,
                                             num_coeffs, qscale))
                            return 0;
                        ctx->dsp.idct_put(dst, stride, ctx->dct_block);
                    } else {
                        unsigned int backref = get_bits(&ctx->gb, 4);
                        int index = (ctx->cur_index+backref)&15;
                        uint8_t *p = ctx->flipped_ptrs[index].data[0];

                        if(p) {
                            p += src -
                                ctx->flipped_ptrs[ctx->prev_index].data[plane];
                            ctx->dsp.put_pixels_tab[1][0](dst, p, stride, 8);
                        } else {
                            av_log(ctx->avctx, AV_LOG_ERROR,
                                     "No such backreference! Buggy sample.\n");
                        }
                    }
                } else {
                    ctx->dsp.put_pixels_tab[1][0](dst, src, stride, 8);
                }
                src += 8;
                dst += 8;
            }
            src += (stride - ctx->num_hblocks[plane])<<3;
            dst += (stride - ctx->num_hblocks[plane])<<3;
        }
    }

    return 1;
}

/**
 * Flip the buffer upside-down and put it in the YVU order to match the
 * way Mimic encodes frames.
 */
static void prepare_avpic(MimicContext *ctx, AVPicture *dst, AVPicture *src)
{
    int i;
    dst->data[0] = src->data[0]+( ctx->avctx->height    -1)*src->linesize[0];
    dst->data[1] = src->data[2]+((ctx->avctx->height>>1)-1)*src->linesize[2];
    dst->data[2] = src->data[1]+((ctx->avctx->height>>1)-1)*src->linesize[1];
    for(i = 0 ; i < 3 ; i++)
        dst->linesize[i] = -src->linesize[i];
}

static int mimic_decode_frame(AVCodecContext *avctx, void *data,
                              int *data_size, const uint8_t *buf, int buf_size)
{
    MimicContext *ctx = avctx->priv_data;
    int is_pframe;
    int width, height;
    int quality, num_coeffs;
    int swap_buf_size = buf_size - MIMIC_HEADER_SIZE;

    /*
     * Header structure:
     *  uint16_t    I_dont_remember;
     *  uint16_t    quality;
     *  uint16_t    width;
     *  uint16_t    height;
     *  uint32_t    some_constant;
     *  uint32_t    is_pframe;
     *  uint32_t    num_coeffs;
     */

    if(buf_size < MIMIC_HEADER_SIZE) {
        av_log(avctx, AV_LOG_ERROR, "insufficient data\n");
        return -1;
    }

    width  = AV_RL16(buf + 4);
    height = AV_RL16(buf + 6);

    if(!ctx->avctx) {
        int i;

        if(!(width == 160 && height == 120) &&
           !(width == 320 && height == 240)) {
            av_log(avctx, AV_LOG_ERROR, "invalid width/height!\n");
            return -1;
        }

        ctx->avctx     = avctx;
        avctx->width   = width;
        avctx->height  = height;
        avctx->pix_fmt = PIX_FMT_YUV420P;
        for(i = 0 ; i < 3 ; i++) {
            ctx->num_vblocks[i] = -((-height) >> (3 + !!i));
            ctx->num_hblocks[i] =     width   >> (3 + !!i) ;
        }
    } else if(width != ctx->avctx->width || height != ctx->avctx->height) {
        av_log(avctx, AV_LOG_ERROR, "resolution changing is not supported\n");
        return -1;
    }

    quality    = AV_RL16(buf + 2);
    is_pframe  = AV_RL32(buf + 12);
    num_coeffs = buf[16];

    if(is_pframe && !ctx->buf_ptrs[ctx->prev_index].data[0]) {
        av_log(avctx, AV_LOG_ERROR, "decoding must start with keyframe\n");
        return -1;
    }

    ctx->buf_ptrs[ctx->cur_index].reference = 1;
    if(avctx->get_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index])) {
        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
        return -1;
    }

    prepare_avpic(ctx, &ctx->flipped_ptrs[ctx->cur_index],
                  (AVPicture*) &ctx->buf_ptrs[ctx->cur_index]);

    ctx->swap_buf = av_fast_realloc(ctx->swap_buf, &ctx->swap_buf_size,
                                 swap_buf_size + FF_INPUT_BUFFER_PADDING_SIZE);
    if(!ctx->swap_buf)
        return AVERROR_NOMEM;

    ctx->dsp.bswap_buf((uint32_t*)ctx->swap_buf,
                        (const uint32_t*) (buf + MIMIC_HEADER_SIZE),
                        swap_buf_size>>2);
    init_get_bits(&ctx->gb, ctx->swap_buf, swap_buf_size << 3);

    if(!decode(ctx, quality, num_coeffs, !is_pframe)) {
        avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);
        return -1;
    }

    ctx->buf_ptrs[ctx->cur_index].pict_type = is_pframe ? FF_P_TYPE:FF_I_TYPE;
    *(AVFrame*)data = ctx->buf_ptrs[ctx->cur_index];
    *data_size = sizeof(AVFrame);

    ctx->prev_index = ctx->cur_index;
    ctx->cur_index--;
    ctx->cur_index &= 15;

    /* Only release frames that aren't used for backreferences anymore */
    if(ctx->buf_ptrs[ctx->cur_index].data[0])
        avctx->release_buffer(avctx, &ctx->buf_ptrs[ctx->cur_index]);

    return buf_size;
}

static av_cold int mimic_decode_end(AVCodecContext *avctx)
{
    MimicContext *ctx = avctx->priv_data;
    int i;

    av_free(ctx->swap_buf);
    for(i = 0; i < 16; i++)
        if(ctx->buf_ptrs[i].data[0])
            avctx->release_buffer(avctx, &ctx->buf_ptrs[i]);
    free_vlc(&ctx->vlc1);

    return 0;
}

AVCodec mimic_decoder = {
    "mimic",
    CODEC_TYPE_VIDEO,
    CODEC_ID_MIMIC,
    sizeof(MimicContext),
    mimic_decode_init,
    NULL,
    mimic_decode_end,
    mimic_decode_frame,
    CODEC_CAP_DR1,
};