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ffmpeg / libavcodec / pngdec.c @ 72415b2a

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1
/*
2
 * PNG image format
3
 * Copyright (c) 2003 Fabrice Bellard
4
 *
5
 * This file is part of FFmpeg.
6
 *
7
 * FFmpeg is free software; you can redistribute it and/or
8
 * modify it under the terms of the GNU Lesser General Public
9
 * License as published by the Free Software Foundation; either
10
 * version 2.1 of the License, or (at your option) any later version.
11
 *
12
 * FFmpeg is distributed in the hope that it will be useful,
13
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
15
 * Lesser General Public License for more details.
16
 *
17
 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20
 */
21
#include "avcodec.h"
22
#include "bytestream.h"
23
#include "png.h"
24
#include "dsputil.h"
25

    
26
/* TODO:
27
 * - add 2, 4 and 16 bit depth support
28
 */
29

    
30
#include <zlib.h>
31

    
32
//#define DEBUG
33

    
34
typedef struct PNGDecContext {
35
    DSPContext dsp;
36

    
37
    const uint8_t *bytestream;
38
    const uint8_t *bytestream_start;
39
    const uint8_t *bytestream_end;
40
    AVFrame picture1, picture2;
41
    AVFrame *current_picture, *last_picture;
42

    
43
    int state;
44
    int width, height;
45
    int bit_depth;
46
    int color_type;
47
    int compression_type;
48
    int interlace_type;
49
    int filter_type;
50
    int channels;
51
    int bits_per_pixel;
52
    int bpp;
53

    
54
    uint8_t *image_buf;
55
    int image_linesize;
56
    uint32_t palette[256];
57
    uint8_t *crow_buf;
58
    uint8_t *last_row;
59
    uint8_t *tmp_row;
60
    int pass;
61
    int crow_size; /* compressed row size (include filter type) */
62
    int row_size; /* decompressed row size */
63
    int pass_row_size; /* decompress row size of the current pass */
64
    int y;
65
    z_stream zstream;
66
} PNGDecContext;
67

    
68
/* Mask to determine which y pixels can be written in a pass */
69
static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
70
    0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
71
};
72

    
73
/* Mask to determine which pixels to overwrite while displaying */
74
static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
75
    0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
76
};
77

    
78
/* NOTE: we try to construct a good looking image at each pass. width
79
   is the original image width. We also do pixel format conversion at
80
   this stage */
81
static void png_put_interlaced_row(uint8_t *dst, int width,
82
                                   int bits_per_pixel, int pass,
83
                                   int color_type, const uint8_t *src)
84
{
85
    int x, mask, dsp_mask, j, src_x, b, bpp;
86
    uint8_t *d;
87
    const uint8_t *s;
88

    
89
    mask = ff_png_pass_mask[pass];
90
    dsp_mask = png_pass_dsp_mask[pass];
91
    switch(bits_per_pixel) {
92
    case 1:
93
        /* we must initialize the line to zero before writing to it */
94
        if (pass == 0)
95
            memset(dst, 0, (width + 7) >> 3);
96
        src_x = 0;
97
        for(x = 0; x < width; x++) {
98
            j = (x & 7);
99
            if ((dsp_mask << j) & 0x80) {
100
                b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
101
                dst[x >> 3] |= b << (7 - j);
102
            }
103
            if ((mask << j) & 0x80)
104
                src_x++;
105
        }
106
        break;
107
    default:
108
        bpp = bits_per_pixel >> 3;
109
        d = dst;
110
        s = src;
111
        if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
112
            for(x = 0; x < width; x++) {
113
                j = x & 7;
114
                if ((dsp_mask << j) & 0x80) {
115
                    *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
116
                }
117
                d += bpp;
118
                if ((mask << j) & 0x80)
119
                    s += bpp;
120
            }
121
        } else {
122
            for(x = 0; x < width; x++) {
123
                j = x & 7;
124
                if ((dsp_mask << j) & 0x80) {
125
                    memcpy(d, s, bpp);
126
                }
127
                d += bpp;
128
                if ((mask << j) & 0x80)
129
                    s += bpp;
130
            }
131
        }
132
        break;
133
    }
134
}
135

    
136
void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
137
{
138
    int i;
139
    for(i = 0; i < w; i++) {
140
        int a, b, c, p, pa, pb, pc;
141

    
142
        a = dst[i - bpp];
143
        b = top[i];
144
        c = top[i - bpp];
145

    
146
        p = b - c;
147
        pc = a - c;
148

    
149
        pa = abs(p);
150
        pb = abs(pc);
151
        pc = abs(p + pc);
152

    
153
        if (pa <= pb && pa <= pc)
154
            p = a;
155
        else if (pb <= pc)
156
            p = b;
157
        else
158
            p = c;
159
        dst[i] = p + src[i];
160
    }
161
}
162

    
163
#define UNROLL1(bpp, op) {\
164
                 r = dst[0];\
165
    if(bpp >= 2) g = dst[1];\
166
    if(bpp >= 3) b = dst[2];\
167
    if(bpp >= 4) a = dst[3];\
168
    for(; i < size; i+=bpp) {\
169
        dst[i+0] = r = op(r, src[i+0], last[i+0]);\
170
        if(bpp == 1) continue;\
171
        dst[i+1] = g = op(g, src[i+1], last[i+1]);\
172
        if(bpp == 2) continue;\
173
        dst[i+2] = b = op(b, src[i+2], last[i+2]);\
174
        if(bpp == 3) continue;\
175
        dst[i+3] = a = op(a, src[i+3], last[i+3]);\
176
    }\
177
}
178

    
179
#define UNROLL_FILTER(op)\
180
         if(bpp == 1) UNROLL1(1, op)\
181
    else if(bpp == 2) UNROLL1(2, op)\
182
    else if(bpp == 3) UNROLL1(3, op)\
183
    else if(bpp == 4) UNROLL1(4, op)\
184
    else {\
185
        for (; i < size; i += bpp) {\
186
            int j;\
187
            for (j = 0; j < bpp; j++)\
188
                dst[i+j] = op(dst[i+j-bpp], src[i+j], last[i+j]);\
189
        }\
190
    }
191

    
192
/* NOTE: 'dst' can be equal to 'last' */
193
static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,
194
                           uint8_t *src, uint8_t *last, int size, int bpp)
195
{
196
    int i, p, r, g, b, a;
197

    
198
    switch(filter_type) {
199
    case PNG_FILTER_VALUE_NONE:
200
        memcpy(dst, src, size);
201
        break;
202
    case PNG_FILTER_VALUE_SUB:
203
        for(i = 0; i < bpp; i++) {
204
            dst[i] = src[i];
205
        }
206
        if(bpp == 4) {
207
            p = *(int*)dst;
208
            for(; i < size; i+=bpp) {
209
                int s = *(int*)(src+i);
210
                p = ((s&0x7f7f7f7f) + (p&0x7f7f7f7f)) ^ ((s^p)&0x80808080);
211
                *(int*)(dst+i) = p;
212
            }
213
        } else {
214
#define OP_SUB(x,s,l) x+s
215
            UNROLL_FILTER(OP_SUB);
216
        }
217
        break;
218
    case PNG_FILTER_VALUE_UP:
219
        dsp->add_bytes_l2(dst, src, last, size);
220
        break;
221
    case PNG_FILTER_VALUE_AVG:
222
        for(i = 0; i < bpp; i++) {
223
            p = (last[i] >> 1);
224
            dst[i] = p + src[i];
225
        }
226
#define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
227
        UNROLL_FILTER(OP_AVG);
228
        break;
229
    case PNG_FILTER_VALUE_PAETH:
230
        for(i = 0; i < bpp; i++) {
231
            p = last[i];
232
            dst[i] = p + src[i];
233
        }
234
        if(bpp > 1 && size > 4) {
235
            // would write off the end of the array if we let it process the last pixel with bpp=3
236
            int w = bpp==4 ? size : size-3;
237
            dsp->add_png_paeth_prediction(dst+i, src+i, last+i, w-i, bpp);
238
            i = w;
239
        }
240
        ff_add_png_paeth_prediction(dst+i, src+i, last+i, size-i, bpp);
241
        break;
242
    }
243
}
244

    
245
static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco)
246
{
247
    int j;
248
    unsigned int r, g, b, a;
249

    
250
    for(j = 0;j < width; j++) {
251
        r = src[0];
252
        g = src[1];
253
        b = src[2];
254
        a = src[3];
255
        if(loco) {
256
            r = (r+g)&0xff;
257
            b = (b+g)&0xff;
258
        }
259
        *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
260
        dst += 4;
261
        src += 4;
262
    }
263
}
264

    
265
static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco)
266
{
267
    if(loco)
268
        convert_to_rgb32_loco(dst, src, width, 1);
269
    else
270
        convert_to_rgb32_loco(dst, src, width, 0);
271
}
272

    
273
static void deloco_rgb24(uint8_t *dst, int size)
274
{
275
    int i;
276
    for(i=0; i<size; i+=3) {
277
        int g = dst[i+1];
278
        dst[i+0] += g;
279
        dst[i+2] += g;
280
    }
281
}
282

    
283
/* process exactly one decompressed row */
284
static void png_handle_row(PNGDecContext *s)
285
{
286
    uint8_t *ptr, *last_row;
287
    int got_line;
288

    
289
    if (!s->interlace_type) {
290
        ptr = s->image_buf + s->image_linesize * s->y;
291
        /* need to swap bytes correctly for RGB_ALPHA */
292
        if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
293
            png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
294
                           s->last_row, s->row_size, s->bpp);
295
            convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO);
296
            FFSWAP(uint8_t*, s->last_row, s->tmp_row);
297
        } else {
298
            /* in normal case, we avoid one copy */
299
            if (s->y == 0)
300
                last_row = s->last_row;
301
            else
302
                last_row = ptr - s->image_linesize;
303

    
304
            png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1,
305
                           last_row, s->row_size, s->bpp);
306
        }
307
        /* loco lags by 1 row so that it doesn't interfere with top prediction */
308
        if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
309
            s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0)
310
            deloco_rgb24(ptr - s->image_linesize, s->row_size);
311
        s->y++;
312
        if (s->y == s->height) {
313
            s->state |= PNG_ALLIMAGE;
314
            if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
315
                s->color_type == PNG_COLOR_TYPE_RGB)
316
                deloco_rgb24(ptr, s->row_size);
317
        }
318
    } else {
319
        got_line = 0;
320
        for(;;) {
321
            ptr = s->image_buf + s->image_linesize * s->y;
322
            if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
323
                /* if we already read one row, it is time to stop to
324
                   wait for the next one */
325
                if (got_line)
326
                    break;
327
                png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
328
                               s->last_row, s->pass_row_size, s->bpp);
329
                FFSWAP(uint8_t*, s->last_row, s->tmp_row);
330
                got_line = 1;
331
            }
332
            if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
333
                /* NOTE: RGB32 is handled directly in png_put_interlaced_row */
334
                png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
335
                                       s->color_type, s->last_row);
336
            }
337
            s->y++;
338
            if (s->y == s->height) {
339
                for(;;) {
340
                    if (s->pass == NB_PASSES - 1) {
341
                        s->state |= PNG_ALLIMAGE;
342
                        goto the_end;
343
                    } else {
344
                        s->pass++;
345
                        s->y = 0;
346
                        s->pass_row_size = ff_png_pass_row_size(s->pass,
347
                                                             s->bits_per_pixel,
348
                                                             s->width);
349
                        s->crow_size = s->pass_row_size + 1;
350
                        if (s->pass_row_size != 0)
351
                            break;
352
                        /* skip pass if empty row */
353
                    }
354
                }
355
            }
356
        }
357
    the_end: ;
358
    }
359
}
360

    
361
static int png_decode_idat(PNGDecContext *s, int length)
362
{
363
    int ret;
364
    s->zstream.avail_in = length;
365
    s->zstream.next_in = s->bytestream;
366
    s->bytestream += length;
367

    
368
    if(s->bytestream > s->bytestream_end)
369
        return -1;
370

    
371
    /* decode one line if possible */
372
    while (s->zstream.avail_in > 0) {
373
        ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
374
        if (ret != Z_OK && ret != Z_STREAM_END) {
375
            return -1;
376
        }
377
        if (s->zstream.avail_out == 0) {
378
            if (!(s->state & PNG_ALLIMAGE)) {
379
                png_handle_row(s);
380
            }
381
            s->zstream.avail_out = s->crow_size;
382
            s->zstream.next_out = s->crow_buf;
383
        }
384
    }
385
    return 0;
386
}
387

    
388
static int decode_frame(AVCodecContext *avctx,
389
                        void *data, int *data_size,
390
                        AVPacket *avpkt)
391
{
392
    const uint8_t *buf = avpkt->data;
393
    int buf_size = avpkt->size;
394
    PNGDecContext * const s = avctx->priv_data;
395
    AVFrame *picture = data;
396
    AVFrame *p;
397
    uint8_t *crow_buf_base = NULL;
398
    uint32_t tag, length;
399
    int ret, crc;
400

    
401
    FFSWAP(AVFrame *, s->current_picture, s->last_picture);
402
    avctx->coded_frame= s->current_picture;
403
    p = s->current_picture;
404

    
405
    s->bytestream_start=
406
    s->bytestream= buf;
407
    s->bytestream_end= buf + buf_size;
408

    
409
    /* check signature */
410
    if (memcmp(s->bytestream, ff_pngsig, 8) != 0 &&
411
        memcmp(s->bytestream, ff_mngsig, 8) != 0)
412
        return -1;
413
    s->bytestream+= 8;
414
    s->y=
415
    s->state=0;
416
//    memset(s, 0, sizeof(PNGDecContext));
417
    /* init the zlib */
418
    s->zstream.zalloc = ff_png_zalloc;
419
    s->zstream.zfree = ff_png_zfree;
420
    s->zstream.opaque = NULL;
421
    ret = inflateInit(&s->zstream);
422
    if (ret != Z_OK)
423
        return -1;
424
    for(;;) {
425
        int tag32;
426
        if (s->bytestream >= s->bytestream_end)
427
            goto fail;
428
        length = bytestream_get_be32(&s->bytestream);
429
        if (length > 0x7fffffff)
430
            goto fail;
431
        tag32 = bytestream_get_be32(&s->bytestream);
432
        tag = bswap_32(tag32);
433
        dprintf(avctx, "png: tag=%c%c%c%c length=%u\n",
434
                (tag & 0xff),
435
                ((tag >> 8) & 0xff),
436
                ((tag >> 16) & 0xff),
437
                ((tag >> 24) & 0xff), length);
438
        switch(tag) {
439
        case MKTAG('I', 'H', 'D', 'R'):
440
            if (length != 13)
441
                goto fail;
442
            s->width = bytestream_get_be32(&s->bytestream);
443
            s->height = bytestream_get_be32(&s->bytestream);
444
            if(avcodec_check_dimensions(avctx, s->width, s->height)){
445
                s->width= s->height= 0;
446
                goto fail;
447
            }
448
            s->bit_depth = *s->bytestream++;
449
            s->color_type = *s->bytestream++;
450
            s->compression_type = *s->bytestream++;
451
            s->filter_type = *s->bytestream++;
452
            s->interlace_type = *s->bytestream++;
453
            crc = bytestream_get_be32(&s->bytestream);
454
            s->state |= PNG_IHDR;
455
            dprintf(avctx, "width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
456
                    s->width, s->height, s->bit_depth, s->color_type,
457
                    s->compression_type, s->filter_type, s->interlace_type);
458
            break;
459
        case MKTAG('I', 'D', 'A', 'T'):
460
            if (!(s->state & PNG_IHDR))
461
                goto fail;
462
            if (!(s->state & PNG_IDAT)) {
463
                /* init image info */
464
                avctx->width = s->width;
465
                avctx->height = s->height;
466

    
467
                s->channels = ff_png_get_nb_channels(s->color_type);
468
                s->bits_per_pixel = s->bit_depth * s->channels;
469
                s->bpp = (s->bits_per_pixel + 7) >> 3;
470
                s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
471

    
472
                if (s->bit_depth == 8 &&
473
                    s->color_type == PNG_COLOR_TYPE_RGB) {
474
                    avctx->pix_fmt = PIX_FMT_RGB24;
475
                } else if (s->bit_depth == 8 &&
476
                           s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
477
                    avctx->pix_fmt = PIX_FMT_RGB32;
478
                } else if (s->bit_depth == 8 &&
479
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
480
                    avctx->pix_fmt = PIX_FMT_GRAY8;
481
                } else if (s->bit_depth == 16 &&
482
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
483
                    avctx->pix_fmt = PIX_FMT_GRAY16BE;
484
                } else if (s->bit_depth == 16 &&
485
                           s->color_type == PNG_COLOR_TYPE_RGB) {
486
                    avctx->pix_fmt = PIX_FMT_RGB48BE;
487
                } else if (s->bit_depth == 1 &&
488
                           s->color_type == PNG_COLOR_TYPE_GRAY) {
489
                    avctx->pix_fmt = PIX_FMT_MONOBLACK;
490
                } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
491
                    avctx->pix_fmt = PIX_FMT_PAL8;
492
                } else {
493
                    goto fail;
494
                }
495
                if(p->data[0])
496
                    avctx->release_buffer(avctx, p);
497

    
498
                p->reference= 0;
499
                if(avctx->get_buffer(avctx, p) < 0){
500
                    av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
501
                    goto fail;
502
                }
503
                p->pict_type= FF_I_TYPE;
504
                p->key_frame= 1;
505
                p->interlaced_frame = !!s->interlace_type;
506

    
507
                /* compute the compressed row size */
508
                if (!s->interlace_type) {
509
                    s->crow_size = s->row_size + 1;
510
                } else {
511
                    s->pass = 0;
512
                    s->pass_row_size = ff_png_pass_row_size(s->pass,
513
                                                         s->bits_per_pixel,
514
                                                         s->width);
515
                    s->crow_size = s->pass_row_size + 1;
516
                }
517
                dprintf(avctx, "row_size=%d crow_size =%d\n",
518
                        s->row_size, s->crow_size);
519
                s->image_buf = p->data[0];
520
                s->image_linesize = p->linesize[0];
521
                /* copy the palette if needed */
522
                if (s->color_type == PNG_COLOR_TYPE_PALETTE)
523
                    memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
524
                /* empty row is used if differencing to the first row */
525
                s->last_row = av_mallocz(s->row_size);
526
                if (!s->last_row)
527
                    goto fail;
528
                if (s->interlace_type ||
529
                    s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
530
                    s->tmp_row = av_malloc(s->row_size);
531
                    if (!s->tmp_row)
532
                        goto fail;
533
                }
534
                /* compressed row */
535
                crow_buf_base = av_malloc(s->row_size + 16);
536
                if (!crow_buf_base)
537
                    goto fail;
538

    
539
                /* we want crow_buf+1 to be 16-byte aligned */
540
                s->crow_buf = crow_buf_base + 15;
541
                s->zstream.avail_out = s->crow_size;
542
                s->zstream.next_out = s->crow_buf;
543
            }
544
            s->state |= PNG_IDAT;
545
            if (png_decode_idat(s, length) < 0)
546
                goto fail;
547
            /* skip crc */
548
            crc = bytestream_get_be32(&s->bytestream);
549
            break;
550
        case MKTAG('P', 'L', 'T', 'E'):
551
            {
552
                int n, i, r, g, b;
553

    
554
                if ((length % 3) != 0 || length > 256 * 3)
555
                    goto skip_tag;
556
                /* read the palette */
557
                n = length / 3;
558
                for(i=0;i<n;i++) {
559
                    r = *s->bytestream++;
560
                    g = *s->bytestream++;
561
                    b = *s->bytestream++;
562
                    s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
563
                }
564
                for(;i<256;i++) {
565
                    s->palette[i] = (0xff << 24);
566
                }
567
                s->state |= PNG_PLTE;
568
                crc = bytestream_get_be32(&s->bytestream);
569
            }
570
            break;
571
        case MKTAG('t', 'R', 'N', 'S'):
572
            {
573
                int v, i;
574

    
575
                /* read the transparency. XXX: Only palette mode supported */
576
                if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
577
                    length > 256 ||
578
                    !(s->state & PNG_PLTE))
579
                    goto skip_tag;
580
                for(i=0;i<length;i++) {
581
                    v = *s->bytestream++;
582
                    s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
583
                }
584
                crc = bytestream_get_be32(&s->bytestream);
585
            }
586
            break;
587
        case MKTAG('I', 'E', 'N', 'D'):
588
            if (!(s->state & PNG_ALLIMAGE))
589
                goto fail;
590
            crc = bytestream_get_be32(&s->bytestream);
591
            goto exit_loop;
592
        default:
593
            /* skip tag */
594
        skip_tag:
595
            s->bytestream += length + 4;
596
            break;
597
        }
598
    }
599
 exit_loop:
600
     /* handle p-frames only if a predecessor frame is available */
601
     if(s->last_picture->data[0] != NULL) {
602
         if(!(avpkt->flags & PKT_FLAG_KEY)) {
603
            int i, j;
604
            uint8_t *pd = s->current_picture->data[0];
605
            uint8_t *pd_last = s->last_picture->data[0];
606

    
607
            for(j=0; j < s->height; j++) {
608
                for(i=0; i < s->width * s->bpp; i++) {
609
                    pd[i] += pd_last[i];
610
                }
611
                pd += s->image_linesize;
612
                pd_last += s->image_linesize;
613
            }
614
        }
615
    }
616

    
617
    *picture= *s->current_picture;
618
    *data_size = sizeof(AVFrame);
619

    
620
    ret = s->bytestream - s->bytestream_start;
621
 the_end:
622
    inflateEnd(&s->zstream);
623
    av_free(crow_buf_base);
624
    s->crow_buf = NULL;
625
    av_freep(&s->last_row);
626
    av_freep(&s->tmp_row);
627
    return ret;
628
 fail:
629
    ret = -1;
630
    goto the_end;
631
}
632

    
633
static av_cold int png_dec_init(AVCodecContext *avctx){
634
    PNGDecContext *s = avctx->priv_data;
635

    
636
    s->current_picture = &s->picture1;
637
    s->last_picture = &s->picture2;
638
    avcodec_get_frame_defaults(&s->picture1);
639
    avcodec_get_frame_defaults(&s->picture2);
640
    dsputil_init(&s->dsp, avctx);
641

    
642
    return 0;
643
}
644

    
645
static av_cold int png_dec_end(AVCodecContext *avctx)
646
{
647
    PNGDecContext *s = avctx->priv_data;
648

    
649
    if (s->picture1.data[0])
650
        avctx->release_buffer(avctx, &s->picture1);
651
    if (s->picture2.data[0])
652
        avctx->release_buffer(avctx, &s->picture2);
653

    
654
    return 0;
655
}
656

    
657
AVCodec png_decoder = {
658
    "png",
659
    AVMEDIA_TYPE_VIDEO,
660
    CODEC_ID_PNG,
661
    sizeof(PNGDecContext),
662
    png_dec_init,
663
    NULL,
664
    png_dec_end,
665
    decode_frame,
666
    CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
667
    NULL,
668
    .long_name = NULL_IF_CONFIG_SMALL("PNG image"),
669
};