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libavcodec/pngdec.c

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00001 /*
00002  * PNG image format
00003  * Copyright (c) 2003 Fabrice Bellard
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00022 //#define DEBUG
00023 
00024 #include "libavutil/imgutils.h"
00025 #include "avcodec.h"
00026 #include "bytestream.h"
00027 #include "png.h"
00028 
00029 /* TODO:
00030  * - add 2, 4 and 16 bit depth support
00031  */
00032 
00033 #include <zlib.h>
00034 
00035 /* Mask to determine which y pixels can be written in a pass */
00036 static const uint8_t png_pass_dsp_ymask[NB_PASSES] = {
00037     0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55,
00038 };
00039 
00040 /* Mask to determine which pixels to overwrite while displaying */
00041 static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
00042     0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff
00043 };
00044 
00045 /* NOTE: we try to construct a good looking image at each pass. width
00046    is the original image width. We also do pixel format conversion at
00047    this stage */
00048 static void png_put_interlaced_row(uint8_t *dst, int width,
00049                                    int bits_per_pixel, int pass,
00050                                    int color_type, const uint8_t *src)
00051 {
00052     int x, mask, dsp_mask, j, src_x, b, bpp;
00053     uint8_t *d;
00054     const uint8_t *s;
00055 
00056     mask = ff_png_pass_mask[pass];
00057     dsp_mask = png_pass_dsp_mask[pass];
00058     switch(bits_per_pixel) {
00059     case 1:
00060         /* we must initialize the line to zero before writing to it */
00061         if (pass == 0)
00062             memset(dst, 0, (width + 7) >> 3);
00063         src_x = 0;
00064         for(x = 0; x < width; x++) {
00065             j = (x & 7);
00066             if ((dsp_mask << j) & 0x80) {
00067                 b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1;
00068                 dst[x >> 3] |= b << (7 - j);
00069             }
00070             if ((mask << j) & 0x80)
00071                 src_x++;
00072         }
00073         break;
00074     default:
00075         bpp = bits_per_pixel >> 3;
00076         d = dst;
00077         s = src;
00078         if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
00079             for(x = 0; x < width; x++) {
00080                 j = x & 7;
00081                 if ((dsp_mask << j) & 0x80) {
00082                     *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2];
00083                 }
00084                 d += bpp;
00085                 if ((mask << j) & 0x80)
00086                     s += bpp;
00087             }
00088         } else {
00089             for(x = 0; x < width; x++) {
00090                 j = x & 7;
00091                 if ((dsp_mask << j) & 0x80) {
00092                     memcpy(d, s, bpp);
00093                 }
00094                 d += bpp;
00095                 if ((mask << j) & 0x80)
00096                     s += bpp;
00097             }
00098         }
00099         break;
00100     }
00101 }
00102 
00103 // 0x7f7f7f7f or 0x7f7f7f7f7f7f7f7f or whatever, depending on the cpu's native arithmetic size
00104 #define pb_7f (~0UL/255 * 0x7f)
00105 #define pb_80 (~0UL/255 * 0x80)
00106 
00107 static void add_bytes_l2_c(uint8_t *dst, uint8_t *src1, uint8_t *src2, int w)
00108 {
00109     long i;
00110     for(i=0; i<=w-sizeof(long); i+=sizeof(long)){
00111         long a = *(long*)(src1+i);
00112         long b = *(long*)(src2+i);
00113         *(long*)(dst+i) = ((a&pb_7f) + (b&pb_7f)) ^ ((a^b)&pb_80);
00114     }
00115     for(; i<w; i++)
00116         dst[i] = src1[i]+src2[i];
00117 }
00118 
00119 static void add_paeth_prediction_c(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
00120 {
00121     int i;
00122     for(i = 0; i < w; i++) {
00123         int a, b, c, p, pa, pb, pc;
00124 
00125         a = dst[i - bpp];
00126         b = top[i];
00127         c = top[i - bpp];
00128 
00129         p = b - c;
00130         pc = a - c;
00131 
00132         pa = abs(p);
00133         pb = abs(pc);
00134         pc = abs(p + pc);
00135 
00136         if (pa <= pb && pa <= pc)
00137             p = a;
00138         else if (pb <= pc)
00139             p = b;
00140         else
00141             p = c;
00142         dst[i] = p + src[i];
00143     }
00144 }
00145 
00146 #define UNROLL1(bpp, op) {\
00147                  r = dst[0];\
00148     if(bpp >= 2) g = dst[1];\
00149     if(bpp >= 3) b = dst[2];\
00150     if(bpp >= 4) a = dst[3];\
00151     for(; i <= size - bpp; i+=bpp) {\
00152         dst[i+0] = r = op(r, src[i+0], last[i+0]);\
00153         if(bpp == 1) continue;\
00154         dst[i+1] = g = op(g, src[i+1], last[i+1]);\
00155         if(bpp == 2) continue;\
00156         dst[i+2] = b = op(b, src[i+2], last[i+2]);\
00157         if(bpp == 3) continue;\
00158         dst[i+3] = a = op(a, src[i+3], last[i+3]);\
00159     }\
00160 }
00161 
00162 #define UNROLL_FILTER(op)\
00163          if(bpp == 1) UNROLL1(1, op)\
00164     else if(bpp == 2) UNROLL1(2, op)\
00165     else if(bpp == 3) UNROLL1(3, op)\
00166     else if(bpp == 4) UNROLL1(4, op)\
00167     for (; i < size; i++) {\
00168         dst[i] = op(dst[i-bpp], src[i], last[i]);\
00169     }\
00170 
00171 /* NOTE: 'dst' can be equal to 'last' */
00172 static void png_filter_row(PNGDecContext *s, uint8_t *dst, int filter_type,
00173                            uint8_t *src, uint8_t *last, int size, int bpp)
00174 {
00175     int i, p, r, g, b, a;
00176 
00177     switch(filter_type) {
00178     case PNG_FILTER_VALUE_NONE:
00179         memcpy(dst, src, size);
00180         break;
00181     case PNG_FILTER_VALUE_SUB:
00182         for(i = 0; i < bpp; i++) {
00183             dst[i] = src[i];
00184         }
00185         if(bpp == 4) {
00186             p = *(int*)dst;
00187             for(; i < size; i+=bpp) {
00188                 int s = *(int*)(src+i);
00189                 p = ((s&0x7f7f7f7f) + (p&0x7f7f7f7f)) ^ ((s^p)&0x80808080);
00190                 *(int*)(dst+i) = p;
00191             }
00192         } else {
00193 #define OP_SUB(x,s,l) x+s
00194             UNROLL_FILTER(OP_SUB);
00195         }
00196         break;
00197     case PNG_FILTER_VALUE_UP:
00198         s->add_bytes_l2(dst, src, last, size);
00199         break;
00200     case PNG_FILTER_VALUE_AVG:
00201         for(i = 0; i < bpp; i++) {
00202             p = (last[i] >> 1);
00203             dst[i] = p + src[i];
00204         }
00205 #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff
00206         UNROLL_FILTER(OP_AVG);
00207         break;
00208     case PNG_FILTER_VALUE_PAETH:
00209         for(i = 0; i < bpp; i++) {
00210             p = last[i];
00211             dst[i] = p + src[i];
00212         }
00213         if(bpp > 1 && size > 4) {
00214             // would write off the end of the array if we let it process the last pixel with bpp=3
00215             int w = bpp==4 ? size : size-3;
00216             s->add_paeth_prediction(dst+i, src+i, last+i, w-i, bpp);
00217             i = w;
00218         }
00219         add_paeth_prediction_c(dst+i, src+i, last+i, size-i, bpp);
00220         break;
00221     }
00222 }
00223 
00224 static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco)
00225 {
00226     int j;
00227     unsigned int r, g, b, a;
00228 
00229     for(j = 0;j < width; j++) {
00230         r = src[0];
00231         g = src[1];
00232         b = src[2];
00233         a = src[3];
00234         if(loco) {
00235             r = (r+g)&0xff;
00236             b = (b+g)&0xff;
00237         }
00238         *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b;
00239         dst += 4;
00240         src += 4;
00241     }
00242 }
00243 
00244 static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco)
00245 {
00246     if(loco)
00247         convert_to_rgb32_loco(dst, src, width, 1);
00248     else
00249         convert_to_rgb32_loco(dst, src, width, 0);
00250 }
00251 
00252 static void deloco_rgb24(uint8_t *dst, int size)
00253 {
00254     int i;
00255     for(i=0; i<size; i+=3) {
00256         int g = dst[i+1];
00257         dst[i+0] += g;
00258         dst[i+2] += g;
00259     }
00260 }
00261 
00262 /* process exactly one decompressed row */
00263 static void png_handle_row(PNGDecContext *s)
00264 {
00265     uint8_t *ptr, *last_row;
00266     int got_line;
00267 
00268     if (!s->interlace_type) {
00269         ptr = s->image_buf + s->image_linesize * s->y;
00270         /* need to swap bytes correctly for RGB_ALPHA */
00271         if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
00272             png_filter_row(s, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
00273                            s->last_row, s->row_size, s->bpp);
00274             convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO);
00275             FFSWAP(uint8_t*, s->last_row, s->tmp_row);
00276         } else {
00277             /* in normal case, we avoid one copy */
00278             if (s->y == 0)
00279                 last_row = s->last_row;
00280             else
00281                 last_row = ptr - s->image_linesize;
00282 
00283             png_filter_row(s, ptr, s->crow_buf[0], s->crow_buf + 1,
00284                            last_row, s->row_size, s->bpp);
00285         }
00286         /* loco lags by 1 row so that it doesn't interfere with top prediction */
00287         if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
00288             s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0)
00289             deloco_rgb24(ptr - s->image_linesize, s->row_size);
00290         s->y++;
00291         if (s->y == s->height) {
00292             s->state |= PNG_ALLIMAGE;
00293             if (s->filter_type == PNG_FILTER_TYPE_LOCO &&
00294                 s->color_type == PNG_COLOR_TYPE_RGB)
00295                 deloco_rgb24(ptr, s->row_size);
00296         }
00297     } else {
00298         got_line = 0;
00299         for(;;) {
00300             ptr = s->image_buf + s->image_linesize * s->y;
00301             if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) {
00302                 /* if we already read one row, it is time to stop to
00303                    wait for the next one */
00304                 if (got_line)
00305                     break;
00306                 png_filter_row(s, s->tmp_row, s->crow_buf[0], s->crow_buf + 1,
00307                                s->last_row, s->pass_row_size, s->bpp);
00308                 FFSWAP(uint8_t*, s->last_row, s->tmp_row);
00309                 got_line = 1;
00310             }
00311             if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) {
00312                 /* NOTE: RGB32 is handled directly in png_put_interlaced_row */
00313                 png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass,
00314                                        s->color_type, s->last_row);
00315             }
00316             s->y++;
00317             if (s->y == s->height) {
00318                 for(;;) {
00319                     if (s->pass == NB_PASSES - 1) {
00320                         s->state |= PNG_ALLIMAGE;
00321                         goto the_end;
00322                     } else {
00323                         s->pass++;
00324                         s->y = 0;
00325                         s->pass_row_size = ff_png_pass_row_size(s->pass,
00326                                                              s->bits_per_pixel,
00327                                                              s->width);
00328                         s->crow_size = s->pass_row_size + 1;
00329                         if (s->pass_row_size != 0)
00330                             break;
00331                         /* skip pass if empty row */
00332                     }
00333                 }
00334             }
00335         }
00336     the_end: ;
00337     }
00338 }
00339 
00340 static int png_decode_idat(PNGDecContext *s, int length)
00341 {
00342     int ret;
00343     s->zstream.avail_in = length;
00344     s->zstream.next_in = s->bytestream;
00345     s->bytestream += length;
00346 
00347     if(s->bytestream > s->bytestream_end)
00348         return -1;
00349 
00350     /* decode one line if possible */
00351     while (s->zstream.avail_in > 0) {
00352         ret = inflate(&s->zstream, Z_PARTIAL_FLUSH);
00353         if (ret != Z_OK && ret != Z_STREAM_END) {
00354             return -1;
00355         }
00356         if (s->zstream.avail_out == 0) {
00357             if (!(s->state & PNG_ALLIMAGE)) {
00358                 png_handle_row(s);
00359             }
00360             s->zstream.avail_out = s->crow_size;
00361             s->zstream.next_out = s->crow_buf;
00362         }
00363     }
00364     return 0;
00365 }
00366 
00367 static int decode_frame(AVCodecContext *avctx,
00368                         void *data, int *data_size,
00369                         AVPacket *avpkt)
00370 {
00371     const uint8_t *buf = avpkt->data;
00372     int buf_size = avpkt->size;
00373     PNGDecContext * const s = avctx->priv_data;
00374     AVFrame *picture = data;
00375     AVFrame *p;
00376     uint8_t *crow_buf_base = NULL;
00377     uint32_t tag, length;
00378     int ret;
00379 
00380     FFSWAP(AVFrame *, s->current_picture, s->last_picture);
00381     avctx->coded_frame= s->current_picture;
00382     p = s->current_picture;
00383 
00384     s->bytestream_start=
00385     s->bytestream= buf;
00386     s->bytestream_end= buf + buf_size;
00387 
00388     /* check signature */
00389     if (memcmp(s->bytestream, ff_pngsig, 8) != 0 &&
00390         memcmp(s->bytestream, ff_mngsig, 8) != 0)
00391         return -1;
00392     s->bytestream+= 8;
00393     s->y=
00394     s->state=0;
00395 //    memset(s, 0, sizeof(PNGDecContext));
00396     /* init the zlib */
00397     s->zstream.zalloc = ff_png_zalloc;
00398     s->zstream.zfree = ff_png_zfree;
00399     s->zstream.opaque = NULL;
00400     ret = inflateInit(&s->zstream);
00401     if (ret != Z_OK)
00402         return -1;
00403     for(;;) {
00404         int tag32;
00405         if (s->bytestream >= s->bytestream_end)
00406             goto fail;
00407         length = bytestream_get_be32(&s->bytestream);
00408         if (length > 0x7fffffff)
00409             goto fail;
00410         tag32 = bytestream_get_be32(&s->bytestream);
00411         tag = av_bswap32(tag32);
00412         av_dlog(avctx, "png: tag=%c%c%c%c length=%u\n",
00413                 (tag & 0xff),
00414                 ((tag >> 8) & 0xff),
00415                 ((tag >> 16) & 0xff),
00416                 ((tag >> 24) & 0xff), length);
00417         switch(tag) {
00418         case MKTAG('I', 'H', 'D', 'R'):
00419             if (length != 13)
00420                 goto fail;
00421             s->width = bytestream_get_be32(&s->bytestream);
00422             s->height = bytestream_get_be32(&s->bytestream);
00423             if(av_image_check_size(s->width, s->height, 0, avctx)){
00424                 s->width= s->height= 0;
00425                 goto fail;
00426             }
00427             s->bit_depth = *s->bytestream++;
00428             s->color_type = *s->bytestream++;
00429             s->compression_type = *s->bytestream++;
00430             s->filter_type = *s->bytestream++;
00431             s->interlace_type = *s->bytestream++;
00432             s->bytestream += 4; /* crc */
00433             s->state |= PNG_IHDR;
00434             av_dlog(avctx, "width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
00435                     s->width, s->height, s->bit_depth, s->color_type,
00436                     s->compression_type, s->filter_type, s->interlace_type);
00437             break;
00438         case MKTAG('I', 'D', 'A', 'T'):
00439             if (!(s->state & PNG_IHDR))
00440                 goto fail;
00441             if (!(s->state & PNG_IDAT)) {
00442                 /* init image info */
00443                 avctx->width = s->width;
00444                 avctx->height = s->height;
00445 
00446                 s->channels = ff_png_get_nb_channels(s->color_type);
00447                 s->bits_per_pixel = s->bit_depth * s->channels;
00448                 s->bpp = (s->bits_per_pixel + 7) >> 3;
00449                 s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3;
00450 
00451                 if (s->bit_depth == 8 &&
00452                     s->color_type == PNG_COLOR_TYPE_RGB) {
00453                     avctx->pix_fmt = PIX_FMT_RGB24;
00454                 } else if (s->bit_depth == 8 &&
00455                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
00456                     avctx->pix_fmt = PIX_FMT_RGB32;
00457                 } else if (s->bit_depth == 8 &&
00458                            s->color_type == PNG_COLOR_TYPE_GRAY) {
00459                     avctx->pix_fmt = PIX_FMT_GRAY8;
00460                 } else if (s->bit_depth == 16 &&
00461                            s->color_type == PNG_COLOR_TYPE_GRAY) {
00462                     avctx->pix_fmt = PIX_FMT_GRAY16BE;
00463                 } else if (s->bit_depth == 16 &&
00464                            s->color_type == PNG_COLOR_TYPE_RGB) {
00465                     avctx->pix_fmt = PIX_FMT_RGB48BE;
00466                 } else if (s->bit_depth == 1) {
00467                     avctx->pix_fmt = PIX_FMT_MONOBLACK;
00468                 } else if (s->bit_depth == 8 &&
00469                            s->color_type == PNG_COLOR_TYPE_PALETTE) {
00470                     avctx->pix_fmt = PIX_FMT_PAL8;
00471                 } else if (s->bit_depth == 8 &&
00472                            s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
00473                     avctx->pix_fmt = PIX_FMT_Y400A;
00474                 } else {
00475                     goto fail;
00476                 }
00477                 if(p->data[0])
00478                     avctx->release_buffer(avctx, p);
00479 
00480                 p->reference= 0;
00481                 if(avctx->get_buffer(avctx, p) < 0){
00482                     av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00483                     goto fail;
00484                 }
00485                 p->pict_type= AV_PICTURE_TYPE_I;
00486                 p->key_frame= 1;
00487                 p->interlaced_frame = !!s->interlace_type;
00488 
00489                 /* compute the compressed row size */
00490                 if (!s->interlace_type) {
00491                     s->crow_size = s->row_size + 1;
00492                 } else {
00493                     s->pass = 0;
00494                     s->pass_row_size = ff_png_pass_row_size(s->pass,
00495                                                          s->bits_per_pixel,
00496                                                          s->width);
00497                     s->crow_size = s->pass_row_size + 1;
00498                 }
00499                 av_dlog(avctx, "row_size=%d crow_size =%d\n",
00500                         s->row_size, s->crow_size);
00501                 s->image_buf = p->data[0];
00502                 s->image_linesize = p->linesize[0];
00503                 /* copy the palette if needed */
00504                 if (avctx->pix_fmt == PIX_FMT_PAL8)
00505                     memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t));
00506                 /* empty row is used if differencing to the first row */
00507                 s->last_row = av_mallocz(s->row_size);
00508                 if (!s->last_row)
00509                     goto fail;
00510                 if (s->interlace_type ||
00511                     s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
00512                     s->tmp_row = av_malloc(s->row_size);
00513                     if (!s->tmp_row)
00514                         goto fail;
00515                 }
00516                 /* compressed row */
00517                 crow_buf_base = av_malloc(s->row_size + 16);
00518                 if (!crow_buf_base)
00519                     goto fail;
00520 
00521                 /* we want crow_buf+1 to be 16-byte aligned */
00522                 s->crow_buf = crow_buf_base + 15;
00523                 s->zstream.avail_out = s->crow_size;
00524                 s->zstream.next_out = s->crow_buf;
00525             }
00526             s->state |= PNG_IDAT;
00527             if (png_decode_idat(s, length) < 0)
00528                 goto fail;
00529             s->bytestream += 4; /* crc */
00530             break;
00531         case MKTAG('P', 'L', 'T', 'E'):
00532             {
00533                 int n, i, r, g, b;
00534 
00535                 if ((length % 3) != 0 || length > 256 * 3)
00536                     goto skip_tag;
00537                 /* read the palette */
00538                 n = length / 3;
00539                 for(i=0;i<n;i++) {
00540                     r = *s->bytestream++;
00541                     g = *s->bytestream++;
00542                     b = *s->bytestream++;
00543                     s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
00544                 }
00545                 for(;i<256;i++) {
00546                     s->palette[i] = (0xff << 24);
00547                 }
00548                 s->state |= PNG_PLTE;
00549                 s->bytestream += 4; /* crc */
00550             }
00551             break;
00552         case MKTAG('t', 'R', 'N', 'S'):
00553             {
00554                 int v, i;
00555 
00556                 /* read the transparency. XXX: Only palette mode supported */
00557                 if (s->color_type != PNG_COLOR_TYPE_PALETTE ||
00558                     length > 256 ||
00559                     !(s->state & PNG_PLTE))
00560                     goto skip_tag;
00561                 for(i=0;i<length;i++) {
00562                     v = *s->bytestream++;
00563                     s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
00564                 }
00565                 s->bytestream += 4; /* crc */
00566             }
00567             break;
00568         case MKTAG('I', 'E', 'N', 'D'):
00569             if (!(s->state & PNG_ALLIMAGE))
00570                 goto fail;
00571             s->bytestream += 4; /* crc */
00572             goto exit_loop;
00573         default:
00574             /* skip tag */
00575         skip_tag:
00576             s->bytestream += length + 4;
00577             break;
00578         }
00579     }
00580  exit_loop:
00581      /* handle p-frames only if a predecessor frame is available */
00582      if(s->last_picture->data[0] != NULL) {
00583          if(!(avpkt->flags & AV_PKT_FLAG_KEY)) {
00584             int i, j;
00585             uint8_t *pd = s->current_picture->data[0];
00586             uint8_t *pd_last = s->last_picture->data[0];
00587 
00588             for(j=0; j < s->height; j++) {
00589                 for(i=0; i < s->width * s->bpp; i++) {
00590                     pd[i] += pd_last[i];
00591                 }
00592                 pd += s->image_linesize;
00593                 pd_last += s->image_linesize;
00594             }
00595         }
00596     }
00597 
00598     *picture= *s->current_picture;
00599     *data_size = sizeof(AVFrame);
00600 
00601     ret = s->bytestream - s->bytestream_start;
00602  the_end:
00603     inflateEnd(&s->zstream);
00604     av_free(crow_buf_base);
00605     s->crow_buf = NULL;
00606     av_freep(&s->last_row);
00607     av_freep(&s->tmp_row);
00608     return ret;
00609  fail:
00610     ret = -1;
00611     goto the_end;
00612 }
00613 
00614 static av_cold int png_dec_init(AVCodecContext *avctx)
00615 {
00616     PNGDecContext *s = avctx->priv_data;
00617 
00618     s->current_picture = &s->picture1;
00619     s->last_picture = &s->picture2;
00620     avcodec_get_frame_defaults(&s->picture1);
00621     avcodec_get_frame_defaults(&s->picture2);
00622 
00623 #if HAVE_MMX
00624     ff_png_init_mmx(s);
00625 #endif
00626 
00627     if (!s->add_paeth_prediction)
00628         s->add_paeth_prediction = add_paeth_prediction_c;
00629     if (!s->add_bytes_l2)
00630         s->add_bytes_l2 = add_bytes_l2_c;
00631 
00632     return 0;
00633 }
00634 
00635 static av_cold int png_dec_end(AVCodecContext *avctx)
00636 {
00637     PNGDecContext *s = avctx->priv_data;
00638 
00639     if (s->picture1.data[0])
00640         avctx->release_buffer(avctx, &s->picture1);
00641     if (s->picture2.data[0])
00642         avctx->release_buffer(avctx, &s->picture2);
00643 
00644     return 0;
00645 }
00646 
00647 AVCodec ff_png_decoder = {
00648     "png",
00649     AVMEDIA_TYPE_VIDEO,
00650     CODEC_ID_PNG,
00651     sizeof(PNGDecContext),
00652     png_dec_init,
00653     NULL,
00654     png_dec_end,
00655     decode_frame,
00656     CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
00657     NULL,
00658     .long_name = NULL_IF_CONFIG_SMALL("PNG image"),
00659 };

Generated on Fri Feb 22 2013 07:24:28 for FFmpeg by  doxygen 1.7.1