/* * PNG image format * Copyright (c) 2003 Fabrice Bellard * * 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 */ #include "libavutil/imgutils.h" #include "avcodec.h" #include "bytestream.h" #include "png.h" #include "pngdsp.h" /* TODO: * - add 2, 4 and 16 bit depth support */ #include <zlib.h> //#define DEBUG typedef struct PNGDecContext { PNGDSPContext dsp; GetByteContext gb; AVFrame picture1, picture2; AVFrame *current_picture, *last_picture; int state; int width, height; int bit_depth; int color_type; int compression_type; int interlace_type; int filter_type; int channels; int bits_per_pixel; int bpp; uint8_t *image_buf; int image_linesize; uint32_t palette[256]; uint8_t *crow_buf; uint8_t *last_row; uint8_t *tmp_row; int pass; int crow_size; /* compressed row size (include filter type) */ int row_size; /* decompressed row size */ int pass_row_size; /* decompress row size of the current pass */ int y; z_stream zstream; } PNGDecContext; /* Mask to determine which y pixels can be written in a pass */ static const uint8_t png_pass_dsp_ymask[NB_PASSES] = { 0xff, 0xff, 0x0f, 0xcc, 0x33, 0xff, 0x55, }; /* Mask to determine which pixels to overwrite while displaying */ static const uint8_t png_pass_dsp_mask[NB_PASSES] = { 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55, 0xff }; /* NOTE: we try to construct a good looking image at each pass. width is the original image width. We also do pixel format conversion at this stage */ static void png_put_interlaced_row(uint8_t *dst, int width, int bits_per_pixel, int pass, int color_type, const uint8_t *src) { int x, mask, dsp_mask, j, src_x, b, bpp; uint8_t *d; const uint8_t *s; mask = ff_png_pass_mask[pass]; dsp_mask = png_pass_dsp_mask[pass]; switch(bits_per_pixel) { case 1: /* we must initialize the line to zero before writing to it */ if (pass == 0) memset(dst, 0, (width + 7) >> 3); src_x = 0; for(x = 0; x < width; x++) { j = (x & 7); if ((dsp_mask << j) & 0x80) { b = (src[src_x >> 3] >> (7 - (src_x & 7))) & 1; dst[x >> 3] |= b << (7 - j); } if ((mask << j) & 0x80) src_x++; } break; default: bpp = bits_per_pixel >> 3; d = dst; s = src; if (color_type == PNG_COLOR_TYPE_RGB_ALPHA) { for(x = 0; x < width; x++) { j = x & 7; if ((dsp_mask << j) & 0x80) { *(uint32_t *)d = (s[3] << 24) | (s[0] << 16) | (s[1] << 8) | s[2]; } d += bpp; if ((mask << j) & 0x80) s += bpp; } } else { for(x = 0; x < width; x++) { j = x & 7; if ((dsp_mask << j) & 0x80) { memcpy(d, s, bpp); } d += bpp; if ((mask << j) & 0x80) s += bpp; } } break; } } void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp) { int i; for(i = 0; i < w; i++) { int a, b, c, p, pa, pb, pc; a = dst[i - bpp]; b = top[i]; c = top[i - bpp]; p = b - c; pc = a - c; pa = abs(p); pb = abs(pc); pc = abs(p + pc); if (pa <= pb && pa <= pc) p = a; else if (pb <= pc) p = b; else p = c; dst[i] = p + src[i]; } } #define UNROLL1(bpp, op) {\ r = dst[0];\ if(bpp >= 2) g = dst[1];\ if(bpp >= 3) b = dst[2];\ if(bpp >= 4) a = dst[3];\ for(; i < size; i+=bpp) {\ dst[i+0] = r = op(r, src[i+0], last[i+0]);\ if(bpp == 1) continue;\ dst[i+1] = g = op(g, src[i+1], last[i+1]);\ if(bpp == 2) continue;\ dst[i+2] = b = op(b, src[i+2], last[i+2]);\ if(bpp == 3) continue;\ dst[i+3] = a = op(a, src[i+3], last[i+3]);\ }\ } #define UNROLL_FILTER(op)\ if(bpp == 1) UNROLL1(1, op)\ else if(bpp == 2) UNROLL1(2, op)\ else if(bpp == 3) UNROLL1(3, op)\ else if(bpp == 4) UNROLL1(4, op)\ else {\ for (; i < size; i += bpp) {\ int j;\ for (j = 0; j < bpp; j++)\ dst[i+j] = op(dst[i+j-bpp], src[i+j], last[i+j]);\ }\ } /* NOTE: 'dst' can be equal to 'last' */ static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type, uint8_t *src, uint8_t *last, int size, int bpp) { int i, p, r, g, b, a; switch(filter_type) { case PNG_FILTER_VALUE_NONE: memcpy(dst, src, size); break; case PNG_FILTER_VALUE_SUB: for(i = 0; i < bpp; i++) { dst[i] = src[i]; } if(bpp == 4) { p = *(int*)dst; for(; i < size; i+=bpp) { int s = *(int*)(src+i); p = ((s&0x7f7f7f7f) + (p&0x7f7f7f7f)) ^ ((s^p)&0x80808080); *(int*)(dst+i) = p; } } else { #define OP_SUB(x,s,l) x+s UNROLL_FILTER(OP_SUB); } break; case PNG_FILTER_VALUE_UP: dsp->add_bytes_l2(dst, src, last, size); break; case PNG_FILTER_VALUE_AVG: for(i = 0; i < bpp; i++) { p = (last[i] >> 1); dst[i] = p + src[i]; } #define OP_AVG(x,s,l) (((x + l) >> 1) + s) & 0xff UNROLL_FILTER(OP_AVG); break; case PNG_FILTER_VALUE_PAETH: for(i = 0; i < bpp; i++) { p = last[i]; dst[i] = p + src[i]; } if(bpp > 1 && size > 4) { // would write off the end of the array if we let it process the last pixel with bpp=3 int w = bpp==4 ? size : size-3; dsp->add_paeth_prediction(dst+i, src+i, last+i, w-i, bpp); i = w; } ff_add_png_paeth_prediction(dst+i, src+i, last+i, size-i, bpp); break; } } static av_always_inline void convert_to_rgb32_loco(uint8_t *dst, const uint8_t *src, int width, int loco) { int j; unsigned int r, g, b, a; for(j = 0;j < width; j++) { r = src[0]; g = src[1]; b = src[2]; a = src[3]; if(loco) { r = (r+g)&0xff; b = (b+g)&0xff; } *(uint32_t *)dst = (a << 24) | (r << 16) | (g << 8) | b; dst += 4; src += 4; } } static void convert_to_rgb32(uint8_t *dst, const uint8_t *src, int width, int loco) { if(loco) convert_to_rgb32_loco(dst, src, width, 1); else convert_to_rgb32_loco(dst, src, width, 0); } static void deloco_rgb24(uint8_t *dst, int size) { int i; for(i=0; i<size; i+=3) { int g = dst[i+1]; dst[i+0] += g; dst[i+2] += g; } } /* process exactly one decompressed row */ static void png_handle_row(PNGDecContext *s) { uint8_t *ptr, *last_row; int got_line; if (!s->interlace_type) { ptr = s->image_buf + s->image_linesize * s->y; /* need to swap bytes correctly for RGB_ALPHA */ if (s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1, s->last_row, s->row_size, s->bpp); convert_to_rgb32(ptr, s->tmp_row, s->width, s->filter_type == PNG_FILTER_TYPE_LOCO); FFSWAP(uint8_t*, s->last_row, s->tmp_row); } else { /* in normal case, we avoid one copy */ if (s->y == 0) last_row = s->last_row; else last_row = ptr - s->image_linesize; png_filter_row(&s->dsp, ptr, s->crow_buf[0], s->crow_buf + 1, last_row, s->row_size, s->bpp); } /* loco lags by 1 row so that it doesn't interfere with top prediction */ if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->color_type == PNG_COLOR_TYPE_RGB && s->y > 0) deloco_rgb24(ptr - s->image_linesize, s->row_size); s->y++; if (s->y == s->height) { s->state |= PNG_ALLIMAGE; if (s->filter_type == PNG_FILTER_TYPE_LOCO && s->color_type == PNG_COLOR_TYPE_RGB) deloco_rgb24(ptr, s->row_size); } } else { got_line = 0; for(;;) { ptr = s->image_buf + s->image_linesize * s->y; if ((ff_png_pass_ymask[s->pass] << (s->y & 7)) & 0x80) { /* if we already read one row, it is time to stop to wait for the next one */ if (got_line) break; png_filter_row(&s->dsp, s->tmp_row, s->crow_buf[0], s->crow_buf + 1, s->last_row, s->pass_row_size, s->bpp); FFSWAP(uint8_t*, s->last_row, s->tmp_row); got_line = 1; } if ((png_pass_dsp_ymask[s->pass] << (s->y & 7)) & 0x80) { /* NOTE: RGB32 is handled directly in png_put_interlaced_row */ png_put_interlaced_row(ptr, s->width, s->bits_per_pixel, s->pass, s->color_type, s->last_row); } s->y++; if (s->y == s->height) { for(;;) { if (s->pass == NB_PASSES - 1) { s->state |= PNG_ALLIMAGE; goto the_end; } else { s->pass++; s->y = 0; s->pass_row_size = ff_png_pass_row_size(s->pass, s->bits_per_pixel, s->width); s->crow_size = s->pass_row_size + 1; if (s->pass_row_size != 0) break; /* skip pass if empty row */ } } } } the_end: ; } } static int png_decode_idat(PNGDecContext *s, int length) { int ret; s->zstream.avail_in = FFMIN(length, bytestream2_get_bytes_left(&s->gb)); s->zstream.next_in = s->gb.buffer; bytestream2_skip(&s->gb, length); /* decode one line if possible */ while (s->zstream.avail_in > 0) { ret = inflate(&s->zstream, Z_PARTIAL_FLUSH); if (ret != Z_OK && ret != Z_STREAM_END) { return -1; } if (s->zstream.avail_out == 0) { if (!(s->state & PNG_ALLIMAGE)) { png_handle_row(s); } s->zstream.avail_out = s->crow_size; s->zstream.next_out = s->crow_buf; } } return 0; } static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, AVPacket *avpkt) { const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; PNGDecContext * const s = avctx->priv_data; AVFrame *picture = data; AVFrame *p; uint8_t *crow_buf_base = NULL; uint32_t tag, length; int ret; FFSWAP(AVFrame *, s->current_picture, s->last_picture); avctx->coded_frame= s->current_picture; p = s->current_picture; /* check signature */ if (buf_size < 8 || memcmp(buf, ff_pngsig, 8) != 0 && memcmp(buf, ff_mngsig, 8) != 0) return -1; bytestream2_init(&s->gb, buf + 8, buf_size - 8); s->y= s->state=0; // memset(s, 0, sizeof(PNGDecContext)); /* init the zlib */ s->zstream.zalloc = ff_png_zalloc; s->zstream.zfree = ff_png_zfree; s->zstream.opaque = NULL; ret = inflateInit(&s->zstream); if (ret != Z_OK) return -1; for(;;) { if (bytestream2_get_bytes_left(&s->gb) <= 0) goto fail; length = bytestream2_get_be32(&s->gb); if (length > 0x7fffffff) goto fail; tag = bytestream2_get_le32(&s->gb); av_dlog(avctx, "png: tag=%c%c%c%c length=%u\n", (tag & 0xff), ((tag >> 8) & 0xff), ((tag >> 16) & 0xff), ((tag >> 24) & 0xff), length); switch(tag) { case MKTAG('I', 'H', 'D', 'R'): if (length != 13) goto fail; s->width = bytestream2_get_be32(&s->gb); s->height = bytestream2_get_be32(&s->gb); if(av_image_check_size(s->width, s->height, 0, avctx)){ s->width= s->height= 0; goto fail; } s->bit_depth = bytestream2_get_byte(&s->gb); s->color_type = bytestream2_get_byte(&s->gb); s->compression_type = bytestream2_get_byte(&s->gb); s->filter_type = bytestream2_get_byte(&s->gb); s->interlace_type = bytestream2_get_byte(&s->gb); bytestream2_skip(&s->gb, 4); /* crc */ s->state |= PNG_IHDR; av_dlog(avctx, "width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n", s->width, s->height, s->bit_depth, s->color_type, s->compression_type, s->filter_type, s->interlace_type); break; case MKTAG('I', 'D', 'A', 'T'): if (!(s->state & PNG_IHDR)) goto fail; if (!(s->state & PNG_IDAT)) { /* init image info */ avctx->width = s->width; avctx->height = s->height; s->channels = ff_png_get_nb_channels(s->color_type); s->bits_per_pixel = s->bit_depth * s->channels; s->bpp = (s->bits_per_pixel + 7) >> 3; s->row_size = (avctx->width * s->bits_per_pixel + 7) >> 3; if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_RGB) { avctx->pix_fmt = PIX_FMT_RGB24; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { avctx->pix_fmt = PIX_FMT_RGB32; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = PIX_FMT_GRAY8; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = PIX_FMT_GRAY16BE; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_RGB) { avctx->pix_fmt = PIX_FMT_RGB48BE; } else if (s->bit_depth == 1 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = PIX_FMT_MONOBLACK; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_PALETTE) { avctx->pix_fmt = PIX_FMT_PAL8; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { avctx->pix_fmt = PIX_FMT_Y400A; } else { goto fail; } if(p->data[0]) avctx->release_buffer(avctx, p); p->reference= 0; if(avctx->get_buffer(avctx, p) < 0){ av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); goto fail; } p->pict_type= AV_PICTURE_TYPE_I; p->key_frame= 1; p->interlaced_frame = !!s->interlace_type; /* compute the compressed row size */ if (!s->interlace_type) { s->crow_size = s->row_size + 1; } else { s->pass = 0; s->pass_row_size = ff_png_pass_row_size(s->pass, s->bits_per_pixel, s->width); s->crow_size = s->pass_row_size + 1; } av_dlog(avctx, "row_size=%d crow_size =%d\n", s->row_size, s->crow_size); s->image_buf = p->data[0]; s->image_linesize = p->linesize[0]; /* copy the palette if needed */ if (s->color_type == PNG_COLOR_TYPE_PALETTE) memcpy(p->data[1], s->palette, 256 * sizeof(uint32_t)); /* empty row is used if differencing to the first row */ s->last_row = av_mallocz(s->row_size); if (!s->last_row) goto fail; if (s->interlace_type || s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { s->tmp_row = av_malloc(s->row_size); if (!s->tmp_row) goto fail; } /* compressed row */ crow_buf_base = av_malloc(s->row_size + 16); if (!crow_buf_base) goto fail; /* we want crow_buf+1 to be 16-byte aligned */ s->crow_buf = crow_buf_base + 15; s->zstream.avail_out = s->crow_size; s->zstream.next_out = s->crow_buf; } s->state |= PNG_IDAT; if (png_decode_idat(s, length) < 0) goto fail; bytestream2_skip(&s->gb, 4); /* crc */ break; case MKTAG('P', 'L', 'T', 'E'): { int n, i, r, g, b; if ((length % 3) != 0 || length > 256 * 3) goto skip_tag; /* read the palette */ n = length / 3; for(i=0;i<n;i++) { r = bytestream2_get_byte(&s->gb); g = bytestream2_get_byte(&s->gb); b = bytestream2_get_byte(&s->gb); s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b; } for(;i<256;i++) { s->palette[i] = (0xff << 24); } s->state |= PNG_PLTE; bytestream2_skip(&s->gb, 4); /* crc */ } break; case MKTAG('t', 'R', 'N', 'S'): { int v, i; /* read the transparency. XXX: Only palette mode supported */ if (s->color_type != PNG_COLOR_TYPE_PALETTE || length > 256 || !(s->state & PNG_PLTE)) goto skip_tag; for(i=0;i<length;i++) { v = bytestream2_get_byte(&s->gb); s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24); } bytestream2_skip(&s->gb, 4); /* crc */ } break; case MKTAG('I', 'E', 'N', 'D'): if (!(s->state & PNG_ALLIMAGE)) goto fail; bytestream2_skip(&s->gb, 4); /* crc */ goto exit_loop; default: /* skip tag */ skip_tag: bytestream2_skip(&s->gb, length + 4); break; } } exit_loop: /* handle p-frames only if a predecessor frame is available */ if(s->last_picture->data[0] != NULL) { if(!(avpkt->flags & AV_PKT_FLAG_KEY)) { int i, j; uint8_t *pd = s->current_picture->data[0]; uint8_t *pd_last = s->last_picture->data[0]; for(j=0; j < s->height; j++) { for(i=0; i < s->width * s->bpp; i++) { pd[i] += pd_last[i]; } pd += s->image_linesize; pd_last += s->image_linesize; } } } *picture= *s->current_picture; *data_size = sizeof(AVFrame); ret = bytestream2_tell(&s->gb); the_end: inflateEnd(&s->zstream); av_free(crow_buf_base); s->crow_buf = NULL; av_freep(&s->last_row); av_freep(&s->tmp_row); return ret; fail: ret = -1; goto the_end; } static av_cold int png_dec_init(AVCodecContext *avctx){ PNGDecContext *s = avctx->priv_data; s->current_picture = &s->picture1; s->last_picture = &s->picture2; avcodec_get_frame_defaults(&s->picture1); avcodec_get_frame_defaults(&s->picture2); ff_pngdsp_init(&s->dsp); return 0; } static av_cold int png_dec_end(AVCodecContext *avctx) { PNGDecContext *s = avctx->priv_data; if (s->picture1.data[0]) avctx->release_buffer(avctx, &s->picture1); if (s->picture2.data[0]) avctx->release_buffer(avctx, &s->picture2); return 0; } AVCodec ff_png_decoder = { .name = "png", .type = AVMEDIA_TYPE_VIDEO, .id = CODEC_ID_PNG, .priv_data_size = sizeof(PNGDecContext), .init = png_dec_init, .close = png_dec_end, .decode = decode_frame, .capabilities = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/, .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"), };