/* * 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/avstring.h" #include "libavutil/imgutils.h" #include "libavutil/stereo3d.h" #include "avcodec.h" #include "bytestream.h" #include "internal.h" #include "png.h" #include "pngdsp.h" /* TODO: * - add 2, 4 and 16 bit depth support */ #include <zlib.h> typedef struct PNGDecContext { PNGDSPContext dsp; GetByteContext gb; AVFrame *prev; 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 > 2 && 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; } if (ret == Z_STREAM_END && s->zstream.avail_in > 0) { av_log(NULL, AV_LOG_WARNING, "%d undecompressed bytes left in buffer\n", s->zstream.avail_in); return 0; } } return 0; } static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame, AVPacket *avpkt) { PNGDecContext *const s = avctx->priv_data; const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; AVFrame *p = data; uint8_t *crow_buf_base = NULL; uint32_t tag, length; int ret; /* check signature */ if (buf_size < 8) { av_log(avctx, AV_LOG_ERROR, "Not enough data %d\n", buf_size); return AVERROR_INVALIDDATA; } if (memcmp(buf, ff_pngsig, 8) != 0 && memcmp(buf, ff_mngsig, 8) != 0) { char signature[5 * 8 + 1] = { 0 }; int i; for (i = 0; i < 8; i++) { av_strlcatf(signature + i * 5, sizeof(signature) - i * 5, " 0x%02x", buf[i]); } av_log(avctx, AV_LOG_ERROR, "Invalid PNG signature %s\n", signature); return AVERROR_INVALIDDATA; } bytestream2_init(&s->gb, buf + 8, buf_size - 8); s->y = s->state = 0; /* 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); ff_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; ff_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 = AV_PIX_FMT_RGB24; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) { avctx->pix_fmt = AV_PIX_FMT_RGB32; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = AV_PIX_FMT_GRAY8; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = AV_PIX_FMT_GRAY16BE; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_RGB) { avctx->pix_fmt = AV_PIX_FMT_RGB48BE; } else if (s->bit_depth == 1 && s->color_type == PNG_COLOR_TYPE_GRAY) { avctx->pix_fmt = AV_PIX_FMT_MONOBLACK; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_PALETTE) { avctx->pix_fmt = AV_PIX_FMT_PAL8; } else if (s->bit_depth == 8 && s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { avctx->pix_fmt = AV_PIX_FMT_YA8; } else if (s->bit_depth == 16 && s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) { avctx->pix_fmt = AV_PIX_FMT_YA16BE; } else { goto fail; } if (ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF) < 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; } ff_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('s', 'T', 'E', 'R'): { int mode = bytestream2_get_byte(&s->gb); AVStereo3D *stereo3d = av_stereo3d_create_side_data(p); if (!stereo3d) goto the_end; if (mode == 0 || mode == 1) { stereo3d->type = AV_STEREO3D_SIDEBYSIDE; stereo3d->flags = mode ? 0 : AV_STEREO3D_FLAG_INVERT; } else { av_log(avctx, AV_LOG_WARNING, "Unknown value in sTER chunk (%d)\n", mode); } 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->prev->data[0]) { if (!(avpkt->flags & AV_PKT_FLAG_KEY)) { int i, j; uint8_t *pd = p->data[0]; uint8_t *pd_last = s->prev->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; } } } av_frame_unref(s->prev); if ((ret = av_frame_ref(s->prev, p)) < 0) goto fail; *got_frame = 1; 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; avctx->color_range = AVCOL_RANGE_JPEG; s->prev = av_frame_alloc(); if (!s->prev) return AVERROR(ENOMEM); ff_pngdsp_init(&s->dsp); return 0; } static av_cold int png_dec_end(AVCodecContext *avctx) { PNGDecContext *s = avctx->priv_data; av_frame_free(&s->prev); return 0; } AVCodec ff_png_decoder = { .name = "png", .long_name = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"), .type = AVMEDIA_TYPE_VIDEO, .id = AV_CODEC_ID_PNG, .priv_data_size = sizeof(PNGDecContext), .init = png_dec_init, .close = png_dec_end, .decode = decode_frame, .capabilities = AV_CODEC_CAP_DR1 /*| AV_CODEC_CAP_DRAW_HORIZ_BAND*/, };