/* * PNG image format * Copyright (c) 2003 Fabrice Bellard * * 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 "avcodec.h" #include "bytestream.h" #include "dsputil.h" #include "png.h" /* TODO: * - add 2, 4 and 16 bit depth support */ #include <zlib.h> //#define DEBUG #define IOBUF_SIZE 4096 typedef struct PNGEncContext { DSPContext dsp; uint8_t *bytestream; uint8_t *bytestream_start; uint8_t *bytestream_end; AVFrame picture; int filter_type; z_stream zstream; uint8_t buf[IOBUF_SIZE]; } PNGEncContext; static void png_get_interlaced_row(uint8_t *dst, int row_size, int bits_per_pixel, int pass, const uint8_t *src, int width) { int x, mask, dst_x, j, b, bpp; uint8_t *d; const uint8_t *s; mask = ff_png_pass_mask[pass]; switch(bits_per_pixel) { case 1: memset(dst, 0, row_size); dst_x = 0; for(x = 0; x < width; x++) { j = (x & 7); if ((mask << j) & 0x80) { b = (src[x >> 3] >> (7 - j)) & 1; dst[dst_x >> 3] |= b << (7 - (dst_x & 7)); dst_x++; } } break; default: bpp = bits_per_pixel >> 3; d = dst; s = src; for(x = 0; x < width; x++) { j = x & 7; if ((mask << j) & 0x80) { memcpy(d, s, bpp); d += bpp; } s += bpp; } break; } } static void sub_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 = src[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] = src[i] - p; } } static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type, uint8_t *src, uint8_t *top, int size, int bpp) { int i; switch(filter_type) { case PNG_FILTER_VALUE_NONE: memcpy(dst, src, size); break; case PNG_FILTER_VALUE_SUB: dsp->diff_bytes(dst, src, src-bpp, size); memcpy(dst, src, bpp); break; case PNG_FILTER_VALUE_UP: dsp->diff_bytes(dst, src, top, size); break; case PNG_FILTER_VALUE_AVG: for(i = 0; i < bpp; i++) dst[i] = src[i] - (top[i] >> 1); for(; i < size; i++) dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1); break; case PNG_FILTER_VALUE_PAETH: for(i = 0; i < bpp; i++) dst[i] = src[i] - top[i]; sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp); break; } } static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst, uint8_t *src, uint8_t *top, int size, int bpp) { int pred = s->filter_type; assert(bpp || !pred); if(!top && pred) pred = PNG_FILTER_VALUE_SUB; if(pred == PNG_FILTER_VALUE_MIXED) { int i; int cost, bcost = INT_MAX; uint8_t *buf1 = dst, *buf2 = dst + size + 16; for(pred=0; pred<5; pred++) { png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp); buf1[0] = pred; cost = 0; for(i=0; i<=size; i++) cost += abs((int8_t)buf1[i]); if(cost < bcost) { bcost = cost; FFSWAP(uint8_t*, buf1, buf2); } } return buf2; } else { png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp); dst[0] = pred; return dst; } } static void png_write_chunk(uint8_t **f, uint32_t tag, const uint8_t *buf, int length) { uint32_t crc; uint8_t tagbuf[4]; bytestream_put_be32(f, length); crc = crc32(0, Z_NULL, 0); AV_WL32(tagbuf, tag); crc = crc32(crc, tagbuf, 4); bytestream_put_be32(f, av_bswap32(tag)); if (length > 0) { crc = crc32(crc, buf, length); memcpy(*f, buf, length); *f += length; } bytestream_put_be32(f, crc); } /* XXX: do filtering */ static int png_write_row(PNGEncContext *s, const uint8_t *data, int size) { int ret; s->zstream.avail_in = size; s->zstream.next_in = (uint8_t *)data; while (s->zstream.avail_in > 0) { ret = deflate(&s->zstream, Z_NO_FLUSH); if (ret != Z_OK) return -1; if (s->zstream.avail_out == 0) { if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100) png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE); s->zstream.avail_out = IOBUF_SIZE; s->zstream.next_out = s->buf; } } return 0; } static int encode_frame(AVCodecContext *avctx, unsigned char *buf, int buf_size, void *data){ PNGEncContext *s = avctx->priv_data; AVFrame *pict = data; AVFrame * const p= &s->picture; int bit_depth, color_type, y, len, row_size, ret, is_progressive; int bits_per_pixel, pass_row_size; int compression_level; uint8_t *ptr, *top; uint8_t *crow_base = NULL, *crow_buf, *crow; uint8_t *progressive_buf = NULL; uint8_t *top_buf = NULL; *p = *pict; p->pict_type= AV_PICTURE_TYPE_I; p->key_frame= 1; s->bytestream_start= s->bytestream= buf; s->bytestream_end= buf+buf_size; is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT); switch(avctx->pix_fmt) { case PIX_FMT_RGBA64BE: bit_depth = 16; color_type = PNG_COLOR_TYPE_RGB_ALPHA; break; case PIX_FMT_RGB48BE: bit_depth = 16; color_type = PNG_COLOR_TYPE_RGB; break; case PIX_FMT_RGBA: bit_depth = 8; color_type = PNG_COLOR_TYPE_RGB_ALPHA; break; case PIX_FMT_RGB24: bit_depth = 8; color_type = PNG_COLOR_TYPE_RGB; break; case PIX_FMT_GRAY16BE: bit_depth = 16; color_type = PNG_COLOR_TYPE_GRAY; break; case PIX_FMT_GRAY8: bit_depth = 8; color_type = PNG_COLOR_TYPE_GRAY; break; case PIX_FMT_GRAY8A: bit_depth = 8; color_type = PNG_COLOR_TYPE_GRAY_ALPHA; break; case PIX_FMT_MONOBLACK: bit_depth = 1; color_type = PNG_COLOR_TYPE_GRAY; break; case PIX_FMT_PAL8: bit_depth = 8; color_type = PNG_COLOR_TYPE_PALETTE; break; default: return -1; } bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth; row_size = (avctx->width * bits_per_pixel + 7) >> 3; s->zstream.zalloc = ff_png_zalloc; s->zstream.zfree = ff_png_zfree; s->zstream.opaque = NULL; compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ? Z_DEFAULT_COMPRESSION : av_clip(avctx->compression_level, 0, 9); ret = deflateInit2(&s->zstream, compression_level, Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY); if (ret != Z_OK) return -1; crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED)); if (!crow_base) goto fail; crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it if (is_progressive) { progressive_buf = av_malloc(row_size + 1); if (!progressive_buf) goto fail; } if (is_progressive) { top_buf = av_malloc(row_size + 1); if (!top_buf) goto fail; } /* write png header */ memcpy(s->bytestream, ff_pngsig, 8); s->bytestream += 8; AV_WB32(s->buf, avctx->width); AV_WB32(s->buf + 4, avctx->height); s->buf[8] = bit_depth; s->buf[9] = color_type; s->buf[10] = 0; /* compression type */ s->buf[11] = 0; /* filter type */ s->buf[12] = is_progressive; /* interlace type */ png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13); /* put the palette if needed */ if (color_type == PNG_COLOR_TYPE_PALETTE) { int has_alpha, alpha, i; unsigned int v; uint32_t *palette; uint8_t *alpha_ptr; palette = (uint32_t *)p->data[1]; ptr = s->buf; alpha_ptr = s->buf + 256 * 3; has_alpha = 0; for(i = 0; i < 256; i++) { v = palette[i]; alpha = v >> 24; if (alpha != 0xff) has_alpha = 1; *alpha_ptr++ = alpha; bytestream_put_be24(&ptr, v); } png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3); if (has_alpha) { png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256); } } /* now put each row */ s->zstream.avail_out = IOBUF_SIZE; s->zstream.next_out = s->buf; if (is_progressive) { int pass; for(pass = 0; pass < NB_PASSES; pass++) { /* NOTE: a pass is completely omited if no pixels would be output */ pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width); if (pass_row_size > 0) { top = NULL; for(y = 0; y < avctx->height; y++) { if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) { ptr = p->data[0] + y * p->linesize[0]; FFSWAP(uint8_t*, progressive_buf, top_buf); png_get_interlaced_row(progressive_buf, pass_row_size, bits_per_pixel, pass, ptr, avctx->width); crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3); png_write_row(s, crow, pass_row_size + 1); top = progressive_buf; } } } } } else { top = NULL; for(y = 0; y < avctx->height; y++) { ptr = p->data[0] + y * p->linesize[0]; crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3); png_write_row(s, crow, row_size + 1); top = ptr; } } /* compress last bytes */ for(;;) { ret = deflate(&s->zstream, Z_FINISH); if (ret == Z_OK || ret == Z_STREAM_END) { len = IOBUF_SIZE - s->zstream.avail_out; if (len > 0 && s->bytestream_end - s->bytestream > len + 100) { png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len); } s->zstream.avail_out = IOBUF_SIZE; s->zstream.next_out = s->buf; if (ret == Z_STREAM_END) break; } else { goto fail; } } png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0); ret = s->bytestream - s->bytestream_start; the_end: av_free(crow_base); av_free(progressive_buf); av_free(top_buf); deflateEnd(&s->zstream); return ret; fail: ret = -1; goto the_end; } static av_cold int png_enc_init(AVCodecContext *avctx){ PNGEncContext *s = avctx->priv_data; avcodec_get_frame_defaults(&s->picture); avctx->coded_frame= &s->picture; dsputil_init(&s->dsp, avctx); s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED); if(avctx->pix_fmt == PIX_FMT_MONOBLACK) s->filter_type = PNG_FILTER_VALUE_NONE; return 0; } AVCodec ff_png_encoder = { .name = "png", .type = AVMEDIA_TYPE_VIDEO, .id = CODEC_ID_PNG, .priv_data_size = sizeof(PNGEncContext), .init = png_enc_init, .encode = encode_frame, .pix_fmts= (const enum PixelFormat[]){PIX_FMT_RGB24, PIX_FMT_RGBA, PIX_FMT_RGB48BE, PIX_FMT_RGBA64BE, PIX_FMT_PAL8, PIX_FMT_GRAY8, PIX_FMT_GRAY8A, PIX_FMT_GRAY16BE, PIX_FMT_MONOBLACK, PIX_FMT_NONE}, .long_name= NULL_IF_CONFIG_SMALL("PNG image"), };