yading@10: /*
yading@10:  * PNG image format
yading@10:  * Copyright (c) 2003 Fabrice Bellard
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: #include "avcodec.h"
yading@10: #include "internal.h"
yading@10: #include "bytestream.h"
yading@10: #include "dsputil.h"
yading@10: #include "png.h"
yading@10: 
yading@10: #include "libavutil/avassert.h"
yading@10: 
yading@10: /* TODO:
yading@10:  * - add 2, 4 and 16 bit depth support
yading@10:  */
yading@10: 
yading@10: #include <zlib.h>
yading@10: 
yading@10: //#define DEBUG
yading@10: 
yading@10: #define IOBUF_SIZE 4096
yading@10: 
yading@10: typedef struct PNGEncContext {
yading@10:     DSPContext dsp;
yading@10: 
yading@10:     uint8_t *bytestream;
yading@10:     uint8_t *bytestream_start;
yading@10:     uint8_t *bytestream_end;
yading@10:     AVFrame picture;
yading@10: 
yading@10:     int filter_type;
yading@10: 
yading@10:     z_stream zstream;
yading@10:     uint8_t buf[IOBUF_SIZE];
yading@10: } PNGEncContext;
yading@10: 
yading@10: static void png_get_interlaced_row(uint8_t *dst, int row_size,
yading@10:                                    int bits_per_pixel, int pass,
yading@10:                                    const uint8_t *src, int width)
yading@10: {
yading@10:     int x, mask, dst_x, j, b, bpp;
yading@10:     uint8_t *d;
yading@10:     const uint8_t *s;
yading@10:     static const int masks[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};
yading@10: 
yading@10:     mask = masks[pass];
yading@10:     switch(bits_per_pixel) {
yading@10:     case 1:
yading@10:         memset(dst, 0, row_size);
yading@10:         dst_x = 0;
yading@10:         for(x = 0; x < width; x++) {
yading@10:             j = (x & 7);
yading@10:             if ((mask << j) & 0x80) {
yading@10:                 b = (src[x >> 3] >> (7 - j)) & 1;
yading@10:                 dst[dst_x >> 3] |= b << (7 - (dst_x & 7));
yading@10:                 dst_x++;
yading@10:             }
yading@10:         }
yading@10:         break;
yading@10:     default:
yading@10:         bpp = bits_per_pixel >> 3;
yading@10:         d = dst;
yading@10:         s = src;
yading@10:         for(x = 0; x < width; x++) {
yading@10:             j = x & 7;
yading@10:             if ((mask << j) & 0x80) {
yading@10:                 memcpy(d, s, bpp);
yading@10:                 d += bpp;
yading@10:             }
yading@10:             s += bpp;
yading@10:         }
yading@10:         break;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void sub_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w, int bpp)
yading@10: {
yading@10:     int i;
yading@10:     for(i = 0; i < w; i++) {
yading@10:         int a, b, c, p, pa, pb, pc;
yading@10: 
yading@10:         a = src[i - bpp];
yading@10:         b = top[i];
yading@10:         c = top[i - bpp];
yading@10: 
yading@10:         p = b - c;
yading@10:         pc = a - c;
yading@10: 
yading@10:         pa = abs(p);
yading@10:         pb = abs(pc);
yading@10:         pc = abs(p + pc);
yading@10: 
yading@10:         if (pa <= pb && pa <= pc)
yading@10:             p = a;
yading@10:         else if (pb <= pc)
yading@10:             p = b;
yading@10:         else
yading@10:             p = c;
yading@10:         dst[i] = src[i] - p;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void png_filter_row(DSPContext *dsp, uint8_t *dst, int filter_type,
yading@10:                            uint8_t *src, uint8_t *top, int size, int bpp)
yading@10: {
yading@10:     int i;
yading@10: 
yading@10:     switch(filter_type) {
yading@10:     case PNG_FILTER_VALUE_NONE:
yading@10:         memcpy(dst, src, size);
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_SUB:
yading@10:         dsp->diff_bytes(dst, src, src-bpp, size);
yading@10:         memcpy(dst, src, bpp);
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_UP:
yading@10:         dsp->diff_bytes(dst, src, top, size);
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_AVG:
yading@10:         for(i = 0; i < bpp; i++)
yading@10:             dst[i] = src[i] - (top[i] >> 1);
yading@10:         for(; i < size; i++)
yading@10:             dst[i] = src[i] - ((src[i-bpp] + top[i]) >> 1);
yading@10:         break;
yading@10:     case PNG_FILTER_VALUE_PAETH:
yading@10:         for(i = 0; i < bpp; i++)
yading@10:             dst[i] = src[i] - top[i];
yading@10:         sub_png_paeth_prediction(dst+i, src+i, top+i, size-i, bpp);
yading@10:         break;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static uint8_t *png_choose_filter(PNGEncContext *s, uint8_t *dst,
yading@10:                                   uint8_t *src, uint8_t *top, int size, int bpp)
yading@10: {
yading@10:     int pred = s->filter_type;
yading@10:     av_assert0(bpp || !pred);
yading@10:     if(!top && pred)
yading@10:         pred = PNG_FILTER_VALUE_SUB;
yading@10:     if(pred == PNG_FILTER_VALUE_MIXED) {
yading@10:         int i;
yading@10:         int cost, bcost = INT_MAX;
yading@10:         uint8_t *buf1 = dst, *buf2 = dst + size + 16;
yading@10:         for(pred=0; pred<5; pred++) {
yading@10:             png_filter_row(&s->dsp, buf1+1, pred, src, top, size, bpp);
yading@10:             buf1[0] = pred;
yading@10:             cost = 0;
yading@10:             for(i=0; i<=size; i++)
yading@10:                 cost += abs((int8_t)buf1[i]);
yading@10:             if(cost < bcost) {
yading@10:                 bcost = cost;
yading@10:                 FFSWAP(uint8_t*, buf1, buf2);
yading@10:             }
yading@10:         }
yading@10:         return buf2;
yading@10:     } else {
yading@10:         png_filter_row(&s->dsp, dst+1, pred, src, top, size, bpp);
yading@10:         dst[0] = pred;
yading@10:         return dst;
yading@10:     }
yading@10: }
yading@10: 
yading@10: static void png_write_chunk(uint8_t **f, uint32_t tag,
yading@10:                             const uint8_t *buf, int length)
yading@10: {
yading@10:     uint32_t crc;
yading@10:     uint8_t tagbuf[4];
yading@10: 
yading@10:     bytestream_put_be32(f, length);
yading@10:     crc = crc32(0, Z_NULL, 0);
yading@10:     AV_WL32(tagbuf, tag);
yading@10:     crc = crc32(crc, tagbuf, 4);
yading@10:     bytestream_put_be32(f, av_bswap32(tag));
yading@10:     if (length > 0) {
yading@10:         crc = crc32(crc, buf, length);
yading@10:         memcpy(*f, buf, length);
yading@10:         *f += length;
yading@10:     }
yading@10:     bytestream_put_be32(f, crc);
yading@10: }
yading@10: 
yading@10: /* XXX: do filtering */
yading@10: static int png_write_row(PNGEncContext *s, const uint8_t *data, int size)
yading@10: {
yading@10:     int ret;
yading@10: 
yading@10:     s->zstream.avail_in = size;
yading@10:     s->zstream.next_in = (uint8_t *)data;
yading@10:     while (s->zstream.avail_in > 0) {
yading@10:         ret = deflate(&s->zstream, Z_NO_FLUSH);
yading@10:         if (ret != Z_OK)
yading@10:             return -1;
yading@10:         if (s->zstream.avail_out == 0) {
yading@10:             if(s->bytestream_end - s->bytestream > IOBUF_SIZE + 100)
yading@10:                 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, IOBUF_SIZE);
yading@10:             s->zstream.avail_out = IOBUF_SIZE;
yading@10:             s->zstream.next_out = s->buf;
yading@10:         }
yading@10:     }
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int encode_frame(AVCodecContext *avctx, AVPacket *pkt,
yading@10:                         const AVFrame *pict, int *got_packet)
yading@10: {
yading@10:     PNGEncContext *s = avctx->priv_data;
yading@10:     AVFrame * const p= &s->picture;
yading@10:     int bit_depth, color_type, y, len, row_size, ret, is_progressive;
yading@10:     int bits_per_pixel, pass_row_size, enc_row_size;
yading@10:     int64_t max_packet_size;
yading@10:     int compression_level;
yading@10:     uint8_t *ptr, *top;
yading@10:     uint8_t *crow_base = NULL, *crow_buf, *crow;
yading@10:     uint8_t *progressive_buf = NULL;
yading@10:     uint8_t *top_buf = NULL;
yading@10: 
yading@10:     *p = *pict;
yading@10:     p->pict_type= AV_PICTURE_TYPE_I;
yading@10:     p->key_frame= 1;
yading@10: 
yading@10:     is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);
yading@10:     switch(avctx->pix_fmt) {
yading@10:     case AV_PIX_FMT_RGBA64BE:
yading@10:         bit_depth = 16;
yading@10:         color_type = PNG_COLOR_TYPE_RGB_ALPHA;
yading@10:         break;
yading@10:     case AV_PIX_FMT_RGB48BE:
yading@10:         bit_depth = 16;
yading@10:         color_type = PNG_COLOR_TYPE_RGB;
yading@10:         break;
yading@10:     case AV_PIX_FMT_RGBA:
yading@10:         bit_depth = 8;
yading@10:         color_type = PNG_COLOR_TYPE_RGB_ALPHA;
yading@10:         break;
yading@10:     case AV_PIX_FMT_RGB24:
yading@10:         bit_depth = 8;
yading@10:         color_type = PNG_COLOR_TYPE_RGB;
yading@10:         break;
yading@10:     case AV_PIX_FMT_GRAY16BE:
yading@10:         bit_depth = 16;
yading@10:         color_type = PNG_COLOR_TYPE_GRAY;
yading@10:         break;
yading@10:     case AV_PIX_FMT_GRAY8:
yading@10:         bit_depth = 8;
yading@10:         color_type = PNG_COLOR_TYPE_GRAY;
yading@10:         break;
yading@10:     case AV_PIX_FMT_GRAY8A:
yading@10:         bit_depth = 8;
yading@10:         color_type = PNG_COLOR_TYPE_GRAY_ALPHA;
yading@10:         break;
yading@10:     case AV_PIX_FMT_MONOBLACK:
yading@10:         bit_depth = 1;
yading@10:         color_type = PNG_COLOR_TYPE_GRAY;
yading@10:         break;
yading@10:     case AV_PIX_FMT_PAL8:
yading@10:         bit_depth = 8;
yading@10:         color_type = PNG_COLOR_TYPE_PALETTE;
yading@10:         break;
yading@10:     default:
yading@10:         return -1;
yading@10:     }
yading@10:     bits_per_pixel = ff_png_get_nb_channels(color_type) * bit_depth;
yading@10:     row_size = (avctx->width * bits_per_pixel + 7) >> 3;
yading@10: 
yading@10:     s->zstream.zalloc = ff_png_zalloc;
yading@10:     s->zstream.zfree = ff_png_zfree;
yading@10:     s->zstream.opaque = NULL;
yading@10:     compression_level = avctx->compression_level == FF_COMPRESSION_DEFAULT ?
yading@10:                             Z_DEFAULT_COMPRESSION :
yading@10:                             av_clip(avctx->compression_level, 0, 9);
yading@10:     ret = deflateInit2(&s->zstream, compression_level,
yading@10:                        Z_DEFLATED, 15, 8, Z_DEFAULT_STRATEGY);
yading@10:     if (ret != Z_OK)
yading@10:         return -1;
yading@10: 
yading@10:     enc_row_size    = deflateBound(&s->zstream, row_size);
yading@10:     max_packet_size = avctx->height * (int64_t)(enc_row_size +
yading@10:                                        ((enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) * 12)
yading@10:                       + FF_MIN_BUFFER_SIZE;
yading@10:     if (max_packet_size > INT_MAX)
yading@10:         return AVERROR(ENOMEM);
yading@10:     if ((ret = ff_alloc_packet2(avctx, pkt, max_packet_size)) < 0)
yading@10:         return ret;
yading@10: 
yading@10:     s->bytestream_start =
yading@10:     s->bytestream       = pkt->data;
yading@10:     s->bytestream_end   = pkt->data + pkt->size;
yading@10: 
yading@10:     crow_base = av_malloc((row_size + 32) << (s->filter_type == PNG_FILTER_VALUE_MIXED));
yading@10:     if (!crow_base)
yading@10:         goto fail;
yading@10:     crow_buf = crow_base + 15; // pixel data should be aligned, but there's a control byte before it
yading@10:     if (is_progressive) {
yading@10:         progressive_buf = av_malloc(row_size + 1);
yading@10:         if (!progressive_buf)
yading@10:             goto fail;
yading@10:     }
yading@10:     if (is_progressive) {
yading@10:         top_buf = av_malloc(row_size + 1);
yading@10:         if (!top_buf)
yading@10:             goto fail;
yading@10:     }
yading@10: 
yading@10:     /* write png header */
yading@10:     AV_WB64(s->bytestream, PNGSIG);
yading@10:     s->bytestream += 8;
yading@10: 
yading@10:     AV_WB32(s->buf, avctx->width);
yading@10:     AV_WB32(s->buf + 4, avctx->height);
yading@10:     s->buf[8] = bit_depth;
yading@10:     s->buf[9] = color_type;
yading@10:     s->buf[10] = 0; /* compression type */
yading@10:     s->buf[11] = 0; /* filter type */
yading@10:     s->buf[12] = is_progressive; /* interlace type */
yading@10: 
yading@10:     png_write_chunk(&s->bytestream, MKTAG('I', 'H', 'D', 'R'), s->buf, 13);
yading@10: 
yading@10:     AV_WB32(s->buf, avctx->sample_aspect_ratio.num);
yading@10:     AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);
yading@10:     s->buf[8] = 0; /* unit specifier is unknown */
yading@10:     png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);
yading@10: 
yading@10:     /* put the palette if needed */
yading@10:     if (color_type == PNG_COLOR_TYPE_PALETTE) {
yading@10:         int has_alpha, alpha, i;
yading@10:         unsigned int v;
yading@10:         uint32_t *palette;
yading@10:         uint8_t *alpha_ptr;
yading@10: 
yading@10:         palette = (uint32_t *)p->data[1];
yading@10:         ptr = s->buf;
yading@10:         alpha_ptr = s->buf + 256 * 3;
yading@10:         has_alpha = 0;
yading@10:         for(i = 0; i < 256; i++) {
yading@10:             v = palette[i];
yading@10:             alpha = v >> 24;
yading@10:             if (alpha != 0xff)
yading@10:                 has_alpha = 1;
yading@10:             *alpha_ptr++ = alpha;
yading@10:             bytestream_put_be24(&ptr, v);
yading@10:         }
yading@10:         png_write_chunk(&s->bytestream, MKTAG('P', 'L', 'T', 'E'), s->buf, 256 * 3);
yading@10:         if (has_alpha) {
yading@10:             png_write_chunk(&s->bytestream, MKTAG('t', 'R', 'N', 'S'), s->buf + 256 * 3, 256);
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     /* now put each row */
yading@10:     s->zstream.avail_out = IOBUF_SIZE;
yading@10:     s->zstream.next_out = s->buf;
yading@10:     if (is_progressive) {
yading@10:         int pass;
yading@10: 
yading@10:         for(pass = 0; pass < NB_PASSES; pass++) {
yading@10:             /* NOTE: a pass is completely omitted if no pixels would be
yading@10:                output */
yading@10:             pass_row_size = ff_png_pass_row_size(pass, bits_per_pixel, avctx->width);
yading@10:             if (pass_row_size > 0) {
yading@10:                 top = NULL;
yading@10:                 for(y = 0; y < avctx->height; y++) {
yading@10:                     if ((ff_png_pass_ymask[pass] << (y & 7)) & 0x80) {
yading@10:                         ptr = p->data[0] + y * p->linesize[0];
yading@10:                         FFSWAP(uint8_t*, progressive_buf, top_buf);
yading@10:                         png_get_interlaced_row(progressive_buf, pass_row_size,
yading@10:                                                bits_per_pixel, pass,
yading@10:                                                ptr, avctx->width);
yading@10:                         crow = png_choose_filter(s, crow_buf, progressive_buf, top, pass_row_size, bits_per_pixel>>3);
yading@10:                         png_write_row(s, crow, pass_row_size + 1);
yading@10:                         top = progressive_buf;
yading@10:                     }
yading@10:                 }
yading@10:             }
yading@10:         }
yading@10:     } else {
yading@10:         top = NULL;
yading@10:         for(y = 0; y < avctx->height; y++) {
yading@10:             ptr = p->data[0] + y * p->linesize[0];
yading@10:             crow = png_choose_filter(s, crow_buf, ptr, top, row_size, bits_per_pixel>>3);
yading@10:             png_write_row(s, crow, row_size + 1);
yading@10:             top = ptr;
yading@10:         }
yading@10:     }
yading@10:     /* compress last bytes */
yading@10:     for(;;) {
yading@10:         ret = deflate(&s->zstream, Z_FINISH);
yading@10:         if (ret == Z_OK || ret == Z_STREAM_END) {
yading@10:             len = IOBUF_SIZE - s->zstream.avail_out;
yading@10:             if (len > 0 && s->bytestream_end - s->bytestream > len + 100) {
yading@10:                 png_write_chunk(&s->bytestream, MKTAG('I', 'D', 'A', 'T'), s->buf, len);
yading@10:             }
yading@10:             s->zstream.avail_out = IOBUF_SIZE;
yading@10:             s->zstream.next_out = s->buf;
yading@10:             if (ret == Z_STREAM_END)
yading@10:                 break;
yading@10:         } else {
yading@10:             goto fail;
yading@10:         }
yading@10:     }
yading@10:     png_write_chunk(&s->bytestream, MKTAG('I', 'E', 'N', 'D'), NULL, 0);
yading@10: 
yading@10:     pkt->size   = s->bytestream - s->bytestream_start;
yading@10:     pkt->flags |= AV_PKT_FLAG_KEY;
yading@10:     *got_packet = 1;
yading@10:     ret         = 0;
yading@10: 
yading@10:  the_end:
yading@10:     av_free(crow_base);
yading@10:     av_free(progressive_buf);
yading@10:     av_free(top_buf);
yading@10:     deflateEnd(&s->zstream);
yading@10:     return ret;
yading@10:  fail:
yading@10:     ret = -1;
yading@10:     goto the_end;
yading@10: }
yading@10: 
yading@10: static av_cold int png_enc_init(AVCodecContext *avctx){
yading@10:     PNGEncContext *s = avctx->priv_data;
yading@10: 
yading@10:     switch(avctx->pix_fmt) {
yading@10:     case AV_PIX_FMT_RGBA:
yading@10:         avctx->bits_per_coded_sample = 32;
yading@10:         break;
yading@10:     case AV_PIX_FMT_RGB24:
yading@10:         avctx->bits_per_coded_sample = 24;
yading@10:         break;
yading@10:     case AV_PIX_FMT_GRAY8:
yading@10:         avctx->bits_per_coded_sample = 0x28;
yading@10:         break;
yading@10:     case AV_PIX_FMT_MONOBLACK:
yading@10:         avctx->bits_per_coded_sample = 1;
yading@10:         break;
yading@10:     case AV_PIX_FMT_PAL8:
yading@10:         avctx->bits_per_coded_sample = 8;
yading@10:     }
yading@10: 
yading@10:     avcodec_get_frame_defaults(&s->picture);
yading@10:     avctx->coded_frame= &s->picture;
yading@10:     ff_dsputil_init(&s->dsp, avctx);
yading@10: 
yading@10:     s->filter_type = av_clip(avctx->prediction_method, PNG_FILTER_VALUE_NONE, PNG_FILTER_VALUE_MIXED);
yading@10:     if(avctx->pix_fmt == AV_PIX_FMT_MONOBLACK)
yading@10:         s->filter_type = PNG_FILTER_VALUE_NONE;
yading@10: 
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: AVCodec ff_png_encoder = {
yading@10:     .name           = "png",
yading@10:     .type           = AVMEDIA_TYPE_VIDEO,
yading@10:     .id             = AV_CODEC_ID_PNG,
yading@10:     .priv_data_size = sizeof(PNGEncContext),
yading@10:     .init           = png_enc_init,
yading@10:     .encode2        = encode_frame,
yading@10:     .capabilities   = CODEC_CAP_FRAME_THREADS | CODEC_CAP_INTRA_ONLY,
yading@10:     .pix_fmts       = (const enum AVPixelFormat[]){
yading@10:         AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,
yading@10:         AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,
yading@10:         AV_PIX_FMT_PAL8,
yading@10:         AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,
yading@10:         AV_PIX_FMT_GRAY16BE,
yading@10:         AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE
yading@10:     },
yading@10:     .long_name      = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
yading@10: };