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/*

 * 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 "internal.h"

#include "bytestream.h"

#include "dsputil.h"

#include "png.h"

#include "libavutil/avassert.h"

#include "libavutil/opt.h"

#include 

#define IOBUF_SIZE 4096

typedef struct PNGEncContext {

    AVClass *class;

    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];

    int dpi;                     ///< Physical pixel density, in dots per inch, if set

    int dpm;                     ///< Physical pixel density, in dots per meter, if set

} 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;

    static const int masks[] = {0x80, 0x08, 0x88, 0x22, 0xaa, 0x55, 0xff};

    mask = masks[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;

    av_assert0(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, AVPacket *pkt,

                        const AVFrame *pict, int *got_packet)

{

    PNGEncContext *s = avctx->priv_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, enc_row_size;

    int64_t max_packet_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;

    is_progressive = !!(avctx->flags & CODEC_FLAG_INTERLACED_DCT);

    switch(avctx->pix_fmt) {

    case AV_PIX_FMT_RGBA64BE:

        bit_depth = 16;

        color_type = PNG_COLOR_TYPE_RGB_ALPHA;

        break;

    case AV_PIX_FMT_RGB48BE:

        bit_depth = 16;

        color_type = PNG_COLOR_TYPE_RGB;

        break;

    case AV_PIX_FMT_RGBA:

        bit_depth = 8;

        color_type = PNG_COLOR_TYPE_RGB_ALPHA;

        break;

    case AV_PIX_FMT_RGB24:

        bit_depth = 8;

        color_type = PNG_COLOR_TYPE_RGB;

        break;

    case AV_PIX_FMT_GRAY16BE:

        bit_depth = 16;

        color_type = PNG_COLOR_TYPE_GRAY;

        break;

    case AV_PIX_FMT_GRAY8:

        bit_depth = 8;

        color_type = PNG_COLOR_TYPE_GRAY;

        break;

    case AV_PIX_FMT_GRAY8A:

        bit_depth = 8;

        color_type = PNG_COLOR_TYPE_GRAY_ALPHA;

        break;

    case AV_PIX_FMT_MONOBLACK:

        bit_depth = 1;

        color_type = PNG_COLOR_TYPE_GRAY;

        break;

    case AV_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;

    enc_row_size    = deflateBound(&s->zstream, row_size);

    max_packet_size = avctx->height * (int64_t)(enc_row_size +

                                       ((enc_row_size + IOBUF_SIZE - 1) / IOBUF_SIZE) * 12)

                      + FF_MIN_BUFFER_SIZE;

    if (max_packet_size > INT_MAX)

        return AVERROR(ENOMEM);

    if ((ret = ff_alloc_packet2(avctx, pkt, max_packet_size)) < 0)

        return ret;

    s->bytestream_start =

    s->bytestream       = pkt->data;

    s->bytestream_end   = pkt->data + pkt->size;

    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 */

    AV_WB64(s->bytestream, PNGSIG);

    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);

    if (s->dpm) {

      AV_WB32(s->buf, s->dpm);

      AV_WB32(s->buf + 4, s->dpm);

      s->buf[8] = 1; /* unit specifier is meter */

    } else {

      AV_WB32(s->buf, avctx->sample_aspect_ratio.num);

      AV_WB32(s->buf + 4, avctx->sample_aspect_ratio.den);

      s->buf[8] = 0; /* unit specifier is unknown */

    }

    png_write_chunk(&s->bytestream, MKTAG('p', 'H', 'Y', 's'), s->buf, 9);

    /* 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 omitted 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);

    pkt->size   = s->bytestream - s->bytestream_start;

    pkt->flags |= AV_PKT_FLAG_KEY;

    *got_packet = 1;

    ret         = 0;

 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;

    switch(avctx->pix_fmt) {

    case AV_PIX_FMT_RGBA:

        avctx->bits_per_coded_sample = 32;

        break;

    case AV_PIX_FMT_RGB24:

        avctx->bits_per_coded_sample = 24;

        break;

    case AV_PIX_FMT_GRAY8:

        avctx->bits_per_coded_sample = 0x28;

        break;

    case AV_PIX_FMT_MONOBLACK:

        avctx->bits_per_coded_sample = 1;

        break;

    case AV_PIX_FMT_PAL8:

        avctx->bits_per_coded_sample = 8;

    }

    avcodec_get_frame_defaults(&s->picture);

    avctx->coded_frame= &s->picture;

    ff_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 == AV_PIX_FMT_MONOBLACK)

        s->filter_type = PNG_FILTER_VALUE_NONE;

    if (s->dpi && s->dpm) {

      av_log(avctx, AV_LOG_ERROR, "Only one of 'dpi' or 'dpm' options should be set\n");

      return AVERROR(EINVAL);

    } else if (s->dpi) {

      s->dpm = s->dpi * 10000 / 254;

    }

    return 0;

}

#define OFFSET(x) offsetof(PNGEncContext, x)

#define VE AV_OPT_FLAG_VIDEO_PARAM | AV_OPT_FLAG_ENCODING_PARAM

static const AVOption options[] = {

    {"dpi", "Set image resolution (in dots per inch)",  OFFSET(dpi), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},

    {"dpm", "Set image resolution (in dots per meter)", OFFSET(dpm), AV_OPT_TYPE_INT, {.i64 = 0}, 0, 0x10000, VE},

    { NULL }

};

static const AVClass pngenc_class = {

    .class_name = "PNG encoder",

    .item_name  = av_default_item_name,

    .option     = options,

    .version    = LIBAVUTIL_VERSION_INT,

};

AVCodec ff_png_encoder = {

    .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(PNGEncContext),

    .init           = png_enc_init,

    .encode2        = encode_frame,

    .capabilities   = CODEC_CAP_FRAME_THREADS | CODEC_CAP_INTRA_ONLY,

    .pix_fmts       = (const enum AVPixelFormat[]){

        AV_PIX_FMT_RGB24, AV_PIX_FMT_RGBA,

        AV_PIX_FMT_RGB48BE, AV_PIX_FMT_RGBA64BE,

        AV_PIX_FMT_PAL8,

        AV_PIX_FMT_GRAY8, AV_PIX_FMT_GRAY8A,

        AV_PIX_FMT_GRAY16BE,

        AV_PIX_FMT_MONOBLACK, AV_PIX_FMT_NONE

    },

    .priv_class     = &pngenc_class,

};