adding ffmpeg specific version

1 files changed, 902 insertions, 0 deletions

diff --git a/ffmpeg1/libavcodec/pngdec.c b/ffmpeg1/libavcodec/pngdec.c
new file mode 100644
index 0000000..086f3b4
--- /dev/null
+++ b/ffmpeg1/libavcodec/pngdec.c
@@ -0,0 +1,902 @@
+/*
+ * 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
+ */
+
+//#define DEBUG
+
+#include "libavutil/bprint.h"
+#include "libavutil/imgutils.h"
+#include "avcodec.h"
+#include "bytestream.h"
+#include "internal.h"
+#include "png.h"
+#include "pngdsp.h"
+
+/* TODO:
+ * - add 16 bit depth support
+ */
+
+#include <zlib.h>
+
+//#define DEBUG
+
+typedef struct PNGDecContext {
+    PNGDSPContext dsp;
+    AVCodecContext *avctx;
+
+    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 pixels are valid in a pass */
+static const uint8_t png_pass_mask[NB_PASSES] = {
+    0x01, 0x01, 0x11, 0x11, 0x55, 0x55, 0xff,
+};
+
+/* 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, 0xff, 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     = png_pass_mask[pass];
+    dsp_mask = png_pass_dsp_mask[pass];
+
+    switch (bits_per_pixel) {
+    case 1:
+        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] &= 0xFF7F>>j;
+                dst[x >> 3] |= b << (7 - j);
+            }
+            if ((mask << j) & 0x80)
+                src_x++;
+        }
+        break;
+    case 2:
+        src_x = 0;
+        for (x = 0; x < width; x++) {
+            int j2 = 2 * (x & 3);
+            j = (x & 7);
+            if ((dsp_mask << j) & 0x80) {
+                b = (src[src_x >> 2] >> (6 - 2*(src_x & 3))) & 3;
+                dst[x >> 2] &= 0xFF3F>>j2;
+                dst[x >> 2] |= b << (6 - j2);
+            }
+            if ((mask << j) & 0x80)
+                src_x++;
+        }
+        break;
+    case 4:
+        src_x = 0;
+        for (x = 0; x < width; x++) {
+            int j2 = 4*(x&1);
+            j = (x & 7);
+            if ((dsp_mask << j) & 0x80) {
+                b = (src[src_x >> 1] >> (4 - 4*(src_x & 1))) & 15;
+                dst[x >> 1] &= 0xFF0F>>j2;
+                dst[x >> 1] |= b << (4 - j2);
+            }
+            if ((mask << j) & 0x80)
+                src_x++;
+        }
+        break;
+    default:
+        bpp = bits_per_pixel >> 3;
+        d   = dst;
+        s   = src;
+            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 - bpp; 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)\
+    for (; i < size; i++) {\
+        dst[i] = op(dst[i-bpp], src[i], last[i]);\
+    }\
+
+/* 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;
+    }
+}
+
+/* This used to be called "deloco" in FFmpeg
+ * and is actually an inverse reversible colorspace transformation */
+#define YUV2RGB(NAME, TYPE) \
+static void deloco_ ## NAME(TYPE *dst, int size, int alpha) \
+{ \
+    int i; \
+    for (i = 0; i < size; i += 3 + alpha) { \
+        int g = dst [i+1]; \
+        dst[i+0] += g; \
+        dst[i+2] += g; \
+    } \
+}
+
+YUV2RGB(rgb8, uint8_t)
+YUV2RGB(rgb16, uint16_t)
+
+/* 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;
+            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->y > 0) {
+            if (s->bit_depth == 16) {
+                deloco_rgb16((uint16_t *)(ptr - s->image_linesize), s->row_size / 2,
+                             s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
+            } else {
+                deloco_rgb8(ptr - s->image_linesize, s->row_size,
+                            s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
+            }
+        }
+        s->y++;
+        if (s->y == s->height) {
+            s->state |= PNG_ALLIMAGE;
+            if (s->filter_type == PNG_FILTER_TYPE_LOCO) {
+                if (s->bit_depth == 16) {
+                    deloco_rgb16((uint16_t *)ptr, s->row_size / 2,
+                                 s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
+                } else {
+                    deloco_rgb8(ptr, s->row_size,
+                                s->color_type == PNG_COLOR_TYPE_RGB_ALPHA);
+                }
+            }
+        }
+    } 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) {
+                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) {
+                memset(s->last_row, 0, s->row_size);
+                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  = (unsigned char *)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) {
+            av_log(s->avctx, AV_LOG_ERROR, "inflate returned %d\n", ret);
+            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_zbuf(AVBPrint *bp, const uint8_t *data,
+                       const uint8_t *data_end)
+{
+    z_stream zstream;
+    unsigned char *buf;
+    unsigned buf_size;
+    int ret;
+
+    zstream.zalloc = ff_png_zalloc;
+    zstream.zfree  = ff_png_zfree;
+    zstream.opaque = NULL;
+    if (inflateInit(&zstream) != Z_OK)
+        return AVERROR_EXTERNAL;
+    zstream.next_in  = (unsigned char *)data;
+    zstream.avail_in = data_end - data;
+    av_bprint_init(bp, 0, -1);
+
+    while (zstream.avail_in > 0) {
+        av_bprint_get_buffer(bp, 1, &buf, &buf_size);
+        if (!buf_size) {
+            ret = AVERROR(ENOMEM);
+            goto fail;
+        }
+        zstream.next_out  = buf;
+        zstream.avail_out = buf_size;
+        ret = inflate(&zstream, Z_PARTIAL_FLUSH);
+        if (ret != Z_OK && ret != Z_STREAM_END) {
+            ret = AVERROR_EXTERNAL;
+            goto fail;
+        }
+        bp->len += zstream.next_out - buf;
+        if (ret == Z_STREAM_END)
+            break;
+    }
+    inflateEnd(&zstream);
+    bp->str[bp->len] = 0;
+    return 0;
+
+fail:
+    inflateEnd(&zstream);
+    av_bprint_finalize(bp, NULL);
+    return ret;
+}
+
+static uint8_t *iso88591_to_utf8(const uint8_t *in, size_t size_in)
+{
+    size_t extra = 0, i;
+    uint8_t *out, *q;
+
+    for (i = 0; i < size_in; i++)
+        extra += in[i] >= 0x80;
+    if (size_in == SIZE_MAX || extra > SIZE_MAX - size_in - 1)
+        return NULL;
+    q = out = av_malloc(size_in + extra + 1);
+    if (!out)
+        return NULL;
+    for (i = 0; i < size_in; i++) {
+        if (in[i] >= 0x80) {
+            *(q++) = 0xC0 | (in[i] >> 6);
+            *(q++) = 0x80 | (in[i] & 0x3F);
+        } else {
+            *(q++) = in[i];
+        }
+    }
+    *(q++) = 0;
+    return out;
+}
+
+static int decode_text_chunk(PNGDecContext *s, uint32_t length, int compressed,
+                             AVDictionary **dict)
+{
+    int ret, method;
+    const uint8_t *data        = s->gb.buffer;
+    const uint8_t *data_end    = data + length;
+    const uint8_t *keyword     = data;
+    const uint8_t *keyword_end = memchr(keyword, 0, data_end - keyword);
+    uint8_t *kw_utf8 = NULL, *text, *txt_utf8 = NULL;
+    unsigned text_len;
+    AVBPrint bp;
+
+    if (!keyword_end)
+        return AVERROR_INVALIDDATA;
+    data = keyword_end + 1;
+
+    if (compressed) {
+        if (data == data_end)
+            return AVERROR_INVALIDDATA;
+        method = *(data++);
+        if (method)
+            return AVERROR_INVALIDDATA;
+        if ((ret = decode_zbuf(&bp, data, data_end)) < 0)
+            return ret;
+        text_len = bp.len;
+        av_bprint_finalize(&bp, (char **)&text);
+        if (!text)
+            return AVERROR(ENOMEM);
+    } else {
+        text = (uint8_t *)data;
+        text_len = data_end - text;
+    }
+
+    kw_utf8  = iso88591_to_utf8(keyword, keyword_end - keyword);
+    txt_utf8 = iso88591_to_utf8(text, text_len);
+    if (text != data)
+        av_free(text);
+    if (!(kw_utf8 && txt_utf8)) {
+        av_free(kw_utf8);
+        av_free(txt_utf8);
+        return AVERROR(ENOMEM);
+    }
+
+    av_dict_set(dict, kw_utf8, txt_utf8,
+                AV_DICT_DONT_STRDUP_KEY | AV_DICT_DONT_STRDUP_VAL);
+    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;
+    AVDictionary *metadata  = NULL;
+    uint8_t *crow_buf_base  = NULL;
+    uint32_t tag, length;
+    int64_t sig;
+    int ret;
+
+    bytestream2_init(&s->gb, buf, buf_size);
+
+    /* check signature */
+    sig = bytestream2_get_be64(&s->gb);
+    if (sig != PNGSIG &&
+        sig != MNGSIG) {
+        av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
+        return -1;
+    }
+
+    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) {
+        av_log(avctx, AV_LOG_ERROR, "inflateInit returned %d\n", ret);
+        return -1;
+    }
+    for (;;) {
+        if (bytestream2_get_bytes_left(&s->gb) <= 0) {
+            av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
+            goto fail;
+        }
+
+        length = bytestream2_get_be32(&s->gb);
+        if (length > 0x7fffffff || length > bytestream2_get_bytes_left(&s->gb))  {
+            av_log(avctx, AV_LOG_ERROR, "chunk too big\n");
+            goto fail;
+        }
+        tag = bytestream2_get_le32(&s->gb);
+        if (avctx->debug & FF_DEBUG_STARTCODE)
+            av_log(avctx, AV_LOG_DEBUG, "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;
+                av_log(avctx, AV_LOG_ERROR, "Invalid image size\n");
+                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;
+            if (avctx->debug & FF_DEBUG_PICT_INFO)
+                av_log(avctx, AV_LOG_DEBUG, "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('p', 'H', 'Y', 's'):
+            if (s->state & PNG_IDAT) {
+                av_log(avctx, AV_LOG_ERROR, "pHYs after IDAT\n");
+                goto fail;
+            }
+            avctx->sample_aspect_ratio.num = bytestream2_get_be32(&s->gb);
+            avctx->sample_aspect_ratio.den = bytestream2_get_be32(&s->gb);
+            if (avctx->sample_aspect_ratio.num < 0 || avctx->sample_aspect_ratio.den < 0)
+                avctx->sample_aspect_ratio = (AVRational){ 0, 1 };
+            bytestream2_skip(&s->gb, 1); /* unit specifier */
+            bytestream2_skip(&s->gb, 4); /* crc */
+            break;
+        case MKTAG('I', 'D', 'A', 'T'):
+            if (!(s->state & PNG_IHDR)) {
+                av_log(avctx, AV_LOG_ERROR, "IDAT without IHDR\n");
+                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 == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
+                    s->color_type == PNG_COLOR_TYPE_RGB) {
+                    avctx->pix_fmt = AV_PIX_FMT_RGB24;
+                } else if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
+                           s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
+                    avctx->pix_fmt = AV_PIX_FMT_RGBA;
+                } else if ((s->bit_depth == 2 || s->bit_depth == 4 || 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 == 16 &&
+                           s->color_type == PNG_COLOR_TYPE_RGB_ALPHA) {
+                    avctx->pix_fmt = AV_PIX_FMT_RGBA64BE;
+                } else if ((s->bits_per_pixel == 1 || s->bits_per_pixel == 2 || s->bits_per_pixel == 4 || s->bits_per_pixel == 8) &&
+                           s->color_type == PNG_COLOR_TYPE_PALETTE) {
+                    avctx->pix_fmt = AV_PIX_FMT_PAL8;
+                } else if (s->bit_depth == 1) {
+                    avctx->pix_fmt = AV_PIX_FMT_MONOBLACK;
+                } else if (s->bit_depth == 8 &&
+                           s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
+                    avctx->pix_fmt = AV_PIX_FMT_Y400A;
+                } else {
+                    av_log(avctx, AV_LOG_ERROR, "unsupported bit depth %d "
+                                                "and color type %d\n",
+                                                 s->bit_depth, s->color_type);
+                    goto fail;
+                }
+
+                if (ff_get_buffer(avctx, p, AV_GET_BUFFER_FLAG_REF) < 0)
+                    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 (avctx->pix_fmt == AV_PIX_FMT_PAL8)
+                    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] = (0xFFU << 24) | (r << 16) | (g << 8) | b;
+                }
+                for (; i < 256; i++) {
+                    s->palette[i] = (0xFFU << 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('t', 'E', 'X', 't'):
+            if (decode_text_chunk(s, length, 0, &metadata) < 0)
+                av_log(avctx, AV_LOG_WARNING, "Broken tEXt chunk\n");
+            bytestream2_skip(&s->gb, length + 4);
+            break;
+        case MKTAG('z', 'T', 'X', 't'):
+            if (decode_text_chunk(s, length, 1, &metadata) < 0)
+                av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
+            bytestream2_skip(&s->gb, length + 4);
+            break;
+        case MKTAG('I', 'E', 'N', 'D'):
+            if (!(s->state & PNG_ALLIMAGE))
+                av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
+            if (!(s->state & (PNG_ALLIMAGE|PNG_IDAT))) {
+                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:
+
+    if (s->bits_per_pixel == 1 && s->color_type == PNG_COLOR_TYPE_PALETTE){
+        int i, j, k;
+        uint8_t *pd = p->data[0];
+        for (j = 0; j < s->height; j++) {
+            i = s->width / 8;
+            for (k = 7; k >= 1; k--)
+                if ((s->width&7) >= k)
+                    pd[8*i + k - 1] = (pd[i]>>8-k) & 1;
+            for (i--; i >= 0; i--) {
+                pd[8*i + 7]=  pd[i]     & 1;
+                pd[8*i + 6]= (pd[i]>>1) & 1;
+                pd[8*i + 5]= (pd[i]>>2) & 1;
+                pd[8*i + 4]= (pd[i]>>3) & 1;
+                pd[8*i + 3]= (pd[i]>>4) & 1;
+                pd[8*i + 2]= (pd[i]>>5) & 1;
+                pd[8*i + 1]= (pd[i]>>6) & 1;
+                pd[8*i + 0]=  pd[i]>>7;
+            }
+            pd += s->image_linesize;
+        }
+    }
+    if (s->bits_per_pixel == 2){
+        int i, j;
+        uint8_t *pd = p->data[0];
+        for (j = 0; j < s->height; j++) {
+            i = s->width / 4;
+            if (s->color_type == PNG_COLOR_TYPE_PALETTE){
+                if ((s->width&3) >= 3) pd[4*i + 2]= (pd[i] >> 2) & 3;
+                if ((s->width&3) >= 2) pd[4*i + 1]= (pd[i] >> 4) & 3;
+                if ((s->width&3) >= 1) pd[4*i + 0]=  pd[i] >> 6;
+                for (i--; i >= 0; i--) {
+                    pd[4*i + 3]=  pd[i]     & 3;
+                    pd[4*i + 2]= (pd[i]>>2) & 3;
+                    pd[4*i + 1]= (pd[i]>>4) & 3;
+                    pd[4*i + 0]=  pd[i]>>6;
+                }
+            } else {
+                if ((s->width&3) >= 3) pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
+                if ((s->width&3) >= 2) pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
+                if ((s->width&3) >= 1) pd[4*i + 0]= ( pd[i]>>6     )*0x55;
+                for (i--; i >= 0; i--) {
+                    pd[4*i + 3]= ( pd[i]     & 3)*0x55;
+                    pd[4*i + 2]= ((pd[i]>>2) & 3)*0x55;
+                    pd[4*i + 1]= ((pd[i]>>4) & 3)*0x55;
+                    pd[4*i + 0]= ( pd[i]>>6     )*0x55;
+                }
+            }
+            pd += s->image_linesize;
+        }
+    }
+    if (s->bits_per_pixel == 4){
+        int i, j;
+        uint8_t *pd = p->data[0];
+        for (j = 0; j < s->height; j++) {
+            i = s->width/2;
+            if (s->color_type == PNG_COLOR_TYPE_PALETTE){
+                if (s->width&1) pd[2*i+0]= pd[i]>>4;
+                for (i--; i >= 0; i--) {
+                pd[2*i + 1] = pd[i] & 15;
+                pd[2*i + 0] = pd[i] >> 4;
+            }
+            } else {
+                if (s->width & 1) pd[2*i + 0]= (pd[i] >> 4) * 0x11;
+                for (i--; i >= 0; i--) {
+                    pd[2*i + 1] = (pd[i] & 15) * 0x11;
+                    pd[2*i + 0] = (pd[i] >> 4) * 0x11;
+                }
+            }
+            pd += s->image_linesize;
+        }
+    }
+
+     /* handle p-frames only if a predecessor frame is available */
+     if (s->prev->data[0]) {
+         if (   !(avpkt->flags & AV_PKT_FLAG_KEY)
+            && s->prev->width == p->width
+            && s->prev->height== p->height
+            && s->prev->format== p->format
+         ) {
+            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_set_metadata(p, metadata);
+    metadata   = NULL;
+
+    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:
+    av_dict_free(&metadata);
+    ret = -1;
+    goto the_end;
+}
+
+static av_cold int png_dec_init(AVCodecContext *avctx)
+{
+    PNGDecContext *s = avctx->priv_data;
+
+    s->prev = av_frame_alloc();
+    if (!s->prev)
+        return AVERROR(ENOMEM);
+
+    ff_pngdsp_init(&s->dsp);
+
+    s->avctx = avctx;
+
+    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",
+    .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   = CODEC_CAP_DR1 /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
+    .long_name      = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
+};