Merge commit '1173320249745eab01c901a39054fc0fced33c87'
[ffmpeg.git] / libavcodec / pngdec.c
index 66afb0e..c92087f 100644 (file)
@@ -2,44 +2,43 @@
  * PNG image format
  * Copyright (c) 2003 Fabrice Bellard
  *
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * 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.
  *
- * Libav is distributed in the hope that it will be useful,
+ * 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 Libav; if not, write to the Free Software
+ * 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 2, 4 and 16 bit depth support
- */
+#include "thread.h"
 
 #include <zlib.h>
 
-//#define DEBUG
-
 typedef struct PNGDecContext {
     PNGDSPContext dsp;
+    AVCodecContext *avctx;
 
-    const uint8_t *bytestream;
-    const uint8_t *bytestream_start;
-    const uint8_t *bytestream_end;
-    AVFrame picture1, picture2;
-    AVFrame *current_picture, *last_picture;
+    GetByteContext gb;
+    ThreadFrame last_picture;
+    ThreadFrame picture;
 
     int state;
     int width, height;
@@ -57,7 +56,11 @@ typedef struct PNGDecContext {
     uint32_t palette[256];
     uint8_t *crow_buf;
     uint8_t *last_row;
+    unsigned int last_row_size;
     uint8_t *tmp_row;
+    unsigned int tmp_row_size;
+    uint8_t *buffer;
+    int buffer_size;
     int pass;
     int crow_size; /* compressed row size (include filter type) */
     int row_size; /* decompressed row size */
@@ -66,9 +69,14 @@ typedef struct PNGDecContext {
     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, 0xcc, 0x33, 0xff, 0x55,
+    0xff, 0xff, 0x0f, 0xff, 0x33, 0xff, 0x55,
 };
 
 /* Mask to determine which pixels to overwrite while displaying */
@@ -77,8 +85,8 @@ static const uint8_t png_pass_dsp_mask[NB_PASSES] = {
 };
 
 /* 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 */
* 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)
@@ -87,40 +95,56 @@ static void png_put_interlaced_row(uint8_t *dst, int width,
     uint8_t *d;
     const uint8_t *s;
 
-    mask = ff_png_pass_mask[pass];
+    mask     = png_pass_mask[pass];
     dsp_mask = png_pass_dsp_mask[pass];
-    switch(bits_per_pixel) {
+
+    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++) {
+        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;
-        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++) {
+        d   = dst;
+        s   = src;
+            for (x = 0; x < width; x++) {
                 j = x & 7;
                 if ((dsp_mask << j) & 0x80) {
                     memcpy(d, s, bpp);
@@ -129,22 +153,22 @@ static void png_put_interlaced_row(uint8_t *dst, int width,
                 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)
+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++) {
+    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;
+        p  = b - c;
         pc = a - c;
 
         pa = abs(p);
@@ -161,34 +185,36 @@ void ff_add_png_paeth_prediction(uint8_t *dst, uint8_t *src, uint8_t *top, int w
     }
 }
 
-#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 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)\
-    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]);\
-        }\
-    }
+         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,
@@ -196,23 +222,22 @@ static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
 {
     int i, p, r, g, b, a;
 
-    switch(filter_type) {
+    switch (filter_type) {
     case PNG_FILTER_VALUE_NONE:
         memcpy(dst, src, size);
         break;
     case PNG_FILTER_VALUE_SUB:
-        for(i = 0; i < bpp; i++) {
+        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;
+        if (bpp == 4) {
+            p = *(int *)dst;
+            for (; i < size; i += bpp) {
+                unsigned 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
+#define OP_SUB(x, s, l) ((x) + (s))
             UNROLL_FILTER(OP_SUB);
         }
         break;
@@ -220,66 +245,45 @@ static void png_filter_row(PNGDSPContext *dsp, uint8_t *dst, int filter_type,
         dsp->add_bytes_l2(dst, src, last, size);
         break;
     case PNG_FILTER_VALUE_AVG:
-        for(i = 0; i < bpp; i++) {
-            p = (last[i] >> 1);
+        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
+#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];
+        for (i = 0; i < bpp; i++) {
+            p      = last[i];
             dst[i] = p + src[i];
         }
-        if(bpp > 1 && 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);
+        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);
+        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;
-    }
+/* 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; \
+    } \
 }
 
-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;
-    }
-}
+YUV2RGB(rgb8, uint8_t)
+YUV2RGB(rgb16, uint16_t)
 
 /* process exactly one decompressed row */
 static void png_handle_row(PNGDecContext *s)
@@ -289,14 +293,6 @@ static void png_handle_row(PNGDecContext *s)
 
     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
@@ -304,40 +300,52 @@ static void png_handle_row(PNGDecContext *s)
 
             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);
+        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 &&
-                s->color_type == PNG_COLOR_TYPE_RGB)
-                deloco_rgb24(ptr, s->row_size);
+            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(;;) {
+        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 */
+                 * 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);
+                FFSWAP(uint8_t *, s->last_row, s->tmp_row);
+                FFSWAP(unsigned int, s->last_row_size, s->tmp_row_size);
                 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(;;) {
+                memset(s->last_row, 0, s->row_size);
+                for (;;) {
                     if (s->pass == NB_PASSES - 1) {
                         s->state |= PNG_ALLIMAGE;
                         goto the_end;
@@ -345,8 +353,8 @@ static void png_handle_row(PNGDecContext *s)
                         s->pass++;
                         s->y = 0;
                         s->pass_row_size = ff_png_pass_row_size(s->pass,
-                                                             s->bits_per_pixel,
-                                                             s->width);
+                                                                s->bits_per_pixel,
+                                                                s->width);
                         s->crow_size = s->pass_row_size + 1;
                         if (s->pass_row_size != 0)
                             break;
@@ -355,291 +363,555 @@ static void png_handle_row(PNGDecContext *s)
                 }
             }
         }
-    the_end: ;
+the_end:;
     }
 }
 
 static int png_decode_idat(PNGDecContext *s, int length)
 {
     int ret;
-    s->zstream.avail_in = length;
-    s->zstream.next_in = s->bytestream;
-    s->bytestream += length;
-
-    if(s->bytestream > s->bytestream_end)
-        return -1;
+    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) {
-            return -1;
+            av_log(s->avctx, AV_LOG_ERROR, "inflate returned error %d\n", ret);
+            return AVERROR_EXTERNAL;
         }
         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;
+            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_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 *data_size,
+                        void *data, int *got_frame,
                         AVPacket *avpkt)
 {
-    const uint8_t *buf = avpkt->data;
-    int buf_size = avpkt->size;
-    PNGDecContext * const s = avctx->priv_data;
-    AVFrame *picture = data;
+    PNGDecContext *const s = avctx->priv_data;
+    const uint8_t *buf     = avpkt->data;
+    int buf_size           = avpkt->size;
     AVFrame *p;
-    uint8_t *crow_buf_base = NULL;
+    AVDictionary *metadata  = NULL;
     uint32_t tag, length;
+    int64_t sig;
     int ret;
 
-    FFSWAP(AVFrame *, s->current_picture, s->last_picture);
-    avctx->coded_frame= s->current_picture;
-    p = s->current_picture;
+    ff_thread_release_buffer(avctx, &s->last_picture);
+    FFSWAP(ThreadFrame, s->picture, s->last_picture);
+    p = s->picture.f;
 
-    s->bytestream_start=
-    s->bytestream= buf;
-    s->bytestream_end= buf + buf_size;
+    bytestream2_init(&s->gb, buf, buf_size);
 
     /* check signature */
-    if (memcmp(s->bytestream, ff_pngsig, 8) != 0 &&
-        memcmp(s->bytestream, ff_mngsig, 8) != 0)
-        return -1;
-    s->bytestream+= 8;
-    s->y=
-    s->state=0;
-//    memset(s, 0, sizeof(PNGDecContext));
+    sig = bytestream2_get_be64(&s->gb);
+    if (sig != PNGSIG &&
+        sig != MNGSIG) {
+        av_log(avctx, AV_LOG_ERROR, "Missing png signature\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    s->y = s->state = 0;
+
     /* init the zlib */
     s->zstream.zalloc = ff_png_zalloc;
-    s->zstream.zfree = ff_png_zfree;
+    s->zstream.zfree  = ff_png_zfree;
     s->zstream.opaque = NULL;
     ret = inflateInit(&s->zstream);
-    if (ret != Z_OK)
-        return -1;
-    for(;;) {
-        int tag32;
-        if (s->bytestream >= s->bytestream_end)
+    if (ret != Z_OK) {
+        av_log(avctx, AV_LOG_ERROR, "inflateInit returned error %d\n", ret);
+        return AVERROR_EXTERNAL;
+    }
+    for (;;) {
+        if (bytestream2_get_bytes_left(&s->gb) <= 0) {
+            av_log(avctx, AV_LOG_ERROR, "No bytes left\n");
+            if (   s->state & PNG_ALLIMAGE
+                && avctx->strict_std_compliance <= FF_COMPLIANCE_NORMAL)
+                goto exit_loop;
             goto fail;
-        length = bytestream_get_be32(&s->bytestream);
-        if (length > 0x7fffffff)
+        }
+
+        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;
-        tag32 = bytestream_get_be32(&s->bytestream);
-        tag = av_bswap32(tag32);
-        av_dlog(avctx, "png: tag=%c%c%c%c length=%u\n",
+        }
+        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) {
+        switch (tag) {
         case MKTAG('I', 'H', 'D', 'R'):
             if (length != 13)
                 goto fail;
-            s->width = bytestream_get_be32(&s->bytestream);
-            s->height = bytestream_get_be32(&s->bytestream);
-            if(av_image_check_size(s->width, s->height, 0, avctx)){
-                s->width= s->height= 0;
+            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 = *s->bytestream++;
-            s->color_type = *s->bytestream++;
-            s->compression_type = *s->bytestream++;
-            s->filter_type = *s->bytestream++;
-            s->interlace_type = *s->bytestream++;
-            s->bytestream += 4; /* crc */
+            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;
-            av_dlog(avctx, "width=%d height=%d depth=%d color_type=%d compression_type=%d filter_type=%d interlace_type=%d\n",
+            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))
+            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->width  = s->width;
                 avctx->height = s->height;
 
-                s->channels = ff_png_get_nb_channels(s->color_type);
+                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;
+                s->bpp            = (s->bits_per_pixel + 7) >> 3;
+                s->row_size       = (avctx->width * s->bits_per_pixel + 7) >> 3;
 
-                if (s->bit_depth == 8 &&
+                if ((s->bit_depth == 2 || s->bit_depth == 4 || s->bit_depth == 8) &&
                     s->color_type == PNG_COLOR_TYPE_RGB) {
-                    avctx->pix_fmt = PIX_FMT_RGB24;
-                } else if (s->bit_depth == 8 &&
+                    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 = PIX_FMT_RGB32;
-                } else if (s->bit_depth == 8 &&
+                    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 = PIX_FMT_GRAY8;
+                    avctx->pix_fmt = AV_PIX_FMT_GRAY8;
                 } else if (s->bit_depth == 16 &&
                            s->color_type == PNG_COLOR_TYPE_GRAY) {
-                    avctx->pix_fmt = PIX_FMT_GRAY16BE;
+                    avctx->pix_fmt = AV_PIX_FMT_GRAY16BE;
                 } else if (s->bit_depth == 16 &&
                            s->color_type == PNG_COLOR_TYPE_RGB) {
-                    avctx->pix_fmt = PIX_FMT_RGB48BE;
-                } else if (s->bit_depth == 1 &&
-                           s->color_type == PNG_COLOR_TYPE_GRAY) {
-                    avctx->pix_fmt = PIX_FMT_MONOBLACK;
-                } else if (s->color_type == PNG_COLOR_TYPE_PALETTE) {
-                    avctx->pix_fmt = PIX_FMT_PAL8;
-                } else if (s->color_type == PNG_COLOR_TYPE_GRAY_ALPHA) {
-                    avctx->pix_fmt = PIX_FMT_Y400A;
+                    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(p->data[0])
-                    avctx->release_buffer(avctx, p);
 
-                p->reference= 0;
-                if(avctx->get_buffer(avctx, p) < 0){
-                    av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+                if (ff_thread_get_buffer(avctx, &s->picture, AV_GET_BUFFER_FLAG_REF) < 0)
                     goto fail;
-                }
-                p->pict_type= AV_PICTURE_TYPE_I;
-                p->key_frame= 1;
+                ff_thread_finish_setup(avctx);
+
+                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          = 0;
                     s->pass_row_size = ff_png_pass_row_size(s->pass,
-                                                         s->bits_per_pixel,
-                                                         s->width);
+                                                            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_buf      = p->data[0];
                 s->image_linesize = p->linesize[0];
                 /* copy the palette if needed */
-                if (s->color_type == PNG_COLOR_TYPE_PALETTE)
+                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);
+                av_fast_padded_mallocz(&s->last_row, &s->last_row_size, 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);
+                    av_fast_padded_malloc(&s->tmp_row, &s->tmp_row_size, s->row_size);
                     if (!s->tmp_row)
                         goto fail;
                 }
                 /* compressed row */
-                crow_buf_base = av_malloc(s->row_size + 16);
-                if (!crow_buf_base)
+                av_fast_padded_malloc(&s->buffer, &s->buffer_size, s->row_size + 16);
+                if (!s->buffer)
                     goto fail;
 
                 /* we want crow_buf+1 to be 16-byte aligned */
-                s->crow_buf = crow_buf_base + 15;
+                s->crow_buf          = s->buffer + 15;
                 s->zstream.avail_out = s->crow_size;
-                s->zstream.next_out = s->crow_buf;
+                s->zstream.next_out  = s->crow_buf;
             }
             s->state |= PNG_IDAT;
             if (png_decode_idat(s, length) < 0)
                 goto fail;
-            s->bytestream += 4; /* crc */
+            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 = *s->bytestream++;
-                    g = *s->bytestream++;
-                    b = *s->bytestream++;
-                    s->palette[i] = (0xff << 24) | (r << 16) | (g << 8) | b;
-                }
-                for(;i<256;i++) {
-                    s->palette[i] = (0xff << 24);
-                }
-                s->state |= PNG_PLTE;
-                s->bytestream += 4; /* crc */
+        {
+            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;
             }
-            break;
+            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 = *s->bytestream++;
-                    s->palette[i] = (s->palette[i] & 0x00ffffff) | (v << 24);
-                }
-                s->bytestream += 4; /* crc */
+        {
+            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;
-            s->bytestream += 4; /* crc */
+            }
+            bytestream2_skip(&s->gb, 4); /* crc */
             goto exit_loop;
         default:
             /* skip tag */
-        skip_tag:
-            s->bytestream += length + 4;
+skip_tag:
+            bytestream2_skip(&s->gb, length + 4);
             break;
         }
     }
- exit_loop:
-     /* handle p-frames only if a predecessor frame is available */
-     if(s->last_picture->data[0] != NULL) {
-         if(!(avpkt->flags & AV_PKT_FLAG_KEY)) {
+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->last_picture.f->data[0]) {
+        if (   !(avpkt->flags & AV_PKT_FLAG_KEY) && avctx->codec_tag != AV_RL32("MPNG")
+            && s->last_picture.f->width == p->width
+            && s->last_picture.f->height== p->height
+            && s->last_picture.f->format== p->format
+         ) {
             int i, j;
-            uint8_t *pd = s->current_picture->data[0];
-            uint8_t *pd_last = s->last_picture->data[0];
+            uint8_t *pd      = p->data[0];
+            uint8_t *pd_last = s->last_picture.f->data[0];
 
-            for(j=0; j < s->height; j++) {
-                for(i=0; i < s->width * s->bpp; i++) {
+            ff_thread_await_progress(&s->last_picture, INT_MAX, 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      += s->image_linesize;
                 pd_last += s->image_linesize;
             }
         }
     }
+    ff_thread_report_progress(&s->picture, INT_MAX, 0);
+
+    av_frame_set_metadata(p, metadata);
+    metadata   = NULL;
 
-    *picture= *s->current_picture;
-    *data_size = sizeof(AVFrame);
+    if ((ret = av_frame_ref(data, s->picture.f)) < 0)
+        return ret;
 
-    ret = s->bytestream - s->bytestream_start;
- the_end:
+    *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;
+fail:
+    av_dict_free(&metadata);
+    ff_thread_report_progress(&s->picture, INT_MAX, 0);
+    ret = AVERROR_INVALIDDATA;
     goto the_end;
 }
 
-static av_cold int png_dec_init(AVCodecContext *avctx){
+static int update_thread_context(AVCodecContext *dst, const AVCodecContext *src)
+{
+    PNGDecContext *psrc = src->priv_data;
+    PNGDecContext *pdst = dst->priv_data;
+
+    if (dst == src)
+        return 0;
+
+    ff_thread_release_buffer(dst, &pdst->picture);
+    if (psrc->picture.f->data[0])
+        return ff_thread_ref_frame(&pdst->picture, &psrc->picture);
+
+    return 0;
+}
+
+static av_cold int png_dec_init(AVCodecContext *avctx)
+{
     PNGDecContext *s = avctx->priv_data;
 
-    s->current_picture = &s->picture1;
-    s->last_picture = &s->picture2;
-    avcodec_get_frame_defaults(&s->picture1);
-    avcodec_get_frame_defaults(&s->picture2);
-    ff_pngdsp_init(&s->dsp);
+    s->avctx = avctx;
+    s->last_picture.f = av_frame_alloc();
+    s->picture.f = av_frame_alloc();
+    if (!s->last_picture.f || !s->picture.f)
+        return AVERROR(ENOMEM);
+
+    if (!avctx->internal->is_copy) {
+        avctx->internal->allocate_progress = 1;
+        ff_pngdsp_init(&s->dsp);
+    }
 
     return 0;
 }
@@ -648,22 +920,30 @@ static av_cold int png_dec_end(AVCodecContext *avctx)
 {
     PNGDecContext *s = avctx->priv_data;
 
-    if (s->picture1.data[0])
-        avctx->release_buffer(avctx, &s->picture1);
-    if (s->picture2.data[0])
-        avctx->release_buffer(avctx, &s->picture2);
+    ff_thread_release_buffer(avctx, &s->last_picture);
+    av_frame_free(&s->last_picture.f);
+    ff_thread_release_buffer(avctx, &s->picture);
+    av_frame_free(&s->picture.f);
+    av_freep(&s->buffer);
+    s->buffer_size = 0;
+    av_freep(&s->last_row);
+    s->last_row_size = 0;
+    av_freep(&s->tmp_row);
+    s->tmp_row_size = 0;
 
     return 0;
 }
 
 AVCodec ff_png_decoder = {
     .name           = "png",
+    .long_name      = NULL_IF_CONFIG_SMALL("PNG (Portable Network Graphics) image"),
     .type           = AVMEDIA_TYPE_VIDEO,
-    .id             = CODEC_ID_PNG,
+    .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"),
+    .init_thread_copy = ONLY_IF_THREADS_ENABLED(png_dec_init),
+    .update_thread_context = ONLY_IF_THREADS_ENABLED(update_thread_context),
+    .capabilities   = CODEC_CAP_DR1 | CODEC_CAP_FRAME_THREADS /*| CODEC_CAP_DRAW_HORIZ_BAND*/,
 };