X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavcodec%2Fpngdec.c;h=feb17630a215d4604a767210d9837ffc2a51372f;hb=9caa9414ccf2dcf8aee2695377dee830a5024c82;hp=4cfdc588a55c91611d135eaac297d2c7f8689f38;hpb=af065bf11b61e3a1c4e3d0e9709584e8b24d9136;p=ffmpeg

diff --git a/libavcodec/pngdec.c b/libavcodec/pngdec.c
index 4cfdc588a55..feb17630a21 100644
--- a/libavcodec/pngdec.c
+++ b/libavcodec/pngdec.c
@@ -24,6 +24,8 @@
 #include "libavutil/avassert.h"
 #include "libavutil/bprint.h"
 #include "libavutil/imgutils.h"
+#include "libavutil/stereo3d.h"
+
 #include "avcodec.h"
 #include "bytestream.h"
 #include "internal.h"
@@ -1014,7 +1016,7 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
             for (x = s->x_offset; x < s->x_offset + s->cur_w; ++x, foreground += s->bpp, background += s->bpp) {
                 size_t b;
                 uint8_t foreground_alpha, background_alpha, output_alpha;
-                uint8_t output[4];
+                uint8_t output[10];
 
                 // Since we might be blending alpha onto alpha, we use the following equations:
                 // output_alpha = foreground_alpha + (1 - foreground_alpha) * background_alpha
@@ -1054,6 +1056,8 @@ static int handle_p_frame_apng(AVCodecContext *avctx, PNGDecContext *s,
 
                 output_alpha = foreground_alpha + FAST_DIV255((255 - foreground_alpha) * background_alpha);
 
+                av_assert0(s->bpp <= 10);
+
                 for (b = 0; b < s->bpp - 1; ++b) {
                     if (output_alpha == 0) {
                         output[b] = 0;
@@ -1087,6 +1091,13 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
     for (;;) {
         length = bytestream2_get_bytes_left(&s->gb);
         if (length <= 0) {
+
+            if (avctx->codec_id == AV_CODEC_ID_PNG &&
+                avctx->skip_frame == AVDISCARD_ALL) {
+                av_frame_set_metadata(p, metadata);
+                return 0;
+            }
+
             if (CONFIG_APNG_DECODER && avctx->codec_id == AV_CODEC_ID_APNG && length == 0) {
                 if (!(s->state & PNG_IDAT))
                     return 0;
@@ -1114,6 +1125,20 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
                 ((tag >> 8) & 0xff),
                 ((tag >> 16) & 0xff),
                 ((tag >> 24) & 0xff), length);
+
+        if (avctx->codec_id == AV_CODEC_ID_PNG &&
+            avctx->skip_frame == AVDISCARD_ALL) {
+            switch(tag) {
+            case MKTAG('I', 'H', 'D', 'R'):
+            case MKTAG('p', 'H', 'Y', 's'):
+            case MKTAG('t', 'E', 'X', 't'):
+            case MKTAG('I', 'D', 'A', 'T'):
+                break;
+            default:
+                goto skip_tag;
+            }
+        }
+
         switch (tag) {
         case MKTAG('I', 'H', 'D', 'R'):
             if ((ret = decode_ihdr_chunk(avctx, s, length)) < 0)
@@ -1164,6 +1189,22 @@ static int decode_frame_common(AVCodecContext *avctx, PNGDecContext *s,
                 av_log(avctx, AV_LOG_WARNING, "Broken zTXt chunk\n");
             bytestream2_skip(&s->gb, length + 4);
             break;
+        case MKTAG('s', 'T', 'E', 'R'): {
+            int mode = bytestream2_get_byte(&s->gb);
+            AVStereo3D *stereo3d = av_stereo3d_create_side_data(p);
+            if (!stereo3d)
+                goto fail;
+
+            if (mode == 0 || mode == 1) {
+                stereo3d->type  = AV_STEREO3D_SIDEBYSIDE;
+                stereo3d->flags = mode ? 0 : AV_STEREO3D_FLAG_INVERT;
+            } else {
+                 av_log(avctx, AV_LOG_WARNING,
+                        "Unknown value in sTER chunk (%d)\n", mode);
+            }
+            bytestream2_skip(&s->gb, 4); /* crc */
+            break;
+        }
         case MKTAG('I', 'E', 'N', 'D'):
             if (!(s->state & PNG_ALLIMAGE))
                 av_log(avctx, AV_LOG_ERROR, "IEND without all image\n");
@@ -1181,6 +1222,11 @@ skip_tag:
         }
     }
 exit_loop:
+    if (avctx->codec_id == AV_CODEC_ID_PNG &&
+        avctx->skip_frame == AVDISCARD_ALL) {
+        av_frame_set_metadata(p, metadata);
+        return 0;
+    }
 
     if (s->bits_per_pixel <= 4)
         handle_small_bpp(s, p);
@@ -1278,6 +1324,12 @@ static int decode_frame_png(AVCodecContext *avctx,
     if ((ret = decode_frame_common(avctx, s, p, avpkt)) < 0)
         goto the_end;
 
+    if (avctx->skip_frame == AVDISCARD_ALL) {
+        *got_frame = 0;
+        ret = bytestream2_tell(&s->gb);
+        goto the_end;
+    }
+
     if ((ret = av_frame_ref(data, s->picture.f)) < 0)
         return ret;