X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=libavformat%2Ficodec.c;h=17acfb4b2fb483da742a8af357c2fb8d9123856b;hb=14478b6c3820339442d8c96b701d021499de0827;hp=22e209903bcad002d775e83eb5b53d183322cf4c;hpb=a240aefc7a2591f7b307e2910df655801ae6ca44;p=ffmpeg

diff --git a/libavformat/icodec.c b/libavformat/icodec.c
index 22e209903bc..17acfb4b2fb 100644
--- a/libavformat/icodec.c
+++ b/libavformat/icodec.c
@@ -27,6 +27,7 @@
 #include "libavutil/intreadwrite.h"
 #include "libavcodec/bytestream.h"
 #include "libavcodec/bmp.h"
+#include "libavcodec/png.h"
 #include "avformat.h"
 #include "internal.h"
 
@@ -44,9 +45,34 @@ typedef struct {
 
 static int probe(AVProbeData *p)
 {
-    if (AV_RL16(p->buf) == 0 && AV_RL16(p->buf + 2) == 1 && AV_RL16(p->buf + 4))
-        return AVPROBE_SCORE_MAX / 4;
-    return 0;
+    unsigned i, frames, checked = 0;
+
+    if (p->buf_size < 22 || AV_RL16(p->buf) || AV_RL16(p->buf + 2) != 1)
+        return 0;
+    frames = AV_RL16(p->buf + 4);
+    if (!frames)
+        return 0;
+    for (i = 0; i < frames && i * 16 + 22 <= p->buf_size; i++) {
+        unsigned offset;
+        if (AV_RL16(p->buf + 10 + i * 16) & ~1)
+            return FFMIN(i, AVPROBE_SCORE_MAX / 4);
+        if (p->buf[13 + i * 16])
+            return FFMIN(i, AVPROBE_SCORE_MAX / 4);
+        if (AV_RL32(p->buf + 14 + i * 16) < 40)
+            return FFMIN(i, AVPROBE_SCORE_MAX / 4);
+        offset = AV_RL32(p->buf + 18 + i * 16);
+        if (offset < 22)
+            return FFMIN(i, AVPROBE_SCORE_MAX / 4);
+        if (offset > p->buf_size - 8)
+            continue;
+        if (p->buf[offset] != 40 && AV_RB64(p->buf + offset) != PNGSIG)
+            return FFMIN(i, AVPROBE_SCORE_MAX / 4);
+        checked++;
+    }
+
+    if (checked < frames)
+        return AVPROBE_SCORE_MAX / 4 + FFMIN(checked, 1);
+    return AVPROBE_SCORE_MAX / 2 + 1;
 }
 
 static int read_header(AVFormatContext *s)