diff --git a/libavformat/thp.c b/libavformat/thp.c
index 870a558a36..bc4f0dafe5 100644
--- a/libavformat/thp.c
+++ b/libavformat/thp.c
@@ -47,11 +47,16 @@ typedef struct ThpDemuxContext {
 
 static int thp_probe(AVProbeData *p)
 {
+    double d;
     /* check file header */
-    if (AV_RL32(p->buf) == MKTAG('T', 'H', 'P', '\0'))
-        return AVPROBE_SCORE_MAX;
-    else
+    if (AV_RL32(p->buf) != MKTAG('T', 'H', 'P', '\0'))
         return 0;
+
+    d = av_int2float(AV_RB32(p->buf + 16));
+    if (d < 0.1 || d > 1000 || isnan(d))
+        return AVPROBE_SCORE_MAX/4;
+
+    return AVPROBE_SCORE_MAX;
 }
 
 static int thp_read_header(AVFormatContext *s)