avformat/rtmpproto: Fix 2 more cases of the 2nd packet size being wrong

This should fix RTMP input which was broken by cbbd906b
the 40 + 11 case is untested as it did not occur in the testcase
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/rtmpproto.c

@@ -2368,8 +2368,9 @@ static int handle_metadata(RTMPContext *rt, RTMPPacket *pkt)
         bytestream_put_be24(&p, ts);
         bytestream_put_byte(&p, ts >> 24);
         memcpy(p, next, size + 3 + 4);
+        p    += size + 3;
+        bytestream_put_be32(&p, size + 11);
         next += size + 3 + 4;
-        p    += size + 3 + 4;
     }
     if (p != rt->flv_data + rt->flv_size) {
         av_log(NULL, AV_LOG_WARNING, "Incomplete flv packets in "
@@ -2559,7 +2560,7 @@ static int inject_fake_duration_metadata(RTMPContext *rt)
     // Finalise object
     bytestream_put_be16(&p, 0); // Empty string
     bytestream_put_byte(&p, AMF_END_OF_OBJECT);
-    bytestream_put_be32(&p, 40); // size of data part (sum of all parts below)
+    bytestream_put_be32(&p, 40 + 11); // size of data part (sum of all parts below)
 
     return 0;
 }