Merge branch '2.0release' into develop

@@ -403,6 +403,7 @@ Remark:
 =======
 ## History
 
+* v2.0, 2016-08-18, fix [srs-librtmp#4](https://github.com/ossrs/srs-librtmp/issues/4) filter frame.
 * v2.0, 2016-08-10, fix socket timeout for librtmp.
 * v2.0, 2016-08-08, fix the crash by srs_info log.
 * <strong>v2.0, 2016-08-06, [2.0 beta0(2.0.210)][r2.0b0] released. 89704 lines.</strong>

@@ -1393,6 +1393,11 @@ int srs_write_h264_raw_frame(Context* context,
 ) {
     int ret = ERROR_SUCCESS;
     
+    // empty frame.
+    if (frame_size <= 0) {
+        return ret;
+    }
+
     // for sps
     if (context->avc_raw.is_sps(frame, frame_size)) {
         std::string sps;
@@ -1425,6 +1430,15 @@ int srs_write_h264_raw_frame(Context* context,
         return ret;
     }
     
+    // ignore others.
+    // 5bits, 7.3.1 NAL unit syntax,
+    // H.264-AVC-ISO_IEC_14496-10.pdf, page 44.
+    //  7: SPS, 8: PPS, 5: I Frame, 1: P Frame
+    SrsAvcNaluType nut = (SrsAvcNaluType)(frame[0] & 0x1f);
+    if (nut != SrsAvcNaluTypeSPS && nut != SrsAvcNaluTypePPS && nut != SrsAvcNaluTypeIDR && nut != SrsAvcNaluTypeNonIDR) {
+        return ret;
+    }
+    
     // send pps+sps before ipb frames when sps/pps changed.
     if ((ret = srs_write_h264_sps_pps(context, dts, pts)) != ERROR_SUCCESS) {
         return ret;