Rtsp-stream pipeline is blocked in sometimes

I create a pipeline by refering to deepstream-apps with version 4.0.1 ,like this, “rtspsrc->rtph264depay->decodebin->fakesink” . I add probe at sink pad of fakesink to get GstBuffer. Sometimes, stream is not not runing. Below is log. I need help of somebody. Thanks.

cb_rtspsrc_select_stream==video
cb_rtspsrc_select_stream==audio
0:00:43.268143482 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:191:gst_rtp_h264_depay_negotiate: allowed caps: video/x-h264, stream-format=(string)avc, alignment=(string)au; video/x-h264, stream-format=(string)byte-stream, alignment=(string){ nal, au }
0:00:43.269777739 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:223:gst_rtp_h264_depay_negotiate: downstream requires byte-stream 0
0:00:43.269907693 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:231:gst_rtp_h264_depay_negotiate: downstream requires merge 1
0:00:43.270050094 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:704:gst_rtp_h264_depay_setcaps: we have 2 params
0:00:43.270380690 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:726:gst_rtp_h264_depay_setcaps: adding param 0 as SPS
0:00:43.270461107 5706 0x7ec0004540 LOG rtph264depay gstrtph264depay.c:559:gst_rtp_h264_add_sps_pps: Adding new SPS 0
0:00:43.270803287 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:726:gst_rtp_h264_depay_setcaps: adding param 1 as PPS
0:00:43.270898136 5706 0x7ec0004540 LOG rtph264depay gstrtph264depay.c:599:gst_rtp_h264_add_sps_pps: Adding new PPS 0:0
0:00:43.271057337 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:386:gst_rtp_h264_set_src_caps: copy SPS 0 of length 16
0:00:43.271183483 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:402:gst_rtp_h264_set_src_caps: copy PPS 0 of length 4
decodebin child: h264parse1
decodebin child: capsfilter1
0:00:43.286202782 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:292:gst_rtp_h264_depay_set_output_caps: downstream ALLOCATION query failed
0:00:43.286387872 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:1027:gst_rtp_h264_depay_process: receiving 5 bytes
0:00:43.286419232 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:1047:gst_rtp_h264_depay_process: NRI 0, Type 6
0:00:43.286457057 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:845:gst_rtp_h264_depay_handle_nal: handle NAL type 6
0:00:43.286475745 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:914:gst_rtp_h264_depay_handle_nal: adding NAL to picture adapter
0:00:43.286498337 5706 0x7ec0004540 DEBUG rtph264depay gstrtph264depay.c:779:gst_rtp_h264_complete_au: taking completed AU
0:00:43.286515970 5706 0x7ec0004540 LOG rtph264depay gstrtph264depay.c:757:gst_rtp_h264_depay_allocate_output_buffer: want output buffer of 9 bytes
decodebin child: nvv4l2decoder1
Opening in BLOCKING MODE
NvMMLiteOpen : Block : BlockType = 261
NVMEDIA: Reading vendor.tegra.display-size : status: 6
NvMMLiteBlockCreate : Block : BlockType = 261

Hi,
There is a sample which is close to your usecase. Please check

That sample is different from my case. It has no reference value.

Hi,
May see if some others can share experience. Or you may try uridecodebin ! nvoverlaysink