<div dir="ltr"><div class="gmail_quote"><div dir="ltr">Hi,<div><br></div><div>I am encountering issues with GStreamer and STAP-A RTP packetization mode. I have a software that encodes a H264 stream and sends it over RTP and I am using GStreamer to play it back on an embedded system? If I use only FU-A and singe NAL packets everything seems to be fine, but when I use STAP-A GStreamer gives no output, seems that it parses only the first NAL unit from the STAP-A packet.</div>
<div><br></div><div>The GStreamer pipeline is: gst-launch-1.0 -v udpsrc multicast-group=<a href="tel:224.13.11.1" value="+37122413111" target="_blank">224.13.11.1</a> port=1312 multicast-iface=eth0 caps="application/x-rtp, media=(string)video, clock-rate=(int)90000, encoding-name=(string)H264, payload=(int)96" ! rtph264depay ! h264parse ! omxh264dec ! eglglessink , I am running this on a Raspberry Pi, GStreamer version is 1.0.10</div>
<div><br></div><div>I've looked at the packets via Wireshark, and the STAP-A format seems fine, 2 bytes NAL length in network order and then the payload. </div><div><br></div><div>What I see from the GStreamer log is:</div>
<div><br></div><div><div>rtph264depay gstrtph264depay.c:874:gst_rtp_h264_depay_process:<rtph264depay0> NRI 1, Type 24</div><div>GST_MEMORY gstmemory.c:133:gst_memory_init: new memory 0x1185828, maxsize:45 offset:0 size:42</div>
<div>GST_MEMORY gstmemory.c:133:gst_memory_init: new memory 0x11446b8, maxsize:11 offset:0 size:8</div><div>GST_MEMORY gstmemory.c:133:gst_memory_init: new memory 0x10a72c8, maxsize:29 offset:0 size:26</div><div>adapter gstadapter.c:294:copy_into_unchecked: bsize 42, skip 0, csize 42</div>
<div>GST_MEMORY gstmemory.c:133:gst_memory_init: new memory 0x116c280, maxsize:76 offset:0 size:76</div><div>GST_MEMORY gstmemory.c:86:_gst_memory_free: free memory 0x1185828</div><div>GST_MEMORY gstmemory.c:86:_gst_memory_free: free memory 0x11446b8</div>
<div>GST_MEMORY gstmemory.c:86:_gst_memory_free: free memory 0x10a72c8</div><div>rtph264depay gstrtph264depay.c:673:gst_rtp_h264_depay_handle_nal:<rtph264depay0> handle NAL type 7</div></div><div><br></div><div>I seems that it correctly splits the chunks but only first one is handled. And then after the next FU-A with a slice is sent, since PPS and SPS are both not present an event is pushed back from the parser: </div>
<div><br></div><div>GST_EVENT gstpad.c:4771:gst_pad_send_event_unchecked:<udpsrc0:src> [00m have event type custom-upstream event at time 99:99:99.999999999: GstForceKeyUnit, all-headers=(boolean)true<br></div><div>
<br></div><div>which corresponds to the code:</div><div><br></div><div><div> } else if (rtph264depay->sps->len == 0 || rtph264depay->pps->len == 0) {</div><div> /* Down push down any buffer in non-bytestream mode if the SPS/PPS haven't</div>
<div> * go through yet</div><div> */</div><div> gst_pad_push_event (GST_RTP_BASE_DEPAYLOAD_SINKPAD (depayload),</div><div> gst_event_new_custom (GST_EVENT_CUSTOM_UPSTREAM,</div><div> gst_structure_new ("GstForceKeyUnit",</div>
<div> "all-headers", G_TYPE_BOOLEAN, TRUE, NULL)));</div><div> gst_buffer_unmap (nal, &map);</div><div> gst_buffer_unref (nal);</div><div> return NULL;</div><div> }</div></div>
<div><br></div><div><div>Wireshark packet:</div><div><br></div><div>00000000 80 e0 00 00 00 00 00 00 00 00 00 00 38 00 26 27 ........ ....8.&'</div><div>00000010 42 40 28 95 a0 12 01 b6 c0 44 00 00 03 00 04 00 B@(..... .D......</div>
<div>00000020 00 03 00 cb 81 00 00 16 e3 60 00 00 e4 e1 cb de ........ .`......</div><div>00000030 f8 1b 43 86 54 00 04 28 ce 3c 80 00 16 06 00 07 ..C.T..( .<......</div><div>00000040 80 6d dd 00 6d dd 40 01 07 00 00 03 00 00 03 00 .m..m.@. ........</div>
<div>00000050 00 04 80</div><div><br></div><div>So if we look at the packet:</div><div>00 26 = 38 bytes of data</div><div>after 38 bytes we have 00 04 = 4 bytes of data</div><div>after 4 bytes of data we have 00 16 = 22 bytes of data</div>
<div><br></div><div>Seems to me that the packet is formatted correctly. Can anyone give me some guidance?</div></div><div><br></div><div><br></div><div>Best Regards,<br></div><div>Rudolfs Bundulis</div></div>
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