# Kurento Java Tutorial - RTP Receiver

This web application consists of a simple RTP stream pipeline: an RtpEndpoint is configured in KMS to listen for one incoming video stream. This stream must be generated by an external program. Visual feedback is provided in this page, by connecting the RtpEndpoint to a WebRtcEndpoint in receive-only mode.

The Java client application connects to all events emitted from Kurento and prints log messages for each one, so this application is also a good reference to understand what are those events and their relationship with how KMS works.

To run this demo follow these steps:

1. Open this page with a WebRTC-compliant browser (Chrome, Firefox).
2. Click on Start to begin the stream negotiation.
3. Copy the KMS IP and Port information to the external streaming program.
4. Click on Stop to finish the test.

Start Stop
Automatic RTP/RTCP port discovery ("Connection-Oriented Media")
Sender uses SRTP
KMS connection info
No info received yet...
SDP response
No info received yet...
Sample RTP sender programs

You should be able to send an RTP stream to Kurento with any external application or device that supports this kind of streams. For example, VLC should be able to output an RTP stream, and also there are some devices in the market -such as video surveillance cameras- which also output an RTP stream. For this tutorial, we provide a sample GStreamer launch command which simulates an RTP streaming application. You just need to copy the provided commands, substitute any placeholder with the actual required values, and run them.
First step is to install the required dependencies for these sample GStreamer commands:

    sudo apt-get install \
    		gstreamer1.0-{tools,libav} gstreamer1.0-plugins-{base,good,bad,ugly} \
    		gstreamer1.5-{tools,libav} gstreamer1.5-plugins-{base,good,bad,ugly}

Sample RTP sender

This sample GStreamer pipeline command includes the following features:
- Sends RTP and RTCP packets to KMS (for both Audio and Video streams).
- Receives and prints Video RTCP packets received from KMS.
- Binds to specific output ports for automatic RTP/RTCP port discovery.

    PEER_A={KMS_AUDIO_PORT} PEER_V={KMS_VIDEO_PORT} PEER_IP={KMS_PUBLIC_IP} \
    SELF_PATH="{PATH_TO_VIDEO_FILE}" \
    SELF_A=5006 SELF_ASSRC=445566 \
    SELF_V=5004 SELF_VSSRC=112233 \
    bash -c 'gst-launch-1.0 -e \
    	rtpbin name=r sdes="application/x-rtp-source-sdes,cname=(string)\"user\@example.com\"" \
    	filesrc location="$SELF_PATH" ! decodebin name=d \
    	d. ! queue ! audioconvert ! opusenc \
    		! rtpopuspay ! "application/x-rtp,payload=(int)96,clock-rate=(int)48000,ssrc=(uint)$SELF_ASSRC" \
    		! r.send_rtp_sink_0 \
    	d. ! queue ! videoconvert ! x264enc tune=zerolatency \
    		! rtph264pay ! "application/x-rtp,payload=(int)103,clock-rate=(int)90000,ssrc=(uint)$SELF_VSSRC" \
    		! r.send_rtp_sink_1 \
    	r.send_rtp_src_0 ! udpsink host=$PEER_IP port=$PEER_A bind-port=$SELF_A \
    	r.send_rtcp_src_0 ! udpsink host=$PEER_IP port=$((PEER_A+1)) bind-port=$((SELF_A+1)) sync=false async=false \
    	udpsrc port=$((SELF_A+1)) ! r.recv_rtcp_sink_0 \
    	r.send_rtp_src_1 ! udpsink host=$PEER_IP port=$PEER_V bind-port=$SELF_V \
    	r.send_rtcp_src_1 ! udpsink host=$PEER_IP port=$((PEER_V+1)) bind-port=$((SELF_V+1)) sync=false async=false \
    	udpsrc port=$((SELF_V+1)) ! tee name=t \
    		t. ! queue ! r.recv_rtcp_sink_1 \
    		t. ! queue ! fakesink dump=true async=false'

Sample SRTP sender

This sample GStreamer pipeline command includes the following features:
- Sends SRTP and SRTCP packets to KMS (only for the Video stream).
- Receives and prints Video SRTCP packets received from KMS.
- Binds to specific output ports for automatic RTP/RTCP port discovery.

    PEER_V={KMS_VIDEO_PORT} PEER_VSSRC={KMS_VIDEO_SSRC} PEER_IP={KMS_PUBLIC_IP} \
    PEER_KEY="343332315A595857565554535251504F4E4D4C4B4A494847464544434241" \
    SELF_PATH="{PATH_TO_VIDEO_FILE}" \
    SELF_V=5004 SELF_VSSRC=112233 \
    SELF_KEY="4142434445464748494A4B4C4D4E4F505152535455565758595A31323334" \
    SRTP_CAPS="payload=(int)103,ssrc=(uint)$PEER_VSSRC,roc=(uint)0, \
    		srtp-key=(buffer)$PEER_KEY, \
    		srtp-cipher=(string)aes-128-icm,srtp-auth=(string)hmac-sha1-80, \
    		srtcp-cipher=(string)aes-128-icm,srtcp-auth=(string)hmac-sha1-80" \
    bash -c 'gst-launch-1.5 -e \
    	rtpsession name=r sdes="application/x-rtp-source-sdes,cname=(string)\"user\@example.com\"" \
    	srtpenc name=e key="$SELF_KEY" \
    		rtp-cipher="aes-128-icm" rtp-auth="hmac-sha1-80" \
    		rtcp-cipher="aes-128-icm" rtcp-auth="hmac-sha1-80" \
    	srtpdec name=d \
    	filesrc location="$SELF_PATH" ! decodebin \
    		! x264enc tune=zerolatency \
    		! rtph264pay ! "application/x-rtp,payload=(int)103,ssrc=(uint)$SELF_VSSRC" \
    		! r.send_rtp_sink \
    	r.send_rtp_src ! e.rtp_sink_0 \
    		e.rtp_src_0 ! udpsink host=$PEER_IP port=$PEER_V \
    	r.send_rtcp_src ! e.rtcp_sink_0 \
    		e.rtcp_src_0 ! udpsink host=$PEER_IP port=$((PEER_V+1)) sync=false async=false \
    	udpsrc port=$((SELF_V+1)) ! "application/x-srtcp,$SRTP_CAPS" ! d.rtcp_sink \
    		d.rtcp_src ! tee name=t \
    		t. ! queue ! r.recv_rtcp_sink \
    		t. ! queue ! fakesink dump=true async=false'

Console