RTSP Sink
Overview
RTSP Sink is a GStreamer element which permits high performance streaming to multiple computers using the RTSP / RTP protocols. The rtspsink element leverages previous logic from RidgeRun's RTSP server with extensions to create a GStreamer sink element providing benefits like greater flexibility to application integrate and easy gst-launch based testing.
With RTSP Sink you have the flexibility to stream different content to the same client, such as streaming audio and video to a client. You also can send different streams to different clients. This means that within a single GStreamer pipeline you can stream multiple videos, multiple audios and multiple lip-sync audio+video streams, each one to a different client using a different RTSP mapping. In the examples section different streaming possibilities are shown.
Features
The rtspsink GStreamer element supports the following features:
- Configurable mappings for each stream. The mapping is the text used at the end of the RTSP URL: rtsp://$SERVER_IP/$MAPPING
- Configurable TCP port number.
- Automatic payloader detection according to the negotiated pipeline capabilities.
- Multiple independent video-only streams.
- Multiple independent audio-only streams.
- Multiple independent audio+video streams.
- Support for:
- H264 video encoding
- MPEG4 video encoding
- MJPEG video encoding
- AAC audio encoding
Getting the code
RTSP Sink is an add-on to RidgeRun's professional SDK. You can purchase RTSP Sink, with full source code, from the RidgeRun Store.
Building the code
Although rtspsink source code is delivered ready to be built along with RidgeRun's SDK, the code is platform independent and can be built on a host PC or other build environment that is configured to build GStreamer plug-ins.
Building rtspsink using RidgeRun SDK
The source code for RTSP sink can be found on
$DEVDIR/proprietary/gst-rtsp-sink
The element will be built along with the SDK if selected on the configuration menu.
make config
'-> Proprietary software
'-> [*] RidgeRun RTSP GStreamer sink element
'-> [] Enable Multicast support
The RTSP Sink can be built manually by:
cd $DEVDIR/proprietary/gst-rtsp-sink make make install
Notes:
- Building the gst-rtsp-sink as a standalone may fail if the package dependencies are not first built properly.
- Enable the Enable Multicast support option to build the element with multicast support
Building for a host PC
- Build the code
cd $DEVDIR/proprietary/rr_rtsp_sink/src # Note the src subdirectory ./configure --prefix=/usr # Prefix is necessary in order to install the plugin in the default gstreamer location make
- Install the plugin
sudo make install # You will need root privileges to install the plugin
Note: Running RTSP Sink on a host PC may require root privileges to open the appropriate sockets. If the debug reveals a permission problem run the pipeline using sudo
Basic usage
RTSP Sink is a GStreamer element which supports consuming the stream from multiple pipeline branches, each one describing a different media to stream.
Requesting pads
The RTSP Sink pads are requested using regular GStreamer notation. For example, using GStreamer textual pipeline notation, attaching three different h.2164 encoded video branches to the sink the pipeline looks like the following:
gst-launch rtspsink name=sink \ < branch 1 > ! sink. \ < branch 2 > ! sink. \ < branch 3 > ! sink.
Graphically, the pipeline would look something like:
Since we didn't specifying the mapping, which is described below, all three pipelines would be mapped to /test.
Combining and naming streams
Each stream needs to be mapped to a different URL so the different clients can access them independently. This is called the mapping of the stream. The RTSP Sink element will try to read the mapping from the caps it negotiates with the upstream element. This means that assigning a mapping to a stream is as simple as setting it in the caps, using the mapping= value. The only rule is that the mapping must always start with a leading slash "/". If no mapping is explicitly provided the it will default to /test
Each mapping will be treated as an individual stream. This means that if you want to combine an audio and a video branch within a single A/V stream, it is as simple as using the same mapping name. The following pipeline will produce 3 independent streams: a video mapped to "/video", an audio mapped to "/audio" and an audio+video mapped to "/audiovideo".
gst-launch rtspsink name=sink \ < branch 1 > ! video/x-h264, mapping=/video ! sink. \ < branch 2 > ! audio/mpeg, mapping=/audio ! sink. \ < branch 3v > ! video/x-h264, mapping=/audiovideo ! sink. \ < branch 3a > ! audio/mpeg, mapping=/audiovideo ! sink.
This will combine branches 3v and 3a as a single streaming under the name of "/audiovideo". This can be shown graphically on figure 2.
Supported formats
The following table conveniently resumes the supported encoding formats and their respective mimetypes for you to build as
gst-launch ... ! mimetype, mapping="/test" ! rtspsink
| Format | Mimetype |
|---|---|
| H264 video | video/x-h264 |
| MPEG4 video | video/mpeg |
| MJPEG video | image/jpeg |
| MPEG TS | video/mpegts |
| AAC audio | audio/mpeg |
Service configuration
Besides the actual streaming data, RTSP is high level protocol that negotiates streaming internals with every client that intends to connect to a mapping. In order to request a stream, the client must connect to the server at a specific port where the RTSP server is up and waiting for connections. The port at which the server is listening to, and the clients must talk to is called the service and it is typically set to 554. RTSP Sink allows to configure the service by means of a GStreamer property like the following:
~# gst-launch audiotestsrc ! ffenc_aac ! audio/mpeg, mapping=/mystream ! rtspsink service="3000"
If no service is specified then it default to 554. The port 554 could cause the pipeline to fail since it is a reserved port of the system, a different service can be specified in order to run the pipeline i.e. 5000; another method is that the port 554 can be opened by modifying the IP tables of the Kernel.
Examples
The following section provides a series of examples of possible use cases of RTSP Sink. For all of them, the different streams can be viewed on a host PC using VLC as the following:
~# vlc rtsp://$SERVER_IP/$MAPPING:$PORT
where $SERVER_IP is the IP address of the RTSP server and $MAPPING is the name of the mapping that the client wants to connect to, and $PORT is the service at which the server is listening to.
Note: When running on a host PC root privileges may be needed to access the respective sockets.
Single MPEG4 video streaming
~# gst-launch v4l2src ! ffenc_mpeg4 ! video/mpeg, mapping=/stream ! rtspsink
Single AAC audio streaming
~# gst-launch alsasrc ! ffenc_aac ! audio/mpeg, mapping=/stream ! rtspsink
Dual H264 video streaming
~#gst-launch rtspsink name=sink \ v4l2src ! x264enc ! video/x-h264, mapping=/stream1 ! sink. videotestsrc ! x264enc ! video/xh264, mapping=/stream2 ! sink.
Audio+Video Streaming
~#gst-launch rtspsink name=sink \ v4l2src ! x264enc ! video/x-h264, mapping=/stream ! sink. alsasrc ! ffenc_aac ! audio/mpeg, mapping=/stream ! sink.
Audio+Video streaming plus H264 single streaming
~#gst-launch rtspsink name=sink \ v4l2src ! x264enc ! video/x-h264, mapping=/stream1 ! sink. alsasrc ! ffenc_aac ! audio/mpeg, mapping=/stream1 ! sink. videotestsrc ! x264enc ! video/x-h264, mapping=stream2 ! sink.
Transport Stream payloader
Often RTSP is used with the RTP payloader encoding. It is also possible to use RTSP with the Transport Stream (TS) payloader. This pipeline was tested on a Leopardboard 368 with an Aptina mt9p031 sensor.
Pipeline to run on target hardware
gst-launch v4l2src input-src=camera always-copy=false ! 'video/x-raw-yuv, width=1920, height=1088, framerate=(fraction)30/1' ! \
dmaiaccel ! dmaiperf ! /
dmaienc_h264 encodingpreset=2 ratecontrol=2 targetbitrate=2000000 intraframeinterval=30 idrinterval=90 bytestream=true ! \
queue ! mpegtsmux ! capsfilter caps="video/mpegts,mapping=/stream" ! rtspsink
Pipeline to run on host PC
TARGET_IP_ADDRESS=192.168.0.10 # replace with the IP address of your target hardware
gst-launch rtspsrc location="rtsp://$TARGET_IP_ADDRESS/stream" ! rtpmp2tdepay ! mpegtsdemux ! queue ! \
ffdec_h264 ! xvimagesink sync=false
Using VLC or mplayer to view streaming video
TARGET_IP_ADDRESS=192.168.0.10 # replace with the IP address of your target hardware vlc rtsp://$TARGET_IP_ADDRESS/stream mplayer rtsp://$TARGET_IP_ADDRESS/stream
Additional documentation
Access the full plugin documentation by making a gst-inspect of the rtspsink
gst-inspect rtspsink
Legacy RTSP Sink
The old version of RTSP Sink maintains the same idea of integrating an RTSP server into a gstreamer pipeline but its developed to support a single video stream. The main difference is that the service is specified by means of a property rather than on the caps.
On target board
gst-launch videotestsrc ! dmaienc_h264 idrinterval=30 targetbitrate=2500000 single-nalu=false ! rtspsink mapping="/mystream" service=554
On host PC
On the host PC you might need to use root privileges to access the respective sockets.
sudo gst-launch videotestsrc ! x264enc ! rtspsink mapping="/mystream" service=554
Client
As an RTSP client vlc may be used as the following:
vlc rtsp://<target.or.host.pc.ip.address>:554/mystream