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| = Introduction = | | {{GstInterpipe/Head| | next=GstInterpipe Overview|metakeywords=}} |
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| == Overview ==
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| GstInterpipe is a Gstreamer plug-in that allows communication between two independent pipelines. The plug-in consists of two elements:
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| * interpipesink
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| * interpipesrc
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| Generally speaking, the idea is that given a source pipeline:
| | The following table of contents offers all you need to know about GstInterpipe project. |
| <pre style="background:#d6e4f1">
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| v4l2src ! interpipesink name=video_src
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| </pre>
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| Various sink pipelines may listen to it by:
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| <pre style="background:#d6e4f1">
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| interpipesrc listen-to=video_src ! xvimagesink
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| interpipesrc listen-to-video_src num-buffers=1 ! jpegenc ! filesink location=snapshot.jpeg
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| </pre>
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| The state of each pipeline is independent, each one can manage events by their own and can be attached or detached at any moment.
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| The concept behind the Interpipes Project is to simplify the construction of GStreamer applications, which often has the complexity of requiring dynamic pipelines. It transforms the construction process from low level pad probe manipulation to the higher level setting an element's parameter value. Application developers don't get mired down in stalled pipelines because one branch of a complex pipeline changed state.
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| For example, take a look in a complex pipeline like the one in the figure 1:
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| [[File:Complex_pipeline.png|thumb|center|800px|Figure 1: Complex Pipeline]]
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| The complex pipeline of figure 1 can be constructed into smaller, independent pipelines using interpipe elements as it is illustrated in the figure 2:
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| [[File:Interpipe_pipeline.png|thumb|center|800px|Figure 2: Pipeline using Interpipes]]
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| This way the stream flow in a complex pipeline is reduced to simply set the correct listeners in the interpipe elements taking away the complexity of re-configuring pads or some other complex and error-prone logic.
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| == Features and Limitations ==
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| The GstInterpipe project exposes the following characteristics:
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| * Inspired by intervideosrc/intervideosink
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| * Uses appsrc and appsink as a base
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| * Generic data handling
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| * Multiple dynamic interpipesink - interpipesrc connections
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| * Replace tee and selector elements allowing dynamic pipeline flow control with GStreamer Daemon
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| The principal features the plug-in exposes are the following. These ones are explained with further detail later.
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| * '''Buffer transfer''' <br>Interpipesink will transfer automagically the buffers it receives to all the interpipesrcs that are currently listening to it.
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| *'''Dynamic switching''' <br> Interpipesrc can switch the interpipesink they are listening to at any time just by setting the property to the new value. No need to worry about the pipeline's state, dangerous events like EOS, pad probes, valves, selectors, pad links, etc...
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| *'''Caps negotiation''' <br> Even though interpipes break a big pipeline into smaller ones, the caps negotiation process takes into account all of them. This means that it is guaranteed that the negotiated caps will be supported by the source and all its listeners (or fail due to missing valid intersection).
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| *'''Event forwarding''' <br> Similar to buffers, events may be forwarded from the interpipesinks to the interpipesrcs, and viceversa. The project takes into account downstream and upstream events, as well as in-bounds and out-of-bands events.
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| *'''Timestamp synchronization''' <br> The base times of independent pipelines will likely be different. Given that a buffer will be transferred from one pipe to another, this may represent a problem in situations where synchronization is a must. GstInterpipe takes care of this situation by compensating the buffer's timestamps according to the pipeline's base time, ensuring appropriate synchronization.
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| The current release exposes the following limitations and known bugs:
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| *'''Specialized clocks''' <br>At the time being, pipelines negotiate their clock independently. If a pipeline uses a special clock (i.e.: GstAudioSinkClock), the associated pipes (being independent) may negotiate different clocks, typically GstSystemClock. This could be a big problem if, for example, synchronization between streams is required. It is currently responsibility of the application to set the special clock in all the involved pipes by calling [https://gstreamer.freedesktop.org/data/doc/gstreamer/head/gstreamer/html/GstPipeline.html#gst-pipeline-set-clock gst_pipeline_set_clock].
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| = Getting the Software =
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| GstInterpipe is an open source project and can be downloaded from GitHub. The project is hosted at:
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| TODO
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| As with every open source project, there's an open invitation to provide feedback to the maintainers as bug reports, feature requests and even source code collaborations. The following table summarizes the recommended methods to collaborate with RidgeRun:
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| {| class="wikitable"
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| ! Collaboration !! Method
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| | Bug report || GitHub's issue tracker
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| | Feature request || GitHub's issue tracker
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| | Patch Submission || Pull request
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| |}
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| = Installation Guide=
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| == Dependencies==
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| The following packages are needed in order to build and use gst-interpipe:
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| * gstreamer-1.0
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| * gstreamer-plugins-base-1.0
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| * gstreamer-video-1.0
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| * gstreamer-app-1.0
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| * gstreamer-check-1.0
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| The are likely already installed in your OS distribution. In case you want to double check and install the missing packages, run the following commands according to your OS:
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| === Debian Based ===
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| This includes Ubuntu, Kubuntu, Debian, etc...
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| sudo apt-get install libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev
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| === Mac OSX ===
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| Using Mac Ports:
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| sudo port install gstreamer1 gstreamer1-gst-plugins-base
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| == Building the project ==
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| In order to build the project run the following commands. Note that the libdir may vary according to your system.
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| ./autogen.sh --libdir /usr/lib/x86_64-linux-gnu/gstreamer-1.0/
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| make
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| The ''autogen.sh'' script will automatically run the ''configure'' script. In case a more complex configuration is needed, the configure step may be executed manually:
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| ./autogen.sh --noconfigure
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| ./configure --libdir /usr/lib/x86_64-linux-gnu/gstreamer-1.0/ <additional advanced options>
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| make
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| Finally, the status of the current version may be checked by running the unit tests:
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| make check
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| == Installing the plugin ==
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| The plugin is installed to the GStreamer's default plug-in location in the file system by running:
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| sudo make install
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| If you don't want to install the plugin in the default location, it may also be found by setting GST_PLUGIN_PATH to the library location. For example:
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| GST_PLUGIN_PATH=/home/mgruner/gst-interpipe-1.0/gst/interpipe/.libs gst-inspect-1.0 interpipe
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| =User Guide=
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| The following sections describe in detail the different capabilities of the elements, configurations and examples.
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| == Features ==
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| === Buffer Forwarding ===
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| The main purpose of the GstInterpipe Project is to communicate buffers from one pipeline to another. This can be done in a safe way, without worrying about the states or events of any of the pipelines. To set an interpipesrc (listener) to listen to a specific interpipesink (node), all it is needed is to set the ''listen-to'' property. A NULL or empty ''listen-to'' will disconnect the listener from any node. The following table summarises the properties involved in buffer transfer.
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| {| class="wikitable" style="margin:auto;"
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| ! colspan="3" | Property
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| | '''Element''' || colspan="2" | interpipesrc
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| | '''Name''' || colspan="2" | listen-to
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| | '''Description''' || colspan="2" | The name of the node to listen to
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| | rowspan="2" | '''Special Values''' || NULL || Stop listening
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| | (empty) || Stop listening
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| |}
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| <br> | | <br> |
| {| class="wikitable" style="margin:auto;"
| | <br> |
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| | <table> |
| ! colspan="3" | Property
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| | <td><div class="clear; float:right">__TOC__</div></td> |
| | '''Element''' || colspan="2" | interpipesink
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| | {{Sponsor Button}} |
| | '''Name''' || colspan="2" | name
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| | </tr> |
| | '''Description''' || colspan="2" | The name of the node
| | </table> |
| |-
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| | '''Special Values''' || colspan="2"|
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| |}
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| The following figures, and their respective gst-launch pipelines illustrate this concept:
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| gst-launch-1.0 videotestsrc ! interpipesink name=camera
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| [[File:Buffer_transfer_not_connected.png|600px|framed|center|Detached pipelines]]
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| gst-launch-1.0 interpipesrc listen-to="" ! fakesink
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| [[File:Buffer_transfer_connected.png|600px|framed|center|Attached pipelines]]
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| === Dynamic Switching ===
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| One of the greatest strength of GstInterpipe is the ability of an interpipesrc to switch between different interpipesinks at runtime. To do so, change the ''listen-to'' property. Similarly, disconnections and reconnections can be performed by clearing and setting the property accordingly. When performing dynamic switching, caps must be taken into consideration. Specifically, a switch can be performed to a node in two scenarios:
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| ;No other listeners
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| :Caps are re-negotiated between the two pipelines, looking for the optimum caps.
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| ;Existing listeners
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| :The sink pipeline must support the caps already configured by the node and listeners, otherwise it'll fail.
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| The following figure illustrates this concept:
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| [[File:Dynamic_switch.png|600px|framed|center|Dynamic Switch Scenarios]]
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| The caps re-negotiation capability can be disabled with the ''allow-renegotiation'' property. The following table summarises the involved property:
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| {| class="wikitable" style="margin:auto;" | |
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| ! colspan="3" | Property
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| | '''Element''' || colspan="2" | interpipesrc
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| | '''Name''' || colspan="2" | allow-renegotiation
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| | '''Description''' || colspan="2" | Allow the interpipesrc to renegotiate caps when attached to an interpipesink with different caps.
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| |-
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| | '''Special Values''' || colspan="2"|
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| |}
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| Programatically, the dynamic switch can be performed as the following:
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| <pre> | |
| /* Create pipelines */ | |
| GstElement *pipe1 = gst_parse_launch ("videotestsrc ! interpipesink name=camera1", NULL);
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| GstElement *pipe2 = gst_parse_launch ("videotestsrc ! interpipesink name=camera2", NULL);
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| GstElement *pipe3 = gst_parse_launch ("interpipesrc name=src listen-to=camera1 ! fakesink", NULL);
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| /* Grab a reference to the interpipesrc */
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| GstElement *src = gst_bin_get_by_name(pipe3, "src");
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| /* Perform the switch */
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| g_object_set (src, "listen-to", "camera2", NULL);
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| </pre> | |
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| === Caps Negotiation === | | ==Quick Overview== |
| | GstInterpipe is a RidgeRun open source [https://www.ridgerun.com/gstreamer GStreamer] plug-in that enables pipeline buffers and events to flow between two or more independent pipelines. It consists of two elements: interpipesink and interpipesrc. The interpipesrc connects with an interpipesink, from which it receives buffers and events. |
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| GstInterpipe takes into account the node and all its listeners during the caps negotiation process. It is guaranteed that the resulting supported set of caps will be an intersection between all the listeners and node caps. This only applies to the listeners that are connected during the caps negotiation process. If a listener is adhered later, it will be handled independently (see [[#Dynamic_Switching|Dynamic Switching]]). | | GstInterpipe is intended to reduce a big complex pipeline system into smaller and simpler independent pipelines. You can view and handle the independent pipelines as different blocks that can be controlled independently. Each pipeline change state, have element properties modified, and can connect or disconnect with other pipelines at runtime. GstInterpipe allows you to have multiple source and sink pipelines in an application. The connections between source pipelines and sink pipelines can dynamically change at runtime. Is like if you have a set of different pipes that you can plug and unplug between them at runtime, so the system changes its behaviour according to the pipe interconnection configuration. |
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| The following figure shows this concept.
| | ==Promo/Demo Video== |
| [[File:Caps_negotiation.png|600px|framed|center|Caps negotiation process]]
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| === Event Forwarding ===
| | '''GStreamer Conference-2017 talk from RidgeRun''' : '''[[GStreamer_Daemon | GStreamer Daemon]] - building a media server in under 30 minutes''' |
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| === Timestamp Synchronization === | | *[https://vimeo.com/240547523 vimeo version] (may have better lipsync) |
| | *embedvideo (below) |
| | <center> |
| | <embedvideo service="vimeo">https://vimeo.com/240547523</embedvideo> |
| | </center> |
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| == Properties == | | == Getting Started == |
| === GstInterPipeSink ===
| | Start navigating this wiki by going to the [[GstInterpipe - GstInterpipe Overview|GstInterpipe Overview]] page in the table of contents. |
| === GstInterPipeSrc ===
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| ==
| | {{ContactUs}} |
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| =Releases= | | {{GstInterpipe/Foot | | next= GstInterpipe Overview}} |
