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88 lines
3.4 KiB
Markdown
88 lines
3.4 KiB
Markdown
---
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title: Interfaces
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...
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# Interfaces
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[Using an element as a GObject][element-object] presents the use of `GObject`
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properties as a simple way for applications and elements to interact. This
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method suffices for simple getters and setters, but fails for anything more
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complicated. For more complex use cases, GStreamer uses interfaces based on the
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`GObject`
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[`GTypeInterface`](http://library.gnome.org/devel/gobject/stable/gtype-non-instantiable-classed.html)
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type.
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This text is meant to be introductory and does not include source code examples.
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Please take a look at the API reference for additional details.
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[element-object]: application-development/basics/elements.md#using-an-element-as-a-gobject
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## The URI Handler interface
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In our examples so far, we have only showed support for local files
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using the “filesrc” element, but GStreamer supports many more location
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sources.
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GStreamer doesn't require applications to know any `URI` specifics, like
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what element to use for a particular network source types. These details
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are abstracted by the `GstURIHandler` interface.
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There is no strict rule for `URI` naming, but in general, we follow
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common-usage naming conventions. For example, assuming you have the
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correct plugins installed, GStreamer supports:
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```
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file:///<path>/<file>
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http://<host>/<path>/<file>
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mms://<host>/<path>/<file>
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dvb://<CHANNEL>
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...
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```
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In order to get the source or sink element supporting a particular URI,
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use `gst_element_make_from_uri ()` with `GST_URI_SRC` or `GST_URI_SINK`
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as `GstURIType` depending in the direction you need.
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You can convert filenames to and from URIs using GLib's
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`g_filename_to_uri ()` and `g_uri_to_filename ()`.
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## The Color Balance interface
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The `GstColorBalance` interface is a way to control video-related properties
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on an element, such as brightness, contrast and so on. Its sole reason
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for existence is that, as far as its authors know, there's no way to
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dynamically register properties using `GObject`.
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The colorbalance interface is implemented by several plugins, including
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`xvimagesink`, `glimagesink` and the `Video4linux2` elements.
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## The Video Overlay interface
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The `GstVideoOverlay` interface was created to solve the problem of
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embedding video streams in an application window. The application
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provides a window handle to an element implementing this interface,
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and the element will then use this window handle to draw on
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rather than creating a new toplevel window. This is useful to embed
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video in video players.
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This interface is implemented by, amongst others, the `Video4linux2`
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elements and by `glimagesink`, `ximagesink`, `xvimagesink` and `sdlvideosink`.
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## Other interfaces
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There are quite a few other interfaces provided by GStreamer and implemented by
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some of its elements. Among them:
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* `GstChildProxy` For access to internal element's properties on multi-child elements
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* `GstNavigation` For the sending and parsing of navigation events
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* `GstPreset` For handling element presets
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* `GstRTSPExtension` An RTSP Extension interface
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* `GstStreamVolume` Interface to provide access and control stream volume levels
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* `GstTagSetter` For handling media metadata
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* `GstTagXmpWriter` For elements that provide XMP serialization
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* `GstTocSetter` For setting and retrieval of TOC-like data
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* `GstTuner` For elements providing RF tunning operations
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* `GstVideoDirection` For video rotation and flipping controls
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* `GstVideoOrientation` For video orientation controls
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* `GstWaylandVideo` Wayland video interface
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