GStreamer -Overview

GStreamer is designed to make it easier to write applications easily that -handle audio, video, or both. Pluggable components can be mixed and matched -into arbitrary pipelines, which consist of a chain of processing elements.

Purpose

GStreamer is an open -source multimedia framework that allows you to write any streaming multimedia -application, not just audio or video. GStreamer can handle any data flow.

GStreamer -core provides the following features:

Plug-in handling
Media type negotiation
Clocking and data flow

GStreamer also provides APIs to write applications using various plug-ins -such as source plug-in, transform plug-in and sink plug-in. The framework -uses these plug-ins to perform various roles such as encoding, decoding and -media processing.

-GStreamer plug-ins - -

Description

Some -GStreamer concepts are as follows:

Element
An element is an object that performs some action -on a multimedia stream. Examples of such actions are reading a file, decoding -or encoding data and capturing data from a hardware device.
Bin
A bin is a subclass of element. A bin acts as a container -for other elements, so multiple elements combine into one logical unit.
Pipeline
A pipeline is a set of data processing elements -connected in series, so the output from one element is the input for the next -element.
In GStreamer the pipeline is a specialized bin subclass that -provides execution of all contained elements. Normally, applications create -one pipeline that will manage all the elements contained within it.

Note: Elements can be added to and removed from pipelines -based on the use-case being handled. For example a use-case such as playing -an MP3 file using GStreamer.

An element can provide a number -of pads, which can be either source or sink pads. A pad is a plug or port -on an element to link with other elements. The pads are responsible for data -flow between the elements. Source pads supply data, and sink pads consume -data. Basically, pads are used to negotiate compatibility and allow data flow -between elements.

An element can be in one of four different states -during the application request:

Null
Ready
Pause
Play

In the Null and Ready states, the element is not processing -any data. The processing of data happens only in the Play state. The Pause state -is used to fill all connected elements in the data pipeline so the Play state -change happens quickly.

GStreamer also provides higher level utilities -and components to detect automatically the media type of an application, and -to create the best possible pipeline for a use-case. This process is called -auto plugging.

GStreamer applications

GStreamer -is used in many types of applications including:

Media playback and streaming
Media recording
Media transcoding
Video editing

For example the diagram below shows how a Media Player uses GStreamer:

-Media playback using GStreamer - -

Sound device is a framework -to perform hardware accelerated audio functionality. Audio Policy manages -the requests to access the audio hardware. Digital Signal Processing converts -the digital audio signal to the analog audio signal.