The GStreamer Pipeline Editor (gst-editor) is a graphical pipeline contruction and manipulation tool. Using the Gnome Canvas as the foundation, it allows you to draw media pipelines very quickly. It's not anywhere near complete yet, but it still lets you do some amazing things.

The example at the right shows a complex pipeline set up for playback of an MP3 in an Ambisonics surround setup. From left to right you have a filesrc to read from disk, mad to decode the mp3, and ladspa_freeverb3 to apply some world-class reverb effects. At the bottom you have ladspa_encode_bformat, which has three arguments: angle, elevation, and distance. This encodes the audio as 4 channels of surround sound. The ladspa_bf2cube element converts this surround data into output channels appropriate for a cube of speakers. Finally, the audio is routed to an 8-channel ALSA audio sink.

The pipeline shown probably works, although gst-editor's author does not have a sound card that can support 8 channels (hint, hint :-).

The second example on the right shows another complex pipeline that was loaded up from gst-launch syntax. Initially, the audio and video pads on the mpeg demuxer were not present. The pipeline was set to PLAYING, and the gstparse code caught the presence of these pads and connected to the audio and video rendering pipelines. As this dynamic connection was made, the editor knew to graphically add the pads to the demuxer and connect them to the proper elements. This is interesting because gstparse knows nothing about gst-editor!

Features

gst-editor, even though it's far from complete, already has a large number of major features:

• Built as a library, so you can trivially embed the editor into your own application.
• Reads and write standard XML descriptions of pipelines, which you can load into your application just as with libglade and GUIs
• Capable of not only building but running most pipelines right in the editor
• A Glade-like interface gives access to the element's arguments, as shown in the shot at right of all the options to the LADSPA gong model reverb filter.
• Threadsafe, so as to safely control threaded pipelines
• Supports rapid prototyping with gst-launch syntax
• Supports cut, copy, and paste in the standard GStreamer XML format
• Has iterative, graphical bin sorting functionality (click the Sort button)
• Integrated with GStreamer's debugging subsystem
• Supports all GStreamer pipeline elements: request pads, ghost pads, dynamic connections, threads, ...
• Built on the solid rock of Gnome 2 and GObject -- code is very clean
• Integrated with the Gnome 2 help system
• Context menus offer context-specific "What's this?"-style help