Song and Dance and TWDusing GStreamer

Thomas Vander Stichele

Overview

● TWD and USP● TMS● VKC of GST● GPE prototyping● LAP for SAD celebrating FTA● Roadmap

software desktops

● Desktops have targets and philosophies– GNOME: less options, less bloat, HIG– KDE: full configurability– MacOS: eye candy, artistic personality– Windows: applications

● Desktops need a USP for better marketing● After-hours business school applied to

GNOME● TMS done by Korean firm

Thorough Market Study

GNOME KDE Mac Windows Other0

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Which desktop are you currently using ?

which desktop ?

Thorough Market Study

GNOME KDE MacOS Windows0

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What do you want in your desktop ?

More options

Less bloat

Stability

More appsKaraoke

Thorough Market Study

Yes No0

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Would you switch to GNOME if it had karaoke ?

well, would you ?

Next year at LWE

Karaoke

● What do we need ?● Why use GStreamer ?● What is GStreamer ?● What needs to be done ?

What do we need ?

● Audio playback● Visualization● Video● Subtitling

Why use GStreamer for it ?

● Lot of elements already present● Framework is there for things you need

– Output– Synchronization– Mixing multiple formats

● Prototyping is easy– gst-launch for quick tests– gst-editor for experimenting with pipelines– Gst-python for testing application structure

GStreamer

● What is it ?● Why is it ?● Why is it not ?● Elements and pads● Graph-based pipelines

What is it ?

● Core: streaming media framework– Arbitrary filter graphs– Extensible pluggable architecture– Data-agnostic, basic elements (GObjects)

● Plug-ins : provide functionality– Audio : filters, codecs, analysis, visuals– Video : filters, codecs, (de)muxers– Sources/Sinks : video/audio/media in/out

What is it ?

● GStreamer is first of all a library– Compare it to GTK

● We provide a few applications– A player as a test bed for features (~ gtk-

demo)– An editor used in debugging (~ glade)

● We provide plug-ins● We provide documentation

Why is it ?

● Linux has bad media handling● many hacked single-purpose apps and libs,

code copies and forks, ...– avifile, Broadcast2000, ...

● other OS's have such a framework– DirectShow, Quicktime framework, Be

Media, RealMedia SDK● LGPL core gives companies the chance to

make binary plug-ins

What is it not ?

● It's NOT a sound server– one could be written with it (maybe)– not important for an app

● It's NOT Gnome-only● It's NOT 100% ABI-stable (partial)● It's NOT perfect

Elements and Pads●element has pads

●chain- or loop-based

●buffer of data comes in on the sink pad

●element processes data

●Processed buffer goes out on the source pad

●This one decodes Ogg/Vorbis audio

Graph-based pipelines

●Pipeline managed by a bin (not visible)

●Links elements by their pads●elements are chain-based or loop-based

●Data will flow left to right

What needs to be done ?

● Experiment– gst-launch– gst-editor

● Write elements● Fix bugs

– In elements– In applications like gst-editor

Let's get to it !

● Audio playback– Guadec-editor 1

● Visualization– Guadec-editor 2

● Subtitling– Guadec-editor 3

Combining the three

● Normal:– Guadec-editor 4

● Threaded:– Guadec-editor 5

Using video footage

● Threaded MPEG playback:– Guadec-editor 6

● With subtitles– -guadec-editor 7

Ideas for improvement

● Use pitchshifter so Stallman can sing● Use festival to replace Stallman

– Play: Guadec-editor 8– Save to vorbis: Guadec-editor 9– Use with subtitles: guadec-editor 10

● Personalise– Find video of friends: guadec-editor 11

Ideas for improvement

● Use live input– Mix in audience audio and video

● Use backing music– Mod files, midi files, ...

● Use color font rendering● Add a bouncing ball plugin

Gkaraoke

● Truth is stranger than fiction

Roadmap

● Actual stuff to work on● What can you do ?

Actual stuff to work on

● Media-info library:– Save and load metadata and streaminfo– Cache it (-> thumbnails)– Playback parameters (mixing, volume)– Shared by all apps

Actual stuff to work on

● Nautilus:– Hoverplay for audio and video– Further audio view improvement

● Encoding profiles– Used by recorder, sound-juicer, ...– Using human-readable names

● Editor:– Educational GStreamer tool

What can you do ?

● Users– Test our applications:

● Gst-totem, gst-player, gst-editor● Rhythmbox, quark, nautilus-media, sound-juicer● Use media files on http://gstreamer.net/media/

– Suggest new applications– Run the upcoming test suite on your computer– Harass developers

What can you do ?

● Developers– Help us fix bugs and implement new features– Document– Write applications– Write/fix elements– Test and use the bindings– Use the tools we provide

● Build scripts● Template tarballs

– Go to Ronald's talk