Learn, hack!

URL

http://events.ccc.de/congress/2004/fahrplan/files/309-avg-aint-vector-graphics-slides.pdf

File name

309-avg-aint-vector-graphics-slides.pdf

File size

3.0 MB

MD5

952b56b8d86f6fb739be733e17bfe5d5

SHA1

d0fdf47db64bbf05feeb23ea0e821ba5457f4046

AVG is an open source plattform for multimedia installations running on Linux and Mac OS X. The lecture will show what can be done using the platform and how installations can be scripted. If there is interest, I can also go into design and implementation details. Multimedia on linux has made great progress. A few years ago, video support was very limited, low-latency-audio was impossible, getting jitter-free performance was a nightmare and fonts were rendered with a quality that made any designer cringe. This has changed, and all that's really missing is some glue that joins the different libraries. avg is an effort to do for multimedia installations what the Gimp did for image editing, what OpenOffice did for word processing... and what Linux did for operating systems in general: give people an alternative that's free (as in speech, not beer). The goal of AVG is to make it almost as easy to build installations as it is to build a web page. Designing interactive systems will still need some programming skills, but this should be kept to a minimum. An avg installation consists of one or more xml files that describe screen layout(s) and corresponding javascript files that describe the dynamics of the installation: What to do when a user interacts with the system, some time has elapsed or any other input has arrived. The result is that the xml files are as easy to edit as html is - and the syntax used for the interactive parts should be very familiar to anyone who's used javascript on a web page. Performance-wise, AVG leaves Macromedia Director, the plattform currently used in most multimedia installations, far behind. The integrated display mixer crops, scales and rotates bitmaps, videos, camera images and text and composites them in real time with full alpha channel and opacity support. On systems that support it, OpenGL is used to render the graphics, making hardware-accelerated scaling, rotation and transparency available at no cost in cpu time. Older systems are supported by an efficient software-rendering backend based on DirectFB. avg supports all major video formats by using libavcodec to decode the files. Text is formatted using Pango, allowing HTML-like markup and high-quality font rendering. AVG has been used for several projects at ART+COM and the c-base and will possibly be used as video mixer at the 21C3. The presentation will use these existing installations to give a real-life tour of the possibilities of the plattform and to present an efficient workflow that can be used by artists and designers to build installations. AVG will be used to hold the presentation, so the audience will be able to judge the possibilities directly. If there is sufficient interest, I can follow up with a corresponding workshop in the Art&Beauty area.