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Re: Showcase Appliance for Schools

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On Sat, Nov 22, 2008 at 06:48:11PM +0100, RalfGesellensetter wrote:
>What do you think? Do you know of any free content display system that 
>is fed by some kind of stream (like rtp/rtsp) and thus made to download 
>a sequence of pictures, texts (pdf?), and presenting them in a kind of 
>slide show? I've seen commercial solutions in "sophisticated" bars.

I threw together an info system a couple of years ago, for a gymnastics, 
climbing and sports center:

A server generates static bitmap images from svg templates and various 
data (I scrabed some web pages for booking info), and serves them 
somehow (I used rsync over ssh but the encryption really wasn't 

The client regularly pulls the images, looped through them and display 
them on the X11 root window.

I deliberately avoided a web browser on the client to save power 
(rendering web pages is far more computing heavy than bitmap images), 
save space (the client fit on a 256MB USB stick), and be more reliable 
(Running only the X11 server with only its root windows arguably has 
less memory leaks than adding a web browser on top of that).

Mirroring the content locally means the system continues to run even if 
network link to server breaks. It then continues to show old data

The client-side display loop should be relatively easy to extend to 
detect and skip time-related images if they get too old, while continue 
looping through other images.

If fancy transitions between each screen are "needed", then some 
slideshow application could be run on top of X11 - but beware that if 
the app crashes, it is visible to the user! (if simpledisplay loop 
crashes then visually it just "freezes" at the last displayed image).

The server part of the system is here: http://info.dgi-huset.dk/img/

Tell me if interested in the client part (homemade script to build a 
live updateable Debian installation on a tiny USB stick + a few helper 
scripts to pull files and invoke feh or qiv to display them).

  - Jonas

- -- 
* Jonas Smedegaard - idealist og Internet-arkitekt
* Tlf.: +45 40843136  Website: http://dr.jones.dk/

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