[mapserver-users] time enabled WMS with <video/> elements instead of <img/> elements

[Tim-Hinnerk Heuer]

Hi,

Interested in HTML5 + MapServer and visualisation, read on.

Happy new year to you all!

I'm working on a rather interesting project at the moment where we need 
to map data over time. We tried experimenting with having one layer for 
each time unit and essentially overlaying them, manipulating their 
opacity to have a mini movie, but we noticed that the downloads of all 
the images become quite significant (61MB for a test extent!). I then 
implemented a proof of concept page (HTML5) where I took an extent's 
images and concatenated them in a webm video over time and then played 
all the videos at the same time, giving me a nice visualisation of that 
area at a relatively low cost (2.3MB per that extent) and the advantage 
of streaming.

I have already written a script that generates all the videos, so I have 
invested considerable amounts of time into this.

It would be great now if I could use the Apache module mapcache to serve 
up these videos listening and responding to WMS requests. So, all I need 
to change about mapcache is to serve a .webm file with MIME type 
video/webm instead of a .png file at the given extent. I guess I could 
write something in PHP or even with MapScript to serve up those files, but

A) I don't know how mapcache finds the right image for an extent and
B) Although I know C, my knowledge of it is a bit rusty and I don't know 
the interface(s) for writing Apache modules in C, let alone a plugin for 
mapcache

I'm keen on learning, but if someone knows where in the code I would 
have to look for this change/feature enhancement it would be really helpful.

Has something like that been done already or is in experiment/planning?

If you could give me some hints of how to approach this in the quickest 
way possible I would be very grateful. Of course this is a project which 
needs to be done quickly but I want to do it anyway, because it's fun.

Thanks for reading and hopefully you have an answer!

Regards,
Tim