I would like to develop a web based interface for creating short video commercials.

1. In web based interface, user chooses 1 of the predefined video (flash) templates
2. enters content (text, photos, prices...)
3. flash application renders everything and outputs HD flv video and stores it to specific folder/ user's commercial channel
4. WIFI box (programmed RASPBERRY micro computer) connected to TV (via hdmi) "picks up"streams HD flv video from user's channel.

I have this "hardware" part setup and tested, but I'm working on first part ( creating web interface and connecting it with application which would process and render video content.

If someone could advise me if FLASH is suitable for this... and can some kind of cloud based FLASH aplication be created which could do the job.

thank you very much for help.