Original Post: Video formats

What is the most widely accepted format these days for video files? I have "Icecream" software to create slideshows but it presents the final format as .webM which then may need converting. I also have another program (Professional Slideshow Maker--AnvSoft) that makes the slideshows as flash, for embedding. I have conversion software (Freemake) that will fix the first issue, but there are lots of formats to choose from.

It is suggested that videos are hosted on places like Youtube, Vimeo, etc but I really can't be bothered to open accounts in these places just for playing around with one or two slideshows. I already have my own full-domain website, so I can use that.....I doubt if thousands of people are likely to click on the vids every day.