Can I have a video with transparent background using HTML5 video tag?

We filmed a spokesperson on a green screen and have the video files ready in multiple formats.

With Flash we could use the wmode transparent within the param and embed tags, but is there something similar to this with the video and source tags in HTML5? Is it even possible to properly save .m4v or .ogv videos so that we can play these files with transparent backgrounds on our browsers?

Thanks

Yes, this sort of thing is possible without Flash:

• http://hacks.mozilla.org/2009/06/tristan-washing-machine/
• http://jakearchibald.com/scratch/alphavid/

However, only very modern browsers supports HTML5 videos, and this should be your consideration when deploying in HTML 5, and you should provide a fallback (probably Flash or just omit the transparency).

Chrome 30> supports video alpha transparency.

http://updates.html5rocks.com/2013/07/Alpha-transparency-in-Chrome-video

Update: Webm with an alpha channel is now supported in Chrome and Firefox.

For other browers, there are workarounds, but they involve re-rendering the video using Canvas and it is kind of a hack. seeThru is one example. It works pretty well on HTML5 desktop browsers (even IE9) but it doesn't seem to work very well on mobile. I couldn't get it to work at all on Chrome for Android. It did work on Firefox for Android but with a pretty lousy framerate. I think you might be out of luck for mobile, although I'd love to be proven wrong.

These days, if you use two different video formats (WebM and HEVC), you can have a transparent video that works in all of the major browsers except Internet Explorer with a simple <video> tag:

<video>
  <source src="video.webm" type="video/webm">
  <source src="video.mov" type="video/quicktime">
</video>

Here's a demo you can test with