翻译强力驱动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:
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
No. This is a limitation of the video codecs supported by the browsers: mp4, ogv, and webm do not currently support alpha channels.
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.
At this time, the only video codec that truly supports an alpha channel is VP8, which Flash uses. MP4 would probably support it if the video was exported as an image sequence, but I'm fairly certain Ogg video files have no support whatsoever for an alpha channel. This might be one of those rare instances where sticking with Flash would serve you better.
While this isn't possible with the video itself, you could use a canvas to draw the frames of the video except for pixels in a color range or whatever. It would take some javascript and such of course. See Video Puzzle (apparently broken at the moment), Exploding Video, and Realtime Video -> ASCII
webm format is the best solution for Chrome > 29, but it is not supported in Firefox IE and Safari, the best solution is using Flash (wmode="transparent"). but you have to forget "ios".
Quicktime movs exported as animation work but in safari only. I wish there was a complete solution (or format) that covered all major browsers.
