AKA why are some of my GIFs being turned into videos?

Overview

• We’re experimenting with serving GIFs as MP4 videos instead of GIFV (which typically serves animated WebP) on the web to a small subset of folks on Tumblr, not everyone. This does not affect anyone using the mobile apps.
• The performance improvements from using MP4s in this way are huge, and will make Tumblr load animated images faster and use less data in almost every circumstance, with no discernible loss in quality.
• This conversion only applies to specific types of GIFs, such as ones without transparency in the first frame. We’ve tested this conversion on thousands of GIFs, and we’re still tuning it to be virtually indistinguishable from the original GIF.
• XKit’s “Vanilla Videos” extension was causing a bug with this experiment, but a recent new XKit version release has fixed that issue.
• If you’re served an MP4 instead of a GIF, clicking on the image will still open it in a lightbox, which you can download as GIFV or GIF, depending on what’s served.
• Since this is still just an experiment, there is no way to opt-out yet; adding some kind of opt-out (on the creator and/or consumer side) is a possibility though.
• If you’re served a GIF as MP4 and it looks wrong, please contact Support with a link to the image and what looks wrong about the conversion. We need examples to help us improve the experience. Also, please do not send duplicate support requests.

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