Would be great to know this beforehand when making another doodle video, Ya know? ╹‿╹)

FLV and MOV are not supported with HTML5 standard which the site relies on.
You can read more about the <video> here: https://www.w3schools.com/html/html5_video.asp

I'm almost certain I have had this topic before. Generally speaking alpha channels are used in editing stages where video needs to be overlayed on top of another. However there does seem to have been rise in demand on having it supported in these final encoding codecs as this way videos could be used as design elements on website also on top rather than just on background for example. These still do not make general sense on videos meant to be watched on various places, because you usually simply end up with black or white background as software has nothing else to fill it with.

So what are supported are MP4, WebM and OGG. e621 right now has only supported WebM as there are more behind the scenes stuff which doesn't make supporting MP4 and OGG as simple as allowing the filetype.

• MP4 h264 does not support alpha channel, not sure of h265 but the support for h265 on HTML5 video embed is extremely bad.
• OGG files, not sure of what codecs HTML5 supports, but I'm assuming Theora/Vorbis and those codecs are so old that I would assume no support.
• WebM:
• VP8 did have partial alpha channel support, but it was extremely limited and I think only worked with chrome. This can be used in extremely hacky way but I would advice againts this.
• VP9 I think did actually finally get proper support for this in form of yuva420p support.

So I took liberty of testing your latest hotness from post #1840071 to try things out.

WebM, VP9 with yuva420p: https://puu.sh/Dtv4B/aa79dcf7f3.webm (right click -> loop)
From what I'm testing, this does actually seem to work properly nowdays. MPC, VLC and WMP both play the file fine with white background. Chrome, Firefox and Edge seem to play the file fine with background color of the new tab. On mobile at least chrome, google photos and VLC play the file fine.

That's actually extremely important as VP9 does have support for even RGB colorspace, however the compatibility with players and browsers have been abysmal and thus we have deemed these files as corrupted thus far. So if yuva420p has as good compatibility as yuv420p which almost all videos here use, then there's your answer.

However the main benefits of lossy video codec is that you can more easily compress complex material and additionally add in sound. You are using tons of flat colored areas and relatively simple and crisp movement. If I were you and I wasn't in to adding in sound, then I would almost use APNG instead.
https://puu.sh/Dtvbl/806e12e1d6.png
It's pretty well supported now and it does allow more colors with better transparency (you can have gradient from color to alpha for example) and higher framerates compared to GIF. Also with help of optimization it should also get you lower filesizes from GIF.

Mairo said:
FLV and MOV are not supported with HTML5 standard which the site relies on.
You can read more about the <video> here: https://www.w3schools.com/html/html5_video.asp

I'm almost certain I have had this topic before. Generally speaking alpha channels are used in editing stages where video needs to be overlayed on top of another. However there does seem to have been rise in demand on having it supported in these final encoding codecs as this way videos could be used as design elements on website also on top rather than just on background for example. These still do not make general sense on videos meant to be watched on various places, because you usually simply end up with black or white background as software has nothing else to fill it with.

So what are supported are MP4, WebM and OGG. e621 right now has only supported WebM as there are more behind the scenes stuff which doesn't make supporting MP4 and OGG as simple as allowing the filetype.

• MP4 h264 does not support alpha channel, not sure of h265 but the support for h265 on HTML5 video embed is extremely bad.
• OGG files, not sure of what codecs HTML5 supports, but I'm assuming Theora/Vorbis and those codecs are so old that I would assume no support.
• WebM:
• VP8 did have partial alpha channel support, but it was extremely limited and I think only worked with chrome. This can be used in extremely hacky way but I would advice againts this.
• VP9 I think did actually finally get proper support for this in form of yuva420p support.

So I took liberty of testing your latest hotness from post #1840071 to try things out.

WebM, VP9 with yuva420p: https://puu.sh/Dtv4B/aa79dcf7f3.webm (right click -> loop)
From what I'm testing, this does actually seem to work properly nowdays. MPC, VLC and WMP both play the file fine with white background. Chrome, Firefox and Edge seem to play the file fine with background color of the new tab. On mobile at least chrome, google photos and VLC play the file fine.

That's actually extremely important as VP9 does have support for even RGB colorspace, however the compatibility with players and browsers have been abysmal and thus we have deemed these files as corrupted thus far. So if yuva420p has as good compatibility as yuv420p which almost all videos here use, then there's your answer.

However the main benefits of lossy video codec is that you can more easily compress complex material and additionally add in sound. You are using tons of flat colored areas and relatively simple and crisp movement. If I were you and I wasn't in to adding in sound, then I would almost use APNG instead.
https://puu.sh/Dtvbl/806e12e1d6.png
It's pretty well supported now and it does allow more colors with better transparency (you can have gradient from color to alpha for example) and higher framerates compared to GIF. Also with help of optimization it should also get you lower filesizes from GIF.

Whoa, This is amazing! ◠‿◠)~★

I can't say how grateful I am that you not only
answered my question but gave me some pretty great
formatting tips too!

Definitely, need to look into VP9-yuva420p and especially
APNG since that may also solve some issues I've
been having with the seem-work that enhanced color
quality and-

DEAR HECK!

I would make Zatch a TOP if it meant that I could
have gradient in a Transparent Animated Doodle!
That would literally be the Best Thing!

Thanks a "9999"Ultima ton for the answer and then
some. Great advice that Without a doubt won't just
help me but, anyone else who sees it! ◠‿╹)