Hello e621,
I'm looking into converting / encoding some mp4 files to webm to upload here. I'm having some trouble deciding on the options for the webm encoding and am hoping someone can help.

Here are the stats for the original mp4:
Filesize: 56.2MB
Resolution: 1920 x 1080
Length: 00:01:05
Bitrate:7142kbps

Audio is 127kbps stereo at 48 kHz

I've tired a few different webm encodes and the two I think work best are:
VP8 constant quality 50 with vorbis audio (same audio bitrate as source):
Filesize: 20.3MB
Resolution: 1920 x 1080
Length: 00:01:05
Bitrate:2602kbps

Looks pretty close to original at half the filesize but some compression is noticeable

or
VP9 constant quality 50 with vorbis audio (same audio bitrate as source):
Filesize: 60.7MB
Resolution: 1920 x 1080
Length: 00:01:05
Bitrate:7775kbps

Looks very close to the original, very crisp but larger filesize.

Which would people prefer to see uploaded? Are there better settings to use for converting? If someone who knows more about this would like the files PM me and I'll send some links, I'd like to make sure I get this right before trying to upload anything here.

Thanks!

I'm just thinking that what does the constant quality 50 mean? CRF 50? That value is from 0-63 where 63 is worst, meaning 50 should look pixelated mess. Or if you are using quality constrains only (-qmin 0 -qmax 50) I would highly suggest using crf only or in addition, using something like 16-20 values. (constraint means the scale which quality it can use, crf means what quality it's aiming)

Difference between VP8 and VP9 is essentially that VP8 is older and VP9 is newer. There are some slight compatibility issues when it comes to VP9, but overall if user has their software up to date and using modern software, they should be able to play both codecs exactly the same. VP9 simply being newer and should be much more efficient and that's what I have been using for ages now.

When it comes to quality, do try to match up visual quality of the source. This way you don't have to forward people to source just to see better quality. Sometimes filesize will be bit larger and sometimes it's insanely much lower, simply because how differend codecs handle their compression. This is also why it's always the best scenario if you can convert the file from lossless/source files, so other fileformats compression isn't there to bloat stuff. If it's visually the same without bloat (using lower settings doesn't look identical) then prefer that.

With audio would use opus for bit more efficiency, but vorbis works fine as well.

I can also check the files if you want to.