if selected quality isn't available, closest one is used instead.

h264: generally better player support, but quality tops out at 1080p.
av1: low player support, but supports 8k & HDR.
vp9: usually highest bitrate, preserves most detail. supports 4k & HDR.

pick h264 if you want best editor/player/social media compatibility.

progressive: direct file link to vimeo's cdn. max quality is 1080p.
dash: video and audio are merged by cobalt into one file. max quality is 4k.

pick "progressive" if you want best editor/player/social media compatibility. if progressive download isn't available, dash is used instead.

when "best" format is selected, you get audio the way it is on service's side. it's not re-encoded. everything else will be re-encoded.

defines which audio track will be used. if dubbed track isn't available, original video language is used instead.

original: original video language is used.
auto: default browser (and cobalt) language is used.