One thing I noticed is that the deinterlace toggle isn't translatable. Even if I put in a translation manually (it's missing in the POT file) it won't get picked up properly. The toggle itself is translatable, the tooltip however is not. The encoding progress label above the progress bar also doesn't pick up translations for some reason. If someone more knowledgeable than me knows how to fix this, my translations should get picked up automatically.
More Difficult Localization Translation
The notification after encoding is done still shows the elapsed time in English. Localizing that is a little more involved. humanize supports i18n methods, but I don't know Python so I'd rather not mess with the code :)
Formatting Errors with Translated Text
Some translations also barely fit the widgets they're put in. German is notorious for its long words and I had to get a little creative so it doesn't break the GUI (e.g. "Perceptual Tuning" -> "Bildoptimierung", lit. "image optimization" because "Wahrnehmungsabstimmung" caused the CRF label to be hyphenated, which looked goofy 🙃). The only place where that didn't work was the label for the audio volume slider, which gets hyphenated next to the normalize toggle due to a lack of space. That could be avoided by increasing the default window size, tho.
@yakushabb Here's the issue. I'm not sure what to do here, so I marked it as "Help Wanted" ... hopefully we can resolve this together, if you have some time!
Missing Translations
More Difficult Localization Translation
Formatting Errors with Translated Text