Subtitle behaviour differs between web and client app

[basinbasin]

If I post a video and add a vtt subtitle file, the subtitles are displayed by default in the web app. On the android client app, no subtitles are shown. There's no indication that the video even has subtitles unless you click on the video, then press the CC icon and then change the dropdown from none to the subtitle language.

This doesn't seem great from an accessibility point of view, and the inconsistency across clients is puzzling. Considering the focus that adding alt-text to images gets, having to click each video in the feed to see if there even are subtitles seems burdensome.