Screenshot of the tracks selector. There are two tabs. First tab allows to manage video quality. By default it is set to auto but it can be forced to different qualities. The second tab allows to manage the audio.
https://storage.gra.cloud.ovh.net/v1/AUTH_91eb37814936490c95da7b85993cc2ff/tootfedilabapp/media_attachments/files/110/049/703/472/906/567/original/d30d3db1a49745d7.jpg