I am watching the recording of the class again with one point twenty-five times speed to review it.
「I am watching the recording of the class again with one point twenty-five times speed to review it.」で「復習のために授業動画を1.25倍にしながら見ている」です。
授業動画: the recording of the class
1.25倍速で: with one point twenty-five times speed(書く場合は1.25x speedでもOK)
復習のために: to review
参考になれば幸いです。