Hi, when embedded .ass subtitles are direct played in the browser, they get extracted on the fly and then sent to the browser for client-side subtitle rendering. When you're not seeing subtitles, what's probably happening is that this extraction is taking a long time in your environment. Depending on the performance of your server machine as well as the disk I/O performance of drive the video is on, it's not always instantaneous. Can you try external .ass for comparison purposes?