If you are going to do the work I would switch to a proper video format. If you are planning a bit into the future this is probably AV1 with h264 fallback. However it is pretty easy to add or remove formats from the list.
I get that you need to change <img> to <video> but that seems like a reasonable thing to do when you are serving video. In exchange you get better mutli-format negotiation, access to controls and seeking if desired, smarter incremental loading...
If you are going to do the work I would switch to a proper video format. If you are planning a bit into the future this is probably AV1 with h264 fallback. However it is pretty easy to add or remove formats from the list.
I get that you need to change <img> to <video> but that seems like a reasonable thing to do when you are serving video. In exchange you get better mutli-format negotiation, access to controls and seeking if desired, smarter incremental loading...