Did some search but didn't find the reason for this.
When using the Azure media player (http://amp.azure.net/libs/amp/latest/docs/), and when I switch to version 1.5.0, suddenly, for a regular mp4 file (not adaptive streaming), my Firefox (version 43.0.4) has a bar saying "The audio or video on this page requires DRM software this FireFox does not support".
Anyone has idea about this? I didn't use any DRM on my page (it is a most basic un-protected mp4 playback).
Thanks!
PS: I tried the official azure media player demo page (http://amsplayer.azurewebsites.net/azuremediaplayer.html), and it has the same issue as well.
This is a known issue that's been fixed in AMP version 1.6.0 (set for release soon). It’s a Firefox bug that pops up when AMP queries APIs to detect browser capabilities. This happens even if the content isn’t using DRM. The message is inaccurate and it’s a little annoying but fortunately it doesn’t affect playback and will be fixed when you upgrade to v1.6.0.