Third party libraries Login as admin. Navigate to Site Administration > Development > Third party libraries. Verify that the version of VideoJS and VideoJS support files is 7.17.0. Media playback Restore this course backup videojs_samples.mbz Make sure that videojs is enabled and on the first place, youtube are checked. Navigate to Site Administration > Media players > Manage media players. Make sure that the VideoJS player is turned on and on the first position. Make sure that Youtube is turned on and on the second position. Click on the Setting link of VideoJS player Make sure as below: Video file ext: html_video,media_source,.f4v,.flv Audio file ext: html_audio View the restored course on different browsers (including mobile) Verify that you can play all videos/audios. Verify that in "html5 embed" you should be able to show captions and jump to chapters .  (The media links added within a label should be embedded and able to be played in the course page, while to test media links added within other resources or activities you will need to access the activity).  Change interface language to one of this list. Verify that the video player buttons are also translated (enough to check in one browser). RecordRTC playback on MacOS/iOS (This one was copied from MDL-65943 ) Device to test this issue macOS machine must have a working microphone and webcam. iPhone. iPad. Initial setup Note: Must use Chrome/Firefox for this Initial part. Enable RecordRTC plugin in the Atto editor. (At: /admin/settings.php?section=editorsettingsatto) Create a course or use an existing one. Create a page activity called Page with Audio: In the Page content, click on the Record Audio button and try to record your voice. Click Save and Return to course. Create a page activity called Page with Video: In the Page content, click on the Record Video button and try to record the video with your voice. Click Save and Return to course. macOS Safari Audio testing Go to Page with Audio. Verify that you will see the UI for VideoJS now. Click on the Play button. Verify that you will hear the audio. Verify that you can pause the player. Verify that you can mute/un-mute the player. Verify that you can control the volume level of the player. Mac OS Safari Video testing Go to Page with Video. Verify that you will see the UI for VideoJS now. Click on the Play button. Verify that you will hear the audio. Verify that you will see the video. Verify that you can pause the player. Verify that you can mute/un-mute the player. Verify that you can control the volume level of the player. Verify that you can fullscreen the player. IPad with iPadOS Safari Audio testing Go to Page with Audio. Verify that you will see the UI for VideoJS now. Click on the Play button. Verify that you will hear the audio. Verify that you can pause the player. Verify that you can mute/un-mute the player. Verify that you can control the volume level of the player. (Some iPad OS versions will not allow controlling the volume level, so it is ok if this failed). IPad with iPadOS Safari Video testing Go to Page with Video. Verify that you will see the UI for VideoJS now. Click on the Play button. Verify that you will hear the audio. Verify that you will see the video. Verify that you can pause the player. Verify that you can mute/un-mute the player. Verify that you can control the volume level of the player. (Some iPad OS versions will not allow controlling the volume level, so it is ok if this failed). Verify that you can fullscreen the player. iPhone with iPhoneOS Safari Audio testing Go to Page with Audio. Verify that you will see the UI for VideoJS now. Click on the Play button. Verify that you will hear the audio. Verify that you can pause the player. Verify that you can mute/un-mute the player. Verify that you cannot control the volume level of the player. (iPhoneOS do not allow media player to control the volume). iPhone with iPhoneOS Safari Video testing Go to Page with Video. Verify that you will see the UI for VideoJS now. Click on the Play button. Verify that you will hear the audio. Verify that you will see the video. Verify that you can pause the player. Verify that you can mute/un-mute the player. Verify that you cannot control the volume level of the player. (iPhoneOS do not allow media player to control the volume). Verify that you can fullscreen the player.