Autoplaying videos is a complicated issue because many browsers are actively working against it. This is because autoplaying videos can create a negative user experience. Imagine visiting a website and suddenly a video starts playing, maybe with a loud sound or inappropriate content. Not ideal, right?
Additionally, autoplaying videos can use up a lot of data or slow down your device, especially if the video is large or high quality. To ensure a good user experience, it’s often better to block autoplaying videos.
Known limitations
Autoplay with sound
Browsers, especially on mobile devices, do not allow videos to be automatically played with sound, as an autoplayed sound could be used to cause a bad experience. If you want your video to play with sound, make sure to turn off autoplaying and let the visitor decide whether they want to start the video or not.
User settings
All browsers have options to turn off video autoplaying, so as not to allow any videos to be automatically played, no matter the circumstances. If you don’t think you should have a browser/device limitation, then it will be a setting within your browser (or within the device’s settings).
Large file size
If your video is too large in size, browsers (typically on iOS) will not load your video, as that would unnecessarily drain the data plan of the visitor. Make sure to optimize your video properly; aim to have as little impact on network usage as possible while still providing a good-quality video. Generally, 2MB would be ideal for a 20-second video at 30FPS and 1080p resolution.
iOS devices
When your phone is in Low Power Mode, video autoplaying cannot happen without user interaction, even if that is muted. YouTube videos cannot be auto-played either, and the volume control might be completely missing regardless of your settings.
Xiaomi MIUI browser
Xiaomi’s built-in MIUI browser opens up all videos inside a pop-up video player, as you can see, for example, in this video, to let users do anything else on their phones while watching the given video. This behavior cannot be changed within the video’s code.
Tablet and mobile devices
Specifically, older devices have a limitation that they do not allow autoplaying, no matter what, due to the network data usage and the lack of memory in such devices. On these, the only way to start a video is with a user interaction, like clicking on the video play button, for example. Some newer devices might also have this limitation.