What’s the Principle Behind the “TV” Button in Video Apps When Mirroring Your Phone?
When you’re watching shows on Tencent Video or iQiyi on your phone and want to cast to a large screen, you’ll always click that magical “TV” button. What technology supports this feature? The answer is DLNA. This article reveals how this most common phone screen mirroring method works.
Behind the “TV” Button: DLNA Protocol in Action
The implementation of this button relies on the DLNA protocol, a digital media streaming standard. When you click it, your phone automatically searches for DLNA-supported receiving devices (such as smart TVs or set-top boxes) under the same Wi-Fi network. It then establishes a connection, sends video streaming playback commands and addresses to the TV, and the TV directly pulls the video stream from the network for playback.
How Is It Different from AirPlay Mirroring?
- DLNA (TV Button): “Streaming” mode. The phone only acts as a remote control, while the TV handles playback. You can turn off the phone screen or use WeChat without affecting the TV playback.
- AirPlay Mirroring: “Duplication” mode. The phone screen content is encoded and transmitted to the TV in real time. The phone must stay on and in the mirroring interface, consuming more power.
Why Can’t the “TV” Button Find Devices Sometimes?
- Inconsistent Networks: The phone and TV are not connected to the same Wi-Fi.
- TV Function Disabled: The TV’s DLNA function (may be called “Multi-Screen Interaction”) needs to be turned on.
- Firewall Blocking: Occasionally, the router or TV’s firewall may block device discovery.
- AirPlay-Only Support: If you’re using an iPhone, some apps prioritize AirPlay. If the TV doesn’t support AirPlay, no devices will be found.
Understanding the DLNA principle behind the “TV” button helps you better use this most convenient wireless screen mirroring method and enjoy the pleasure of watching shows on the big screen.
