Why Is Screen Mirroring Lagging & 7 Practical Fixes

Whether you're showing a presentation, streaming a video, or gaming, screen mirroring is an incredibly convenient feature that allows you to share content from your smartphone or laptop onto bigger screens. Despite its convenience, there are still many complaints about the laggy screen mirroring experience. Casting from phones to TVs does not always go seamlessly. Why is that?

Why Is Screen Mirroring Lagging?

What causes a delay in screen mirroring? Well, the technique that used to connect those devices is the main factor at play.

Mostly, screen mirror tools like Miracast, AirPlay, or Chromecast use Wireless Display (WiDi) - a technology that allows you to transmit audio and video content from one device to another without using physical cables - to establish a connection. When using WiDi to connect devices, data is transmitted over a network involving encoding, compressing, decoding, and displaying. Each process may cause screen mirroring lagging.

Some factors impact the performance and reliability of the wireless display technology:

• Wifi network - quality, bandwidth, encryption, interference
• Device itself - operating system, hardware (e.g.,CPU), software, refresh rate
• Hardware, processing power, Refresh Rate
• Distance between devices

More than listed. Factors that cause lagging in screen mirroring are various and vary with devices. Let's talk about screen cast lagging reasons based on device types.

Common Reasons for Screen Mirroring Lag on TV

Delays occur in Apple TVs, Samsung TVs, and LG TVs are often mentioned. The main reasons are as follows.

1. Weak Wi-Fi

When casting a phone to TV, wifi is commonly used. A weak wifi signal leads to packet loss, where parts of the data stream are delayed, resulting in the freezing of the video or image.

2. Insufficient Bandwidth

Bandwidth refers to the amount of data that can be transmitted over a network. Insufficient bandwidth will limit data during the transmission.

This often happens in mirroring a 4K movie from your smartphone to a smart TV. 4K mirroring could demand 25 Mbps or higher. When the bandwidth is not supported, frequent lags occur.

3. Incompatibility of Device and Software

Compared to tablets and laptops, smart TVs are less frequently used in many cases. They often run on different operating systems and are not in the same ecosystem as the phones. This places higher demands on software compatibility. If you use a poor performance app to cast your screen, it is not surprising that screen mirroring delays on TV.

Common Reasons for Screen Mirroring Lag on Phone

Although mobile phones are used as the sender in screen mirroring commonly, the devices can be a reason for the choppy sharing.

1. Limited CPU or RAM

It can introduce delays as the phone is unable to encode and transmit the screen's data smoothly.

2. Poor Conversion Technology

Since screen mirroring is to make the image/video appear on different screen sizes, it involves the process of resolution compression and enlargement. When the converting tech is unable to handle the adjustment, you will see the delay.

3. App Interference

Apps running in the background on your phone can consume processing power and network bandwidth. They can steal resources from your screen mirroring process, causing lag.

How to Fix Screen Mirroring Lagging?

Now that we know what causes the lag, let's explore how to fix these issues and ensure smoother screen mirroring experiences.

1Use a 5 GHz Wi-Fi band Instead of 2.4 GHz

The 2.4 GHz frequency band is often crowded and can be prone to interference from other devices, like microwaves and cordless phones. Switching to a 5 GHz band (if your router and devices support it) can provide faster, more stable connections for screen mirroring. The 5 GHz band is less congested and typically offers better speeds for wireless streaming.

2Enable Quality of Service (QoS) on Your Router

Many modern routers have a feature called Quality of Service (QoS) that allows you to prioritize certain types of traffic on your network. You can set your router to prioritize screen mirroring or streaming traffic over other less critical devices. This can help ensure that your screen mirroring gets the necessary bandwidth for smooth playback.

3Turn Off VPNs or Proxy Servers

If you're using a VPN (Virtual Private Network) or a proxy server on your device, it could be introducing extra latency, slowing down the mirroring process. Disable any VPNs or proxies temporarily to see if they're the cause of the lag. These services often route your internet traffic through distant servers, which can add delays.

4Check for Background Network Usage

Ensure no other devices on your network are hogging bandwidth. If someone is streaming Netflix in 4K, downloading large files, or playing online games, it could significantly reduce the available bandwidth for screen mirroring. Pause or stop these activities to free up bandwidth for a smoother mirroring experience.

5Adjust Resolution Settings for Mirroring

Sometimes, screen mirroring lag is caused by trying to mirror content at too high of a resolution. If you're trying to stream 4K content but your wifi or devices are not up to the task, consider lowering the resolution. Adjust your source device's screen resolution or the mirroring app's settings to a more manageable resolution (e.g., 1080p or 720p).

6Reduce Other Wireless Interference

Wireless interference can be caused by a variety of devices operating on the same frequency. Devices like cordless phones, baby monitors, Bluetooth devices, or even microwaves can interfere with wifi signals. Ensure that your screen mirroring devices are as far away from these sources of interference as possible. Additionally, make sure other wireless devices (such as Bluetooth speakers or keyboards) are not competing for the same bandwidth.

7Check the Mirroring Device's Settings

Some smart TVs, media players, or streaming devices (like Roku or Chromecast) have built-in settings that can impact the screen mirroring experience. Check your receiving device's settings to ensure features like screen mirroring or casting are properly configured for the best performance. Also, look for any firmware updates for these devices.