Video splitters are commonly used to distribute a video signal from one source to multiple displays. While they are useful in many scenarios, such as digital signage, presentations, and multi-monitor setups, they come with some technical limitations. One of the primary drawbacks of using a video splitter is the reduction in available bandwidth, which can impact the maximum resolution and refresh rate achievable.
In this article, we will explore how video splitters affect video signal quality and why they can impose these limitations.
Understanding Bandwidth in Video Transmission
Video signals require a certain amount of bandwidth to transmit data effectively. The bandwidth required depends on factors such as:
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Resolution – Higher resolutions (e.g., 4K, 8K) require more data to be transmitted per frame.
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Refresh Rate – Higher refresh rates (e.g., 120Hz, 144Hz) require more frames to be sent per second, increasing the total data load.
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Color Depth – Higher bit-depth color (e.g., 10-bit HDR) increases the amount of data needed per pixel.
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Compression and Encoding – Some transmission methods use compression to reduce bandwidth needs, but uncompressed signals require full data transmission.
A video splitter takes a single video input and distributes it to multiple outputs, and this process can introduce bandwidth limitations depending on the type of splitter used.
How a Video Splitter Reduces Supported Bandwidth
1. Bandwidth Splitting Across Outputs
Most passive video splitters (such as simple HDMI or VGA splitters) do not increase the total available bandwidth. Instead, they share the available signal among multiple outputs. If the video source provides a limited bandwidth, splitting it means that each output might receive a weaker or downgraded signal.
For example, an HDMI 2.0 signal supports a maximum of 18 Gbps, allowing for 4K at 60Hz. If a passive splitter is used, the total bandwidth may be divided between the outputs, reducing the resolution and refresh rate each display can handle.
2. Signal Degradation
Even if a splitter does not explicitly divide bandwidth, it can cause signal degradation. The longer the cable runs and the more connections involved, the greater the potential loss of signal quality. This can result in:
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Reduced resolution due to data transmission errors.
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Lower refresh rates if the signal is not stable enough at higher frequencies.
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Color loss or artifacts in the image.
3. Compatibility with Different Displays
When using a splitter with multiple displays of different resolutions and refresh rates, the system often defaults to the lowest common denominator. For example, if one display supports 4K at 60Hz and another supports only 1080p at 60Hz, the splitter may force both displays to operate at 1080p.
This happens because many splitters are not capable of scaling resolutions independently for each output. Instead, they synchronize to the lowest supported format among connected devices.
4. Limitations of the Splitter’s Internal Hardware
Active video splitters (which amplify the signal) may have built-in chipsets with specific limitations. Some older or lower-quality splitters may not fully support high-bandwidth formats such as:
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4K at 120Hz (which requires HDMI 2.1 or DisplayPort 1.4).
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High Dynamic Range (HDR) content.
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Variable Refresh Rate (VRR) technologies like G-Sync or FreeSync.
If a splitter does not support the required bandwidth or protocol, the signal will be downgraded to a lower resolution, refresh rate, or color depth.
How to Minimize Bandwidth Limitations
To avoid or reduce the impact of bandwidth reduction when using a video splitter, consider the following solutions:
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Use a High-Quality Active Splitter – Active splitters amplify the signal and can better maintain high resolutions and refresh rates.
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Check the Splitter’s Specifications – Ensure the splitter supports the desired resolution, refresh rate, and features (e.g., HDMI 2.1 for 4K at 120Hz).
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Use High-Quality Cables – Poor-quality cables can degrade signals, especially over long distances. Use certified HDMI, DisplayPort, or VGA cables with sufficient bandwidth.
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Use a Matrix Switch Instead of a Splitter – A video matrix switch can route signals dynamically and may offer better bandwidth management.
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Match Display Capabilities – If possible, use displays with similar resolutions and refresh rates to avoid forced downscaling.
Conclusion
While video splitters are useful for distributing video signals, they can introduce bandwidth limitations that reduce the supported resolution and refresh rate. Passive splitters share bandwidth between outputs, while active splitters depend on their internal hardware capabilities. Choosing the right splitter, cables, and display setup can help minimize these limitations and maintain high-quality video output.