HDMI vs. MIPI DSI

Choosing the right interface for a device or machine isn’t the easiest task. There are a whole host of factors that will impact the way it functions in its context. Such factors include how a display performs, the image quality, power consumption, or how data is transferred and interpreted. HDMI and MIPI DSI are two of the most common mediums of communication between displays and other systems. They’re frequently used in consumer electronics, the automotive industry, medical imaging, and telecommunication.

Since both interfaces see such pervasive use, how do you choose when facing a manufacturing decision or a procuring decision?

What is HDMI (High Definition Multimedia Interface)?

For many, the acronym HDMI often sparks images of a connecting cable for a TV. Over the past two decades, HDMI cables have become a household staple. Certainly when it comes to audio and video transfer, whether we’re connecting laptops, gaming consoles, or other multimedia devices. 

What many don’t know is that HDMI applications aren’t just limited to the residential home. HDMI is also heavily used in commercial and industrial sectors where high-quality video or audio is required. Within the healthcare sector, HDMI is extremely important to all sorts of devices. Examples of such are endoscopes, ultrasound systems, and other diagnostic tools that help immensely with diagnosis and patient care.

Key features and specifications

Since its release in 2002, HDMI has undergone several evolutions allowing it to cater to a variety of modern technologies. This small connector was designed to improve connectivity standards and later became a standard port in a range of devices.

• Standard, mini, and micro sizes – With three different cable specifications, HDMI is compatible with a range of devices and applications. They’re also available in different configurations, with versatility that caters to situations that require gripping or locking or angled connectors. 
• Deep color –  Useful especially in display circumstances where distinguishable colors are required. HDMI can produce 48-bit color depth with a 281.5 trillion gamut.
• Fast transmission rates – Plenty of audio-visual data can be transferred from the source device to the display thanks to the up to 48 Gb/s maximum transmission rate available.
• Single cable convenience – Audio and video signals are both transmitted through the same cable. This provides simplicity and efficiency during the setup process.
• High-definition support – In its infancy, the max resolution refresh rate for HDMI was 1080p @ 60 Hz. As of 2017, with updates to the technology, it boasts up to 8K @ 30 Hz. It supports standard, enhanced, and high-definition video formats, compatible with a variety of media requirements.
• Transition-Minimized Differential Signaling (TMDS) – Digital data transmission is typically affected by distance. HDMI signals can be encoded using TMDS to protect them from noise and signal interference.
• Lengthy signal transmission capabilities – Thanks to the array of HDMI extenders and long passive and active cables, HDMIs can function at their optimal state up to 65 feet.

What is MIPI DSI (Mobile Industry Processor Interface Display Serial Interface)?

MIPI DSIs are high-speed interfaces that are more common in smaller-screen applications. It was developed by the MIPI Alliance for in-sight and head-mounted devices, embedded displays, smart meters, smart watches. Meanwhile, more commonplace applications include tablets, smartphones, and automotive applications.

Unlike HDMI though, MIPI DSI is more of a complete protocol. Accordingly, it provides more control over aspects of the screen’s performance, such as pixel format and image data flow. It thus strikes a balance between power efficiency and high-speed performance. This is particularly useful for devices that run on battery power. If we take the realm of Internet of Things (IoT) Devices or portable industrial devices, we can see that plenty of them require compact, high-resolution screens with long battery lives.

Key features and specifications

• Power efficiency – MIPI DSIs have a stringent focus on power efficiency. At the interface level, there are low-power, ultra-low power, and high-speed settings that can be adjusted, conserving power when high speeds or resolutions aren’t required.
• Control over display functions – Instead of acting as a simple transmit-and-display interface, MIPI DSI can handle many aspects of the display. It supports compressed and uncompressed pixel formats, lets you control how image data translates to the display in terms of color rendering and more.
• Bidirectional communication – Being able to send and receive data means enhanced interactivity for the user. For example, MIPI DSIs can permit touchscreen capabilities, where taps and swipes can be communicated back to the processor to interpret.
• Scalability – The interface’s scalability makes MIPI DSI capable of supporting a broad spectrum of display resolutions, which means manufacturers can use the same standard interface to meet different requirements. This flexibility also applies to data transmission and power efficiency, scaling to meet these needs or lack thereof.
• Reduced electromagnetic interference (EMI) – Boasting reduced electromagnetic interference, this interface enjoys a boost in signal quality and integrity as these signals won’t likely be as disrupted by electromagnetic fields in the environment.
• High resolution and color depth without increasing data line count – With its high data transmission rate, users can take advantage of sharper images and richer, more vibrant displays without the need for additional data lines.

Choosing Between HDMI and MIPI DSI

HDMI is globally renowned for transmitting high-quality audio and video data in situations where superior digital quality is required. It has the capabilities to handle uncompressed signals and deliver vibrant sounds and images, making it a sure choice for medical imaging, corporate communications, and other important industries. 

MIPI DSI has also proven its effectiveness and reliability in audio and video transfer, but it tacks on the consideration of balancing power efficiency and high-speed data transmission. If you’re looking for an interface that has the advantage of conservative power use, particularly for portable devices, MIPI DSI allows for that. In addition, it provides comprehensive control over display features, which enhances its appeal in sectors like the automotive industry and the IoT realm.

Conclusion

Making a final decision during procurement or manufacturing is, all in all, about the needs of your application or device. HDMI and MIPI DSI are both mature, industry-grade interfaces that can handle just about any objective – however, they certainly come with their own advantages. Brushing up on your knowledge of each of their specifications and features will help you choose based on operational demands and user expectations, leading you to a strategic choice that will deliver the most value.