This blog post was originally published at e-con Systems’ website. It is reprinted here with the permission of e-con Systems.
The GMSL interface plays a key role in embedded vision systems across industries. It can handle high-resolution video with low latency for long-distance data transmission. Discover more about the GMSL camera interface, its principles and types, as well as how it works.
Embedded vision systems are crucial in industries like life sciences, manufacturing, and sports broadcasting. Their performance depends on selecting the right interface for transmitting images from the camera’s capture system to the processing unit without disruption. The interface must maintain high throughput, avoid data flow bottlenecks, and ensure an appropriate transmission distance for the application.
The GMSL (Gigabit Multimedia Serial Link) interface has enhanced these capabilities by enabling high-quality, low-latency image data transmission over distances up to 15 meters. Primarily, this interface’s capability to handle high-resolution video with low latency and support for long-distance data transmission makes it an immediate choice for many cutting-edge embedded vision systems.
In this blog, you’ll discover everything you need to know about the GMSL technology.
What is GMSL Technology?
Gigabit Multimedia Serial Link (GMSL) camera interfaces are built to manage high-speed and high-resolution video output. It uses a serializer on the transmitter side to convert parallel data into a high-speed serial stream, which reduces the complexity of data lines and minimizes the risk of signal interference. On the receiving end, a deserializer converts the serial data back into its original parallel form, ready for processing.
The GMSL interface can handle video transfer speeds of up to 6 GB per second, making it capable of transmitting uncompressed, high-resolution video streams with minimal latency. Such speed is crucial for applications requiring real-time data processing.
Core Principles of the GMSL Camera Interface
Serializer/Deserializer (SerDes) technique
The core of GMSL technology lies in the Serializer/Deserializer (SerDes) technique. The serializer takes incoming parallel data from the camera sensor and converts it into a sequential serial stream. The conversion process helps simplify the cable design and reduce potential signal interference, maintaining the integrity of high-speed data transmission.
The deserializer, located at the receiving end, reverts the serial data into its original parallel form, ensuring that the receiving system can correctly process it.
Cabling
The GMSL interface uses coaxial cables, known for their excellent shielding and ability to carry high-frequency signals over long distances without major loss. Coaxial cables help maintain signal integrity, prevent data corruption and minimize interference from external electromagnetic sources. GMSL interfaces can also function over twisted-pair cables, which offer a cost-effective alternative while still supporting high-speed data transmission.
Data rate and resolution
GMSL technology supports high data rates, which enables the transmission of uncompressed video and high-resolution images. By supporting data rates of up to 6 GB per second, GMSL ensures that even the most data-intensive applications can operate smoothly without any compromise in performance.
Multiple interface support
The GMSL interface is compatible with various data formats, including HDMI, CSI-2, DSI, and eDP. This ability ensures that it can meet the specific requirements of each application.
Bidirectional communication
GMSL supports bidirectional communication for camera-based applications to send and receive control signals over the same physical medium used for video data transmission. It is crucial for real-time feedback and control. As it supports video and control data over a single interface, GMSL simplifies system design and reduces the need for additional wiring. It results in more streamlined product development and deployment.
Types of GMSL Camera Interfaces
GMSL1
GMSL1 provides high-speed data transmission suitable for various applications, including automotive video streaming. GMSL1 uses coaxial cabling and offers data rates up to 3.125 Gbps. It can transmit 1080p60 uncompressed video with a typical latency of less than 1 microsecond.
GMSL2
GMSL2 provides even higher bandwidths, supporting data rates up to 6 Gbps over a 15-meter cable. It also features higher resolutions (4K), increased cable length support, and enhanced data integrity checks. Hence, the GMSL2 interface is perfect for demanding environments where data quality and higher bandwidth are critical.
GMSL3
GMSL3 supports data rates up to 12 Gbps in the forward channel and 187 Mbps in the reverse channel. It enables uncompressed 4K resolution at 90 fps, delivering smooth video streams. Also, GMSL3 enables the integration of three 4K streams over a single PoC cable for real-time 3D imaging and surround-view capabilities.
How GMSL Technology Works
- The GMSL camera interface operates on the principle of high-speed data serialization. Once the camera sensor captures an image, the raw pixel data, typically in parallel format, is directed to the serializer.
- The serializer converts this parallel data into a high-speed serial stream, reducing the number of data lines required and minimizing potential interference.
- The serialized data stream is then transmitted over a cable, such as a coaxial or shielded twisted pair cable, chosen for its resistance to noise and interference.
- Upon reaching its destination, which could be a display or a processing unit, the data undergoes deserialization.
- The deserializer converts the serial data back into its original parallel form, making it ready for processing.
The GMSL protocol also integrates error correction techniques to maintain data integrity during transmission.
GMSL Cameras Offered by e-con Systems
e-con Systems is an industry pioneer with over 20 years of experience in designing, developing, and manufacturing OEM cameras. We offer several GMSL, GMSL2, and GMSL3 cameras for various use cases – from industrial and agriculture to medical.
These state-of-the-art cameras are equipped with world-class features like HDR, IP66/67 rated enclosures, global shutter/rolling shutter, LED flicker mitigation, and more. e-con Systems’ GMSL cameras are also compatible with various platforms,  including the NVIDIA Jetson development kit.
Check out the Camera Selector page to have a look at our full product portfolio.
If you are looking for help in integrating GMSL cameras into your embedded vision applications, please write to us at [email protected].
Prabu Kumar
Chief Technology Officer and Head of Camera Products, e-con Systems
