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Why Semtech’s BlueRiver® ASIC Is a Superior Solution for AV Extension

19 May 2020 / by Gareth Heywood

Semtech Intros BlueRiver for AV Extension

In the world of Pro AV, point-to-point cable extension technologies are essential for transmitting AV content from point A to point B, where standard cabling just cannot go the distance. With the advent of HDMI, full bandwidth AV signals are sent in digital form at high data rates over shielded twisted pair (STP) cables, which typically max out at around 20 meters of reach. When carrying 4K video content, HDMI operates at up to six Gigabits per second (Gbps), and as data rate increases, so does the challenge of transmitting it over longer distances. Soon after HDMI transformed AV connectivity to digital, another technology was developed to extend these signals over standard copper networking infrastructure. This technology is called HDBaseT.

Semtech Introduces BlueRiver for AV Extension

Semtech’s BlueRiver chipset is uniquely designed to transmit AV signals, up to 4KP60 4:4:4, over both copper category cabling and optical fiber. By utilizing the same technology used for 10G Ethernet, BlueRiver provides transmission up to 100m using Cat-6a unshielded twisted pair (UTP) cable, or tens of kilometers using optical fiber. BlueRiver-based products simultaneously transmit uncompressed-quality 4K video, multi-channel audio, Gigabit Ethernet, USB, and other control signals, offering unprecedented levels of performance for AV extension applications, including standalone point-to-point cable extenders, matrix switches and KVM (USB) extension.

Read more about BlueRiver applications here.

BlueRiver vs. HDBaseT

The launch of the BlueRiver ASIC in January 2020 created a significant buzz within the Pro AV industry. Finally, equipment makers are not tied to a single AV extension technology and can take advantage of out-of-the-box support for full 4K video formats at lower cost points. There’s clear industry recognition that Semtech’s ASIC solutions for Pro AV are a game changer, and that Semtech’s leadership in AV transmission technologies positions BlueRiver as the future of AV extension. However, I’m sure many of you reading this have questions, so here’s what I’ve been telling people who want to know why BlueRiver is the right choice.


True 4K60 4:4:4 requires up to 18Gbps of link bandwidth. HDBaseT will fully support this, operating at 18Gbps. How can BlueRiver achieve the same performance?

BlueRiver uses standard 10G Ethernet signalling combined with an ultra-lightweight, 100% artefact-free compression to keep any format that exceeds 9Gbps within the 10G bandwidth limit. By doing this, BlueRiver provides guaranteed 100m reach performance, even over UTP cables. At 18Gbps, HDBaseT reach performance is severely limited and it is mandatory to use more costly shielded cables to get better than 50m reach.

HDBaseT has the advantage of a fully integrated copper PHY. Isn’t this a big advantage over BlueRiver?

No! The HDBaseT PHY is completely proprietary and not based on the IEEE 10G Ethernet standard. It does not have the advantages a truly compliant 10G PHY includes, such as noise immunity and crosstalk cancellation. This really limits the reach performance of HDBaseT and mandates the use of more costly STP category cabling, such as Cat-7 or even Cat-8.

What is the reach advantage over category cable using BlueRiver vs. HDBaseT?

BlueRiver uses a fully IEEE-compliant 10G Ethernet copper PHY which guarantees 100m reach performance over Cat-6a UTP cable. HDBaseT can only support uncompressed 4K60 4:4:4 transmission at 70m or less, with reach performance further limited in the presence of electrical noise or transient interference.

Do the additional components required by the BlueRiver solution mean that the board size needs to be physically large?

No. With just a handful of major components, it is possible to make boards as small as a credit card, as shown.

BlueRiver Credit Card Comparison

Using a companion chip, HDBaseT also supports fiber connectivity. What about BlueRiver?

HDBaseT requires an additional device to convert the HDBaseT electrical signals to fiber, which is costly and power hungry. Using any one of the three BlueRiver devices, direct connection to standard 10G SFP+ modules is possible, greatly reducing the cost, power and footprint of fiber-based AV extender solutions. The following block diagrams illustrate a simple fiber transmitter and receiver solution using the AVP1000.


AVP1000-based Fiber Transmitter


AVP1000-based Fiber Receiver

Enabling a New Class of AV Extender

The flagship AVP2000T is the industry’s first truly bidirectional HDMI connectivity solution for both copper and fiber infrastructure. The device also includes a powerful AV processing engine which provides broadcast quality scaling. The chipset lowers system cost by reducing the number of devices required and removing the need to use costly FPGA and image scaling devices. The AVP2000T consumes less than 2.5W with fiber connectivity, compared with existing fiber extension technologies in the 6W-8W range. Additionally, the AVP2000T provides a full USB-HID interface, enabling highly integrated low-cost products for KVM applications.

HDBaseT chipsets just provide AV extension. If the output resolution of the receiver needs to be fixed to the connected display resolution, a scaler would be required. Is this the case for BlueRiver too?

No. Both the AVP2000 and AVP2000T integrate a broadcast quality scaler which can be used to convert the image format at the transmit or receive end. Using an AVP1000-based transmitter paired with an AVP2000-based receiver, the output resolution can be fixed to that of the connected display resolution regardless of the original source format. The scaler can also be used to crop and scale images for video wall applications, saving the significant additional costs associated with dedicated video wall processors.

Extending HDMI signals in both directions, for example, between two rooms, requires two sets of HDBaseT extenders. Since 10G Ethernet is full duplex (10G in both directions simultaneously), is it possible to reduce this cost using a BlueRiver-based solution?

Absolutely! As already noted, the AVP2000T is the first truly bidirectional HDMI transceiver solution, allowing simultaneous receive and transmit of HDMI signals, up to 4K60 4:4:4, in both directions over a single copper category cable or fiber pair. The AVP2000T enables a new class of products which can dramatically reduce both product and system costs. 


AVP2000T-based Fiber Transceiver with AV Processing

So now there’s no question that BlueRiver is the preferred solution for AV cable extension. Applications based on BlueRiver chipsets provide unprecedented levels of performance, best in class noise and crosstalk immunity, full support for industry standard cabling, and are future-proofed with fiber connectivity for longer distance and higher bandwidth operation.

Read more frequently asked questions about Semtech’s BlueRiver Solutions.



Semtech, the Semtech logo and BlueRiver are registered trademarks or service marks of Semtech Corporation or its subsidiaries.

Topics: Professional AV, BlueRiver

Written by Gareth Heywood


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