HDMI 2.0 Has Several Flavors so Be Careful

I bet most of you thought that when you had a device with HDMI 2.0 that it can support 4k at 60fps and included HDCP 2.2. It turns out that just like previous generations of the standard, there are optional items that may or may not be included. And today, all are being marketed as HDMI 2.0, so you better dig a little deeper, especially on the professional side, to see what exactly the connection can support.

HDCP is the content protection scheme that Hollywood is insisting is needed to protect against piracy. And in the consumer space, most TV, set top boxes, AVRs and other related equipment will have HDCP 2.2 installed. But according to H C Chee, marketing director at Silicon Image, a company that makes the chips used in HDMI 2.0, the China consumer market is probably not going to have HDCP 2.2 built into components. That means upcoming Hollywood movies won’t play on these TVs.

But the most troubling aspect is the data rate capability of an HDMI 2.0 product. As shown in the chart below, there are essentially two levels of HDMI. Level A is the one most expect to get when they buy a product. It will support 18 Gbps in a 600 MHz chip set. But the current HDMI chips run off a 300 MHz clock and offer 10.2 Gbps. This is actually fast enough to support 4k/UHD at 60 fps but with only a 4:2:0 color sampling and 8 bits. This is the capability that probably every TV out there today supports.

The current Blu-ray spec outputs content in 8-bits per color and 4:2:0 color sub-sampling so that may indeed be sufficient for most consumer needs in the short term, but it creates a really confusing marketing message. When the 600 MHz chips are in TVs next year, what will they be called – HDMI 2.0 or something else to differentiate from the current crop of 300 MHz transceivers? And what happens when the new Blu-ray spec is finalized?

What we know about the new Blu-ray format is that it will support various frame rates (23.976p/24p, 25p ,50p, 59.94p/60p), UHD resolution and 10 bits and is likely to support all this with 4:2:0 color sub-sampling. It will use HEVC encoding with data rates in the 50-60 Mbps range, with a possible mode at 100 Mbps. We hope to meet with the organization at CES to learn more, but the company has not been very forthcoming in the past, so don’t hold your breath.

Silicon Image focuses mainly on providing chip sets to support consumer applications for HDMI (and MHL). Chee says that Silicon Image has been shipping the bridge chip to TV makers since last January. This includes the 300 MHz (10.2 Gbps) transceiver with a bridge chip that sits between the in-coming connector and HDMI decoder. This chip does the HDCP 2.2 decryption.

When will it ship the 600 MHz/18 Gbps chips? Chee says the company is now in final sampling and should enter mass production in January 2015. Therefore, it seems likely that TVs shipping after April or so could have the new transceivers. And while the Blu-ray spec may support UHD at 60 fps and 10-bits, that option is not included in the current HDMI 2.0 specification. That will have to be addressed in a future version of HDMI, noted Chee.

On the professional side, especially in ProAV and a number of specialized vertical markets where HDMI is seeing more adoption, the ability to deliver a 4k signal using the 600 MHz chips will be much more important. How are folks like Crestron or MuxLab going to differentiate between equipment that has the 300 MHz transceivers and those with 600 MHz? In this space concern about HDCP 2.2 protection is a lot less as most of the content is self generated, but the wider bandwidth is critical for discerning image quality applications.

On this side, some of the makers of Pro gear I talked to said they had hoped to get the new 600 MHz silicon this past summer, but it has yet to arrive, delaying planned roll outs. Silicon Image is one of the suppliers of silicon and core IP that can be integrated into FPGAs and SoCs, but the company is more focused on the consumer market. Therefore, other companies are working on HDMI silicon for the pro side. FPGA supplier Altera has an IP core and I suspect Xilinx has one too, but neither are promoting this on their web sites yet.

However, pro gear is being announced with HDMI 2.0 functionality, so you need to ask if it has the 300 MHz or 600 MHz chips. I did just that when I saw the announcement for the V-Tune Pro 4K product from Aurora Multimedia. This device is “a total 4K2K High Definition worldwide tuning solution for any integrated system which requires IPTV, ATSC, QAM, DVB, NTSC & PAL. The tuner is capable of decoding MPEG2, MPEG4, VC-1, H.264, and H.265 with resolutions up to 4k @ 60Hz via RF and LAN”. And the output is specified as HDMI 2.0, so I asked product manager Paul Harris about the HDMI chips. It is the 600 MHz variety and it is integrated into an SOC within the product. – Chris Chinnock