Does 4K mean that everything is new?

Requirements for HDMI cables

The constantly growing range of Ultra-HD TVs and monitors poses not just the question of the right content, but also the right connection. Full HD has been part of the mainstream for some time, but now Ultra HD is conquering the current market landscape with an even better format (four times the resolution of Full HD). Excellent – because for the best image you simply can't have enough pixels. But how does this affect the connections between the new components? We have compiled the most important questions and technical issues for your here.

The newest HDMI 2.0b version – What are the differences?

The HDMI organisation has released a new HDMI 2.0b standard. The main difference is that the new standard supports the HDR (High Dynamic Range) format. HDR improves the contrast ratio because the source sends additional information (metadata) to the television - information that regulates the television's backlight. The source and TV must of course also support HDR. It also supports dynamic synchronization between video and audio streams. This new standard does not require a new cable type! That means that high-speed HDMI cables with Ethernet are still suitable. There are also no resulting changes to the categories of these cables.

Do I need new cables?

The important thing for the transfer of Ultra-HD (4k) formats is the bandwidth, which is indicated in BPS (bits per second). The 4K TVs currently on the market generally function at only 25 or 30 frames per second and perform acceptably with the “old” HDMI 1.4 interface. The next generation of devices will support 50 or 60 frames per second, which leads to a higher data rate across the HDMI cable, thus bringing about the new HDMI 2.0 standard. But with an alteration of the interface, developers have been able to increase bandwidth from 10.2 Gbps to the required 18 Gbps - all with the same cable specification. This means that no new cable category is planned for the HDMI 2.0 specification.

Do we need to brace ourselves for new standards?

The HDMI interface has taken root in the consumer market and, with the establishment of the new 2.0/HDMI 2.0a standard, it will maintain its status over the coming few years. However, this standard is only planned as a short-term solution. At the same time, the demand for larger cable lengths is constantly increasing. This means there is a clash of conflicting interests: on the one hand, higher-resolution formats with higher data rates and greater technical demands, while on the other, there is a desire for ever greater cable lengths. Therefore, we believe that the HDBaseT standard, which is primarily used by professionals for large-scale installations, will find its way into the consumer market. This cable standard allows for data to be transferred across distances of up to 100m – and with 4K formats.

Meanwhile, DisplayPort cables are of little relevance to the consumer electronics industry. The Apple world includes the Thunderbolt multifunction interface, although this is also not of relevance to the general consumer electronics industry as things stand.

 

 

What are the most important requirements for an HDMI cable for 4K operation?


The HDMI specifications of the HDMI organisation essentially differentiate between two versions: Standard and High Speed or Standard with Ethernet and High Speed with Ethernet. The High Speed versions allow for a higher data rate, which is especially necessary for 4K formats. The Standard version is thus a non-starter for the transfer of 4K formats on the basis of its limited data rate. In addition, it is important to watch out for differences in cable quality as relates to manufacturing, material and shielding. Potential pixel errors notwithstanding, basic wiring may work for shorter cable lengths. But the difference will certainly become apparent in the case of longer transfer distances. A build-up of pixel errors results in image interference and picture loss. There may even be no connection to begin with. The key to a good cable is proper shielding and a sufficiently thick copper signal line, not basic copper-plated aluminium wiring. This allows for an adherence to the impedances of the data cables and ensures flawless manufacturing in the connectors.

HDMI 2.0

The HDMI Forum, to which 88 companies from the multimedia branch belong, released the new HDMI 2.0 specification on 4 September 2013. The most important new feature of HDMI 2.0 is the much higher data rate of up to 18 gigabytes per second it makes possible, with this being necessary for the latest 4K content with double the refresh rate. The High Speed HDMI cables with Ethernet made by in-akustik are HDMI 2.0-compatible and therefore optimally suited to future requirements. This applies for lengths of up to, and including 3.0 m for HDMI cables in the “Star” category, and up to, and including 5.0 m for the “Premium” HDMI cables, with a length of 15 m possible for the “Exzellenz” cables due to an intelligent chip in the connector.

Differences in Quality

What distinguishes an Exzellenz HDMI cable from a standard HDMI cable? Many users are under the false impression that the transmission of digital data always functions without any errors. Something better or worse isn’t supposed to exist. The same applies to the Internet. On the Internet, the receiver keeps asking the transmitter for the digital data until the content has been transmitted properly (check test). However, in the audio/video sector, there is no time to compare digital data and request it again. Instead, error correction is used in the TV or beamer.

The higher the resolution and the faster the picture sequences, the higher the data rate that needs to be transmitted as well. However, this also increases the error rate caused by the HDMI® cable at the same time. The more often the television’s error correction needs to intervene, the poorer the picture becomes. A better quality cable allows the error rate to be reduced, and the picture gains brilliance and sharpness.

 

 

High quality cables such as the Exzellenz HDMI cable feature sophisticated shielding and high quality conductor and insulation materials. The meticulous manufacturing process also guarantees extremely low production tolerances in relation to all cable parameters. All in all, this ensures lower error rates and therefore a better picture and audio quality in comparison to standard cables. And this even over short transmission paths.

 

 

 

 

Additional Color Space

While RGB is still the dominant color space in most video applications, other color models are gaining popularity, particularly in digital still photography. Version 1.4 of the HDMI® specification adds support for three additional color spaces (also known as color gamuts), enabling manufacturers to deliver better and more accurate color to users when they view their digital photos on an HDTV. In addition to RGB color and x.v.Color, the HDMI® standard now offers native support for three additional color spaces: sYCC601 color, Adobe RGB color and Adobe YCC601 color. Like x.v.Color, each of these color spaces defines a palette of available colors that is larger than the traditional RGB color model, and closer to the full range of colors perceptible to the human eye.

HDMI Ethernet Function

No additional network cable required between internet access and AV components.

Audio Return Channel

No additional audio cable required between TV and AV reveiver.

To produce a moving picture, several images are shown successively within a certain period of time – just like a flipbook. The more images that are shown within the same time, the smoother the movements seem. A prime example of this are tennis or football matches. If there are only a few images, the motion of the balls across the screen seems to judder. The number of images is specified in Hertz (Hz) or Frames per Second (FPS). Both indicate how many images per second are transmitted. The refresh rate does, of course, have an immediate effect on the required data rate. Doubling the refresh rate requires the data rate to be doubled. There are decisive differences for refresh rates when it comes to 4K formats in particular. Older 4K devices usually only support 4K with 25 or 30 FPS. Only newer devices with HDMI 2.0 also support 50 and 60 FPS.

Because the HDMI interface can provide picture and audio content in absolutely perfect resolution, the film industry is now obliged to release this content in encrypted form. This is where HDCP, High Definition Content Protection, is used. Because earlier versions were cracked by criminals, then new HDCP2.2 standard has been introduced

The dynamic range, which is the difference between the brightest and darkest light that the human eye can see, is gigantic. Cameras and televisions can only capture and render a fraction of it. Technical tricks artificially enlarge the native dynamic range of cameras and televisions. This technology is known as High Dynamic Range, or HDR for short. The result is pictures that make significantly more details visible, especially in dark areas.

If you watch a DVD or Blu-ray using a surround system, the surround sound amplifier transmits the audio track to high quality surround speakers. If, in contrast, the DVB tuner integrated in the TV is used, or you watch online content on a Smart TV, the sound is automatically transmitted back to the surround sound amplifier via the same HDMI cable by the Audio Return Channel (ARC), and is also played by the high quality speakers.

One of the biggest problems when saving and transmitting picture data used to be the quantities of data and the transmission bandwidths. This is why the same technique has been used for reducing data quantities while maintaining acceptable quality for years. Because the human eye can see black and white images much more clearly than colour images, a technique was developed that transmits the black-white, or brightness information, in full sharpness and the colour information in reduced sharpness in order to reduce the quantity of data. The first prerequisite for this is splitting the brightness and colour information, which is realised using the YUV coding technique. When chroma subsampling 4:4:4 is used, in contrast, all brightness and colour information is transmitted in full sharpness, which is the best-quality solution, however also involves a correspondingly high data rate. 4K formats with 50 images per second and 4:4:4 chroma subsampling therefore require an HDMI 2.0 interface with a bandwidth of up to 18 Gbps. At lower chroma subsampling of 4:2:0, in contrast, the HDMI 1.4 interface with “only” 10.2 Gpbs will suffice.

Display Resolution

Ultra-HD (4K) and Full-HD describes the resolution capability of the individual components, such as LCD, LED-TV, DVD- or Blu-ray player. The original PAL standard works with just about 576 lines. Devices labelled as Full HD must show a resolution of at least 1920 x 1080 pixels. 4K x 2K describes a four-times higher resolution. Ultra-HD and Full-HD enables a larger display (Fig. 1) or far better Picture quality with the same screen size (Fig. 2).

Comparison of a circle in PAL/NTSC, Full HD 1080p and 2160p / 4K x 2K Resolution.

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HD-Base-T Special

In our HD BaseT Special we have put together more information about the lossless transport of HDMI signals over distances up to 100m.

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