What is HDCP? How does it work? – Technopat

In this article, we will talk about HDCP technology, the digital content protection system frequently used by online VoD services.

If you remember, recently started broadcasting life Exxen Some spectators who wanted to watch the content on the platform had some problems. In fact, this is due to the content protection system used in many online publishing platforms. HDCP. For example, you cannot take screenshots and record videos while watching content in any service with this protection.

For this feature to work, as you can see from its name, you must use connection means that digitally transfer image data such as HDMI, DisplayPort or DVI. In this article, the protection system used in all these digital interfaces HDCP You will find answers to all your questions about.

Digital and Analog Signal Difference

To better understand what HDCP is, we first need to take a look at the difference between digital signals and analog signals.

In fact, it comes from the word digit (number) in computer and display systems digital (digital) and analog There are two signals, namely. Here we will talk about analog and digital signals in imaging devices. In these signals transmitted via cables, the shape of the signal changes depending on the connection type and device used.

Analog is the transfer of current, frequency or voltage through various processes in various ways in which the transmitted data is transformed into electricity. In analog signals, for example, if the transmitted data is sound, the voltage changes continuously depending on its intensity. Thus, the data in the virtual environment electrically corresponds to our real world. Analog signals may deteriorate due to environmental factors. At the same time, they have an inevitable noise value that affects the data due to their nature.

In digital signals, if you are unfamiliar with the computer world, all of the data is transmitted as binary signals, ie signals corresponding to 1s and 0s. Boolean logic According to these two numbers, which mean true and false, the 0 is known as ground or 0 volts, and the other is the supply voltage. Binary signals are expressed as 1 bit in size. In this way, data are transmitted numerically in a more reliable way, without affecting the data in a minimum of noise.

Some of the view ports used today use analog signals, while others use digital signals. Best known analog portların at the beginning VGA on the way, the most known digital viewports if at the beginning HDMI is coming.

If we talk about the types of viewports;
  • VGA (Video Graphics Array / Video Graphics Array): IBM 15-pin D-Sub is an analog video streaming connection method. It also refers to VGA, 640 × 480 image. Although it was launched on the market a long time ago, it was a very popular and common method of connection until 7-8 years ago. Due to the failure to keep up with the developing technology over time, DVI ve HDMI Various alternatives have been developed.
  • DVI (Digital Visual Interface) : Released in April 1999, Digital Display Working Group New image transmission standard developed by DVIwas developed to replace the actually deficient VGA display standard. This port is designed to transmit uncompressed raw data; DVI-A (analog only), DVI-D (digital only), DVI-I (hem dijital hem analog) It is separated from each other in 3 main ways. Thanks to its support for old VGA resolution and its flexible structure, it is a rapidly accepted connection form worldwide. We can say that it is still a used connection point today. As a single link 3,96 Gbit/s, also as dual link 7,92 Gbit/s supports data transfer. Accordingly, the highest quality image offered in dual link digital connection 2560 × 1600 60 Hz ‘dir.
  • HDMI (High Definition Multimedia Interface): Developed by HDMI Founders and the HDMI Forum of many industry-leading companies, this connection standard uses fully digital signals. Uncompressed video and compressed / uncompressed audio data can be transmitted to various display devices via the HDMI cable. Which is a much newer standard than VGA and its replacement DVI standard HDMIuses CEA-861 signals in data transmission. Since the same signals are used by the DVI DVI to HDMI We can say that the adapters are electrically compatible without any loss. HDMI 2.1 as of version 48 Gbit/s supports up to data transfer. The highest quality image it can deliver can vary depending on bandwidth.
  • DisplayPort: DisplayPort, which was developed by Vesa in 2008 to be used instead of VGA, DVI and FPD-Link, is one of the most preferred ports today. It also stands out with its backward orientation with the help of the converter with other ports. Unlike other digital video and audio streaming connections DisplayPort’ta The data to be transmitted is transferred to the destination with the packaging logic used in technologies such as network and PCI-Express. In this way, higher resolutions can be supported by using fewer pins. Where mobility is important today, Mini-DisplayPort connection points are used quite frequently for this reason.

What is HDCP, What Is It Used For?

It is the most preferred digital content protection method used by video content services on many media platforms. High Bandwith Digital Content Protection / High Definition Content Protection so briefly HDCP a method we call.

Intel If we simply explain this content protection system developed by, basically the logic of operation is based on encryption and decryption. Content encrypted using HDCP cannot be processed on unauthorized devices or special video cards designed for content copying. Therefore, before the data is transmitted to the receiving device, it is checked whether the receiving device is HDCP licensed. If the target device has an HDCP device, content related to the key exchange logic is displayed. We can compare this to the handshake of two people who know each other and speak the same language.

HDCP logic. Image Source: PengoHome

A subsidiary of Intel for a display device manufactured by manufacturers to be HDCP licensed Digital Content Protection LLC’ye one patent and some license fees. In addition, some rules must be followed by the manufacturers. For example, the device manufacturer cannot design its product to allow content copying and cannot attempt to circumvent content protection requirements.

Although some of the manufacturers are at a distance, many of them accept these rules and the license fee and offer HDCP support. However, not every display device can have HDCP support due to such reasons; We recommend that you make sure that the monitor, HDTV or display you will purchase is licensed.

Working by Device

HDCP (High Bandwith Digital Content Protection) it does not work the same for every device. Because as you know, computers with various specific configurations that we call “aggregation” are the market leaders. In addition, it is difficult to set a specific standard when it comes to some other devices with older generation DVI support. Devices without HDCP license can be used with the connection method (this can be DisplayPort, DVI, HDMI) through which digital signals are transferred.

However, if the device in question is an HDCP supported player, it will only work properly on an HDCP compatible screen.

Is HDCP Available With The Help Of The Converter?

HDCP’nin Due to the working logic, content protection will not work properly if any device intervenes that will affect the signal flow and the communication of the data. VGA to HDMI with additional devices that convert analog signal to digital HDMI signal, such as VoD HDCP protected content on their platforms normally you cannot view it.

If the converter in question is a device that converts digital signal to digital (eg DVI to HDMI), it can be used at ports such as DVI and HDMI where the signals are compatible with each other. However, it is possible that some problems may occur with some old devices and players. Therefore, if you want to access HDCP protected content, we recommend that you do not use a converter as much as possible.


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