What is HDMI2.1 again?Birth of birth
Now, the HDMI terminal is equipped with Blu -ray equipment, game consoles, and PCs, as well as digital cameras and car navigation systems.
HDMI became widespread around 2005.Sony's PS3 was the first HDMI as a home game console.HDMI1.3 was adopted in PS3.There was a bandwidth of up to 10.2Gbps at the transmission speed.However, the HDMI of PS3 was a very flexible implementation with a system, such as supporting the 3D video output standardized in HDMI1.4 by system update.
PlayStation 3In PS4, this evolved to HDMI1.4.The maximum transmission speed remains 10.2 Gbps, but the coordination of a wide area peripheral device is handled, and the "audio return channel" (ARC) and the HDMI data transmission channel, which improves the convenience of connecting to AV amplifiers, etc.HECs to be converted to to to.
In PCs and AV devices, there were examples of applications that transmit 4K (3,840 x 2,160 pixels) resolutions in the band range (10.2Gbps) of HDMI1.4.By the way, the 4K transmission within the 10.2Gbps range can be transmitted to 30 fps at the color of RGB888 or YUV444, and 60fps if the color resolution is reduced to YUV420.
Since 2015, HDMI2.0 will spread to a popular device at once.In the background, the spread of 4K TVs, the appearance of 4K Ultra HD Blu-ray (UHD BD), and the release of PS4 Pro had a strong effect.
2015年11月に発売した、世界初Ultra HD Blu-ray再生に対応したパナソニックレコーダー「DMR-UBZ1」2016年6月に発売した「マッドマックス 怒りのデス・ロード <4K ULTRA HD&ブルーレイセット>」In HDMI2.0, the maximum transmission bandwidth was increased to 18Gbps so that 4K/60 fps transmission could be performed in all color depth mode.The support of the high -dynamic range (HDR) video, which was standard with the birth of UHD BD, was also standardized in HDMI2.0.
In 2016, PS4 Pro appeared as a 4K/HDR compatible game console.At this time, a special firmware update for HDR is provided with HDMI1.4 for the conventional PS4 (but 4K is not compatible).
PlayStation 4Xbox One XThe HDMI2.1 standard was born in 2017, but the development and spread of transmitter and receivers were delayed, and the spread period was about around 2020.
The appearance of the 8K (7,680 x 4,320 pixels) TV was released.If the conventional HDMI transmission method is used, a 72Gbps transmission band is required for calculation.However, this was determined to be impossible in the current HDMI standard transmission method.
As a result, HDMI2.1 renewed almost everything, such as function allocation and electrical signal characteristics of each terminal, while diverting only the "physical HDMI terminal" standard (details will be described later), and "this is no longer called HDMI.Is it okay? "
However, even though the terminal shape is the same, "it cannot be used even if it is connected" makes the user inconvenient.Therefore, in HDMI2.1, we decided to maintain compatibility by recognizing version differences in the transmitter and receiver chips and switching the operation mode.
By the way, Bluetooth is a familiar standard that maintains solid compatibility while adopting a completely different technical infrastructure by giving such "adaptive wisdom" to the interface chips.。
So, this HDMI2.1.
Although it was very hard and standardized, the maximum transmission band was 48Gbps.The 72Gbps required for the requested 8K/60fps transmission was not achieved.
Therefore, we decided to use a license -free real -time non -possible reversal compression technology called DSC (Display Stream Compression) to support 8k/60fps (8K 24fps and 30fps can be transmitted without DSC compression).。However, due to the non -frolted algorithm, the image quality deteriorates due to this DSC compression.Finally, HDMI is a version 2.1 and has become a standard that tolerates image quality deterioration even though it is digital transmission.
HDMIで規定されている解像度・フレームレートを記した一覧。「Speed」の欄が、伝送可能なHDMIケーブルを指している。“赤字でUltra”となっているのが、圧縮伝送しなければ伝送できない信号。8K/60fps 4:2:2 10bitや、8K/120fps 4:2:0 10bitなどがこれに該当するAt present, the game industry is less interested in 8K/60fps.This is because GPUs that can draw 8k/60fps stably are not popular at this time, and there are not so many displays that can display 8k/60fps images.
It is impossible to draw 8K graphics in 60fps stably with PS5.The ultra high -end GPU is not impossible, but the threshold is still too high.The price of the 8K TV itself has fallen, but the 8K broadcast is only NHK's BS8K, the appeal of the 8K environment introduction is weak, and the appeal is not enough.
On the other hand, "4K/120fps", which is possible with HDMI2.1, is considered to be compatible with games with reality.
For example, in the case of PS5, Xbox Series X equipped with a 10TFLOPS class GPU, if the graphics quality is not so high, the realization of 4K/120fps is enough to be realized.In PC gaming, 4K/120fps can be achieved even for quite high -quality graphic quality with high -end class GPUs with over 20TFLOPS.
For 4K/120fps transmission, a bandwidth of about 36 Gbps is required for calculation, which can be covered in 48Gbps of the maximum transmission band of HDMI2.1, so it can be transmitted without using the above -mentioned DSC compression.
4K/120fpsの場合、4:4:4 12bitまでは非圧縮で伝送できるYes Yes.In the previous article, it was alerted that "4K/120fps input support is different from double -speed drive support."It seemed to be a shock between beginners.
The complaints of "double -speed drive support" (may be called frame interpolation function depending on the model) on TVs with mid -level machines and above are listed in the specifications and catalogs, but this is "4K/120fps input support".Please note that it is a completely different function.
The "double -speed drive support" television is a function that displays the input 60fps video in an intermediate frame, which is insufficient by the video engine, and is displayed as 120 fps, and is 120fps output on the game console and PC side.It is completely different from "4K/120fps input support" that displays the video as it is.I want to be careful again.
ソニー・ブラビアでの「倍速駆動」説明図。テレビで倍速駆動を行なう場合、同じコマを複数回表示、もしくは補間コマを挿入するのが一般的。こうした倍速機能と「4K/120fps入力対応」とは全く別モノなので注意With such a flow, if you are considering purchasing a gaming display now, the user psychology is increasing, saying, "I want to choose an HDMI2.1 compatible display that can input 4K/120fps."
