What is image compression? Part 2
Why is the standard name so long?
There are several organizations that go for standardization. Each has independently conducted research. As we proceeded with our research, each of us also gave our own name to the new technology. The research conducted by the two organizations was very similar and, as a result of discussions between the two organizations, a jointly formulated standard was created. Therefore, it was renamed “H.265 / MPEG-H HEVC”, named after both organizations. Each organization has its own specialty, but “H.265 / MPEG-H HEVC” is a technology that can be used in a wide range.
Latest “H.265 / MPEG-H HEVC” video compression technology
What is “H.265 / MPEG-H HEVC”?
The reading is “H.dot Nee Rokugo M Peg H.H.C.”. “HEVC” is an abbreviation for High Efficiency Video Coding.
Characteristics
High compression rate (by optimizing the block size, the amount of data is reduced to 1/4 compared to MPEG-2)
Low bit rate (same image quality as H.264 / MPEG-4 AVC, video bit rate reduced by half)
* Bit rate represents “how much information is packed in one second” and the unit is bps (bit per second).
Application example
Super high definition, 8K streaming, 4K streaming, Internet streaming, the latest smartphones, next-generation Blu-ray, etc.
High compression rate: by optimizing the block size, it will be 1/4 of MPEG-2
The entire screen is finely disassembled (the size of a block when divided into blocks is small). Sending the part of the modified image is the same as MPEG-2, but since the whole screen is divided into smaller parts and only the modified information is sent, the amount of information can be reduced even for the same modified image.
Low bit rate: If the image quality is the same as MPEG-2, the video (video) bit rate can be reduced to 1/4.
If you can lower the bit rate (bit rate), you can watch beautiful videos even when the internet line is busy (bit rate is the amount of data that can be sent and received per second). As for the changed information (information about how much has moved in which direction), “MPEG-2” can acquire the change information only in 0.5 pixel units, so the amount of information sent at one time is big. Since “H.265 / MPEG-H HEVC” can acquire change information in units of 0.25 pixels, the amount of information sent at one time may be small.
Questions corner for researchers
What are the benefits of a lower bit rate (less information sent per second)?
For example, we are currently sending high definition video in the MPEG-2 standard on a digital satellite transmission channel (transmission line), but if we use the HEVC standard, we will be able to send 4K and 8K video with a large amount of information with the same end.
Is satellite broadcasting different from digital terrestrial broadcasting (terrestrial broadcasting)?
If it is not. There are two types of television transmission: terrestrial transmission (digital terrestrial transmission) and satellite transmission. “Terrestrial broadcasting” sends radio waves establishing a relay station between the broadcasting station and the home. It is called terrestrial broadcasting because it uses facilities on the ground to send radio waves. “Satellite broadcasting” uses artificial satellites located 36,000 km above the equator to send radio waves directly to homes. Satellite transmission can also send radio waves to areas with many obstacles, such as mountains.
Fujitsu’s strengths
Images that people feel “beautiful”
Even high-quality images with the same amount of information will look different if they are mechanically compressed evenly and processed with a balance that makes humans feel “clean.” We have developed an image control technology that uses human visual characteristics.
What is the high image quality that a computer judges?
When processed with international standard software, the entire screen is processed smoothly and with high image quality. Everything is compressed evenly, which is why the computer considers it high-quality. However, when viewed by humans, it looks a bit blurry overall.
