Original title: official popular Science: what is the HEIF format photo of XIAOMI 10?

The XIAOMI 10 series is not only equipped with a 100-megapixel rear quad shot, but also supports the new HEIF picture format, which you can choose to open in the camera settings, with a warm reminder: "efficient picture format can save more storage space, but some applications may not support this format. "

So, what exactly is the HEIF format? How is it different from our common picture formats such as JPG, PNG and so on? XIAOMI officials specially did a simple science popularization today.

Some common picture formats

No matter on the computer or on the mobile phone, the most common picture format is JPG (full name Joint Photographic Experts Group, Joint Image expert Group), which is a kind of static document, that is, the image content, which is motionless, still.

JPG, which was first born in 1992, describes how to convert image content into a data stream. In short, it is an algorithm standard.

JPG is a lossy compression format, which has the advantages of very popular, the best compatibility, relatively small space, and the disadvantage is that there is a certain compression of image quality, or loss.

In addition to the most common JPG, picture formats include BMP, PNG, TIFF, GIF, and so on, which are very different from each other.

For example, BMP format is usually not compressed, and the image quality is the best, but it takes up more storage space; PNG format supports transparent layers; GIF is dynamic, and almost all the dynamic emojis we send every day are based on GIF format.

What is the HEIF format? What are its benefits?

HEIF, whose full name is High Efficiency Image File Format, is suspected to be an "efficient image file format" in Chinese. It was first defined in 2013 and developed in 2015.

When using pictures in HEIF format, the general suffix of the file name is .HEIC (and other unusual suffix formats), which brings the direct benefit of reducing the file size of the photo by 50% while ensuring the image quality.

HEIF can also store multiple image files in one file. For example, when we use the phone's continuous shooting function, multiple photo files will be generated from the beginning to the end of the continuous shooting, but using the HEIF format, we can save all the resulting continuous photos with one a.heic image.

In this way, when you open the album preview, there will be no trouble that similar photos occupy the entire phone screen, and they will be aggregated into a single photo, making the album display more efficient and elegant, and making it easier for us to choose the most satisfactory one.

How do photos take up space?

When taking pictures, the more "high-profile" the content is, the smaller the size of the photos will be.

For example, if you take a very bright picture, the background is almost overexposed, and only the main body is valid content, the volume of the photo generated at this time will be very small, because the overexposed part does not store valid information, so it will not take up too much space.

Normal exposure, photo size is 5MB

Intentional overexposure reduces the details of the photo record and reduces the file size to 3.3MB.

The resolution also affects the volume of the photo. The higher the pixel of the phone's camera, the larger the size of the photo file.

For example, when using XIAOMI's 10.1 billion-pixel main photo, due to the high resolution of the photo, the corresponding amount of information stored is also very large, the volume of a photo is about 12MB.

At this point, if we use HEIF format to save the same photos, the volume is only 4.43MB, directly reduced by 64%, but the quality of the photos is not compromised at all.

For example, a 512GB version of XIAOMI 10 Pro can save 36522 photos in JPG format if the remaining storage space is 428GB, while nearly 100000 photos can be saved in HEIF format, which is almost twice as many.

HEIF format is so good, why don't other phones work?

It takes time for new things to be popular and popularized. For example, 5G technology has just emerged, and the construction of 5G base stations in various cities is under way. It must take some time from the time when everyone starts to use 5G.

As a new image format, HEIF also needs the support of all kinds of systems and software to be popular.

Fortunately, HEIF is becoming more and more popular. For example, Apple Inc has saved photos in HEFI format by default since iOS 11, and Android 9.0 has been natively supported, but the speed of follow-up varies from Android to Android vendor.

At this stage, HEIF shot and saved photos does not affect daily use, such as Weibo Corp, Wechat and other common social software, choose to send photos, open photo albums, you can successfully see these HEIF format images, choose to send them, as convenient as using the common JPG format.

Therefore, you can safely turn on the "use HEIF format" switch, and then forget about the image format, to enjoy the advantage of a very small file volume.

Finally, I also hope that more mobile phone manufacturers can support this efficient future image format as soon as possible, and the popularity of HEIF will certainly accelerate.