Website video is not clear? Talking about the non-negligible bit cost

Youku's highest video resource is 1080P resolution that members can enjoy

At present, the popular Ghost Lights TV drama for Tencent video broadcast only the same members can enjoy 1080P resolution

For the computer platform, with the current network environment in our country, the resolution of the mainstream video website resources is generally around 256P-720P, and it is far from meeting the hardware effects of the mainstream display with 1080P resolution, not to mention the current living room environment. The raging 4K TV has actually caused such a situation. It is also a video site that is unwilling to see it but cannot do anything. This involves a very large bit cost problem.

To understand the principle of video transmission on a video site, it is necessary to refer to a name "bit rate" which is a relatively important part of the bit cost, and then give you a brief explanation.

What is the minimum knowledge knowledge rate?

The bit rate is also called the bit rate, which indicates how many bits per second the video and audio data after compression encoding needs to be represented. That is, the amount of data compressed per second of the displayed image is generally expressed in units of "KB" or 1000. Bits per second.

Video file clarity and footprint table (approximate)

In general, the larger the code rate, the closer the processed file is to the original file, but the file size is proportional to the code rate, so almost all coding formats value how to use the lowest code rate to achieve the least distortion. The fixed bit rate and dynamic bit rate derived from this core are all articles in this area:

Fixed code rate: It means that the file is a code rate from beginning to end. This is based on the fixed file size as the premise of compression.

Dynamic code rate: It means there is no fixed code rate. According to the video and audio data, it can be used to determine what code rate to use when compressing. This is based on the premise of quality, taking into account the size of the file. Many people may find that when watching a program on a video site, many programs stop moving after the progress bar position has been loaded. If they jump to the progress point, they will be reloaded. This kind of segmented video connection mode It is also to save bandwidth.

Average bit rate: Usually refers to the average bit rate of digital music or video. For example, if an MP3 file is said to have an average bit rate of 128 kbps, that is, on average, 128,000 bits per second are transmitted/decoded. Bit rate is not the only standard for measuring audio/video quality. For example, some other formats, such as wma and ogg formats, can provide better sound quality at the same average bit rate as mp3 files.

Comparison of video quality (You can see that the quality of online video is much worse than that of local video, which is also a virtual sign to save bandwidth)

If you are dealing with mp3 with an average value, you will see that the bit rate you specified (for example, 222KbPS) is the preferred decompression for the current player, while the constant bit rate just compresses the file with a fixed compression ratio. What is the relationship between code rate and bandwidth? How is the bit and bandwidth cost calculated?

Bit cost conversion code rate how to convert bandwidth

WEB-Side Video Server is divided into three types of technologies, and it is possible to benefit from network video service technology. Adobe's Flash media service transmission from traditional AVI, RM, WMV, MPEG and other early streaming media videos has been going on for about 5 years, from FMS video. Server-to-Flash technology makes it possible to implement P2P transmission between web pages, and it has been almost 5 years since. The advent of FMS has made large-scale video services a reality, but its high server bandwidth load costs have still been criticized within the industry. This situation did not change until P2P technology emerged.

Three bit server technology

The method of conversion of KB bits into bits generally calculates related data, and the relationship between the data represented is consistent. First of all, we must first clarify a few points:

1, usually an online audience to watch smooth video needs about 30k ~ 40k of bandwidth traffic.

2. The bandwidth conversion method is that the traffic of 128k requires 1M of network bandwidth. Generally, the download speed corresponding to our home network bandwidth is generally 2M bandwidth is about 256KB/sec download speed, 4M is about 512KB/sec, and 8M-10M is about 1024KB/sec.

3. Similarly, the bandwidth required by the server is also calculated based on the highest concurrent traffic that can be carried. Concurrent traffic refers to the traffic value of accessing resources at the same time. If you are using FMS technology, you need to accumulate traffic to meet the demand for concurrent traffic. For example, 100 people can access the video resource at the same time and can calculate: 100 people by 30k is about 3000k; 3000k divided by 128k/M is about 23.4M. If the site's video viewer has the highest concurrent amount of 100 people, it needs at least 20M of bandwidth. If the site's video viewers reach a maximum of 1,000 concurrent users, they will need at least 200 Mbits of bandwidth, and websites such as Tencent and Youku may not be able to handle a few million data points or millions of views.

At present, the regular configuration of 100M bandwidth for domestic regular server providers costs about 100,000 yuan/year. It can be calculated that if the maximum concurrent amount of the website is expected to reach 1,000 people, the server bandwidth cost will need to be at least 200,000/year, and if it reaches 5,000 people, it will need at least 1 million/year. The above calculations are all rough theoretical values, and are full-load calculations. In actual operation, the server will not only consider the full load and theoretical conditions. Most of the servers use the server bandwidth resources of multiple orders of magnitude to ensure the operation safety. The cost of running the website has pushed a very scary figure.

As the number of people changes, only a small amount of user information interaction increases. Therefore, the greater the amount of user pressure in the FMS mode, the greater the amount of users in the P2P mode, the better, facing the increase in the user presents two different situations. With the rapid development of the mobile market and the gradual relaxation of domestic bandwidth traffic, the demand for video program users has already presented significant high-intensity demand. Diversified video services with high volume have gradually thaw, and the collapse of high-funded thresholds is the tip of the iceberg.

Coding is also important or the best way to solve problems

The so-called encoding is to compile video source files that have been shot into another format to reduce the “weight” of the video files, reduce the data throughput caused by the playback of web video resources, and achieve more efficient and smooth video playback. The most important coding and decoding standards in the transmission are ITU H.261, H.263, H.264, and now the H.265 coding format. In simple terms, an excellent coding format optimizes the video processing steps. Let's take a look at the comparison chart of a set of H.264 and H.265 compilers, so that the performance is relatively intuitive.

Comparison between H.265 encoding and H.264 encoding

Through the above figure, we can simply understand the two encoding formats as the process in which the two painters are drawing. We see that the H.264 format compiles the video image into small regions and the rendering process is complicated. , so the file size is larger, and H.265 is calculated similar to the color and background blur, need to focus on the display area for detailed encoding, so that selective encoding can reduce the volume of the video file is about 50%, which is a The highly efficient upgrade also provides optimization from the source of the video to the bit rate for storing files and websites.

H.265 aims to transmit higher-quality network video under limited bandwidth, and only needs the original half bandwidth to play the same quality video. This also means that our smartphones, tablets and other mobile devices will be able to play 1080p full HD video directly online. The H.265 standard also supports 4K and 8K ultra high definition video. It can be said that the H.265 standard allows online video to keep up with the "high resolution" display.

H.265 encoding format

Although there are still less video resources than 1080P resolution, many device manufacturers have now begun to popularize H.265 encoding technology. The mainstream TV and HD set-top boxes are all equipped with the latest decoding H.265 video functions from another. In terms of sense, this is also the first move the troops and horses have made.

For many video companies, the bit cost to earn revenue, even the amount of income. If you look at the development, the bit cost may have a certain degree of decline, but it is certain that neither the existing standards such as ADSL, 3G, WiFI, etc., nor the subsequent E1, LTE can make the bit cost drop to video. Website's expectations. Based on the understanding of the telecommunication service facilities and evolutionary situation, the bit cost of China's video services will be difficult to reduce to less than half of the revenue within the next five years, which also poses a great challenge to the increase of the marginal revenue of scale.

To maintain the website running requires renting the server

The cost of Internet video service providers who want to promote their own industry development and the costs involved are not only the high cost of program resources. At the same time, the pressure on data flow and storage has also made many video service providers overwhelmed. From the perspective of rigid bit cost, search function is the lowest cost, it has only a simple input box, input and output are mainly text, the amount of information transmitted on the network is very small, and obtained from each user The most profitable. The bit cost of the video service is the highest, and the main transmission on the network is streaming media, which consumes a lot of bandwidth, takes a long time, and has a large amount of data.

For the user, the TV is a back-end experience, the PC is a forward-leaning experience, and the mobile phone is an experience of the thumb. These three things are related, but they are not the same. The time cost that users are willing to spend on these three things is not the same. How much can an Internet video experience experience disruptive changes? For video sites, following the higher-level and more interactive directions of traditional television will only increase the cost of bits. More massive resource levels require more bandwidth support, and data storage is also a part of the cost. This makes it difficult to get rid of the huge amount of resources to make profits, and it takes a huge bit of cost to realize the high quality and clarity. With the popularity of video resources, there is still a long way to go, and the real meaning of 4K Internet video signals, based on the current results, it is very difficult to achieve.
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