Shulou(Shulou.com)06/02 Report--

What is the hottest look in early summer? Many people may blurt out-"yellowish skirts, fluffy hair." no, no, no. no, no, no. "

Even I, an old man in ancient times, began to click on iqiyi's home page on time every Thursday and Saturday to take a sip of beautiful young girls. For no other reason, in the grey period of the epidemic, what could be more worthwhile than the bright smile of a beautiful little sister? And the last time I finished chasing a women's draft may be traced back to …... Super Girl.

No matter whether my sisters and sisters of pick can make their debut smoothly or not, it is absolutely a happy thing to enjoy their faces on the screen today at least. You don't have to put up with the "mosaic quality" of TV, and you can take out your mobile phone anytime and anywhere to enjoy the cuteness of your sisters today.

I don't know if everyone has the same kind of happiness, that is, watching Blu-ray 1080p on 4G network, there is no "traffic anxiety", and the chances of buffering and rotating "little chrysanthemums" are quietly reduced. This optimization of viewing experience, in addition to changes in the communications network environment, a key technology for creating this visual pleasure-video coding, like dark matter in the universe-is little known, but very important.

To put it simply, the upgrade of video coding technology allows you to see higher-definition video pictures with less traffic, lower bandwidth and faster speed. For example, is the feeling of "Youth with you 2" spilling over the screen more exciting than the hazy beauty of 2005?

Users who are used to 1080p HD definitely don't want to go back to the automatic mosaic era of 480p. So what magical chemical reaction does video coding play in the cooking of high-definition videos? Apart from doing a show, you might as well learn about the past life and this life of video coding and see how countless tech giants have torn it apart.

Giants are scrambling to buy shares, what is the attractiveness of video coding standards?

Why do these famous giants, such as Cisco, Microsoft, Apple, Google, Netflix and iqiyi, think that video coding technology has "nothing to lose" and that pick must help them make their debut?

Before answering this question, it is necessary to briefly explain what video coding technology is for. To put it simply, it is to compress the video into a certain format, remove the space redundancy and time redundancy, and form a code stream that is more suitable for storage and transmission. The main reason why it needs to be encoded and compressed is that the amount of data of the original video is too large. High-definition video files are often as high as 1G or more, and even if they are played locally, once they need to be uploaded and shared with others, the transmission network and storage devices cannot handle such a huge amount of data.

Therefore, the video platform needs to reconstruct the played files, reduce the amount of data through compression coding to facilitate transmission, and then rely on decompression and decoding on the user side to restore the video image. To sum up, coding efficiency determines how many HD videos your phone can download.

If you go through a night without turning off your phone and finally download a 2G video, only to find that the player pops up with a line of big words: "the video cannot be played", you will certainly applaud the update of the codec technology.

Of course, some "capricious" partners will also choose to watch video online directly on the 4G network, so the size of the video doesn't matter, right? It would be naive to think so. The stronger the video coding technology, the smaller the bandwidth required for transmission, just like the dyke is not reinforced, but the water that hits the river becomes smaller, so there will be no blockage at the outlet, and the accident of stuttering and frame dropping will not happen.

For example, during the epidemic, the proportion of network traffic is increasing, which brings great challenges to Internet service providers. The traditional solution is to reduce the definition of video under the premise of limited network bandwidth. For example, YouTube, Amazon's Prime Video, Netflix and many other Internet video providers have reduced the video quality in Europe, India, Australia and other countries, and users can only watch standard definition videos by default.

However, after getting used to the delicacy of high definition, which user is willing to put up with low picture quality? In order to retain picky content diners, platforms have to do everything they can to improve their cooking skills for video.

So, what are the video codec technologies that allow us to follow the drama anytime, anywhere?

At present, there are mainly several mainstream video codec standards (international standardization of audio and video coding technology), including VPx (VP8,VP9), H.26x (H.264 H.265), AVS (AVS1,AVS2), AVx (AV1) and so on. Video platforms use a common coding format standard and develop their own encoders so that they can mass-produce videos with more powerful standards.

What are these standards? Which is better? Why do I know every character but have no idea what it is? There is even a kind of fear dominated by Zhang Hanyun, Zhang Shaohan, Zhang Yuxi, Zhang Xinyu and so on. Don't worry, in fact, even for streaming media practitioners, few people figure them out. In fact, you only need to know three key points, and you can easily become a "technocratic" to crush a lot of people in the industry.

To put it simply, different video coding standards are "quantum entanglement" around three elements:

Element 1: high definition

The first generation of video coding standards H.261 and MPEG-1 began to emerge in the 1990s and have been updated iteratively almost every decade since.

The core element of starting the evolution of video coding technology is people's continuous pursuit of high definition and higher definition. With each evolution of video coding technology, the video compression efficiency is at least doubled. For example, more than a decade ago, the second generation video coding standards VP8 and H.264 can only be applied to medium and small resolution videos lower than HD, with a little bit of 1080p resolution. In 2012, Ericsson launched the first H.265 codec, leading the third-generation video coding HEVC standard, which can play the same quality video with only half the bandwidth of H.264.

What do you mean? If you are an early Internet pioneer with a MP4 device and the same amount of storage space, you can download twice as many videos and say goodbye to the hard days of borrowing hard drives everywhere.

Watching video online is even better, based on codec standards, smartphones, tablets and other mobile devices can also directly play 1080p full HD video online, and also support 4K and 8K UHD. In other words, as long as there is content willing to produce 8K video, the platform can give you 100% of the original image, without being limited by the highest definition of 720p.

So why are consumer devices in AV1 format emerging again two years after the introduction of the HEVC standard? Due to the outbreak of mobile Internet, the original coding standard still can not completely solve the problem of bandwidth consumption. Therefore, more efficient video coding standards such as AVS3, H.266 and so on have been arranged by R & D personnel.

Why do video platforms have so many "walls" about coding standards?

Just imagine, if you use a high-resolution smartphone, but the video can only reach the definition of 480p, the money spent on high hardware configuration will be in vain. Some users need a third-party decoder such as perfect decoding and format factory to convert the video before they can watch it in order to prevent stutter or blur.

As long as the video platform supports a more efficient codec standard, it can achieve the non-stutter effect of playing high-definition video in low bandwidth. Who wants to wait for a packed box lunch if there are hot dishes that are fried right now? So careful readers will find that the continuous upgrading of coding technology has begun to let third-party coding tools quietly withdraw from the party's toolbox.

Element 2: patent

Although user experience is the primary evolutionary principle of video coding technology, the limitations and costs brought about by patents have also become an important incentive for the industry.

HEVC Advance, the H.265 patent alliance formed by GE, Technicolor, Dolby, Philips and Mitsubishi, charges royalties from manufacturers who use the standard.

As a result, many open source standards are on the rise. The VP9 standard created by Google is one of the most famous. It is not only close to HEVC/H.265 in actual efficiency, but also much better than H.264 and its predecessor VP8, and can be used free of charge for patents. Soon, YouTube fully supported VP9 ultra-high definition streaming programs, including Netflix and Apple.

At that time, iqiyi's "Ice Breaking Action" was undoubtedly one of the hottest "blockbuster dramas", which once caused popularity, and the smooth and high-definition picture texture added a lot of color to it, so it used a new encoder based on the VP9 standard, and a new encoder developed based on the VP9 standard, such as facial details, and other aspects of the picture realism is particularly significant.

The emergence of AVS, the second generation source coding standard of independent intellectual property rights in China, is inextricably linked with patents.

Have you ever seen DVD in your childhood? the pleasure of renting a TV show without waiting for a weekend update is no less than the honorable "P in VIP" member who buys the video platform today. However, China's DVD industry has also encountered a serious patent crisis.

In 2002, a batch of exported DVD products were seized because the payment of technology patent fees was not resolved. So in June of the same year, the Digital Audio and Video Codec Technical Standard working Group was established. In 2006, the first generation video coding standard AVS1 was launched, and the compression efficiency was the same as that of H.264, and each codec only symbolically charged a royalty of 1 yuan, and the software services on the Internet were exempted from the royalty, thus getting rid of the dilemma of only using international standards and being choked by high patent fees.

It can be said that the two mainstream standards, VP9 and AVS, are the wings of freedom grown in the chains of patents.

Element 3: monopoly

Now that VP9 is open source, why don't you just hold on to Google's thighs and apply it again? Most of the videos in a country are located on a certain standard system, which is tantamount to handing over the bargaining power of the standard to others. In the face of this "monopoly advantage", Google said, "I may even beat myself when I am crazy." in order not to do evil, you'd better cultivate an opponent for yourself.

So in 2015, a new standards organization initiated and participated by Google in an attempt to replace VP9 and HEVC/H.265 was formed: the Open Media Alliance Alliance for Open Media (AOM). This new open source standard quickly attracted the participation of giants such as Adobe, Amazon, AMD, Netflix, Facebook, Cisco, Apple, Intel, Nvidia and so on. China's iqiyi also took the lead in joining the AOM alliance.

This membership alliance, composed of more than 30 leading high-tech companies, soon developed a new generation of open source video coding standard AV1 (AOMedia Video Codec 1.0), that is, today we can see the high-definition version of "Youth has you 2", especially the rap and dance pictures on the talent stage are more clear and smooth "backstage".

The reason why AV1 has been launched rapidly in the industry has become the goal of Netflix, YouTube, BBC, iqiyi and other platforms, mainly in terms of user experience.

Higher coding efficiency, lower bit rate, and the same quality can save more than 20% of the bandwidth. For example, download the entire 1080p version of "Youth has you 2", which originally requires 10 gigabytes of mobile phone storage, but only 8 gigabytes under the AV1 standard can be done. Wouldn't it smell good if we saved some PLMM (pretty sister) high-definition pictures to lick it with the remaining 2G space?

Watching online is also cool. Not only do sisters' faces look clearer, but they also take up less bandwidth to play in HD. At the same time, downloading something and browsing on Weibo won't get stuttered because of network congestion.

As video viewers, who doesn't want the platform to work hard for us silently, taking care of every bit of traffic, bandwidth and memory cards?

It is not difficult to see that video coding standard iteration is not only the exploration of the technical ceiling, but also the experience highland that the whole video platform must occupy.

Rush coding standard track: experience butterfly change of Chinese video platform

Specific to the Chinese video platform, the current competitive position of coding standards and what tough battles to fight in the future are topics worthy of our focus. We might as well be specific to the exploration experience of a certain platform, and use the perspective of history to sort out what kind of experience butterfly changes video coding technology has brought to netizens in this land of China.

Through research, it is found that iqiyi launched the AVS2 format in the universal player in 2016, which was the only platform in China to support this standard at that time, and it was also the first video manufacturer in China to implement the VP9 standard, AV1 standard and application. It can be said that in the field of coding standards, both technical leadership and layout perfection can represent the key choices of China's streaming media industry to a certain extent.

What about iqiyi's standard journey of exploration? We might as well break it down into three parts:

1. Technical exploration.

With the standard, do you just need to use it directly? The answer is obviously no.

Let's take the current most efficient AV1 standard as an example, its algorithm has high computational complexity and takes a long time to encode, so processing all the videos on the platform may lead to users saying, "Grandma, your AV1 format is online!"

Therefore, in order to improve the coding efficiency, so that the processing effect can be fast and meticulous, without affecting the coding quality, and reach the industrial application standard, the standard encoder has to rely on each platform to play its own initiative.

Iqiyi, for example, while keeping a close track of each generation of open source technology, will also give play to his own technical expertise to carry out targeted iterations, so that the application of the same standard on the iqiyi platform has a better performance.

For example, when the VP9 standard was launched, iqiyi's technical team made a special algorithm optimization based on the open source version of the VP9 encoder, and the rate of the QVP9 encoder developed was about 5.4 times that of the open source version. As the first video manufacturer in China to support VP9, its picture quality is particularly realistic in terms of fast shots, contour edges and facial details, and its compression efficiency is double that of the mainstream standards in the market. May also be unwittingly, suddenly found that those high-speed fighting scenes in the video seem to be more delicate and smooth, the character's skin has become more three-dimensional and easy to identify, even the acne on the heroine's forehead is so obvious.

With the increasing demand of users to watch videos in mobile scenes, for example, I like to browse short videos on the subway. Don't ask, it is how rich and wayward the traffic is! At this time, to ensure that it is smooth and not stuttered, the VP9 that focuses on the PC may not be enough, so the AV1, which is more friendly to mobile devices, is also clearly arranged by iqiyi soon after its launch.

The independently developed QAV1 encoder not only reduces the bandwidth by nearly half compared with H265, but also saves more than 40% bit rate. And it is about five times faster than the open source encoder SVT-AV1. For example, watching "Youth has you 2", the picture shown with QAV1 is better and more beautiful, but it saves more bandwidth, which directly helps me save a lot of traffic and make the full speed limit come later.

two。 Industrial linkage

It is not difficult to find that even open standards such as VP9 and AV1 need to be redeveloped on the video platform. The resulting technical problems will also shut out some enterprises. After all, not every content party has the same scale and technical capability as Netflix and Facebook, and is willing to invest a lot of manpower and resources to follow up the latest standards.

How did iqiyi always play the role of a pioneer in Chinese video coding technology? This is directly related to maintaining the same frequency evolution with global technological trends and peers.

We know that iqiyi is the first Chinese member of AOM. Through many times of communication with Google, iqiyi found that the AV1 standard is indeed more efficient than expected. Because members of the alliance communicate closely and obtain earlier and more advanced technical information. QAV1 has carried on the meticulous design optimization to each module of the coding, and the optimization algorithm of each module has a total of nearly 100 items.

Recently, iqiyi launched the AV1 video coding format (Alliance for Open Media Video 1) on computer browsers (PC web) and Android mobile devices, becoming the first and only video website in China to apply AV1.

Of course, the relationship with VP9 continues. When we open a video, we will whisper, "Why does Aidou look more beautiful today?" maybe the TA in the camera hasn't changed, but iqiyi stunned the time again with VP9.

This ability to resonate at the same frequency with the pulse of the international industry also gives iqiyi a head start.

3. Application landing

At present, the first movies using AV1 have been launched on iqiyi, and users can watch them on computer browsers and Android mobile devices. Is it difficult to do this?

The answer is yes. For example, the maturity of the terminal hardware decoding chip is directly related to the value of a certain standard. For example, H.265 has a wide range of hardware support, which is related to the fact that the chips of Apple, Qualcomm and Intel all support H.265 hardware decoders.

Therefore, encoders often need to be combined with specific application scenarios for improvement and depth optimization.

Taking AV1 as an example, in order to better adapt to the massive content of iqiyi, QAV1 achieves a more reasonable bit rate allocation through pre-analysis of scene complexity. For simple scenarios, QAV1 can adaptively reduce the bit rate and save user bandwidth while ensuring the image quality; at the same time, it will appropriately improve the bit rate for complex scenes and bring users a higher picture quality experience.

At present, the functions supported by QAV1 include a variety of speed grades, a variety of rate control methods, 8K video coding and so on. This detail polishing that matches the differentiated environment takes into account both network bandwidth and user experience.

The long-awaited 5G naturally needs matching video coding standards to echo. As far as we know, iqiyi's AVS3 app is on its way, watching 8K UHD videos, browsing VR news and information, and interacting with virtual idols on his mobile smartphone. These new entertainment experiences may be presented to us with the help of video coding magic.

From iqiyi's video coding exploration, it is not difficult to see that the express train in the era of technology is not easy to get tickets. Only by cutting through difficulties for a long time can we win the crown smoothly.

Riding on the wind and waves, what does video codec mean?

In this extremely competitive track, how did iqiyi's leading position come into being? We believe that the reason may lie in three winners and losers:

1. Technology-driven genes.

As an entertainment company driven by scientific and technological innovation, iqiyi launched a technology experience upgrade program as early as 2016. Upgrade the online experience of video users through a series of independent technological innovations.

At present, artificial intelligence technology has become the driving force of iqiyi, deep into the production, broadcasting, distribution, publicity and other links. Specific to the coding standard, it is through the combination of traditional AI+ coding technology, so that the compression efficiency has more room for improvement.

two。 Streaming media professionalism.

No matter how awesome the standard is, it is always the professional technical personnel behind it who finally decide the progress of deployment.

One of the technical details of iqiyi attracted our attention. When promoting the AV1 standard, Google actually visited many video platforms in China, but at that time, the whole industry evaluated that the actual effect of AV1 was not much different from that of the previous generation, and held a skeptical attitude towards it, believing that it would not put manpower and material resources into development for the time being. However, iqiyi's technical team made a fair comparison based on professional and neutral evaluation tools and methods, and AV1 did have a significant improvement in efficiency.

When the technicians made this result, iqiyi did not have any doubt inside, and directly chose the interior to support his research and development. This also decided that iqiyi stood on the earlier starting line of the AV1 standard.

3. Mature industrial capacity.

Any technology needs to be put on the ground in reality and tested in the storm of users. In particular, the coding and decoding technology is very low-level, how to turn a pile of laboratory data into the actual effect of restraint.

As early as when launching the VP9, iqiyi conducted a complete "exercise" on the launch process of the new standard, from the specific packaging format, player debugging, program arrangement, playback plan determination, computer browser and other terminal adaptation, and so on. The mobility of this standard deployment also foreshadowed the rapid launch of AV1.

So far, video coding and decoding has produced a series of chemical reactions in the streaming media industry from content production, business process, user experience and business model.

Next, we will see that codec technology will be integrated into the details of video content in a faster way, becoming a red line between you and my users and our favorite characters and characters.

The relationship between the codec standard and the video platform is also destined to be together for a long time.

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