This article will briefly introduce the current mainstream Internet video coding technology, and try to analyze the advantages and disadvantages of each solution from multiple perspectives, hoping to provide a reference perspective for developers and application manufacturers who are just beginning to understand the field of audio and video development.
Mainstream Video Coding Technology
H.264
H.264, which was born in 2004, is the most widely used video coding technology standard in the Internet today and occupies the largest share. H.264 ended the situation of many video encoding specifications and uneven quality in the old era, provided the best compression ratio at the same image quality at that time, and won the unanimous support of almost all the giants in the industry. After more than ten years of promotion and application, today all video websites, applications, video shooting equipment, and playback equipment support the main encoding branches (Main level to High Level 5.1) of H.264 by default, which has become an undisputed de facto standard in the industry .
However, H.264 encoding, which was formed at the beginning of the century, has been difficult to meet the higher requirements of Internet video services in the new era today, creating market opportunities for the birth of more new-generation solutions.
advantage
Excellent compatibility; has the most abundant community ecological support; can provide a good compression ratio in low-demand scenarios; mainstream CPU, GPU and DSP and other proprietary hardware provide good H.264 hardware codec support.
shortcoming
In scenarios with higher requirements (4k, 8k, high frame rate, HDR, VR), the compression ratio is obviously inferior to that of the new generation encoding scheme, which brings higher storage, bandwidth and cost requirements.
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H.265/HEVC
H.265, also known as HEVC (High Efficiency Video Coding), was born in 2013 and is the replacement solution introduced by the industry for H.264. Compared with H.264, HEVC can improve the compression ratio by 50%-100% under the same image quality, and has good support for 4k, 8k, HDR, high frame rate video and other scenes.
Driven by hardware vendors such as PCs and smartphones, HEVC has become the mainstream video encoding option second only to H.264 in adoption. The vast majority of smartphones produced in recent years provide HEVC hardware encoding and decoding capabilities, effectively solving the problem that the consumer-side encoding and decoding HEVC requires too much computing power. However, because Google chose to support the VP9 video encoding format, HEVC failed to achieve the ideal of "unification" like H.264, and more manufacturers realized the market opportunity to promote other encoding formats.
advantage
Compared with H.264, it can provide a higher compression ratio (50%-100%) under the same image quality, and can well support various high-demand application scenarios. It has received unanimous support from mainstream hardware and equipment manufacturers, and has an extensive software and hardware ecological environment.
shortcoming
Failing to gain full support from YouTube, the world's largest long-form video site, YouTube recommends users to use VP9 as an alternative, which is a heavy blow to the full popularity of HEVC. On the other hand, compared with H.264, the encoding and decoding computing power requirements of HEVC have increased by several times or even more than ten times, forcing video service manufacturers and cloud service providers to increase hardware procurement expenditures to make up for the computing power gap, partially offsetting the benefits brought by HEVC. cost reduction advantage. In addition, manufacturers often need to pay licensing fees when adopting HEVC solutions, which is undoubtedly a major disadvantage in today's industry where openness and open source are generally pursued.
AV1
The success of VP9 has inspired organizations such as Google that promote open video encoding solutions. When VP9 was far from reaching the end of its life cycle, Google and other manufacturers jointly launched the AV1 encoding format. The goal of AV1 is to further increase the compression ratio of video coding by 50%-100%, and to replace HEVC and VP9 at the same time, becoming the standard option for the new generation of video coding schemes. Major manufacturers have injected strong impetus into the ecological development of AV1, so that the AV1 released in 2018 has gained a high degree of attention and community support in just a few years. Since the orthodox successor of HEVC, the H.266 VVC standard, was launched late and still requires licensing fees, its momentum was obviously overwhelmed by AV1.
advantage
Next-generation video coding standard that provides 50%-100% higher compression ratio than HEVC/VP9 without licensing fees. AV1 has begun to gain support from a number of hardware manufacturers. The new generation of smartphones and PC CPU/GPU have begun to provide AV1 hardware encoding and decoding capabilities, laying the foundation for the widespread popularization of AV1. Video sites including YouTube have also begun to experiment with AV1 solutions, giving AV1 a first-mover advantage in the competition for next-generation video coding standards.
shortcoming
Compared with the previous generation encoding scheme, the higher computing power requirement once again limits the promotion speed of AV1. On the other hand, AV1's technical solutions and community ecology are far from mature, and it will take some time for development to be widely recognized. At the same time, AV1 must face the strong competition of the H.266/VVC standard. Whether it can reverse the disadvantage of VP9 and defeat VVC in video shooting and other scenes is still unknown.
other
In addition to the above solutions, there are some other video coding standards in the industry, but basically none of them have or have not yet formed a great influence.
How should app developers choose
For app developers, choosing which video encoding schemes to support is a topic that requires careful consideration. First, because of H.264's market position, any application must support H.264 by default as an underlying video encoding option. The real difficulty lies in how to choose in higher demand scenarios.
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If the application does not exist or only a few scenarios require features such as 4k, high frame rate, HDR, etc., developers can continue to stay on H.264 and make choices after future demand increases.
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If the application server has a large amount of high-quality video data that needs to be provided to users, HEVC can be selected as the main encoding scheme to effectively reduce storage and bandwidth requirements. It should be noted here that the UE must generally provide HEVC decoding support, otherwise it still needs to stay on the H.264 scheme.
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If the cloud service provider provides support or even preferential options, and users have early adopter needs and device support, the AV1 encoding scheme can be applied in a small number of extremely high-quality (such as 8k, 120fps, HDR) video scenarios on a pilot basis.
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Considering that many end-user devices do not yet support VP9 hardware decoding, the use of VP9 as the primary video encoding option for applications is not recommended.
Summarize
In the past ten years, the field of video coding standards has gradually shifted from the dominance of H.264 to the coexistence and competition of multiple coding schemes. For the overall market, more competition can undoubtedly break the monopoly, bring more choices, and promote faster technological progress in the industry. Looking forward to the future, we are likely to see the coexistence of H.264, HEVC, VVC, VP9, AV1 and even more encoding schemes. Application developers also need to be prepared for this, understand relevant knowledge in advance, and make the most appropriate decisions according to their own conditions. good decision.