A look at the new generation and types of video codecs


A look at the new generation and types of video codecs

A look at the new generation and types of video codecs

EMGblog.com: Along with upgrading video images from SD to 4K Full HD, HD and finally 8K, technologies related to video processing, coding and compression must also evolve. Improving the quality and resolution of images is naturally accompanied by an increase in the amount of data. As a result, more bandwidth will be required to transfer them over the Internet, more storage space to store them on different devices, and more powerful GPUs to play them. Especially with the ever-increasing prosperity of online video streaming services and Internet TV, it is necessary to somehow improve the algorithms related to video processing and compression.

The improvement mentioned in this section is for easier and faster processing of videos and at the same time reduces the size of the relevant files as much as possible.

What is a codec?

Before that Let’s introduce and review new video codecs, maybe it is better to explain the concept of codec for those readers of this article who are not familiar with it. The word codec is a combination of two words “code” and “decode” and refers to an algorithm or computer program that receives and changes audio or video files. These changes can have different aspects. But in general, most of the changes made by codecs are aimed at changing the size or compression of audio and video files. Audio and video files are very large in their raw state, and without using codecs for coding and compression, it will be very difficult and time-consuming to transfer these files over the Internet. To enable fast sharing and online video streaming, it is necessary that the relevant files are encoded or compressed using standard algorithms before being sent on the Internet, and after being transferred to the user’s device, based on the same standard or codec for View, decode. Without going through this process and if codecs are not used, downloading and playing audio and video files can be 3 to 5 times longer and, accordingly, require higher bandwidth and more storage space.

When you shoot a video using your smartphone camera, the corresponding file is encoded using a video codec – which is pre-set by you or by default – and saved on the memory. will be Now suppose you send this file to one of your friends through e-mail, messengers or social networks. After receiving the file, he will have a video file player software to view it, which can decode the relevant file and then play it with the support of that specific codec. For this reason, it is very important that manufacturers and developers who are influential in the technology world agree on the support of one or more specific codecs so that users do not have problems transferring their files between different devices. MP3 and MPEG-2, AAC and MPEG-4 can be mentioned among the most famous and important audio and video codecs of the last few decades. For example, more than 20 years ago, the MP3 codec was able to create a revolution in the music playback and consumption industry by providing the possibility of compressing the content of an audio CD to less than one-tenth of its original size.

Getting to know the types of codecs and their efficiency measurement criteria

Generally, codecs can be divided into two categories: Lossless and Lossy. The first type refers to codecs that preserve all the information related to the image of the original content. In such codecs, the final image after decoding will be exactly the same as the original image. The application of these types of codecs is more in the industry and jobs related to multimedia content. H.265 Lossless, H.264 Lossless and Motion JPEG Lossless are among the most used lossless codecs today. The advantage of these types of codecs is high quality and access of professionals to all image information to make changes and use its content. In the second type of codecs, with the aim of reducing the size of the final file and increasing its portability, some image information is lost during the compression process. Lossy codecs are commonly used to provide multimedia content to the end user and transfer them over the Internet. Most of the codecs mentioned in this article are of the same type.

An important and natural criterion for any video codec is the quality of the image reconstructed by that codec. This feature is very important in lossy codecs that inevitably lose part of the image information. In addition to quality, a good video codec should perform compression operations as quickly, easily, and powerfully as possible. Codec developers are always trying to design an algorithm for image compression that is able to reduce the encoded file as much as possible while maintaining the desired quality, and at the same time perform encoding and decoding operations with acceptable speed and ease. The most important conventional measure for measuring the efficiency of codecs and image compression algorithms is “bit rate”. Bit rate is the number of zeros and ones or bits used by a video codec to store information about each second of video. The ultimate goal for any video coding algorithm is to keep the bitrate as low as possible and the image quality as high as possible. Any codec that performs better on the way to this goal and of course performs the relevant operations at the right time, with the need of reasonable processing resources, will be a more efficient solution for compressing and presenting video content. Regarding the bit rate criterion, it is not bad to point out that if a specific video codec is used, usually a higher bit rate means a better image quality.

A brief look at the past and present status of video codecs

In the past few decades, video codecs have developed and evolved in 2 main directions and through 2 reference bodies. The International Standard Organization – better known by its acronym ISO – is one of the most important standards-setting bodies for photography, computers and consumer electronics. This organization introduced its first video standard called MPEG-1 in 1993. Likewise, ISO released the MPEG-2 codec in 1994 and MPEG-4 in 1999 as its approved standard for video codecs. The other path of video codec evolution goes through the International Telecommunication Union (ITU). An institution that, as the main agency of the United Nations in the field of information and communication technology, is responsible for introducing international standards related to telephone, radio and television communications. This agency first unveiled its first video conferencing standard in 1984 called H.120. Other standards of this family with codes H.262, H.261 and H.263 were introduced in 1990, 1994 and 1995 respectively.

Finally, since 2001, these two different development paths of video codecs and standards joined each other, and a team of relevant experts from both ISO and ITU institutions started the design and development of a new video codec standard. The result of this collaboration was the publication of a new standard called Advanced Video Coding or AVC for short, the first version of which was published in 2003. This Advanced Video Coding (AVC) standard is also known as H.264 or MPEG-4 Part 10 in the world. Since the initial introduction of the AVC standard, this standard has been updated many times and 26 versions of it have been published. Also, in these years, the scope of its use has expanded day by day, to the point where by conquering many industries and markets such as streaming services and Internet TVs, digital cameras, mobile devices and even satellite networks, it is currently the most widely used international standard. It is considered in the field of video codecs. After that, MPEG-2, despite its age, can be considered as the second most common and widely used standard.

A decade after the introduction of AVC and after increasing the quality of video images from HD to Full HD and 4K, a new standard called High Efficiency Video Coding or abbreviated HEVC, was released jointly by ISO, ITU and IEC organizations in 2013. This video coding standard, which is also known as H.265 and MPEG-H Part 2, is able to compress videos at a certain quality level from 25 to 50% better than the older AVC standard or at a certain bit rate. Provide a much better quality video. This means that, for example, if you need an internet bandwidth of 32 Mbps to play a 4K quality video online using the H.264 codec, playing the same video using the H.265 or HEVC standard will only take 16 Mbps. It occupies your internet bandwidth per second.

Comparison of the image quality of H.264 and H.265 codecs when playing video online with a bandwidth of 1 Mbps

Conceptually and structurally, HEVC is very similar to the AVC standard and is a development It is based on the same technology. The basis of the work of both standards is to compare different parts within a frame of video or between consecutive frames of it, to find similar and repetitive areas. Thus, by identifying these types of areas, instead of storing all the data related to their pixels, only a short description is stored for each area. Despite its good technical characteristics and high power in the field of video compression, the HEVC codec suffers from two major drawbacks. The most important problem related to this codec is the need to spend money to obtain a license or license to use it, as well as the relative complexity of the conditions for obtaining this license. Another weakness of this codec compared to its predecessor is that it requires much more time and processing resources to run the video coding process.

Emergence of a new generation of video codecs

H.264 and most of the older video standards provided by ISO and ITU have developed over time to meet the needs of television and traditional video file transfer solutions. are designed As a result, none of them could be a suitable standard for use in streaming services or online video streaming. With the emergence and increasing development of these types of services, as well as the expansion of the use of 4K and 8K quality videos, the need for new and efficient standards for the future of this industry seemed obvious. In this regard, during the past years, various groups of experts and international institutions have conducted research and development in this field and presented new standards for this purpose. The most important of these standards are EVC, H.266/VCC, AV1 and LCEVC, which we will briefly introduce below.

AV1: an open source and free video codec

AV1 First released in 2018, it is a video codec and file format for transmitting video over the Internet. One of the most important features of this technology is its open source and the possibility of using it completely free. Many of the technologies that are widely used today for video compression and streaming are not free and require the purchase of a license for commercial use. From the old and widely used MPEG-2 codec to various technologies based on the H.264/AVC standard as well as H.265/HEVC, all of them have been patented by various companies and institutions, and as a result, electronic equipment manufacturers and software developers to use them. They must receive the relevant permits. Obtaining these licenses in some cases is done without paying a fee, and sometimes it is associated with the payment of significant amounts. For example, Samsung owns more than 4000 patents (patent) is related to H.265 standard and Panasonic also has more than 1000 patents in the field of technologies based on the H.264 standard.

The AV1 codec was designed from the beginning with this goal in mind to be freely available to everyone. This codec was developed by an organization called AOMedia or “Alliance for Free Media”. A non-profit organization that aims to develop free and open source technologies in the field of providing multimedia content in 2015 by super companies such as Amazon, Cisco, Google, Intel, Microsoft, Mozilla and Netflix were formed . The support and participation of the big players in the technology world for this codec can somehow guarantee its success and remain free. An event that, considering the complexities of this technology, would be impossible without relying on the huge support of patents and legal power of these companies.

Of course, in order to achieve success and stabilize its position in the world, this new codec, in addition to being free and open source, must also have a significant advantage over existing technologies in terms of efficiency and quality. AOMedia experts claim that AV1 performs about 30% better in terms of compression than H.265/HEVC codecs while providing the same image quality. This means that the amount of data stored for a 4K video using the AV1 codec is nearly 30% less than the file size for the same video with the HEVC codec. Of course Results of tests conducted by researchers at the University of Waterloo indicate that for a sample video with 4K quality, the AV1 codec was able to achieve 9.5% lower bitrate quality. Provide an image on par with HEVC. The AndroidAuthority website also compressed a video with 3 codecs HEVC, AV1 and AVC and the results obtained in an article with the same theme published. This test shows that AV1 and HEVC standards do not have significant differences in terms of compression power and the quality of reconstructed images.

A free codec with higher compression power than the H.265/HEVC standard – which is not open source and free – looks very attractive. But everything does not end here. Along with these advantages, the AV1 codec suffers from an important drawback. Encoding of videos with this codec is slower than other currently common codecs such as H.264 and H.265. So that the time required for software coding of a video with AV1 is almost 2 times that of H.265/HEVC. Of course, this problem may become less prominent and even solved over time and with the development of more optimized coding tools. Especially since coding tools based on AV1 codec have not yet been officially released for use by the public. It is expected that with the passage of time, more efficient and optimized software for this codec will be provided, and with the support of this codec at the hardware level, the speed of the coding operation will be significantly improved.

In any case, it seems that AV1 It has been well supported and welcomed by large companies active in the field of online video streaming and providing multimedia content. For example, since this year (2020), YouTube has started broadcasting videos based on the AV1 codec in a limited way. The YouTube app for Android TV has the ability to play AV1 videos since version 2.10.13, released in early 2020. The Netflix company also announced by supporting this codec 4 years ago that it expects to be one of the first users of AV1. This company finally started using the AV1 codec for online streaming of some videos on the Android operating system in February 2020. The use of this new codec by Netflix results in 20% better compression and, as a result, less bandwidth consumption for streaming online videos of this Internet TV. Also, following the publication of good results from its tests on the AV1 codec and the coding software developed by the company, Facebook has announced that as soon as Internet browsers start supporting this video codec, it will start using it for streaming videos online. did In addition, other major companies including Twitch and iQIYI (a popular Chinese streaming service) have also officially announced their plans to use this video codec.

One of the most important factors affecting the success of any video codec is the support of widely used software. Thanks to the support of most of the major companies in the world of technology, AV1 is currently supported by many popular international software. PotPlayer, Bitmovin, MediaInfo, GStreamer, VLC media player, Opera, Microsoft Edge, Google Chrome, Mozilla Firefox and Google Duo are among the most important and well-known software.

H.266/VVC: legacy of traditional codecs H.26x family and MPEG

VVC (Versatile Video Coding) video compression standard, also known as H.266 and MPEG-I Part 3, by teams of experts from ISO, IEC and ITU-T international bodies it is developed. The VCC codec standard is actually intended to replace HEVC or H.265 as an international standard for video codecs. For the first time, at the end of 2017, an official call was given in connection with the presentation of specialized proposals for this standard. In 2018, the received proposals were evaluated and the first draft of this standard was prepared. Until finally, in July of this year (2020), the final standard was completed.

The specifications set in the final standard emphasize that codecs based on this standard should perform 30 to 50% better than HEVC codecs in video compression without reducing image quality. In other words, a VVC codec must encode videos with at least 30% lower bit rate in a certain quality. If this feature is implemented accurately, it will have a significant impact on reducing the size of video files and the bandwidth required for their transfer. For example, storing 60 seconds of 4K video on an iPhone at 30 fps with the HEVC codec requires about 170 MB of space.

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