Contents
Video Encoder
H.264
1. Definition
2. Features
HEVC
1. Definition
2. Features
VP9
1. Definition
2. Features
AV1
1. Definition
2. Features
Video Encoder Advantages and Disadvantages
Video Encoder Comparison
Video Encoder
H.264
1. Definition
H.264, also known as H.264/AVC (or AVC/H.264 or H.264/MPEG-4 AVC or MPEG-4/H.264 AVC), is a highly compressed digital video codec standard , is the tenth part of MPEG-4, and collects royalties.
The main parts of the H264 standard include Access Unit delimiter (access unit delimiter), SEI (additional enhancement information), primary coded picture (basic image coding), and Redundant Coded Picture (redundant image coding). There are also Instantaneous Decoding Refresh (IDR, instant decoding refresh), Hypothetical Reference Decoder (HRD, hypothetical reference decoding), Hypothetical Stream Scheduler (HSS, hypothetical stream scheduler).
2. Features
The most common video encoding format is formulated by the International Telecommunication Union, focusing on network transmission.
H.264 has a higher data compression ratio. At the same image quality, H.264 is 1.5~3 times higher than other encoding formats, so less bandwidth is required in network transmission, and it is mainly used in real-time transmission, such as video Meeting.
The disadvantage of H.264 encoding is that the hardware system requirements for playback are relatively high.
HEVC
1. Definition
High Efficiency Video Coding, also known as H.265/HEVC, is a new video compression standard used to expand the H.264/AVC coding standard. On January 26, 2013, HEVC officially became an international standard. Collect royalties.
Developed in response to the increasing demand for higher compression rates for moving images in various applications such as Internet streaming, communications, video conferencing, digital storage media, and television broadcasting.
2. Features
HEVC has seen the most successful adoption in the living room, where it is seen as an enabler for 4K video, especially 4K with high dynamic range (HDR).
VP9
1. Definition
An open format video compression standard developed by Google without licensing fees. VP9 was named Next Gen Open Video (NGOV, Next Generation Open Video) and VP-Next in the early stages of development. VP9 will be the successor of VP8.
2. Features
VP9 is the successor product of VP8, and its main competitor is MPEG's high-efficiency video coding standard HEVC. Compared to HEVC, VP9 has better support in web browsers. It is also widely used in Internet video sites for its excellent video encoding quality and compression efficiency.
AV1
1. Definition
Alliance for Open Media Video 1 is an open-source, royalty-free program developed by AOM (Alliance for Open Media, Open Media Alliance, including Tencent, Amazon, Cisco, Google, Intel, Microsoft, Mozilla and Netflix). Video coding format, the goal is to solve the expensive patent fees and complex patent licensing issues of H265 and become a new generation of leading copyright-free coding standards. In addition, AV1 is the successor of the VP9 standard developed by Google and a strong competitor of H.265.
2. Features
The goal of AV1 is to replace its predecessor, the VP9 video compression format developed by Google, and with the High Efficiency Video Coding (HEVC) developed by the Moving Picture Experts Group (MPEG) and the digital audio and video coding technology standard developed by China The working group led the development of the second-generation digital audio and video codec technology standard (AVS2) competition.
Summary of advantages and disadvantages of video encoders
Note: The advantages and disadvantages of this table are not inconsistent with the current state. The former mainly summarizes the characteristics of a certain encoder when it was first launched, while the latter emphasizes the comparison between encoders.
Name Advantages Disadvantages Main applications Current status
H.264 1. High coding efficiency: adopt hybrid coding structure
2. Good video quality: low bit rate and low bandwidth provide high-quality image transmission
3. High efficiency of compression technology: guarantee data quality Under the premise, the data compression ratio is high.
4. Strong network adaptability: can apply low-latency mode in real-time communication, and work in video storage or video streaming server without delay. 5. Good
compatibility: Compatible with almost all browsers, all Mobile and smart TV/OTT (OTT: refers to providing content distribution services to users through public networks. OTT can use any network access. Content and services can skip operators and provide users directly through the network. OTT is completely based on the Internet architecture. Basic, typical representatives include American Google TV (Google TV, Hulu, Netflix)
6. Less encoding options: reduce encoding complexity
7. Error recovery function: provide tools to solve the problem of network transmission packet loss, suitable for transmission in wireless networks with high bit error rates Video data 1. High encoding and decoding complexity. H.264 compression efficiency is more than double that of MEPG-2. At the same time, decoding difficulty is increased by at least 3 times, and the calculation requirement is as high as 100GOPS: 2. For the playback
hardware The system requires high real-time transmission, such as video conferencing, live broadcast 1. It has been invented for a long time and is very mature
2. It has very comprehensive hardware compatibility
3. The encoding is very fast, and the video can be encoded into H.264 format quickly File
4. It will produce a particularly large file
5. The efficiency of compressing video is not high
6. It does not support video with a resolution above 4K
7. The image quality is not high, and things that are originally black look gray. And when the bit rate is very low, the encoding result will be piece by piece, this kind of problem is very common
HEVC (H.265) 1. Low code rate and high coding efficiency: H.265/HEVC provides more different tools to reduce the code rate. In terms of coding units, each macroblock (macroblock/ MB) size is fixed at 16x16 pixels, and the coding unit of H.265 can be selected from the smallest 8x8 to the largest 64x64, and the image is encoded in a focused way, thereby reducing the overall bit rate and the coding efficiency is corresponding Improvement
2. Less storage space: With the same picture quality and the same bit rate, H.265 takes up 50% less storage space than H2.64 in theory.
3. Saving bandwidth: H.265 can use less bandwidth to provide part The same function as H.264
4. Stronger network adaptability: H.264 can realize standard definition digital image transmission at a speed lower than 2Mbps, while H.265/HEVC can realize 1080p at a transmission bandwidth lower than 1.5Mbps Full HD video transmission 1. Poor compatibility: Compatible with few browsers, Android, IOS in mobile devices, and all smart TVs/OTT 2.
More difficult to decode
3. High power consumption when decoding video
4. Real-time encoding Difficulty: Compared with H.264, the encoding complexity of H.265 increases geometrically, and the encoding time also increases accordingly. It is difficult to realize real-time encoding with existing terminal equipment. 5.
Difficulty in using the encoder: H.265 only specifies a The range of technologies available, many features may or may not be used when coding. Therefore, the difficulty of using the H.265 encoder is about 2-3 times that of x264. 1. At present, H.265 is hardly used in the field of live broadcast, but mostly in the field of on-demand. 2. It is
widely used in enterprises and security.
3.4K Blu-ray video is mainly used Using HEVC 1. Compared with H.264, the compression efficiency is greatly improved. 2.
When HEVC files encode the same video, the file volume is only 50% of the latter compared with H.264, but it can be obtained same video quality
3. Compared with H.264, the color looks better, and the artificial changes look less obvious
4. Supports 8K (8192×4320) and above resolutions
5. Not supported by iOS devices, and on most PCs The performance is very poor; HEVC-encoded video cannot be uploaded to YouTube, because YouTube does not support this input format
6. Patent authorization is complicated
7. The price to pay for ensuring a small file size is longer encoding time , and more power required for playback
8. Chip manufacturers are releasing SDKs to allow HEVC video to use hardware acceleration in the process of encoding and decoding, which can greatly improve processing speed
VP9 1. Low encoding cost: the same as AV1 Compared with VP9, it can save a lot of encoding time and computing cost. For videos that are not watched for a long time, the cost increase caused by AV1 multi-bit rate encoding may be more than the traffic cost saved by AV1. 2. Chrome browsers do not
support HEVC decoding, and VP9 content videos can be accelerated by using hardware Play on some mainstream devices
3. Play better on low-end Android devices: HEVC and AV1 cannot play well on some low-end Android devices. For 1080p+ or film noise video, the performance of VP9 is close to HEVC, and in some cases, the performance of VP9 is sometimes even better than HEVC 4.
No copyright fee
1. Not widely used: in actual promotion, Microsoft, Apple and other companies I would like to see VP9 as the only one, and other Internet manufacturers do not want the mainstream video encoding format to be monopolized, so it is mainly supported by Google's own products at present, and there are not many other major manufacturers using VP9. 2. Encoding speed is slow:
with Compared to HEVC, it will be slower since there is no hardware accelerated encoding available for VP9
3. Not suitable for some video players: such as VLC, cannot play VP9 smoothly, other players based on FFplay, such as MPC-VC, do not have this problem
. Simple, practical solution and development of free features 1. Compared with H.265, VP9 is better at compressing video files larger than HD, so VP9 may be very suitable for high-resolution VR video AV1 1
. High compression rate: Compared with VP9, the compression rate is further improved, and the bit rate can be saved by 30% compared with VP9 under the same image quality. 2.
No copyright fee 1. Slow encoding speed: AV1 encoding is slow. Fundamentally speaking, it is because the calculation is too complicated
2. Involving monopolistic competition: TV system giant ROKU stated that Google "requires partners to support AV1 in newly launched products, including Android TV, Google system TV and other smart TVs that support related software , all have to support the AV1 encoding format" is to force all TVs to support the AV1 system, which is a monopolistic behavior. The application scenario is streaming media, which supports live broadcast and on-demand. Many streaming videos watched on Youtube, Netflix and Amazon have adopted the AV1 encoding format, especially 8K video
Video encoder comparison
Release time:
H.264 (2003) –> H.265 (2012) –> VP9 (2013) –> AV1 (2018)
Do you need patent authorization fee:
H.264 (need) –> H.265 (need) –> VP9 (no need) –> AV1 (no need)
Compatibility:
H.264>VP9>AV1>HEVC
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