The world of video streaming has witnessed some major technological improvements; among them, the most notable is the introduction of a new video compression standard known as the HEVC (High-Efficiency Video Coding) or H.265. This standard has come as a significant leap forward in boosting video quality.
HEVC allows videos to be compressed in an effective way, resulting in an average bitrate. That means it will enable you to immerse in higher-quality video content without consuming more data or additional storage. HEVC is particularly beneficial when streaming videos on mobile devices, where processing power and data usage are often restricted. Now, this blog will give you a detailed guide on H.265/HEVC that will focus on facts like how it works, its features, applications, pros and cons, and why you should choose this video codec.
What do you mean by a video codec?
A video codec is a software tool for compressing and decompressing digital videos. In simple terms, it converts a video file into a smaller one or back to its original form. With the increasing demand for streaming services, video encoding has become necessary for quickly sending videos over the Internet.
Some of the most common video codecs available on the market are the H.264 (AVC) and the H.265 (HEVC). These video compression standards are beneficial for maintaining high-quality video with reduced file size and give a seamless viewing experience to the audience on their laptops and smartphones.
What is HEVC/ H.265 Video Coding?
H.265, also known as High-Efficiency Video Coding (HEVC), is the successor to MPEG-4, which was introduced to deliver improved video quality with a higher average bit rate reduction. One of the major reasons for its popularity in the market is its quick adaptation to 4K content everywhere. H.265 offers video compression at half the bitrate of its predecessor, H.264, without sacrificing video quality—thus making it theoretically twice as efficient.
In simple words, when you compress a video with H.265 at the same bitrates as H.264, the video quality will be much better with H.265. These benefits make it a widely accepted video compression standard for streaming and downloading 4K videos, which was challenging with H.264 due to the large file size and high bitrates.
How Does It Work?
The HEVC codec works on a concept and structure similar to its predecessor, the H.264 standard. Like before, it processes source video consisting of a sequence of frames, which are compressed or encoded by an encoder, resulting in a compressed bitstream. This compressed bitstream can be stored or transmitted, and a decoder on the receiving end decompresses it to reconstruct the original sequence of frames.
The HEVC codec’s encoding process involves several steps,
Prediction & Computation: In the first step, the encoder starts the process by predicting each unit and performing necessary computations. It takes a 16x16 pixel block (macroblocks) from the current frame and generates a prediction based on the current or previously transmitted frames.
Transformation & Quantization: Encoders transform and quantile residuals, which differ between predictions and original picture standards. This process involves utilizing an approximate Discrete Cosine Transform (DCT), producing a set of coefficients representing basic patterns' weightings. These coefficients are then combined to form the initial residual.
Entropy Encoding: Finally, the encoder applies entropy encoding, a lossless data compression technique. The aim is to transform the output, along with mode information, prediction data, and headers.
The HEVC decode reverses the whole step,
Entropy Decoding: It first reserves the entropy encoding process to extract the original elements from the coded sequence.
Inverse Transform & Rescaling: The decoder then inverts the transformation and rescales the data.
Prediction & Reconstruction: Next, it predicts each unit and combines it with the output of the inverse transform to reconstruct the final decoded video image.
What are the key features of HEVC?
Improving Coding Efficiency: HEVC, also known as High-Efficiency Video Coding, is the latest video compression standard that aims to enhance video quality. Compared to the widely used H.264, HEVC can reduce the bitrate requirements by half without compromising image quality. This means viewers will experience high-quality video streaming without consuming too much computing power on their devices.
Supporting Higher Resolution: HEVC has come to the market to transform the way we consume video content on the Internet. Featuring high-resolution videos, HEVC is perfect for next-generation HDTV displays and content-capturing systems. Viewers can expect a crystal-clear and high-quality video sequence while enjoying it on a large screen or on their smartphones.
Compression Ratio: Another notable feature of HEVC is its compression, which can deliver a data compression ratio of up to 1000:1. This allows you to store more videos on your device without the concern of quickly depleting storage space.
Intra Prediction: HEVC provides enhanced intra-prediction capabilities in comparison to H.264, offering 33 intra-prediction modes. These include various directional models, planer prediction, and the DC intra-prediction, all contributing to better prediction accuracy and image quality.
Enhanced Parallel Processing: The H.265 video compression standard aims to deliver high-quality video while focusing on efficiency. Tools, including tiles and wavefront parallel processing (WPP), allow the picture to be delivered into rectangular regions that can be processed independently. This division allows for more efficient and faster encoding by enabling parallel processing of different image parts. By utilizing enhanced parallel processing tools, HEVC increases video processing speed and allows users to experience seamless real-time video streaming without any lag.
Video Coding Layer: HEVC employs a hybrid method in its video coding layer, which combines inter-and intra-picture prediction with 2D transform coding. This method enhances the visual quality of the videos and ensures you get shaper and more transparent images.
Introducing New Coding Tools: HEVC comes with advanced coding tools to enhance coding efficiency, including the Coding Tree Unit (CTU). It replaces traditional macroblocks and allows for larger block structures, resulting in more efficient encoding and improved overall coding performance.
Entropy Coding: HEVC utilizes context-adaptive binary arithmetic coding (CABAC) for entropy coding, which provides higher throughput and more efficient compression than H.264/MPEG-4 AVC. That ultimately results in better compression performance with reduced file size.
Range Extensions: HEVC features range extensions that support bit depths greater than 10 bits, providing greater color accuracy and dynamic range. In addition to this, it includes intra-profiles that enable faster and random access decoding and still picture profiles that optimize image file formats for high efficiency.
Motion Vector Prediction: HEVC enhances motion vector prediction with Advanced Motion Vector Prediction (AMVP) and merge mode. These improvements allow for greater precision in predicting the motion within the video sequences. That leads to more accurate and efficient encoding of moving objects.
Loop Filters: HEVC specifies two loop filters: the deblocking filter (DBF) and the sample adaptive offset (SAO). These filters refine the quality of inter-picture prediction by reducing blockiness and improving the visual appearance of the content.
Advantages & Disadvantages of Using HEVC/H.265
Advantages
Superior Compression Efficiency: HEVC can reduce the file size of videos while managing and improving the video quality in comparison to H.265. Thus, we can call it an ideal tool for streaming services, optimizing bandwidth usage and reducing storage costs.
Supporting Ultra HD Resolution: HEVC can handle resolutions of up to 8K, making HEVC a future-proof video resolution that will continue to increase.
Enhancing Video Quality: HEVC features better motion estimation, advanced transforms, and improved coding structures to provide users with better visual quality. And it is especially true for high-motion content, such as action scenes and sports or events.
Reducing Bandwidth Usage: By halving the bitrate needed for the same quality, HEVC offers an efficient transmission of HD content over limited bandwidth connections. It makes it ideal for mobile networks and other constrained environments.
Disadvantages
Complex Licensing: One of the major challenges of using HEVC video compression is its complicated and unclear licensing schemes. Covered by multiple patent pools, it often creates confusion and higher costs for small companies and developers who want to integrate this into their systems.
Computational Requirements: HEVC’s advanced compression techniques require more processing power for both the encoding and decoding processes. It results in slower processing time and powerful hardware especially when you encode 4K and 8K content.
Slow Adaptation Rate: The H.265 version has a complex licensing procedure and requires complex hardware, making it less approachable to consumers. Instead of relying on this new standard, they would have better go with the older version, such as MPEG-4/H.264.
Compatibility Issues: Not all devices and platforms support HEVC, especially the older version. It may lead to compatibility issues when streaming and sharing video content and compel users to rely on older or less sufficient versions.
What are the Applications of H.265?
Video Streaming Services: With the increasing popularity of 4K and 8K content, HEVC has become integral to streaming platforms like Amazon, YouTube and Netflix. Its impressive ability to compress high-resolution video helps to reduce the bandwidth requirements while improving streaming quality.
Broadcasting: HEVC is often used in digital broadcasting, particularly in places where 4K Ultra HD content is becoming the standard. Broadcasters will be able to deliver high-quality video to users without upgrading their existing bandwidth infrastructure.
Surveillance: HEVC’s high compression efficiency benefits security and cameras. It allows you to store high-quality video content over an extended period without requiring excessive storage space.
Video Conferencing: HEVC is a useful tool in video conferencing also. It enables high-quality video transmission while reducing bandwidth requirements and leading to a seamless online meeting.
H.264 vs. H.265
When you are confused between H.264 and H.265, try to consider the following points,
Compression: H.265 excels in compression, offering up to 50% smaller file sizes than H.264 while maintaining the same video quality.
Compatibility: H.264 leads in compatibility and supports almost every device with a screen. H.265 is gaining ground, but you might face playback issues on older devices and platforms.
Processing Power: H.265 advanced compression requires more processing power for encoding and decoding. Older devices might struggle with this, but the newer ones easily handle it.
Quality: Both codecs offer impressive video quality, but H.265 delivers high quality at lower bitrates, resulting in smaller files without compromising visual fidelity.
Which Codec Should You Choose?
There is no point in debating which codec is better, HEVC or AVC. Instead, you need to choose the one that will be perfect for your task.
Consider End Users: Check the type of devices your customers use. Older devices might lack support, while the new standards will work well with the HEVC encoding. If the audience relies on legacy devices, they might face issues receiving the content through HEVC.
The Content-Type: When you try to choose between HEVC and AVC for standard-definition content, you might find minimal differences between these two. However, if your priority is delivering high-quality content (4K or higher than that), HEVC will be the right choice for you.
Check your Budget: Costs must be considered when choosing between video compression standards. HEVC offers superior compression so extra costs might be required for hardware upgrades or licensing.
Final Say
Technology is evolving continuously, with each new standard getting more advanced than the last. While H.264 was a solid compression standard overall, it also had limitations. H.265 noticed those shortcomings and introduced a better, more efficient compression standard. We all know it is just a matter of time before an even more advanced version appears in the tech market, offering more innovative features. So, to stay ahead, you must keep up with the latest updates to make quick decisions while choosing a video codec.
