HEVC (High Efficiency Video Codec)

HEVC (High Efficiency Video Coding), also known as H.265, is a video compression standard that was developed by the Joint Collaborative Team on Video Coding (JCT-VC), which is a collaboration between the International Telecommunication Union (ITU-T) and the International Organization for Standardization (ISO)/International Electrotechnical Commission (IEC). HEVC was developed to address the limitations of its predecessor, H.264/MPEG-4 AVC, by providing more efficient compression and reducing the amount of data needed to transmit high-quality video.

The goal of HEVC is to provide up to 50% more compression than H.264 while maintaining the same level of video quality. HEVC achieves this by using a combination of advanced techniques such as improved prediction modes, larger block sizes, and better motion compensation. HEVC also introduces new tools such as flexible partitioning, intra prediction filtering, and sample adaptive offset (SAO).

HEVC is capable of encoding video with resolutions up to 8K, as well as high dynamic range (HDR) video and 10-bit color depth. HEVC also supports a wide range of video formats including progressive and interlaced video, and both YUV and RGB color spaces. HEVC can be used for a wide range of applications including video streaming, broadcast, surveillance, and virtual reality.

One of the key features of HEVC is its ability to use larger block sizes for encoding. H.264/MPEG-4 AVC uses fixed block sizes of 16x16 pixels or 8x8 pixels, while HEVC supports block sizes up to 64x64 pixels. Larger block sizes allow HEVC to capture more spatial redundancy in the video, which results in better compression efficiency.

HEVC also introduces a new prediction mode called the intra prediction filtering mode. In this mode, the encoder predicts the values of the pixels in a block based on the values of the neighboring pixels within the same block. The encoder then applies a filter to smooth out any remaining noise or artifacts. This mode is particularly effective in areas with high levels of detail, such as textures or edges.

Another key feature of HEVC is its improved motion compensation. Motion compensation is the process of predicting the movement of objects in a video frame from one frame to the next. HEVC uses more advanced motion vectors and allows for more precise sub-pixel motion compensation. This results in better video quality and smoother motion.

HEVC also supports flexible partitioning, which allows the encoder to divide the image into variable-sized rectangular blocks, rather than using fixed-size blocks. This enables the encoder to adapt to the content of the video, resulting in better compression efficiency.

HEVC also introduces sample adaptive offset (SAO), which is a filtering process that adjusts the pixel values of the image to reduce noise and artifacts. SAO is particularly effective in areas with high levels of detail and can help to reduce banding and other compression artifacts.

Overall, HEVC provides a significant improvement over its predecessor, H.264/MPEG-4 AVC, in terms of compression efficiency and video quality. HEVC is becoming increasingly popular for a wide range of applications including video streaming, broadcast, surveillance, and virtual reality. However, HEVC does require more processing power and memory than H.264, which can be a challenge for some applications. Despite this, HEVC is expected to become the dominant video compression standard in the coming years, as more and more applications require high-quality video with efficient compression.