Video encoding | Focus the visual quality. So, whenever that happens, the network should synthesise new details. The residual auto-encoder component achieves this. In a user study, this approach significantly outperformed previous neural and non-neural video compression methods, setting a new state of the art in visual quality for neural methods. Traditional video compression However, there is still plenty of focus on traditional compression technology in several respects. The first silicon design to implement an MPEG-5 Low Complexity Enhancement Video Coding (LCEVC) decoder design block is boosting the development of more efficient chips. MPEG-5 part 2 LCEVC is the latest standard from MPEG and the ISO. It specifies an enhancement layer which, when combined with a base video encoded with a separate codec such as H.264, HEVC or VVC, produces an enhanced video stream. This stream provides new features such as extending the compression capability of the base codec, lowering encoding and decoding power consumption, and providing a platform for additional future enhancements. The latest LCEVC decoder IP supports picture resolution up to 8K, pixel widths from 8 to 12 bits and chroma subsampling formats ranging from 4:2:0 up to 4:4:4. The IP also features fast and easy integration into a chip and is delivered with fully user-configurable control software. The latest low-bandwidth H.265 video encoders support low-latency video streaming at up to 4K resolutions. Users can choose H.265, H.264 or motion JPEG (MJPEG) that compresses each frame individually for the video compression, with configurable bitrates, encoding profiles and the option for embedded digital or analogue audio. H.266/VVC uses the same underlying architecture as HEVC but brings enhancements to each of the coding tools. The enhancements include video frame structuring to allow the encoder to focus on specific areas of less interest for higher compression to reduce the overall bit rate. A common approach uses the fact that successive frames in a video are often visually comparable and can be efficiently predicted from preceding reference frames by motion compensation, called temporal prediction. When temporal prediction is used, the coded signal is the difference between the blocks of the frame to be encoded alongside the predicted motion of the block. Video codecs exploit this by only sending some independently coded frames (the I-frames or key frames) along with frames using temporal prediction that refer to already decoded frames. VVC improves the motion vector prediction compared to HEVC, reducing the coding overhead for determining the motion vectors. It supports two motion vector prediction methods, Merge Mode and AMVP Mode. In both modes, a list of candidate motion vectors is built, and an index is signalled to indicate which candidates to pick from the list for deriving the final motion vectors. Frames are examined and subdivided into smaller sections for processing. Like HEVC, VVC uses coding tree units that can be divided into smaller coding units but has larger block structures of up to 128 x 128 pixels. VVC can combine several blocks into logical areas defined as tiles, slices and sub-pictures so that the decoder might elect to decode only the areas of the video that are necessary, such as in the application of panoramic and 360o video, where the viewer might see only a small section of the entire frame. In HEVC, there was a single tree structure that allowed the splitting of each square block into four square sub-blocks recursively. VVC extends this, allowing each block to be further subdivided horizontally and vertically into two or three smaller elements. Applying this technique improves the adaptation of the encoder to the input, but at the expense of a considerable increase in the complexity of the video coding process. The latest real-time VVC software encoder for 4Kp60 60 frames/second video now gives an 18% bitrate saving at equal quality compared to the HEVC real-time encoder. For 8Kp30 30 fps streams, the saving is 27%. For standard resolution, the difference is even greater, at 40%, but this gets better over time as the implementation of VVC is improved. Over the years, for example, HEVC has improved the 45 The Zcube H.265 encoder card (Courtesy of Z3) Compared to HVEC, VVC improves the prediction over HEVC, which reduces the coding overhead for determining the motion vectors Uncrewed Systems Technology | October/November 2023
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