![]() JPEG XS is easily integrated with a wide variety of applications. And, for a long time, while the conventional wisdom with JPEG-based compression systems was not to exceed 4:1 compression, JPEG XS has lifted much heavier weight than that, going up to 10:1 with acceptable results while retaining low latency. One Pro AV brand has used it to compress Full HD signals and pass them through a 1 Gbps network switch. JPEG XS as a codec has been around for more than a decade. ![]() NHK demonstrated 8K video passing through a 10 Gbps network switch using a “mezzanine level” codec, JPEG XS, at the 2018 NAB Show. ![]() But it was difficult to see any evidence of aliasing or other artifacts in the decoded signal. As anyone well-versed in video compression knows moving and splashing water is very difficult to compress without introducing artifacts. They used video of a water polo match and showed the compressed signal on a 70-inch 8K LCD TV. (For those interested in the math, the uncompressed data rate was 47.7 Gbps, and the resulting compressed signal was just under 8 Gbps).Īnd NHK didn’t cheat on the demo. Because JPEG XS uses less compression than MPEG codecs, but more than other JPEG-derived codecs, it’s sometimes referred to as a “mezzanine level” codec.Īt the 2018 NAB Show, the Japanese broadcast network NHK demonstrated 8K video (7680x4320 pixels) with 4:2:2 10-bit color, compressed 6:1, passing through a 10 Gbps network switch. While DSC has been demonstrated in the past with as much as 3:1 compression, a version of JPEG known as JPEG XS (ISO/IEC 21122) has achieved much higher compression ratios and was found to exhibit minimal signal deterioration. The difference between DSC and JPEG codecs is that DSC is limited to 2:1 compression-just enough to push an Ultra HD (4K) video signal with 8-bit RGB color through a 10 Gbps network switch. All the luminance and color information in each JPEG frame of video is complete and can stand separate from preceding and subsequent video frames.ĭisplay Stream Compression (DSC), another light compression method that was originally developed in 2014 for display signals, works in a similar manner and is the basis for a proprietary video codec now being marketed for AV signal management, using the older HDMI version 2.0. Unlike MPEG compression, which uses a “copy and repeat” method to minimize redundant picture information from frame to frame, combined with frames that look forward and backward to predict spatial and temporal changes (hence, all that latency), JPEG uses no frame interpolation and prediction at all. (Think of those flip movies you made as a kid.)Īnyone anywhere in the world-using a compliant TV, computer, tablet, phone, or other viewer-can watch MPEG video streams and JPEG-compressed photos over wireless or wired connections. JPEG codecs do this by performing light compression on a series of still frames of video, which are then played back at standard frame rates. There are many ways video signals can be compressed. But which is the best choice? Point of Order: Compression Logically, if we want to replace HDMI-based signal management systems with an AV-over-IP equivalent to deliver low-latency high-quality video, then a JPEG-based codec-or a similar proprietary system that uses light compression-is the only way to go. On the other hand, JPEG-derived codecs have very low latency and use much less compression, but the resulting video streams have higher data rates and large file sizes. So, they’re not suitable for real-time signal distribution and playback. They’re designed for efficiency first and foremost, minimizing bit rates and file sizes. MPEG-derived codecs typically have high compression ratios and correspondingly high latency. The advantages of standardizing on these open-source codecs are obvious: Anyone anywhere in the world-using a compliant TV, computer, tablet, phone, or other viewer-can watch MPEG video streams and JPEG-compressed photos over wireless or wired connections.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |