Frame and refresh rates explainedIf you believe you know all about 100Hz, 200Hz, judder and motion blur, think again. They can actually be mind-boggling because of the myriad video standards and behind-the-scene processing implemented by each TV manufacturer. For starters, have you ever wondered how Blu-ray discs played back at 24 frames per second "gel" with any of the above-mentioned screen refresh rates? We've approached major vendors with 200/240Hz HDTVs, such as Samsung, Sony, Philips, Toshiba and LG, for clarification. Here're some of our findings.
What is frame rate? A motion picture is depicted by many frames of static images.A moving picture comprises a sequence of static images with each of them referred to as a frame. Most movies, for example, are filmed and transferred onto Blu-ray discs at a frame rate of 24 frames-per-second (fps). For DVDs and TV broadcasts, these 24fps films are converted to 25fps and 30fps for Europe-oriented PAL and US-centric NTSC video standards, respectively. There're also the console games mastered at higher 50fps and 60fps.
The most common frame rates a TV will have to deal with.There're two types of judder associated with frame rates: Film and 3:2 pull-down. The former is inherent in movies due to the low 24fps bottleneck in capturing fast motion. The latter is caused by auxiliary video processing applied by the display (more on this later). What is refresh rate?While refresh rate is technically applicable only to CRTs, it has been loosely used to describe the frequency at which images are rendered on a TV screen. This can range from 48Hz up to 240Hz, depending on display type, supported video standards (NTSC, PAL, etc.) and played back content. In a nutshell, each refresh rate will output the corresponding number of picture frames per second. Take a 100Hz screen which will reproduce images at 100fps. A higher refresh rate not only reduces flickering for all TVs, but minimizes motion blur specifically for LCD panels.
Some of the common refresh rates found in TVs.To adapt the earlier-mentioned frame rates from different content to a TV's compatible refresh rates requires frame rate conversion. These include various pull-down schemes as well as motion estimation motion compensation (MEMC) algorithms. Tags: Samsung Electronics Co. Ltd., TV, Blu-ray Disc, Image, Console Game |
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