> Kieran Kunhya <kier...@obe.tv> schrieb am Fr, 10.3.2017: > Hi, > > Just wondering, did you see what this looks like on a CRT, especially with > interline twitter. > The original method is similar to what an interlaced camera does, averaging > alternate lines, deliberately lowpassing the data. > Hi Kieran,
Fortunately I still got some Sony Multiformat CRT at work. I don´t have special test pattern that I could use, but some real life clips that produce heavy twitter when interlaced without filtering. My filter reduces this almost the same as existing linear filter does. I tested several filter designs and parameters, but (-1 2 6 2 -1) gave the best results. Sharpness impression is subjective the same as without filtering. Only details that produce twitter are extinguished. There are some rare scenes that already doesn´t look totally clean with linear filter. This is slightly increased with complex filter, but it is the same amount that sharpness is increased and far away from twitter you get when filter is disabled. I also tested with several deinterlacers, software and professional hardware like AJA or Lynx Converters, Sony and TV Logic monitors. They all showed good results. Btw, the (-1 2 6 2 -1) filter also does averaging alternate lines. Black - white - black - white .... lines will result in a 50% gray output. Only lower frequencys and block edges are less influenced. I don´t know if modern interlaced cameras still using linear filters, however they definitely having detail/contour/aperture circuits to compensate blurring. Regards, Thomas _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
