#711 Suppressing background noise in video frames


I'm an amateur astronomer, testing tightvnc to access remote video from a planetary telescope. My video data is contained in windows with sizes like 640x480 or 800x600, but the planet itself is generally very small (maybe 50 or 100 pixels across) and the rest of the frame is "black". Video noise is always present at a low level due to the very high camera gain used for this recording, and this causes tightvnc to spend 90% of it's work encoding and transmitting this low-level, unwanted background noise.

I've installed the dmirror driver, and enabled the video hinting to tightvnc by giving it the classname for the window where the video is being displayed, but would you consider adding a lower threshold setting such that any pixel values below the given threshold in video windows are clamped to black? This would increase my usable bandwidth by 3x or more. Planetary video generally runs at speeds of 30fps or more, and even with a 300Mbit link between the scope and my house I can't get that rate due to the overhead of encoding and sending noisy frames.

In my case I would set this clamping value to something like 15 (on the scale 0-255), but it would naturally appear as a setting available to the user in the video tab.

ps I have to keep the video jpeg quality set fairly high so I can clearly see what is happening as the telescope is recording, and keep the focus adjusted accurately, so I can't "solve" this problem by simply using a very low quality setting. I've tested that and it doesn't give me a good enough image.

Many thanks for your time, and I hope you'll consider this request. Please contact me directly if you want more info or sample imagery.

Anthony Wesley


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