cant do perfectly... if the watermark is on the black label, then resize the video to remove watermark, cuttin out the black part. Use TMPGEnc for it.
In-movie watermarks can be removed using software like VirtualDub & Adobe Premiere.
The closest u can come to watermark-removal for free r using filters for VirtualDub - DeLogo and LogoAway.
Blurs/Heals/Masks the area. U might end up with a fuzzy greyish, translucent box where the logo was.
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I also heard sometime back that DScaler 5 has real-time watermark removal.
DScaler is an open-source video deinterlacer & scaling program. It captures video, processes it, and scales it for presentation on a projector or computer monitor. Grabbing video from a DVD player, TV, game console, laserdisc, or VCR. Deinterlacing video source, Detecting and removing 2:2 pulldown (PAL) and 3:2 pulldown, Reducing video noise.
Of course, it is a media player too.