Try this out:
http://sight-creations.com/fxexchange/TCWmarkRemover.zip [free - license]
It does exactly what I described, with some extra optional enhancement tools.
To start with, don't stray too far from the default settings.
There's an onscreen control so you can drag the effect over the timecode (or watermark). Use the Size Height and Size Width sliders to cover the TC area. The rest can be used to "blend" pieces of the surrounding video into the space (but blur should still be used.)
Brief explanation of parameters:
Offset Distance: there are 2 copies of the video used to fill the masked area. This parmater controls sliding the copies, one from above and one from below into the space. They are blended together.
(I consider all the following "expert" settings)
Max Stretch Horizontal/Vertical: These controls scale the copies. It is not recommended that you go below 85%, just because when the mask is close to an edge of the canvas, you'll not have enough material to fill the space.
Mode: How the two copies are blended together. There are two. Lighten and Darken. They're both about the same except that in lighter video (surrounding the mask) Lighter will match better than Darker, and vice versa. It's not overwhelmingly important which you pick (there's more! see below)
Blur: applies a Gaussian Blur. Zero blur is available... recommended range: 200-400.
Feather: helps smooth the effect into the surrounding video... sometimes (it can create a kind of border effect OR a kind of "lens" effect.) You can do some interesting and/or weird stuff by abusing this parameter 😉 [along with Scale Height -- if you need > 400%, click and drag up on the number value.]
Roundness: lets you taper the corners
Saturation/Value: These two parameters let you try to match the surrounding video a little better and can be used to enhance or override the Mode you picked somewhat. Typically, use the "lightest" touch on Saturation. Value is the parameter you'll use the most. Left of 1.0 is darker. Right is lighter. 1.0 is no change/default.
Center: this is the location of the Onscreen Control. Typically, a watermark or timecode is NOT going to move over the course of a clip. That said, who says you have to use this just for those two things 😉 You might want to keyframe this to follow something...
All parameters, except the Mode, can be keyframed, so if you really want to work at it, you have the ability to minimize the visual effect that a portion of the screen is blurred out/obscured.
