From a video? I dont think you can, hence the whole point of it, unless you chop out the whole half of the video where the watermark is
paste any thing where water mark shown in video BY edit your video in any video editing software.......
add a good designed banner at the top of the video right where the watermark is. unless the watermark is on the whole video you wont be able to do anything about it.
You can blur part of video by using blur filter... or use nearest pixels to fill watermark area... CROP it isnt better way to remove watermark. I use to it VideoCharge Studio. You can 1. Crop 2. Blur 3. Compensive - try all methods and select better for your!