I have been asked by one of my (web development) clients to edit a video. This isn't something I claim to know much, or anything really, about.

I've removed the irritating audio, played with effects and adding fade in/out. All so far so easy and liking how straight forward it has been so far using Kdenlive (on Fedora)!

The video has a small amount of text on a black background that my client wants removing. I've tried both Obscure and AutoMask filters, which hide the text but leave a blurry image in place.

Is it possible to change settings of one of those to render just a black rectangle over the area defined rather than try and blur it? Or is there another approach I should be using?

There might be other ways, but what does work is:-

Add a colour clip and select black. Place it over the top of your video clip. Right click on your colour clip and select Transition > composite. Now add effect Crop, Scale and Position to the colour clip. Make sure your timeline cursor is somewhere over the two clips and play with the settings in the effect. You'll soon get the idea.

Thanks Normcross, with a bit of fiddling and gnashing of teeth that seems to have worked, if I transcode without any rescaling of video.

If I attempt to rescale to a smaller size during the transcoding, in the output video the cropped layer retains its full size as it was in the original project rather than being resized to fit the scale video.

Is there a way to rescale both clips together into the product file or do I have to transcode to merge layers/clips then open that file to retranscode to smaller dimensions?

Actually I've never used transcode the way you're using it, but if the colour clip doesn't resize I guess you'll have to go the way of two transcodes. Anyone else know?

Alternatively, just render out that section of the clip with the text/colour clip and pop that in the timeline.

It's a bit of a long way round but I managed to get the results I needed in the end.

Another way to black a region is as follows:
1. position the cursor in the timeline where you can see the text to be blackened. This will be helpful in later steps.
2. add a new title clip. In the title editor click on the checkbox at the bottom of the dialog to show the background-- so you can see the text to black out.
3. Draw a black rectangle in the title editor, position it, etc. Close the dialog.
4. Add the title to the timeline in a track above your video with the text. Add composition as mentioned above. Resize title clip length as necessary.

Of course, that's the way to do it! Don't know why I didn't think of it. Cheers DiveO. I suppose his rescaling problems would still exist though.

Maybe this is the same composition behavior I also experienced when converting my projects from 720p to 1080p: several compositions got scaled down to 66.7 from 100 percent. I had to manually fix them.