Ironic really that you should choose "He Who Knows" as your moniker ;-)
Trimming usually refers to reducing a clip's duration, not its size.
If you want to reduce its size in pro you can scale it in Video Effects/Motion/Scale. Thus...
If, on the other hand, you want to crop a clip, trimming so that only a portion remains visible it's...
Video Effects/ Transform/ Crop. Thus...
To become the one "who knows" you must learn and to learn you most not be afraid of asking stupid questions :-)
But thanks guys, that was a great help to me!
Well, I have one additional question.
Now I used the crop-function to hide all elements which should not be visible leaving only the recording of the actual browser contents.
The crop tool, however, "blacks out" the area which is cropped away, rather than resizing the output size. I suppose this is done because in a real world production intended for viewing on a TV or in the cinema you would want to stick to standard resoulutions. The current resolution of my "canvas" (Photoshop terms?) is 1440x900 as this was the resolution I did the original screenrecording in. The cropped area is somewhat smaller, but still larger than 1280x720 which is what I would like to export to.
What is the easiest way to go from the current scenario to an 720p output file, while only cropping the contents which is currently black bars in the process?
Below I added a screenshot to show what my program monitor currently looks like. The resolution is 1440x900 and I need to remove as much as possible of the black area and go down to 720p.
If you do not want that black border, you can then use the fixed Effect>Motion>Scale to Scale up the Cropped Clip.
For Export, many/most formats/CODEC's allow one to adjust the output Frame Size from the original. What is you output scheme? What format/CODEC are you planning on using?
For now I am using the scale function to scale the video back up to 1440x900 (with a thin black border on top and bottom, which is ok). I am exporting to both H264 and Flash in 720p.
My issue right now, however, is that screenrecordings are quite sensitive to video-scaling (text readability) and it seems that the picture gets slighty blurry (although it could be related to the encoding as well) from first the upscaling to 1440x900 and then the downscaling to 720p during export, but I can't seem to find any other way of doing it.
If I had planned the recording better I could have set up the browser window to a size of exactly1280x720 enabling me to to avoid any scaling.
Its not good to scale things up and then scale them down.
Just start off with a 720p timeline and then just scale it down to the size that works for you.
Yes, if things match, between the source footage, and the Project Preset, there should be zero Scaling going on. That is best. Then, one would Scale with the output, to the desired output specs.