Originally Posted by
Manfred M
Grahame - check your output settings. There has to be a place where you can set the output side, frame rate and codec. Your 1920 x 1080 is an HD configuration so you need to output to that size. I suggest that you also ensure that your output is progressive (not interleaved) and at least 24 frames per second (which is a feature film standard). I tend to use a 30 fps for online videos. I have found that the H.264 codec gives me decent HD results.
I do my work in Adobe Premiere Pro and these settings are made on the media rendering side, not the input side.