I am using a Mac with a screen of 1920x1200 pixels and on both the streamed version and the downloaded version of content from BBC HD, the video size is much smaller than 1280x720
The 1hr file size is 1.2GB as opposed to 600MB for the SD version but the window in which the programme plays is identical (832x440)

Can you tell me how I can watch HD programmes at 100% on my screen i.e 1280x720 pixels please?

I realise I can watch it at "full screen" but this is not ideal as the image will be larger than 100% and there is no more detail is present in the image.

This is the reply I got from the BBC iPlyer forum:

The desktop application will rescale up or down to match the aspect ratio (16:9) within the video window . So whilst the SD and HD versions are playing in the same sized window they are being scaled differently to fit.

If you have a widescreen monitor that is 1080 capable and do not wish to view it in full screen mode I'd suggest you adjust the video window (click and drag the bottom right corner) to be in proportion to the 720 window from this image - en.wikipedia.org/wik... - or roughly 70-75% of the area of your monitor (note it might be slightly different proportions if you have a standard 4:3 monitor).

Hope this helps

Dave-iPlayerOps