I made a video from photographs in WMM 6.0 and saved it as a WMV, it came out at about 200 MB.
Loaded it to YT and then embedded it in my website at 1440x1080, all very easy no problems at all, shows up as 1080 HD. http://www.jemraid.co.uk/ysp.html
Then I went onto MSP13 saved a similar video as MP4 at 900+ MB converted it using Any Video Converter to a lower file size but still as an MP4 at about 230 MB, loaded it to YT only to find that it was at 1920x1080, useless for my website far too small.
Then I saved it again in MSP13 as an AVCHD at 700+ MB which unlike the MP4 was at 1440x1080 converted this in AVC to about 200 MB MP4 at 1440x1080 loaded it and YT converted it to 16:9 at 360p only.
My last attempt was to convert the AVCHD to a WMV using AVC this showed up on YT as 640x480 at 360p but laughingly the wrong way round 640 high 480 wide
I am going back to using WMM 6.0 sadly for my purposes MSP13 is worse than useless.
Such is life
Cheers - Jem