Once in a while I like to edit videos using Sony Vegas (Video editing software), I mainly upload to 2 websites: YouTube and Vimeo. I like to keep my videos both un-edited and edited at the highest resolution possible. My camera shoots at 1080P resolution (1920X1080 pixes). Like many other consumer and prosumer software editors, Sony Vegas can edit/create videos at 1080P.
When I render my final edited project I rendered in MP4 container extension using “MainConcept AVC/AAC” which is an H.264 codec, this format plays in most environments and plays with no problem in windows 7 and it also turns out to be the format that Vimeo prefers.
When using this format you can choose to use Constant Bit Rate (CBR) or Variable Bit Rate (VBR) I usually used CBR, the problem when using CBR is that the file size is bigger than the same video using VBR, because when using VBR the bit rate at which the video is played changes depending on how complex or simple is the scene.
I recently created a 4.5 minute video using CBR at 1920X1080 resolution, and it was just short of 1GB in size, which I was not able to upload to Vimeo since it only allows me a 500MB max quota because I have the free version of vimeo.
I did try to lower the resolution to 1280X720 still using CBR, this reduced the file size to almost 500MB which I could used to upload to Vimeo, but I really wanted to upload the highest resolution possible, so I created the same video using Variable Bit Rate instead of Constant Bit Rate, which allowed me to create the same HD video (1920X1080) at a file size to almost of 500MB.
Short story: to maximize resolution and video size use the following settings:
Use MainConcept AVC/AAc codec
Use VBR (2 passes) instead of CBR to make the final file size smaller
Also you can try to play around with the maximum and average bit rate, but keep in mind that a lower maximum and average bit rate might decrease video quality.
For more information about HD TV formats see this good explanation in wikipedia: