CBR bitrate calculations should consider factors other than resolution

Currently, we only use the resolution to determine our -b:v and -maxrate argument values. However, we should consider other factors in this calculation:

• The hard cap file size limit of 200 MB.
• The duration of the cut
• If we are downscaling the source video

No one should be using this bitrate control mode unless something is wrong. This should be low priority IMO.