Starting a new thread to document a discussion about encoding speeds that I had with Ramit within this thread -
From our discussion, it's my understanding that the fastest profile is handbrake, followed by ffmpeg and then mencoder. However, if you are doing commercial removal, mencoder will skip commercials while encoding, making it the fastest method for a standard
TV show where 25-30% of your file is commercials.
You can also use the preconversion commercial removal flag to remove commercials prior to encoding with any profile. However, the preconversion removal feature may leave behind some artifacts at the cut point, so it is not the default setting.
To summarize, the fastest profiles are:
No commercial removal or preconversion removal = handbrake<ffmpeg<mencoder.
Standard commercial removal = mencoder<handbrake<ffmpeg.
If anyone has done side-by-side comparisons of encoding time for different profiles, post them here.