Best video encoding to preserve Macbook Air battery life?

I am about to take a long flight and would like to take my 13" Macbook Air (late 2010 model) to watch some movies. I don't have a DVD drive, so I will be ripping DVDs (that I own), encoding them, and transferring the video files to the Macbook Air. I would like the battery to last as long as possible. What encoding methods should I use so that the Macbook Air uses the least amount of battery?

(I will be using Mac the Ripper to rip the DVDs and Handbrake to encode the video files)

Update: According to some notes by a Stanford student in 2009 about video encoding:

H.264 better video quality but more processor intensive, than MPEG-4 (easier for older or legacy machines). MacBook Air couldn't keep up! Video takes full advantage of processor for encoding and decoding. MPEG-4 worked fine on the original MacBook Air.

Not sure, but it makes it sound as if H.264 makes the Macbook Air work harder, thus draining the battery more quickly.

Solution 1:

You can measure the best for yourself by trying a few settings.

In general, you want the encoding to play without stretching or pixel doubling (and no pixel shrinking) so make sure to pick something that fits your screen naturally. H.264 is by far the best since the GPU does the decoding and it's more power efficient than the CPU for processing video. The data rate can be too high - but most people choose a rate to make the movie small so that's not usually an issue.

Fire up activity monitor from the Applications/Utilities folder and see the CPU usage graph while you are playing various movies. The terminal command pmset -g pslog is also nice to have running while you are testing so you can see the battery estimates over time. If there are no spikes in CPU use the estimate will move down linearly - so you could measure the same 10 minutes or so of a movie and convince yourself you have a good compromise.

The default handbrake settings are probably just fine, so start there and play as needed.

Solution 2:

H.264

It is Apple's preferred codec. Though on it's site it doesn't say anything about battery life. The closest article that I can think of that explains how h.264 is better than another codec for battery life is Chris Foresman's post about flash's effect on the MacBook Air and that generally had to do with displaying ads. However I know that on my MacBook my fans don't kick on when I watch h.264/html5 on youtube verses watching it in flash which kicks my fans on. But I doubt you will be converting the video to flash.

Having Flash installed can cut battery runtime considerably — as much as 33 percent in our testing