I am going to be doing a bit of traveling and I'm planning on transcoding some of my DVDs to my laptop drive before I leave so I can watch them on the plane. I was wondering if anyone had any experience with specific video codecs and battery life during playback. I'm not as concerned about file size and picture quality as I am about being able to get the most hours out of my battery. Although I guess smaller files would allow for less harddisk reads, which helps, but codec computational complexity has to factor in there too. Anyone have any experiences with this?

There are more factors to it, but basically i'd look for lowest CPU load during playback. Make some short test files to check that. I'd also try different media players, but i reckonMedia Player Classic should be pretty good in this regard.

for low battery consumption DivX 3.11 might be worth looking into

For the lowest processor usage, first of all reduce the resolution. Also, if you are planning to use an mpeg4 codec don't use something like qpel. Probably, b-frames are ok. Use mp3 audio or something like that, no ac3 or dts audio obviously . And if you use mpeg4 make sure you use ffdshow to decode. There is no faster mpeg4 decoder that I know of than this one. I wouldn't use divx 3.11, I don't see any advantage over mpeg4 in this instance as long as you carefully choose your setting like I said before, no gmc or qpel. Divx3.11 is not going to decode that much faster than mpeg4 with b-frames and certainly not any faster if you just use simple profile mpeg4 (ie no b-frames or other asp tools).

Plain mplayer is even faster than ffdshow.

Sure, if cool with command line ffdshow uses the same code though so it won't be *that* much faster. Basically, it depends how it was built . But, you are probably right mplayer might be somewhat faster.

It is likely that Direct Show bloats the hole thing.

VLC for windows is even faster than plain mplayer for windows

but I've never seen anything faster than mplayer in linux!

O yes it is faster

i can kinda watch divx 3.11 on my pentium 200... mpeg4 SP was impossible to watch. i didnt use ffdshow though, but i suspect the orignal DivX 3.11 decoders to be faster anyway... and ffdshow wouldnt run on Win95

Just wanted to throw this out. Instead of using divx or some other mpeg4, would just ripping the vob files off the dvd and playing those off the hard drive less cpu intensive? The files would be huge though. Or what about vcd or svcd?

Just a thought.


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After seeing how much CPU divx uses, I'm considering that, possible with a requantizing of the MPEG-2.

If quality is not a problem, MPEG-1 at a resolution around 352*288px would use less CPU than MPEG-2 and other codecs. For playing you can use the default Windows codec or the Ligos one using a small player like VLC.

i vote mplayer.

for the same source (stupidly intensive for my machine - 512x384x50fps xvid+ac3), ffdshow+MediaPlayerClassic gave me 100% CPU, decoding speed of just under 50fps (it'd drop frames about 3 times a second in parts), whereas mplayer gave me 50% CPU use, and obviously no drops at all. when set to null output i got 30% CPU, but i suppose that doesn't count.

mplayer in linux would be something to observe indeed! if you're all for battery loife, then CLI is the way to go. try one of those live-boot distros made specially for playback on any machine.

vobs are a bad idea - too much data to move around, regardless of requanting. remember there's still full-size frames that are being sent to the display card.

yeah, i'd go xvid, halfpel, and probably mp3 sound (though i suspect ac3 isn't really that CPU intensive - after all it's a pretty old codec that's been around since laserdisc's hayday in the very early '90s).