Ideal settings for iPod compression?

[thefiddler]

I would assume that the h.264 codec is ideal using the ipod's native resolution. But what's best? If we're talking only for viewing on an iPod screen, what settings are best to preserve battery life, and display a good quality video on the screen? I know that if you compress AAC files too much, it can actually take more processing power to play them, and therefore take down battery life. I assume it's the same with video, does anyone know is there a sweet spot? And if so, is divx or h.264 better for this? And what bitrate is ideal?

[teegee420]

I use 320x240 H.264, 768kbps video, 64kbps audio. I've pretty happy with the quality for both. I get at least 3 hours of playback. I could try dropping the video resolution, bitrate and frame rate to squeeze more juice out, but it's just not worth it for me.

[thefiddler]

You know, I tried encoding some stuff with 15fps instead of 30. It made almost no difference in filesize. Must have something to do with the efficiency of the h.264.

Do you have the 30gb or 60? I need to know for comparison. The 30 & 60 have different battery sizes.

Back to my original question: Anyone know? Like has anyone done any extensive testing to see if there are some "ideal" settings just like 128kbps 44khz is best for AAC audio on the ipod? Or has apple ever said at any point?

[jagabo]

You know, I tried encoding some stuff with 15fps instead of 30. It made almost no difference in filesize. Must have something to do with the efficiency of the h.264.

You probably used the same bitrate for both. File size = running time * bitrate. You can use a lower bitrate with lower frame rates and get the same picture quality.

I believe the iPod has a 320x240 display. You're probably best off encoding with that frame size (if you only plan to watch on that display).

There is no optimal bitrate for video. Every video is different. Use h.264 in Single Pass Quantizer mode (constant quality). Pick a quality level you're happy with and encode. The codec will use whatever bitrate is necessary, at every frame, to get the quality you specified.

[teegee420]

Do you have the 30gb or 60? I need to know for comparison. The 30 & 60 have different battery sizes.

I have the 60gb one.