Video iphone question - 720p on iphone 3g/3gs?

This may be a ridiculous question - but I know nothing about videos, video files or playback.

If I have videos in 720p format (high definition) will they play normally on an iphone 3g/3gs which doesn't support hi开发者_StackOverflow社区gh def? Or will I have to have 2 different videos and test the device?

Thanks Tom

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I'm just doing some tests with html5 video and it looks like the 3/3GS will only play video upto 640px wide. This is via Safari so not sure if the same rules apply to native video.

The solution might be to encode the video as mp4 but include 2 video tracks (one as a baseline profile - low quality/small size video and one as a high def profile video). I'm not sure how to acheive this but will report back once I figure it out.

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The iPhone 4 is technically capable of 1080p playback, while the 3G[S] is capable of 720p. I am not sure about the 3G, but I'm assuming it's less than the 3G[S], most likely it's max is slightly above VGA resolution.