I just recently received my iPad and besides using the much appreciated and wonderful AirVideo (when at home or within reach of a decent pipe to the Internet), I want to take some video with me on the road for offline playback.
As with all Apple products, this means that I have to get the videos to the right format. From the Apple Web site:
H.264 video up to 720p, 30 frames per second, Main Profile level 3.1 with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; MPEG-4 video, up to 2.5 Mbps, 640 by 480 pixels, 30 frames per second, Simple Profile with AAC-LC audio up to 160 Kbps, 48kHz, stereo audio in .m4v, .mp4, and .mov file formats; Motion JPEG (M-JPEG) up to 35 Mbps, 1280 by 720 pixels, 30 frames per second, audio in ulaw, PCM stereo audio in .avi file format
iTunes is very strict in which content it will copy over to any device and there is no exception. Main Profile level 4.1 videos aren’t copied over. However, using for example GoodReader I succeeded in copying Profile level 4.1 videos onto my iPad and they played back nicely. You might want to check your video files codec details using MediaInfo Mac.
In the past I mostly relied on Handbrake to do the conversion for iPhone or AppleTV playback. And Handbrake always did a nice job, the only caveat is, that it takes a quite while to completely re-encode a video file and utilizes even my iMac with the Core-i7 massively.
As the iPad has more horse power at hand to play back video (read: 720p input files are fine) I tried out a different approach and succeeded. As a starting point I use an 720p-H.264-MKV file (MKV is a container format for any mostly any kind of video and audio codec – more details found on Wikipedia). This MKV file I load into avidemux. The application detects the H.264 codec and provides an option for further processing. As I don’t want to do any editing I choose “No”.

avidemux dialog during opening an H.264 file
As the video track with H.264 is in the right format, the “Copy” option is just fine. For the audio track I choose “AAC (Faac)” and the output format is set to “MP4″. With these settings the video is saved as MP4 file.
The beauty of this approach is, that only the audio track needs re-encoding, the video track remains unchanged. And this saves a lot of time.

Settings for the export as MP4 file
Depending on the size and length of the source video file it may take some seconds to some minutes. From there it’s up to you how you want to proceed.

Processing the video during export
For a test I used the Panasonic demo file (Panasonic.HD.Demo-Flowers.720p.X264.mkv). This file has an original size of 130 MB and a runtime of 3 minutes 20 seconds. Saving it back to the hard disk took about 10 seconds.
You might want to add the resulting MP4 to your iTunes video library (but you have to stay within the Apple allowed Profiles) and sync the file over to your iPad. Or you “attach” the MP4 file to an App within the iTunes ‘App’ tab. Or with an App like e.g. GoodReader you transfer the file via WLan to you iPad. Due to the sheer size of the MP4 files I mostly prefer the USB sync via iTunes.
– PersTechLife –