Compression Jeff Greenberg Compression Jeff Greenberg

Way too much on Handbrake, iPad video Compression

I was answering a question over on CreativeCow about iPad Compression...

The poster is saying he's had odd problems with Handbrake and his iPad. And I thought it really belonged cleaned up and on my blog.

On Handbrake and other converters.

I use handbrake (but I also use a bunch of other tools.) It is important that you have the latest handbrake 0.9.8 and you update the presets (the gear at the bottom of the presets allows updating.) If you've been using handbrake for more than a year, one of two common errors are not picking the right preset or not having the preset updated.

Additionally, I've had success with some of the free converters from the Apple App Store (just search video convert.) Another strong free converter (cross platform just in case you're on windows) is the Miro Converter.

Most of the free converters (including handbrake) are generally using the same engine - ffmpeg. Handbrake was originally unique because it could decode DVD VOBs and get around copy protection. It's great, but there are gobs of other well done ffmpeg free converters.

The common Pro Converters (in alphabetical order) Adobe Media Encoder, Apple Compressor, Sorenson Squeeze and Telestream Episode, will absolutely work all the time - it's their product.

On iTunes sync

I've (personally) become a little frustrated on the pro video side with itunes; the sync process/time is at best annoying. I'm a fan of the third party players (like gPlayer, flex player, CineXPlayer) as I can add a video in the apps tab of itunes without having to sync the entire device. One, which I can't recall at the moment, will give you the option to use the hardware chip (or not).

Specific Apple guidelines

Apple has very specific guidelines for what your video has to be to work on the iPad (or other iOS devices.)

I dug up the specs from this webpage

Video formats supported:

  • H.264 video up to 1080p, 30 frames per second, High Profile level 4.1 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 per channel, 48kHz, stereo audio in .m4v, .mp4, and .mov file format
  • 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

You probably will want the first one - the High Profile 4.1.
The High profile part refers to a strict set of rules - necessary in this case because there's a hardware decoder chip that allows playback (this is similar to what all of these devices are using.)

The High profile part refers to very strict ways the encoder is supposed to work (what video space it uses, how b frames should be ordered)
The 4.1 part is the specific sizes, fps and data rate that it supports. It does specifically 1080p and 720p. I didn't know till I looked that it specifically does 2048x1024 - probably wasted on all of us anyway.

In conclusion

Yes, some non-broadcast standard sizes may work; other sizes aren't particularly well tested. I do know that if you conform to the specs, it's playable 100% of the time. You just need a good encoder with the right settings.

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