iBooks File Size Limitation and Optimizing Media for it

Question

iBooks File Size Limitation and Optimizing Media for it

I am a high school yearbook adviser. I have undertaken the task of making an iPad edition of our 2012 yearbook. I have run into a few questions:

1) iBooks are limited to 2GB. I seem to have little control over, or little knowlege on how best to optimize the media going into IBA.Do I need to spend time resizing the images or optimizing video before adding them to IBA in order to control the size of the final product?

For example, I hope to create a book with 20+ videos in the 2-5 minute range. The book would obviously have hundreds of photos. The school has more than 2000 students, so class images alone would be contain more than 1500. That would be the bulk of it, but there could easily be another 1000+ images covering the many aspects of the year.

I don't see any way all that will fit into a 2GB file....does IBA attempt to compress your content into the requisite file size? Is there a way to better optimize the media going into IBA to attempt to meet the final file size? Is the 2GB file size limitation a rigid restriction?

2) All our videos are being accessed online via QR codes in the print book. It is being handled by yearbookunlimited.com and they use a CDN to deliver the content as it is called up. I have access to the URL's for each. Would it be better (in terms of keeping the file size down) to send the user to that link instead of housing the actual video in IBA? I would rather have the video within the document itself. I think it would be a better experience, but I don't know that it is feasible given the file size restrictions.

Posted on Apr 19, 2012 6:01 AM

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Answer 1

Apr 19, 2012 6:31 AM in response to James Roller1

I have about 2 hours and 10 minutes of 640 x 480 video in my book. That accounts for around 1.3 GB. If you use 1024 x 768 images, expect to use about 0.8 MB per image. If you want high resolution for the new iPad at 2048 x 1536, expect to use about 1.8 to 2 MB per image, call it 500-600 images per GB at high resolution, or around 1100 images per GB at lower resolution.

As far as I know, IBA doesn't increase compression to keep things below the 2GB limit. I haven't tried this, but I suspect that IBA might well create a file that's larger than 2GB. If so, you won't be able to publish the book via the iBookstore, but you could still export the .ibooks file and distribute it via download, memory stick, or DVD.

If the 2GB limit really hurts you, why not just make it volume 1 and volume 2? Voila, double the space 🙂

Michi.

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Answer 2

Apr 19, 2012 6:50 AM in response to MichiHenning

Excellent information, Michi. Thanks.

You say, if you use 1024 x 768 images... that's just it: I'm just using the images without resizing. Some may be 4MB files when dragged in; others may be 300kb. I am not doing anything to them. Should I? Does that help? Or does IBA "handle all that" when I drag and drop?

Also for the video: we're using iMovie and we just "Share" to iTunes and choose Large. Should I be choosing a lower setting or, again, does IBA not care and will take the Large and resize it?

I just don't know how it works or what are the "best practices" for this platform. Obviously, we are in the early stages of IBA and the documentation and experience of the community surrounding it is still maturing, so I guess these best practices are still in the formative stage.

I have to say I chuckled at the wisdom and simplicity of the 2 Volume suggestion. I'd like to keep it as one, and I'd like to sell it on the store, but your idea is ingenious in its simplicity: just make 2!

Thanks, again...

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Answer 3

Apr 19, 2012 6:59 AM in response to James Roller1

James Roller1 wrote:

You say, if you use 1024 x 768 images... that's just it: I'm just using the images without resizing. Some may be 4MB files when dragged in; others may be 300kb. I am not doing anything to them. Should I? Does that help? Or does IBA "handle all that" when I drag and drop?

It's not well documented. I get the impression that, if you drop an image that has resolution higher than 2048 x 1536, it is down-sampled to that size. You should at least crop the image outside IBA before dropping it in. If you want to save space, down-sample the image first to 1024 x 768 (after cropping).

James Roller1 wrote:

Also for the video: we're using iMovie and we just "Share" to iTunes and choose Large. Should I be choosing a lower setting or, again, does IBA not care and will take the Large and resize it?

Instead of sharing to iTunes, export the movie to iPad format (File -> Export) and select 640 x 480. That'll give you reasonable quality at around 12 MB per minute.

James Roller1 wrote:

I have to say I chuckled at the wisdom and simplicity of the 2 Volume suggestion. I'd like to keep it as one, and I'd like to sell it on the store, but your idea is ingenious in its simplicity: just make 2!

Thanks! Two's better'n one 😉

Michi.

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Answer 4

Nov 8, 2012 5:35 PM in response to James Roller1

Don't forget that this limit only applies to the iBookstore. If your yearbook is free, you can distribute it from your web site or wherever. It can be 10 MB or more. Still, that can be a barrier to those with limited bandwidth available to them.

BTW, I think that this is a really cool project.

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