Video and iOS device fragmentation

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Video and iOS device fragmentation

Although the ability to differentiate versions of a collection by Audio, HD video and SD video are welcome, our target audiences are more varied than that, especially in the mobile space. We now have multiple generations of every iOS device and those imply an increasing number of optimal formats. Not only do we have the obvious iPad vs iPhone/iPod touch window size difference, we also have differences in MPEG-4 profiles (Base vs Main).

In QuickTime X Player, there is a function called "Export for Web" that creates a package of files which include a reference movie that detects whether the request for a video comes from a regular computer, a WiFi iPhone or iPod touch or an iPhone on cellular. I would suppose that this will be expanded to include iPad when Lion ships. The point here is that Apple has a very effective mechanism for reducing this complexity to clicking on a poster image to invoke the selection of the appropriate version of a video.

However, I see no support for this in iTunes U. Expanding the Audio/SD/HD selector won't scale well in my opinion because most end users will not understand that their second generation iPod touch won't play video optimized for iPhone 4.

How do others deal with this? What's the prevalent thinking on how to handle this now and into the future where it will only become more complex?

Dual Quad 3.0 GHz PowerMac, Mac OS X (10.6.2), 1G iPad 2G iPod touch

Posted on Mar 25, 2011 8:30 AM

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Answer 1

Mar 29, 2011 10:54 AM in response to Frank Lowney

We're close to launching our public iTunes U store and I gave a lot of thought to this issue before I encoded our back catalogue of around 300 longform videos for iTunes U.

I decided to keep things simple and use a single format. I encode all our 16:9 video at 640x360, 600 or 1000kpbs, h264 mp4 baseline profile using the iPhone preset in Sorenson Squeeze. This is the highest resolution that I can use while maintaining compatibility with legacy devices. It's also a good size for delivery to the flash media player on our website so we kill two birds with one stone.

For now I have decided against using HD - too much hassle and not enough bandwidth!

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Answer 2

Frank Lowney Author

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111 points

Mar 30, 2011 1:23 PM in response to Tom_Williams

Agreed that this is a good one-size-fits-all approach. One thing though, I have found that 640x480 fits better (no scaling or black bars) on Apple mobile devices, including the classic iPod.

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Answer 3

Mar 31, 2011 4:21 AM in response to Frank Lowney

Hi Frank

I agree 640x480 would be a better size for devices like the classic iPod that have a 4:3 square screen. However I suspect there are more users with devices like the iPhone and iPod Touch which are better suited to 16:9 aspect ratio.

The reason I use 640x360 is that (almost) all of our video is recorded in wide screen 16:9 aspect ratio. If I were to use 640x480 I would need to stretch the video vertically or have it postbox with black bars at the top and bottom which would compromise the viewing experience. Where we record video in 4:3 aspect ratio, however, I do use 640x480. Either way the video should scale to fit to device screen so I prefer to use the aspect ratio that was used when the video was recorded.

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Answer 4

Frank Lowney Author

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111 points

Mar 31, 2011 6:11 AM in response to Tom_Williams

Actually, 4:3 works better on iPad and iPhone/iPod touch IMO. I base my conclusion on the work of Jan Ozer reported here: http://digitalcontentproducer.com/videoencodvd/revfeat/encodingapple_ipad0420/ and empirical testing of my own. Initially, I too thought that 640x360 was as close to universal as one could get but then did actual testing as reported here: http://frank-lowney.blogspot.com/2011/02/revisiting-audio-and-video-in-epub.html.

As you'll see from the screen shots, 640x360 introduces black bars and cropping/scaling that do not make the best use of available screen real estate. Of course this is virtually unavoidable if your source is 16:9 as my test example was. I do plan to follow up with another blog post that uses SD (4;3) source to 640x480 and that will show that no black bars or cropping/scaling is introduced on iPad, iPhone/iPod touch or classic iPod with video -- a better use of available screen real estate IMHO.

So 16:9 is great for targeting the desktop (viz. the iTunes.app) but 4:3 is best for targeting playback on all of Apple's mobile devices. Anamorphic widescreen techniques may offer other options that I am not currently aware of (see: http://en.wikipedia.org/wiki/Anamorphic_widescreen).

I suppose that this is the reason why the new iTunes U Public Site Manager (PSM) enables one to specify a "Collection Media Format" for collections that is divided into audio SD video and HD video labels. If you identify a collection as one of these, you are prompted to identify collections for which one or both of the other two labels is appropriate. How this appears to the audience is something that I will have to investigate by experiment. It may actually be the answer to my initial question.

Thanks for the discussion. It has been very productive for me.

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Answer 5

Mar 31, 2011 9:43 AM in response to Frank Lowney

Me too and thanks for those links there's some very usual information that I wasn't aware of.

Tom

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