Quicktime Pro, Components, and the iPhone …
Tired of all the iPhone news and buzz? Sorry about that. As media producers I believe it is our responsibility to educate ourselves entirely when a new and viable method of content access surfaces. Video on portables is obviously nothing new. However *if* this device is destined to set a new standard in terms of portable video consumption, various aspects of optimized content distribution need to be addressed.
First let me state that I have an iPhone. I purchased it here in NYC on the Monday following the release date. My entire purchase and setup experience took less than 15 minutes. What drove me to buy this device? The new video specification that Apple has implemented. I truly believe Apple will maintain the exact same video specification with the inevitable release of the widescreen video iPod that will not include phone features. In any case I was anxious to begin to experiment with it. So far my experience has been 100% positive. More on this in a moment …
As HD camcorders continue to become more affordable, many video prosumers are shooting native widescreen video. If you intend to prepare your produced widescreen video for optimized iPhone viewing, I have a few suggestions:
Typically widescreen distribution aspect ratios are calculated by dividing a predetermined horizontal pixel measurement by 1.78. For example: if you decided to embed a widescreen video clip on your site with a horizontal measurement of 640 pixels, 640 divided by 1.78 = 359.550. In this case the widescreen aspect ratio of the site video should be 640×360. What is the significance of 1.78? Since the 16×9 spec is nothing more than a relationship of numerical units and not pixels, dividing 16 by 9 gives us 1.777 [1.78], our magic number. Ultimately 16:9 is equivalent to a ratio of 1.78:1 [1.78 units wide by 1 unit high].
As I stated in the previous post, the native aspect ratio of the iPhone is 480×320. Not true 16×9. In order to maintain proper scaling of your widescreen iPhone videos in the landscape position, encode your distribution copies at 480×270. The one caveat is that the viewer will need to enter the theatrical aspect ratio mode by double tapping the iPhone screen in order to view the video as intended. Skipping this step will force the video to play back in a cropped state.
What about containers, codecs, frame rates, and data rates? Lot’s of interesting stuff to talk about here. Acceptable results can be achieved by simply following the QT Pro settings recommended by Apple, located here. I went ahead and made a few changes that in my opinion result in improved quality.
It’s important to remember that enhanced parameters will increase the size of your files, and in some cases create playback snafu’s due to the lack of sufficient bandwidth. For example Apple recommends restricting the video Data Rate to 900 kbps for WiFi access. I decided to bump this up to 1500 kbps. In this example I used the MPEG-4 container and the H.264 video codec [Single-Pass, Baseline], 480×270, 30fps, and Keyframe every 96 frames. I had no trouble accessing and playing the encoded movie directly from the web on the iPhone using my internal WiFi network, a phantom network in my building, as well as in a public place. As far as EDGE compatibility, forget it. Video encoded using the specified parameters would never playback. This makes no difference to me due to my total lack of interest in ever using the EDGE network for casual video viewing.
I would also like to suggest that you look into the 3ivx MPEG-4 Codec. This is sort of a secret weapon of mine. It can be purchased for $20 [for personal use] and easily installed/incorporated into your QT Pro workflow. According to the site, 3ivx “features enhanced compression efficiency and introduces new Advanced Simple Profile features such as B-Frame and QPel encoding. The Mac OS X versions are compatible with QuickTime 7 and are Universal Binaries optimized for Intel based Macs.” It also performs well when incorporated with Compressor, Episode Pro, and MPEG Streamclip. Needless to say video encoded using this codec looks great on the iPhone.
I’m trying to secure permission to use 30 seconds of high quality HD footage that I will optimize for the iPhone for demonstration purposes on this site. I’ll point to it in a future post. For now you have my initial thoughts.
Well encoded video looks amazing on the iPhone. Bring on those widescreen video iPods …
** Please note: Be careful when installing video codecs on your system! Please read the supplied documentation thoroughly, and install at your own risk …
** Be sure to check out MPEG Streamclip, a fabulous piece of free software.
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