What happens if I want instead to feed the movie to an iPhone?
In Movies: TiVo to Mac to Apple TV & iPhone (Part I), software called ImTOO HD Video Converter 6 (HDVC) converted my Gigi MPG.mpg movie file — the original TiVo recording, moved to my Mac and no longer DRM-protected — from its original MPEG-2 digital video format to the MPEG-4/H.264 digital video format. The output file was made by HDVC in a manner suited to an Apple TV — including the use of honest-to-goodness high-definition (HD) video in the output file.
But an iPhone can't and won't use the same MPEG-4/H.264 video output file as is appropriate for the Apple TV. The iPhone's small touchscreen is incapable of all that wonderful video resolution, and its onboard processor can't keep up with decoding an HD file's high bitrate. In fact, iTunes will simply refuse to sync the HDVC HD output file to an iPhone.
To get an output file that will sync to an iPhone, I need to use a different HDVC profile and make a second MPEG-4/H.264 copy of the movie:
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| Selecting iPhone - H.264 Video Profile |
I select HDVC's built-in iPhone - H.264 Video profile in the graphic above to get:
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| HDVC Set Up for Converting for iPhone |
That profile would make the output video use Zoom: Letterbox — see the setting just above the little Preview window — which is not ideal. Better I should use:
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| Using Zoom: Full Instead |
Zoom: Full (Keep aspect ratio), which is now the Zoom: setting shown just above the small Preview window in the graphic above, is a better choice because the movie as originally recorded in my Gigi MPG.mpg movie file has a widescreen Cinemascope image. The film frame's aspect ratio is wider than that implied by Video Size: 480x320.
Below, I show how HDVC can actually Preview its output image and thereby see what Zoom: Full (Keep aspect ratio) does:
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| Preview shows black bars at top and bottom |
The black bars at top and bottom in the little image Preview window just below the Zoom: Full (Keep aspect ratio) selection are actually encoded into the output file — a waste of precious Bitrate.
If Zoom: Letterbox is used, the black bars get yet bigger:
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| Letterbox bars bigger with Zoom: Letterbox |
So with Zoom: Full (Keep aspect ratio), there are fewer "black bar bits" cutting into the useful Bitrate of the video in the output file.
Unfortunately, the "image itself" as recorded from the TCM HD cable channel already contains the vertical black bars seen at left and right of the film frame in the Preview. They can't be removed. Also, even with Zoom: Full (Keep aspect ratio) there are some "black bar bits" above and below the image in the Preview. I don't yet know how to get HDVC to eliminate those entirely.
I can at least, though, save a new, user-defined profile that in the future I can use to automatically select Zoom: Full (Keep aspect ratio) for iPhone - H.264 Video output:
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| Saving an HDVC Profile |
I simply click on Save As... and enter the profile name iPhone - H.264 Zoom Full, then click OK. After I do that, I can ...
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| Selecting the new Profile |
... select my new Profile whenever I want to use it. Now the main HDVC window becomes:
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| New Main HDVC Window |
Profile: iPhone - H.264 Video Zoom Full confirms that the new profile is is use. This profile employs Zoom: (Keep aspect ratio), exactly as intended.
Keep in mind that my going to all this trouble to remove a few "black bar bits" from iPhone-compatible output video is strictly optional on my part. You do not have to follow suit, if all you want is to get usable iPhone-compatible output.
Here is QuickTime Player's rendition of the Zoom: Letterbox video output with the extra "black bar bits" in it:
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| "Letterbox" Version of the Gigi Image in QuickTime |
Below, the extra "black bar bits" have been avoided by means of using Zoom: (Keep aspect ratio):
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| "Widescreen" Version of the Gigi Image in QuickTime |
Not only are the top and bottom bars smaller, the image itself shows up as wider. This is so despite the fact that both images have a nominal Video Size of 480x320 pixels!
How does this magic happen? The pixels in the "widescreen" version have been "squeezed" horizontally by HDVC, and QuickTime simply expands the pixels' width to make the image seem wider. And so does the iPhone, which, after all, uses QuickTime.
The experts call this kind of "squeezed-pixel" encoding of the video image "anamorphic." When the image is instead enclosed in a "letterbox," the pixels are not "squeezed" horizontally, and the player won't "unsqueeze" them for a wider aspect ratio.
One advantage of using anamorphic encoding rather than letterbox is that the playback image on an iPhone can be expanded slightly by double-tapping it — albeit with the sides of the image being cropped. A letterbox image cannot be so expanded on an iPhone.
Whether or not you use anamorphic encoding in your iPhone-compatible output from HDVC, the file that HDVC creates is quite small. My high-definition input file for Gigi was 8.42 gigabytes in size. The iPhone-compatible anamorphic output file used only 968 megabytes. The output file is only 11.5 percent of the size of the original file! I can get over eight of those iPhone-compatible output files in the same hard drive space as the original file takes up!
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