iPod-Ready Videos? Not So Fast, and Not So Clear

The debut of Apple Computer’s new “iPod (with video)” last week set off a firestorm of discussions on video encoding techniques, playback, and quality. To date, however, Apple has only disclosed two formats that are guaranteed to play on the new iPod, and it has released only one affordable encoding tool to create iPod video files. That program, QuickTime Pro 7.0.3, is available for $29.99 from Apple, and it is assured to properly convert your existing videos into the recently released H.264 video format.

Several members of the iLounge editorial team have been working on converting videos to iPod-ready format since immediately after Apple’s announcement last Wednesday, and what follows are some preliminary notes on the wisdom – or lack thereof – of doing so, as well as downloading iTunes music videos and TV shows. If you want to avoid the initial $29.99 cost of QuickTime Pro, which itself is a surprise given that CD-to-iPod conversion is free with iTunes, there is a $1.99 charge for every iPod-formatted video you download from Apple. (Alternatives to QuickTime Pro are also available for more advanced users, and we’ll be discussing their performance in our upcoming tutorials.)

Our conclusion is that – at least for now – only hard-core users will even consider converting multiple full-length movies for the iPod, and even the conversion of short video clips requires time and involves consequences you should know about early on. Similarly, you may be surprised by the low image quality of iTunes music videos, especially by comparison with free videos the same bands have posted online, and even by comparison with seemingly better-encoded iTunes TV shows. We both hope and strongly believe that Apple will take further steps to ease the video encoding process for users in the months to come, as well as to guarantee superior picture quality for its paid video downloads.

How Long Does Conversion Take?

We’ve run tests on different machines and with video files of numerous sizes, but generally, the answer ranges from “longer than you’d expect” to “unbelievably longer than you’d expect.” Here are some of the findings on a dual 2.0GHz Power Macintosh G5 computer – more powerful than the average Mac, and comparable to the mid-class Windows PCs being sold today.

Source: Full-Length Movie (MPEG-4), 625×352 23.98fps, AAC Stereo 48kHz, 1 hour 42 minutes duration.
Result: Full-Length Movie (H.264), 320×179 23.98fps, AAC Stereo 44.1kHz, conversion time: 10 hours, 11 minutes (approx. 6x realtime).

Source: iPod Introduction Video (Sorenson Video 3), 320×240 15fps, QDesign Music 2 22.05kHz stereo audio, 6 minutes 52 seconds duration
Result: iPod Introduction Video (H.264, 320×240 15fps, AAC 44.1kHz stereo audio, conversion time: 10 minutes (approx. 1.45x realtime).

Source: Tokyo Game Show Footage – RR6 (DIVX), 960×540 50fps, no audio, 1 minute 20 seconds duration.
Result: Tokyo Game Show Footage – RR6 (H.264), 320×180 46fps, no audio, conversion time: 11 minutes (approx. 8.25x realtime).

Source: Tokyo Game Show Footage – PDZ (DIVX), 960×540 25fps, no audio, 1 minute 6 seconds duration
Result: Tokyo Game Show Footage – PDZ (H.264), 320×180 25fps, no audio, conversion time: 3 minutes (approx. 2.73x realtime).

Source: Home Movie.mov (H.264), 320×240 29.97fps, AAC Mono 48kHz, 1 minute 4 seconds duration
Result: Home Movie.m4v (H.264), 320×240 29.97fps, AAC Stereo 44.1kHz, conversion time: 2 minutes (approx. 1.88x realtime).

What do these findings suggest? Even on a good computer, converting videos for iPod playback is nowhere near as fast as ripping your CDs into iPod-ready music files. Techies will say “duh,” but first-time video encoders need to realize that under most circumstances, conversion from most unprotected digital video files will take at least two times as long as the original running time of the video, and quite possibly substantially longer – 10 hours is not unusual for an under two-hour movie. Two factors – videos with high frame rates and/or long running times – are most likely to drag out your encoding process.

Note: We are not factoring in the additional time it may take to break the encryption of DVDs and copy their files to your computer. All of our tutorials going forward will assume that you are the complete rights holder for the DVDs you are ripping, having made them yourself with a program such as iDVD, and therefore have the right to break your own encryption. This process can add another hour or two to the full-length movie estimate above, depending on the speed of your DVD drive and other factors.

What Do I Lose During Conversion?

The simple answer is detail. In our testing, no matter what format or quality the original source material was in, the iPod-ready video file didn’t look as good. But for videos that started out at 320×240, they didn’t look too much worse: only a little dimmer and a tiny bit blurrier. Here’s a set of two images from the iPod Introduction Video, displayed at the same resolution as they’d be on an iPod screen, showing the slight difference. The re-compressed video is on the right.

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Not bad at all, right? There’s a hint less contrast and a little smoothing of fine detail, but both are barely apparent at this size. The problems only start when you begin to expand the videos to the size they’d be on a modern television set. At that point, you’ll notice very significant artifacting and loss of detail. Again, the re-compressed video is on the right. (Right-click the image and copy its location to your web browser’s window to see the same image at full-size, where the differences are more apparent. Note that this is the same frame on both videos, then look at the top of the tongue and both eyes.)

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With higher-quality videos – ones that are closer to or higher than DVD-quality – the loss of detail is profound when viewed at higher resolutions. Images become highly blurry. You can guess which one of these images is the original, and which is the iPod-formatted duplicate.

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On a positive note, the high-resolution version looks very acceptable – not perfect, but good enough – viewed at smaller, iPod-ready resolution. In fact, one of our 50 frame per second videos stuttered when played back on even our dual-2.0 G5 computer. But not surprisingly, when QuickTime Pro converted it to a 46 frame per second video at iPod-ready resolution, it ran far more smoothly.

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Problems were evident when we expanded the compressed video back up to its original 960×540 resolution. At that point, it looked as it did a couple of shots up.

Is QuickTime Pro Really That Dumb?

The “Movie to iPod” conversion tool used by QuickTime Pro appears to be intentionally locked in a way that precludes users from tampering with the settings – for better or worse. Consequently, when on iPod setting, QuickTime only outputs to H.264, and seems to love to make 44.1kHz stereo audio tracks from anything but silent movies. These settings resulted more than once in this problem: low-quality iPod-ready video files that were actually larger than their higher-quality source materials.

The iPod Introduction Video, for instance, started out as a 31.9MB file in outdated 2001 video and audio formats. But when converted to Apple’s newest and most efficient 2005 video and audio formats, it became a 33.8MB file, most likely because QuickTime doubled the audio sample rate. This could have been avoided, potentially, by giving users control through a menu like the one you can pull up by fooling around a little with the Movie to QuickTime Movie export settings:

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Why hasn’t Apple done this? Most likely because QuickTime generally compresses audio and video well enough. Our 960×540 Tokyo Game Show videos started life as 162.57MB and 36.32MB files, shrinking to 5.67MB and 4.76MB files, respectively. That’s plenty of saved space.

Our full-length (1 hour, 42 minute) movie, encoded in H.264, similarly nosedived in total space required. It started as a 1.02GB file, and QuickTime Pro shrunk it to a 512MB file. In other words, you could expect to fit around 58 movies of that size on a 30GB iPod, and 116 on a 60GB iPod, assuming you had no music, photos, or data files on there.

Do I Really Want to Convert Full-Length Movies to iPod Format?

So far, because of the time required and quality of the resulting files, our feeling is “probably not.” It’s a lot of work to convert even one movie, and we feel pretty confident that you’re going to want to re-convert everything again six months or a year from now when a better iPod video player comes out. Apple’s continued references to the new iPod’s “video as a bonus” strongly suggest that while these low-res H.264-encoded QuickTime movies will play on future iPods, they won’t be the best those iPods can do. We’re strongly hoping that’s correct.

If you’re planning on trying to watch movies on your TV without an iPod USB Power Adapter and Dock, the answer is much more likely to be “definitely not.” As you’re probably aware, Apple has already disclosed that a fully charged 30GB iPod will run for only 2 continuous hours in video playback mode, which we believe at this point is based on on-screen display of video rather than iPod-to-TV display. So you’ll probably want to consider an add-on battery pack – groan – if you’re going to both listen to music and watch even one full movie on the iPod while in transit.

But on-iPod versus on-TV watching is an important difference, because last generation’s color iPods/iPod photos take a significant battery hit when outputting to a TV. In a test of color 4G iPods this weekend, an on-screen photo slideshow ran for 5 hours, 51 minutes – a bit higher than Apple’s 5-hour estimate – but when output to a TV, fell to only 2 hours and 6 minutes. That’s a loss of 64% of the iPod’s play time. Because of different battery capacities, the new iPods do not claim to be able to run in photo slideshow mode for that long, and it is highly likely that they will have similar limitations when outputting to a TV. (If the numbers carry over, which we hope they won’t, the 30GB iPod will run for only 43 minutes through a TV, and the 60GB for only 65.)

What About iTunes Music Store Video Downloads?

At this point, we’re not very enthusiastic about the quality of the videos we’re seeing at the iTunes Music Store – a fact we’re inclined to attribute to the early growing pains of rushing a video store together rather than any inherent problem with the concept or technology. Positively, we’ve found videos easy to download. We are still reeling from our attempts to purchase and download videos months ago from iTunes, when a video-laden Gorillaz album aborted transfer part way through and never sent the videos we’d bought. So far, the videos we’ve downloaded in iTunes 6 have each taken a bit of time, but come through and played properly.

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Less positively, the video quality has been somewhere between mixed and poor. The sample episode of Desperate Housewives we downloaded was very acceptable for tiny (read: iPod) screen viewing, and just acceptable (a bit artifacted and jagged-looking) when made larger on the computer screen. But the otherwise beautiful video for Only by Nine Inch Nails, which shows a PowerBook G4 with Altec XT1 speakers playing the song through an iTunes-like visualizer, displayed visible compression artifacting and jaggedness even at a small size, and in a very prounced way as it scaled larger. It’s worth a brief note that the Only video is 4 minutes, 41 seconds long, requires 18.6MB, and listed as a “low complexity” “protected MPEG-4 video file.” The Desperate Housewives video has the same characteristics, but consumes 209MB and 43 minutes, 31 seconds.

Except under unusual circumstances, we are going to hold off on downloading videos – particularly music videos – from the iTunes Music Store until the quality level is noticeably better, and/or the price drops. In a smart promotional move, Nine Inch Nails offered the same video for free download from its web site in four versions, two of which are QuickTime, and one at a higher resolution and file size. We have to assume the $1.99 video at iTMS is just the poorly compressed one, possibly recompressed another time, but in any case, it wasn’t worth paying for.

Parting Thoughts

We’ll obviously have more to say on these video features in the days to come, but for now, we offer the following three pointers: think twice about transferring full-length movies to the iPod, and if you do, don’t toss your originals away. And be judicious about buying this first crop of low-resolution videos. Apple has pulled off an impressive coup by offering videos and TV shows through its store, and a simple video encoder for at least some of your existing video content, but it still has several steps left to take before iPod and iTunes video as anywhere close to the excellent experience of iPod and iTunes audio.

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