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), 625x352 23.98fps, AAC Stereo 48kHz, 1 hour 42 minutes duration.
Result: Full-Length Movie (H.264), 320x179 23.98fps, AAC Stereo 44.1kHz, conversion time: 10 hours, 11 minutes (approx. 6x realtime).
Source: iPod Introduction Video (Sorenson Video 3), 320x240 15fps, QDesign Music 2 22.05kHz stereo audio, 6 minutes 52 seconds duration
Result: iPod Introduction Video (H.264, 320x240 15fps, AAC 44.1kHz stereo audio, conversion time: 10 minutes (approx. 1.45x realtime).
Source: Tokyo Game Show Footage - RR6 (DIVX), 960x540 50fps, no audio, 1 minute 20 seconds duration.
Result: Tokyo Game Show Footage - RR6 (H.264), 320x180 46fps, no audio, conversion time: 11 minutes (approx. 8.25x realtime).
Source: Tokyo Game Show Footage - PDZ (DIVX), 960x540 25fps, no audio, 1 minute 6 seconds duration
Result: Tokyo Game Show Footage - PDZ (H.264), 320x180 25fps, no audio, conversion time: 3 minutes (approx. 2.73x realtime).
Source: Home Movie.mov (H.264), 320x240 29.97fps, AAC Mono 48kHz, 1 minute 4 seconds duration
Result: Home Movie.m4v (H.264), 320x240 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.
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