Eric Carlson schrieb:
QuickTime has used this method this since it started supporting VBR mp3 in 2000, and in practice it works quite well. I am sure that there are degenerate cases where the initial estimate is way off, but generally it is accurate enough that it isn't a problem. An initial estimate is more likely to be wrong for a very long file, but each pixel represents a larger amount of time in the time slider with a long duration so changes less noticeable.
Well, I do believe this works fine for audio (which usually hasn't a wildly fluctuating bitrate if you e.g. average over a second or two), I'm mostly concerned about video. An example for an outrageously off estimate would be the trailer for "Generic space-pirate movie".
The first few seconds would be mostly a static green/red/yellow/whatever screen ("This pirate movie has been rated ARRRRRR!") - this part would be coded with like 100 kbit/s or less. The next few scenes (this is a trailer, after all) would mostly show exploding ships, genetically engineered mutant parrots attacking space-adventurers and a few cuts into random love scenes - so this part can be multi-megabit/s. After this the bitrate would dramatically decrease again as the last few seconds will just show "Summer 2010".
Does QuickTime also handle such content gracefully (e.g. display a position slider that doesn't jump around wildly)? Am I overestimating the problem?
Maik
