As usual I reviewed chapters 28-30, that's frames 140155 - 153948 from a total of 196155.
Chapter 28
This is a chapter with very little action. On the other hand we have many close-ups and hard to encode background like uniformly colored walls that have a lot of film grain on them.
It is now possible to switch between the screenshots for a certain scene using the links below the image. The comment concerning the screenshot that is currently shown is displayed below the screenshot. By default, the source image from the DVD is shown. Many thanks to Zolaerla for the image switching and zooming script.
Then my usual disclaimer: Screenshots are not necessarily representative of the video quality. It might be that a screenshot of codec A just happens to fall onto an I-frame which is the least compressed (and thus looks pretty good), whereas quality quickly degrades after the frame shown in the screenshot. And a codec B might have a heavily compressed B-frame at the same position, so comparing the two would be inherently unfair. Bottom line: Take screenshots with a grain of salt, make sure you read all my comments and perform your own tests when in doubt. Every human being perceives visual quality differently and you might come to completely different conclusions watching the same clips as I did.
Also, I put up screenshots of two contestants already disqualified: Theora and QuickTime. I did this because I had the full Theora file already and was curious how it would look, and for QT I simply encoded just these three chapters (which already required that I create a 4.3 GB temporary file so that QT could process my content). I realize this isn't perfectly fair because other codecs had a whole movie over which to distribute the available bits, but if you're disqualified, you hardly have the opportunity to complain..
After having multiple looks at the first part of the interrogation I decided not to include any images of it. While you can still spot some differences on the walls, all codecs do a pretty good job, you can only spot a small difference in detail levels on the actor's faces, and different blocks where the grain is on the walls.
In the end, this scene is just not hard enough to really make a big difference between codecs, so let's proceed to the weapon's rack. The fast change from low motion to high motion shows how rate control can cope with extreme scenarios.
The rest of this chapter is pretty uneventful, so I fast forwarded directly to the next one:
There's not much to be said for the lobby shoot-out, I'm sure it made a lasting impression to everybody who saw it on the big screen.
The last chapter has everything. Still scenes, scenes that will go from slow to action packed within seconds, a huge explosion, water, everything it takes to give a codec a good beating.
The next one shows how fast the bitrate can be increased to cope with a difficult situation.
Let's now conclude this chapter.
As I have written back in 2003, this source isn't hard enough anymore, but it makes for a soft entry to the brutal world of codec comparisons. And when we take the winner of the quality / performance competition, and best ranking ASP codec as reference, I feel confident that I make a pick that will make for an interesting main round. Since there is no other movie to be tested in the qualification round, I've put my write-up in the conclusion.
This document was last updated on December 15, 2005