Unfortunately, when any particular scene ramps up the motion, the encoding solution Square has employed collapses horribly. Detail disappears in a sea of macroblocking and banding, while the PS3 version remains pretty close to pristine thanks to the incredible amount of bandwidth (and thus video information) available.
While the shots here look pretty poor, seeing the whole picture really amplifies the effect still further. Markedly so in fact, and we've got a comparison gallery to prove it.
The tragedy here is that the CG is a core part of the presentation in FFXIII and it seems to be the case that the company has paid little attention to the poor quality of the final assets on the Xbox 360 version. The Microsoft XDK ships with a VC1 decoder, giving it the ability to playback video files encoded using technology supported by Blu-ray discs and players. Indeed, movie pirates out there get excellent quality VC1 encodes of Blu-ray movies that manage to fit onto a dual-layer DVD and run from the Xbox 360 dashboard.
Decent encoding takes time and effort, but the results can look good - even on challenging material. Combine this with the fact that the game doesn't need the 1080p-sized video the PS3 version boasts, and we have the ways and means with which to attack the compression issue from two different angles.
Square-Enix has bought in the Bink compression system for FFXIII on 360 and its failure in high-motion, colourful scenes does suggest a constant bitrate is being used as opposed to variable bandwidth that allocates more data to maintaining image quality on more complex scenes.
This failure is compounded by the fact that Square-Enix hasn't even made full use of all the disk space it has available. Around 1GB of storage is left empty on discs one and two of FFXIII, and you have to wonder why all that empty space couldn't have been repurposed for higher bandwidth encoding. Perhaps it's because of the background loading taking place while the cut-scenes play out, but regardless, the hit to quality using Bink is often unacceptably bad.
Perhaps Square Enix might like to take some cues from the movie industry: top-tier studios employ compressionists whose sole job it is to make movie encodes look as good as they can possibly be within the confines of the disc space available. The parallel is not without some merit: the same encoding tools Microsoft developed for Blu-ray and HD-DVD movie compression might even be deployed for exactly this kind of thing, assuming that the 360's VC1 decoder is up to scratch.
Failing that, there are any number of h264 decoders out there that could be licensed and ported to the Microsoft console. The bottom line is that if FMV is so crucial to your game, and the storage on offer is limited, care needs to be taken so that every byte of available space makes a difference.
The results in Final Fantasy XIII aren't up to snuff - frankly, the encoding looks amateurish. To give some idea of how this all fares in motion, here's the final comparison video, showing the same scenes from FFXIII running on Xbox 360 and on PS3, in 720p mode.
So, occasionally fine, sometimes grim: a statement that effectively sums up how much of Final Fantasy XIII looks on Xbox 360 when compared to the PlayStation 3 game, meaning that if you own both consoles, there really is only one choice when it comes to the purchasing decision.
But bearing in mind that Oli Welsh's Eurogamer review is based on the superior PS3 build, commentary for those who only own an Xbox 360 is probably worthwhile. In this respect, Final Fantasy XIII is clearly still a worthwhile experience, despite the resolution drop and the frequently awful cut-scene quality. In terms of basic content, story, and core functionality, it's all there.
Despite the cutbacks, the in-game graphics are still attractive, the gameplay is fundamentally the same as the PS3 version and it's clearly a cut-above much of the other JPRG fare available on the console. That being the case, despite falling short in direct comparison with its PS3 sibling it's still a decent game, though I daresay that the retooling of the formula into a more linear experience with obvious cutbacks in the exploration element is likely to frustrate many of the core fanbase.
However, with Crystal Tools set to become the in-house engine for future Square products, you can help but hope for more time to be spent improving the Xbox 360 rendition of the engine, and if the company wants to rely so much on streamed video sequences, clearly there are some very obvious lessons to be learned from the Final Fantasy XIII experience.