Friday, June 27, 2008

Streaming Video Comes of Age

A long break between blogs, but with so much going on behind the scenes, time really is at a premium. For the time being though, it's back once again to my Eurogamer contributions.
I was recently asked by new editor Tom Bramwell to introduce video to the Xbox 360/PS3 comparison features I put together for them. In theory, it should be easy: Digital Foundry TrueHD already provides lossless dumps of the HDMI ports of the respective consoles, so I already have the videos, it's just a case of formatting them courtesy of Adobe After Effects.
Well, no it's not. Matching up specific screenshots takes time enough, but synchronising entire feeds of video at 60fps is exponentially more difficult. And working with uncompressed video as I do all the way up to the h.264 encoding stage also takes a long time, but is important for features where the user really has to have faith in the workflow used. It's worth pursuing as nobody else appears capable of achieving 24-bit precision with games capture and more than that, they're often working with some pretty awful compression methods, compromising the quality right from the initial capture phase.
Bearing in mind the large audience these features attract, I think it's worth pursuing the highest quality results.
The video linked below basically took around 4-5 days of work (including time taken to play both versions of the game up until the end of Chapter One), producing two versions: one at 728x544 for the video Eurogamer site, and one at 632x400 to embed into the feature itself.

Click through to see all eight minutes of the original Grand Theft Auto IV comparison piece, including a fair few clips that were never seen in the actual article. Thanks to Eurogamer for hosting.

I've just spent the last few days working on the latest feature, five games (four with video) and you can see that here.
Introducing video at all was a tall order. Up until that point I thought that video comparisons were a complete waste of time; streaming video just isn't up to the job. However, Eurogamer's video player is state-of-the-art - as far as Flash goes - and definitely the best on the market if given decent enough material to work with. x264's HQ-Insane profile is used for the very best possible results and to ensure minimal macroblocking or picture break-up, I slow the video down to 50% or 25% speed. It sounds far from ideal, but as you can see from the link above, it works in that it gives you more time to analyse the video differences. The video is cropped so that one HD pixel is one pixel in the player. Another advantage of slowing the video down is that typically, streaming video online runs at 30fps. Usual form is to dump every other frame, but some games do not update at an even frame rate - so in many cases, video information is being thrown away. Using the slo-mo method, every frame is retained.
The more experience I have making these videos, the more I learn about streamlining the process. The GTA footage was done clip by clip, with both the embedded and versions individually rendered. Now I have a process whereby all clips are joined together, rendered as one file, with that file then used as the basis for the smaller embedded version. A quick Premiere Pro edit can then be used on both renders to make both videos in quick succession.