Running same COD: Ghosts tech on both Xbox One and Xbox 360 was "tough", admits Infinity Ward

"For a while I wasn't sure if it was going to make it," says Rubin

Speaking to Aoife at a Call of Duty: Ghosts event, Infinity Ward's Mark Rubin has shared a bit more about how the current and next generation versions differ. Bringing the game's new locational audio systems to Xbox 360 was "tough", he said - at one point, Rubin and his team feared they wouldn't be able to manage it.

"Basically what we do is for a weapon sound you used to have an interior sound and an exterior sound," he said. "If I'm inside play the inside sound, if I'm outside play the outside sound, that's how simple it was. What we did for Xbox One is, we created a full Attack-Decay-Sustain-Release reverb system that models the geometry in real time to determine what the sound will sound like.

"And it takes into effect the materials, not just the volume. So if I'm in a room and it's a metal room, it's going to sound 'tingy'. I'm going to have a 'tingy' sound. If I'm in a stone room, it's going to sound muted and sharp, and the tail will get cut off. And if I go outside, you'll have a longer tail."

Audio designers seldom enjoy the same prominence as game designers and artists - there are all sorts of subtleties that are easy to overlook. "It is a challenge, and it's funny because the audio guys are always complaining that they're always left out of the new features in every game!" Rubin jokingly conceded. "That's totally true, and we're guilty of it."

However, he continued, "with this game we actually put a lot of effort into audio in general - the ADSR reverb, the reactive emitters, which basically populate the entire volume with reactive sounds. It's not just the sound of rubble falling. If I throw a grenade over here and there's a chainlink fence behind me, I'll hear the chainlink fence rattle as I'd expect it to in real life, so you'll hear things shake and move from things that are happening on the map."

This was harder to pull off within Xbox 360's relatively modest RAM allowance, but Infinity Ward has gone the distance. "The cool thing though is that system we put on Xbox One and then looked at 360 and said can we do this? And the guys went 'oh, this is going to be tough,' and for a while I wasn't sure if it was going to make it, but we ended up getting it onto 360 so the 360 has all that new tech in audio, which is really exciting."

For more about how audio design could evolve on Xbox One, read this in-depth chat with the composer of Dead Space 3. For more on the new Call of Duty, read this full report on Call of Duty: Ghosts multiplayer. I'll be playing the latter soon - anything in particular you want to know?