Digital Foundry did some number crunching on direct feed video from the Titanfall beta and walked away with an estimate that the Xbox One title (in its current form) renders at approximately 1408x792p. Their guess ended up being pretty good, as developer Respawn confirms to the unofficial Titanfall Blog that the beta version of game runs at a native 792p resolution, upscaled to 1080p.
Titanfall is far from the only title that upscales to 1080p from a lower resolution, but it does boast a fairly unconventional pixel count for modern games. Respawn maintains its goal is get Titanfall's native resolution to be somewhere closer to 900p while remaining at a solid 60 frames per second for the release build.
To this end they've been providing Microsoft with some valuable feedback on how to improve things like the Xbox One's hardware upscaler. Microsoft is already improving the analog sensitivity for the Xbox One controller at Respawn's request via the upcoming system update.
Sign-ups for the Titanfall beta on Xbox One and PC are underway, and interested players can get a shot at entering by registering at the application page on the official site before this Friday... which is not a whole lot of time left at time of writing!