As more smartphones become fast enough to record and encode 1080p on the fly, they'll also become fast enough to scale 1080p down to 480p or lower for sending over 3G. In other words, if the CPU has direct access to the video encoder (and not just a pre-encoded stream of 1080p H.264 video coming from a separate camera chip), then the CPU can probably use that same encoder to transcode videos as necessary for uploading, on the fly.