Short audio burst on initial recording (550D - 1.09)

Created originally on Bitbucket by Anonymous

On various T2i ML 1.09 builds, I get a short audio burst after about 1 or 2 seconds of video recording. This happens using the internal mic and external microphones with AGC turned OFF.

It sounds like AGC gets bumped on for a second and then gets turned off. This only happens on the initial video recording after turning on the camera. All subsequent recordings are normal.