According some aspects, a secondary device may display secondary audiovisual content along with playback of a video on a primary device. For example, the secondary device may display an augmented reality application synchronized with the video. Aspects may predetermine a set of frame transition ranges for the video, where each respective frame transition is determined based on frames of the video that are determined to be substantially identical by a frame reference function and frames that are determined to be different. Two frames may be substantially identical even if they are different in the source video. This may be due to shortcomings in the frame reference function, or encoding/compression losses in transmission and playback of the video. Playback may be synchronized based on a first detected frame, but synchronization may be refined upon detecting a frame transition to a second frame that is no longer substantially identical to prior frames.