Embodiments may be disclosed herein that provide systems, devices, and methods of processing a program stream, the program stream comprising a video and an audio stream. One such embodiment is a method comprising: initializing an audio reference clock to a value associated with a presentation timestamp for a decodable audio frame which is the first audio frame capable of being decoded in the audio stream; initializing a video reference clock to a value associated with a presentation timestamp for a decodable video frame which is the first video frame capable of being decoded in the video stream; storing audio frames received prior to receipt of the decodable video frame which is the first video frame capable of being decoded in the video stream in an audio frame buffer; starting audio and video reference clocks after a video preroll delay, which is the difference between the first decodable video frame PTS and the value of PCR at the time that PTS is received, has elapsed; decoding the audio stream in accordance with the audio reference clock; and decoding the video stream in accordance with the video reference clock.