Whats the difference between locked and unlocked audio?
Locked audio is “audio done right”: the audio sample clock (the digital time reference used in the sampling process) is precisely locked to the video sample clock such that there is exactly the same number of audio samples recorded per “audio frame” of video (not all TV formats and sound sample rates have a neat integer relationship between audio samples and frames, so an “audio frame” is my term [similar to a “color frame”] for the number of video frames it takes for audio and video to match up in the same phase relationship). For PAL, 625/50 video, locked audio provides exactly the same number of samples per video frame with either 32 or 48kHz audio, but for NTSC, 525/59.94 video, the 48kHz “audio frame” is 5 video frames: locked audio will provide exactly the same number of audio samples for every five video frames, though not every frame within that 5-frame sequence has an equal number of audio samples. 32kHz locked “audio frames” cover a whopping 15 video frames!. [There is such a
