How can it? Video is exact frames 29.97fps. The audio sample rate for instance cannot be 44.1. The DV format has an exact specification for what is allowed in the format. What is the difference? there have been quite a few posts regarding audio sync problems.ĭoes this come from the application itself? then have quite noticeable sync problems with FCPX. I'm not questioning you, just trying to get a grasp on why the OP would not have problems with Avid and older versions of FCP. 'the application assumes an exact 48k sample rate.'ĭoes this come from the application itself? Does FCPX adjust both audio and video to it's internal 'exact 48K sample rate'? I was asking where FCPX was getting it's sample rate. however, the computer does have internal digital clocks that applications can sync to. I understand the 'timing' of the computer has nothing to do with the digital clock. If the recording sample is not accurate there will be drift. Therefore at 48k the sample count reaches to a specific length. The application counts how many samples are in the track. The timing on the computer has nothing to do with a digital clock of the the computer. The older applications probably pickup sync from the Firewire input and not the computers digital clock. The OP's video/audio sync would vary depending on the computer being used. this is wrong as it means every system will have slightly different timing. What you're saying is FCPX (the application) takes it's digital clock from the system rather than from the Firewire input. all digital clocks are inaccurate, there are slight variations in clock frequency with ALL digital devices, that is why a digital recording studio either uses wordclock or the clock of a single device to sync all devices. why does the OP not have a problem with older versions of FCP or Avid and yet has a sync problem with FCPX? How can the application expect an exact sample rate of 48kHz. I can't remember the figure but there is only so much deviation allowed and the end result is that video and audio stay in sync over any length of time. such as phase-lock-loop.Īny of the inexpensive methods use a give and take method where some video frames have more samples some less. An unlocked DVCAM uses a less expensive method to lock audio to video. In the simplest terms, locked digital video/audio uses a single digital clock, in this case the video clock. Ok, I understand digital clock, I've set up recording studios with multiple digital devices using a single master wordclock. This was a significant problem in older DV cameras, and may change over the life of the camera. Most cameras shoot unlocked and the sample rate variation builds over time.

Locked formats like DVCAM adjust the sample count once every second, so even if there is a single sample variation it doesn't go beyond one second. If the sample rate of the camera is not accurate when the tracks are separated the timing will drift because the application assumes an exact 48k sample rate.

Dvdstyler audio out of sync