How do I sync Pro Res 422 30 fps video with 48khz wave?
How do I sync Pro Res 422 30 fps video with 48khz wave?
Thinks fall out of sync at a rate of about 1 sec every 12 minutes.
I do a lot of video on FCP X and pro audio for music recording on pro audio gear. When I put the two together for a music video it is usually pretty close. Still, I have used certain audio recorders, or various cameras, that could not keep sync for more than approximately 5 minutes. If they both use a SMPTE timecode that is recorded, they can be locked back up together, otherwise you are just hoping they were close.
Your camera uses a crystal oscillator as a clock reference for recording, and your audio recorder uses another. They can never be truly dead on in time due to the variations in the different references UNLESS they both record a timecode that can be referenced to bring them back together. Some pro video gear and a lot of pro audio gear have that capability. Cheaper gear does not.
Your best bet is going to probably be to split your audio clip when its waveform starts to fall out of sync with the camera clip's audio and becomes noticeable to the eye. Split the audio-only clip somewhere before that becomes noticeable (every few minutes) and simply mute out the video audio up to that point and use only the other audio-only clip as your audio for the project. Then sync the new audio segment, after the split, to the video and repeat that process until problems are noticed again. You only need the camera audio to line up the waveform features. After that you can mute your camera audio or bring it down to the -96dB that FCP X allows. In all this the audio-only clips are simply "connected clips" and your video is your main storyline. You never need to split your video to solve this kind of audio problem ... only the audio clips. Dirty ... but gets you by in a pinch. Best wishes.
stephen
