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syncing sound between two cams with kdenlive

Thu May 21, 2015 10:43 am Hello,

I just add this entry to give some details about sound sync. I have to do this quite often and it's pretty tedious to to manually, but I never could make the kdenlive function work before reading this page:

I summarize what I do most:

I shoot gigs of local bands. I have two camcorders, one for large scope, the other for close ups and one audio recorder I use to get the sound from the audio mixer when possible. So two video/audio tracks and one audio.

To make kdenlive work with this, you have to import all the tracks and sync them approximately. It's very important to sync them as well as possible before asking kdenlive to fine tune it.

Then select the main audio track. If you don't have one (no mixer access, for example), you have to split audio from the best camcorder to be able to set it as reference. You probably also have to ungroup the video and audio of the same clips (was necessary for me just now). Then you have to select all the audio clips using Ctrl right clic. It's not obvious because it do not show very well on screen, but it works. Then align to audio (right click context menu)...

Two things more: you can't sync the audio when it's grouped with the video so you have to not only separate the audio from the video, but also ungroup the two parts. Do not forget after sync is done to move the video part to set it back aligned to the audio track that was moved. It's easy if the default snap is enabled.

If you have the whole shooting recorded as many files, like it's usually, load all the clips at the same time in kdenlive, keep the two first clips at the beginning of the timeline (one for each cam) and move the others somewhere on the right, then sync the two first clips. When syncing is done, snap the other clips to the first ones, they should be also in sync (providing the camcorder didn't stop between clips).

When the sync is done it's good for all the shot, as long as you never stop the camcorder, witch is easy with a real camcorder but not with photo cameras :-). However, no two camcorder will have the exact same clock, so a shift is possible and kdenlive correct is very easily.

It's so good that you can even let the two tracks play together, but do not keep it on final, it adds the defects of the two tracks :-(.

Verify the result looking at the image of closeup while listening to the other sound track :-).

Obvious when you know it :-)) jdd