Synching external audio

[deednets]

Hi from Auckland,
I have been looking all over the net for a simple answer as to how to synch external audio, I read somehere, but was unable to re-visit that site that you can simply compare the waveform lines on your audio track with the waveform on the embedded audio, but when I was trying to make this visible ...
Lets just say I clearly struggle making the audio file in the time line appear as a waveform so I could then match up the same pattern with the embedded audio.
Am I on the wrong track here??
Cheers
Deed

[Liverpool TV]

If you get your separate audio track lined up as best as you can with the audio off the video track, using a recognisable or percussive peak. You can then do single frame nudges of one against the other until they sync. You are best doing it by ear rather than by eye with the waveforms. There are ways of doing it with dedicated software, but I don't do this myself.

If both pieces of media were recorded with common time code, you may be able to match them that way. As long as there is no camera/audio latency or too big a distance between the camera and audio recorder if they where both off air.

Regardless of how you go about it, you are always best making the final sync judgement yourself with the separate audio against the the video track.

[DiSoFilm]

If your question is "how do I get to see the waveform on the track?" here's one way: (See numbered screen shots as per numbered steps below)

1) Expand the A tracks by clicking the triangles that face right
2) When expanded, the triangles face down
3) Right click the mouse in the track area, select Height, click e.g. 4
4) Do that for both tracks that need to be sync'd
5) Set the TL to display 1 frame units and manually sync the tracks.

[Liverpool TV]

I wasn't questioning what you were doing, just making suggestions on how to go about it. The main problem is treating an NLE like it's a DAW, that's why I suggested you do it by ear.

If you didn't take care of the audio properly and use a common time code, you will never get 100 percent sync between the two devices anyway. You will always be out by so many samples or sub frames. Not many NLE's allow you to unlink the audio from its video clip and move it independently to sample accuracy, or match independent audio in the same way.

You are probably hearing phase or flange effects between the two audio elements, if they are close in time on the time line. Or hearing early reflection reverb/short delay if they are closer to a half frame out. I wouldn't worry about this. If it's the independent audio that you want, just get it as close as possible, it can only be a maximum of a half frame out. Switch off the video track's audio and make sure it looks fine as far as sync is concerned. Then group the two parts together.

Unless anything has changed in Edius or I've missed the point and it does sub frame or sample accurate editing. Then this is the best you will get.

[Bluetongue]

Unless anything has changed in Edius or I've missed the point and it does sub frame or sample accurate editing. Then this is the best you will get.

Maybe this will help, select the audio clip or the audio of a video clip
Right Click and select "Audio Offset" and the timing can be moved by either Audio Sample or part of seconds
Moves the Waveform on the timeline so should be able to get almost perfect sync, but it is manual!

May be what he is looking for
Regards Barry

[Liverpool TV]

Maybe this will help, select the audio clip or the audio of a video clip
Right Click and select "Audio Offset" and the timing can be moved by either Audio Sample or part of seconds
Moves the Waveform on the timeline so should be able to get almost perfect sync, but it is manual!

May be what he is looking for
Regards Barry

Thanks Barry.

With sample accuracy, you can put the track anywhere. This would also work for 0 phase, if there are multiple recordings of the same audio source being mixed.

For straight dialogue etc. from single sources, simple frame adjustments would do. But in any event, and as you say, it is all manual.

If you use a DAW for audio with sources that are technically correct. Then it's a little easier judging timing by eye by waveform matching. This isn't that easy with NLE's, especially Edius.

Cheers,
Dave.

[Ron Evans]

The audio offset works fine if the record clocks are accurate over the time of recording. Still have to keep trying for time. However if using a separate audio recorder without gen lock it is almost certain to drift if recording is more than a few minutes. Only way to correct this is with a true multitrack DAW that can stretch or squeeze the tracks to correct clock drift and get them in sync as well as perform the offset. It is why I use Vegas for all my audio outside Edius.

I use my main closeup camera as the reference and then bring into sync all the others. This is even true when I get a feed from the audio board on one channel and shotgun on the other both recorded on my NX5U. These are always off by at least a frame. Sound takes longer to get to the camera at the back of the theatre than coming from the audio board !! At least these stay in sync !!!

Ron Evans

[scroogie]

and..just as a quick reminder: when visually syncing never trust MP3 waveform!
it's usually out of synch...with itself! visual wave doesn't match sound

sauro