Sync and Drift Fixes Using the Manual Method

[Ezad]

Hello

The films recorded, 1971,  were converted from Super 8 to MOV format. The films were without  audio, with no markers. The video photographer ran a microphone during the interviews from the subject to a tape recorder.

What I have are hundreds of 3:30 reels that I need to manually sync.
I am able to locate sync points. What I find is that the sync drifts out of rhyme.

I did searches and found information. Nothing useful that would prevent drifting other than to cut the film (3:30) into sections. However, a few days ago I found an article that was helpful. (I will insert the article below.)

What I need help on is a method to prevent drift. I don’t know exactly how to do that. I will insert the lines here that I need to understand:

“. Mark your sync points at the beginning and end on the video and audio clips separately.”

I don’t know how to put 2 ‘markers’ on the timeline, in the video area; and then I need to put 2 ‘markers’ on the timeline, in the audio area.

If I understand how to do:  ‘four markers’ – 2 for film, 2 for audio – I may be able to correct drift issues.

Thanks for any advise!

The author states:
I know the problem you’re talking about. The recording starts off in sync, and as you progress the sync ‘drifts’ and gets worse and worse. Here’s my strategy:

Don’t change the length of the audio.

Find two sync points, one as close to the start, and one as close to the end as possible. Something abrupt like a slate, clap, tap, car door slam, or plosive sound etc. Mark your sync points at the beginning and end on the video and audio clips separately. Alt+Left click to select just audio, or just video (assuming they’re linked, or ctrl+L to toggle linking when both are selected). Done correctly the ‘start sync’ marker for both audio and video probably appear very close in the timeline, possibly already sync’d; and the second marker for video will not look sync’d, but early/late.

Now, we know an exact sync point at the beginning and end where we need the video to match the audio. The problem was the video progresses too quickly or slowly relative to the audio - let’s match the video. Cut the video only at the video track markers we just added, delete the head/tail beyond the markers. Align the first marker of video with the first marker of audio (if they’re not already aligned)

Choose the time stretch tool (R), drag the tail end of the video clip so the end video marker aligns with the end audio marker. Look at the clip speed, probably something like 100.xx, 101.xx%, 98.xx% or 99.xx% This is the step which should sync it up by correcting the video playback speed thus preventing drift.

Now test for sync - it should be perfectly aligned not only right by the markers - but in the middle as well.

If you need the head and tale of the video back, just extend them out from where they’re cut - they will extend at the new sync’d playback speed.

[Kevin-Monahan]

Hi Ezad,

Thanks for posting. Glad you found the Speed tool. I had a feeling that the problem would be solved by changing the speed of the audio. Thanks for sharing and let me know if there's anything I can help with.

Best Wishes,
Kevin

[Ezad]

I wrote  because I don't know how to use the 'speed tool'

Here is the remark in my post:

“. Mark your sync points at the beginning and end on the video and audio clips separately.”

I don’t know how to put 2 ‘markers’ on the timeline, in the video area; and then I need to put 2 ‘markers’ on the timeline, in the audio area.

[Kevin-Monahan · Accepted solution]

Got it, Ezad. Thank you for clarifying. I hope I can help you.

“. Mark your sync points at the beginning and end on the video and audio clips separately.”

1. Click the Linked Selection button on the upper left of the timeline (to the right of the magnet)
2. Click on the video portion of the clip. It is selected.
3. Play to the sync point.
4. Press the M key.
5. Repeat the process for the end sync point marker for the video.
6. A marker appears on the audio clip.
7. Click on the audio portion of the clip. It is selected.
8. Play to the sync point.
9. Press the M key.
10. Repeat the process for the end sync point marker for audio.

Now that you have your markers set up, can you follow the rest of the steps, OK? Let me know.

Thanks,
Kevin

[Ezad]

Thank you, sir, for this advice. 

A God Send!

[Kevin-Monahan]

Cool!