Lip-Sync Audio and Video

iabbott wrote on 3/22/2009, 9:11 PM
I frequently need to lip-sync Audio and video recorded on seperate devices. The subject matter is speakers at conferences. Does anyone have any hints on syncing the audio and video? I have used Vegas for a number of years, and understand the technoloogy, but am looking for some clues on technique, such as what words are easier to key on (do I look for words starting with "P"? etc.).

Comments

jrazz wrote on 3/22/2009, 9:27 PM
I assume your cam is recording audio as well yes? If so, sync up the audio from the cam with the audio from the separate device.

If that is not the case, before everything gets going, get in front of the camera and have your audio recorder on and make a loud clap (or find something that will make a loud noise that is about a frame long) and use that to sync up with.

j razz
TheHappyFriar wrote on 3/22/2009, 10:21 PM
do one at the end too. I've found that even though they're digital, cameras + recorders + computers all can be off very very very slightly.

When syncing up audio turn off quantize to frames.
DavidMcKnight wrote on 3/23/2009, 12:08 AM
when syncing two tracks, pan one hard left and one hard right (using headphones is best). Get the volumes as close as possible in your ears. Choose which track you're going to move, get them close based on waveforms, and then loop a section with some plosives - P's, T's, etc. Use the 1 and 3 on the numeric keypad to advance one frame at a time (you have to be somewhat zoomed out of the timeline to do one frame at a time). When it's perfectly lined up it will sound and feel like it melted into place and one frame on either side will produce a noticeable echo. That's when ya know you got it.
Serena wrote on 3/23/2009, 12:42 AM
If you don't have a guide track you have to look for visual cues, which means watching lips. Presuming that you can generally locate the appropriate audio for the visuals, the cues are sounds made with lips closed. P (posted, paper), M (mother, mud, muppet), B (but, bother). Sometimes F (feather) and V (violet), but depends on the speaker. Have to be less than 2 frame error, which is very noticeable in a CU. In fact need to be frame accurate in CU.
John_Cline wrote on 3/23/2009, 12:45 AM
I do this ALL the time and it can be done accurately to within a few samples without even turning the sound up, much less doing it with headphone and listening to panned tracks. It can all be done visually using the waveforms on the timeline, in fact, I just got finished doing this very task for over 15 hours of conference video that I shot over the last few days and I was watching television while I was doing it. It's really much easier to do than to explain, but it's late and I need some sleep, I'll try to post a step-by-step explanation tomorrow.
iabbott wrote on 3/25/2009, 7:34 PM
We use two studio cameras that do not record audio. The vision is recorded directly to two hard drive recorders. The audio comes from the sound desk, and is recorded via Adobe Audition direct to a notebook PC.
Jim H wrote on 3/25/2009, 8:59 PM
Sounds like a job for a clapboard. It's so hard for me to match voice and lips and it's so unforgiving. I did a job once where I lost control of the audio on a clip and spent a long time trying to make it look right. Though that was before I knew I could turn off quantize to frames which might have made things easier.
baysidebas wrote on 3/26/2009, 9:29 AM
The technical term is slate. Clapboard is a siding material ;>)
iabbott wrote on 3/27/2009, 12:07 AM
Hi Jim, thanks. We use a clapperboard when we can, but in these jobs we are videoing in front of a live audience of 6-8,000 people. This week end I'll video myself saying a lot of Bs and Ps and just find out where my mouth is when the waveform peaks.
newhope wrote on 3/27/2009, 1:10 AM
Silly question but can you get one of your speakers to tap the mike just prior to the beginning of the talk but after you've begun recording? It will give you a visual and audible sync point like clapping a slate shut and is a simple cheat for replacing a slate/clapper when you can't use one.

An alternate is a bright led on the lectern or somewhere in shot connected to a circuit with a button to turn it on/off and produce a sound beep (tone) via an audio output that you feed into your audio recorder... a simple light slate that you can set off at the beginning and end of the recording for head and tail sync.

You can by kits for these in most electronics shops.

New Hope Media