Audio and Video question

[nate_dennis]

I'm playing a show next week and want to do a cool little video of the event. I'm going to record the audio seperately. Because of the limited routing of the in house system I will use the tape out from their mixer into a small mixer (probably a eurorack . . .but no behri bashing please, I know they aren't great.) Then I'll use the mic pres in the eurorack to capture room sounds with two SDCs. I'll mix those two sources (the ambient mics and the line outs from the house) into my two channel USB interface. Complicated? Maybe a bit, but it's the best I can do.

I want to use two digital video cameras to caputure different angles of the show. Here is where my main question comes in . . . .

How would you go about syncing the audio to the video? I do have a SMPTE synchronizer (JL Cooper PPS100.) I intend to sync the audio to both videos so that they could stand on their own, then using editing software, cut them and fade them together to make a more polished vid.

I know it's possible to visually sync them, but that's tedious and unreliable. I'll do it if its the best option. But is there a better way? Would my JL Cooper be of use?

Thanks guys!!!!!


-Nate

 

[mattdee1]

I'm playing a show next week and want to do a cool little video of the event. I'm going to record the audio seperately. Because of the limited routing of the in house system I will use the tape out from their mixer into a small mixer (probably a eurorack . . .but no behri bashing please, I know they aren't great.) Then I'll use the mic pres in the eurorack to capture room sounds with two SDCs. I'll mix those two sources (the ambient mics and the line outs from the house) into my two channel USB interface. Complicated? Maybe a bit, but it's the best I can do.

I want to use two digital video cameras to caputure different angles of the show. Here is where my main question comes in . . . .

How would you go about syncing the audio to the video? I do have a SMPTE synchronizer (JL Cooper PPS100.) I intend to sync the audio to both videos so that they could stand on their own, then using editing software, cut them and fade them together to make a more polished vid.

I know it's possible to visually sync them, but that's tedious and unreliable. I'll do it if its the best option. But is there a better way? Would my JL Cooper be of use?

Thanks guys!!!!!


-Nate

About a year ago I did exactly what you're describing. I was playing a show with the band, and before we started, the sound guy mentioned he had the capability to take the board mix and dump it to CD as a stereo mix. I was totally expecting the result to be unlistenable but I ended up being extremely surprised with how well it turned out. Heck, I have a few friends that still have that show on their iPod and consider it to be the definitive record of our band's music.

Anyway, I happened to have a few friends that were planning to capture decent quality digital video of the show as well, and I got to thinking that I would eventually like to try to sync up the board audio with the available video.

Thinking on the spot, I came up with the idea of nonchalantly striking a random chord on my guitar during between-song banter, which I could use as a synchronization reference later on. I ended up using some cheap software to manually/visually align the audio with the video (heck, might have even been WMM, I don't recall), and using the single chord reference, it was a snap.

 

[nate_dennis]

Thinking on the spot, I came up with the idea of nonchalantly striking a random chord on my guitar during between-song banter, which I could use as a synchronization reference later on. I ended up using some cheap software to manually/visually align the audio with the video (heck, might have even been WMM, I don't recall), and using the single chord reference, it was a snap.

Yeah, I've read/heard of doing the same thing with a clap or something. Did you do that multiple times to get multiple ref. points? Or did just once do well enough to keep it from drifting? Thanks again.

-Nate

 

[Ethan Winer]

How would you go about syncing the audio to the video? I do have a SMPTE synchronizer

I do this all the time and never bothered with SMPTE. When you record the video, the camera also records audio. You won't play that audio in the final video mix, but you can use it as a visual reference. So when you place the two sets of audio tracks, and the two camera tracks, into your video editing software, just look at the waveforms and slide the video clips to match.

Video cameras can drift in sync over time, but you'll switch back and forth between cameras often enough that this won't matter. Even if you had one camera showing for 20 minutes straight and it drifted from the main audio, you could always drop or repeat a frame to get them back in sync. But I can't imagine that will be necessary.

--Ethan

 

[SouthSIDE Glen]

Yeah, I've read/heard of doing the same thing with a clap or something. Did you do that multiple times to get multiple ref. points? Or did just once do well enough to keep it from drifting? Thanks again.

I used to do three-camera shoots of weddings, conferences, recitals, etc. with similar setups to what you describe. No TC needed as long as you're shooting everything in digital.

There are so many natural cues you can use to line up video and audio shots throughout the shoot; electronic camera flashes are great for syncing video, snare or cymbal hits and especially drummer song count-offs work great for video and audio syncing, etc. Even an audience member letting out a distinctive whistle or yell can work as a syncable reference. Just look and listen for natural stuff happening in the content and you should have plenty of reference points to ensure sync between your clips.

G.

 

[bouldersoundguy]

Manually sync the video to the audio in post and manually resync once in a while when you cut from one camera to another.

 

[oretez]

If your camera(s) are not generating time code to which you sync the audio as you record then with in the time frame you indicate sync'ng manually will tend to be less frustrating

camera's will not only be offset but will drift, a reason why having gear that can sync is nice but the cheap stuff aint cheap and typically has issues with universality

dropping in audio markers, short, sharp, loud, think film clapper; as the first reply suggested, is not a bad idea. And manual adjust is less tedious then it might at first seem. Unfortunately it is another of those things that gets easier and quicker the more you repeat it

I have had some luck generating time code after the fact via software. If you are using AVI as vid packager you might look at here for an app that at least used to be free that can do this. By the time you have dealt with all the variables it tends to be just as quick to align manually . . . but the experience can be beneficial, particularly if you think you are going to continue to explore vid+music

depending on all sorts of things, including the quality of the board mix at the show, you don't need two mics for the ambient. Mention this because while even a single mic plus the board mix will introduce phase issues (that will be more or less troubling depending on all the usual suspects), introducing the 2nd ambient complicates things without necessarily adding anything not provided by a single mic

 

[nate_dennis]

Thank you all for all of your responses. I will just go about this the most basic way then, and use naturaly occuring visual/auditory references and manually allign them.

depending on all sorts of things, including the quality of the board mix at the show, you don't need two mics for the ambient. Mention this because while even a single mic plus the board mix will introduce phase issues (that will be more or less troubling depending on all the usual suspects), introducing the 2nd ambient complicates things without necessarily adding anything not provided by a single mic

I have considered the phase issues at great length. I intend to use an XY pattern for the mics to avoid phase issues there. And if I understand things correctly (which I admit I may not) using the line out from the main board into my "video board" will avoid phase issues since I won't be capturing that same source again. Again, I may be wrong. Since it's a smaller venue and a solo show, I wanted to room ambience to make it more of an intimate sounding recording. But I am trying to learn to cut what needs to be cut even if I want it. SO if it would be more hassle/trouble than asset I'll let it alone.

 

[mattdee1]

Yeah, I've read/heard of doing the same thing with a clap or something. Did you do that multiple times to get multiple ref. points? Or did just once do well enough to keep it from drifting? Thanks again.

-Nate

The audio was recorded continuously for the whole show, whereas the video was shot in clips, so I had to do the syncing song by song. I simply aligned each song clip using my cue, and the video seemed to sync perfectly. Our tunes are typically 2.5 to 5 minutes long, and there was never any noticeable drift in the end product.

In any case, so long as everything stays in the digital domain, I don't know why drifting would be a problem. Can anybody explain?

Glen's right in that you should easily be able to get by with whatever naturally occurring cues are available, but I decided to create my own because I figured that I'm front-and-center on the stage with my amp mic'ed so the cue would be loud, clear, and distinct on both the video and audio.

 

[SouthSIDE Glen]

In any case, so long as everything stays in the digital domain, I don't know why drifting would be a problem. Can anybody explain?

As long as everything is edited and mixed using the same base sample rate, drift should not be much of an issue. I have recorded events up to 2.5 hours long mixing audio and video from many different sources and have never experienced any problems with drift or alignment. Of course rarely have any two tracks both been the whole 2.5 hours long, typically the 2.5 hours is assembled form several shorter clips or takes.

Where you have to be careful with digital, though, is making sure your editing system isn't treating (just as one of many possible examples) a 48k audio track from video as a 44.1k audio file or vice versa, as that can easily mess up the playback speed making it impossible to align with everything else, in a kind of digital form of "drift". But as long as you avoid that problem (one easy way is just to track everything at 48k), you should not see/hear any "drift" issues in a typical editing situation.

That's not to say it can't happen over very long duration clips, however. The longer the duration of a clip, the more likely that any differences in th clock speeds of each recording device may cause "drift" between the two of them. But honestly, these days you'd have to have a pretty poor or malfunctioning clock in one of the machines for even that to come into play for the kind of durations we're talking about.

G.

 

[nate_dennis]

You guys are the shiz!!!!

I'll use my original set up and track through my US122 interface. I'll just be using one sound source, so differnt rates won't be an issue. I really do appreciate all the help. If you all are interested in how it all comes out I'll post links to the vids when they are done. Thanks again for everything all of you do with/for/on these boards.


-Nate

 

[NYMorningstar]

You guys are the shiz!!!!

I'll use my original set up and track through my US122 interface. I'll just be using one sound source, so differnt rates won't be an issue. I really do appreciate all the help. If you all are interested in how it all comes out I'll post links to the vids when they are done. Thanks again for everything all of you do with/for/on these boards.


-Nate

How far away from the source will your mics be? If it's set back aways you'll have phase issues from the desk feed mixing with the mics. If so, make sure you line up the audio before sincing with the video. Track with the 48k like Glen says.

 

[nate_dennis]

How far away from the source will your mics be? If it's set back aways you'll have phase issues from the desk feed mixing with the mics.

No, the mics will be in an XY pattern with the capsules being no more than . . . say . . . 20ft from the source. It's a small room and it's a solo show. (Don't know if that matters or not.) But durring sound check I'll make sure I/we check for phase issues before hand.

I don't know if my interface goes up to 48, but I'll check.

 

[miroslav]

As long as everything is edited and mixed using the same base sample rate, drift should not be much of an issue.

What he ^^^ said...
...and I'll just add that if you want to avoid even the smallest, frame-level sync issues between your audio and the camera audio when you go to line them up...
…also use the same SMPTE frame rate in your DAW as what is set in the cameras (probably 29.97).

Most audio DAWs might default at 30 fps...which makes perfect sense for pure audio, and what I always use. But when you try and line up the audio and camera audio exactly...if they were recorded with different frame rates, you'll find that you will be off, ever so slightly.
I mean, you won't end up with a bad Kung Fu movie......but it's that much more accurate if you use the same sample rate for everything, even the DAW audio.

 

[mattdee1]

What he ^^^ said...
...and I'll just add that if you want to avoid even the smallest, frame-level sync issues between your audio and the camera audio when you go to line them up...
…also use the same SMPTE frame rate in your DAW as what is set in the cameras (probably 29.97).

What is SMPTE frame rate?

 

[SouthSIDE Glen]

What is SMPTE frame rate?

SMPTE time code can work at any of the standard video format frame rates.

The typical standard frame rates go as follows:

Prro film: 24 fps
Europen (PAL) & eastern bloc (SECAM) TV: 25 fps
Amateur video (aka "non drop frame video"): 30 fps
Pro video & US (NTSC) TV (aka "drop frame video"): 29.97 fps

G.

 

[nate_dennis]

Even if Reaper isn't syncing to anything via SMPTE does it still generate SMPTE frame rates?

 

[SouthSIDE Glen]

Even if Reaper isn't syncing to anything via SMPTE does it still generate SMPTE frame rates?

I think you may be confusing frame rate with sample rate. Frame rate only applies to video. Think of frames like frames of film and how fast they run though a projector (though it applies to digital video as well.)

Digital audio cares more about audio sample rate, which is not directly related to SMPTE time code. The standard audio sample rate used by most digital video camcorders is 48k/sec, or simply, 48k. That's how you should be setting any audio from video in Reaper.

G.

 

[nate_dennis]

What he ^^^ said...
...and I'll just add that if you want to avoid even the smallest, frame-level sync issues between your audio and the camera audio when you go to line them up...
…also use the same SMPTE frame rate in your DAW as what is set in the cameras (probably 29.97).

SMPTE time code can work at any of the standard video format frame rates.

The typical standard frame rates go as follows:

Prro film: 24 fps
Europen (PAL) & eastern bloc (SECAM) TV: 25 fps
Amateur video (aka "non drop frame video"): 30 fps
Pro video & US (NTSC) TV (aka "drop frame video"): 29.97 fps

G.

I think you may be confusing frame rate with sample rate.

I understand the differnce in frame rate and sample rate. What I'm trying to understand is Miroslovs point about SMPTE frame rate in the DAW. Is "SMPTE frame rate" the same as the cameras frame rate or does it have more to do with SMPTE Time code? Sorry if I'm being dumb.

 

[SouthSIDE Glen]

I understand the differnce in frame rate and sample rate. What I'm trying to understand is Miroslovs point about SMPTE frame rate in the DAW. Is "SMPTE frame rate" the same as the cameras frame rate or does it have more to do with SMPTE Time code? Sorry if I'm being dumb.

No apologies required. SMPTE is just a time code format that can encode any given frame rate. What frame rate it encodes matches whatever the camera fame rate is.The time code is typically written to the recording medium (e.g. digital video tape) on a separate data track or "stripe" 'by the recording device itself. Called "striping the tape", this can be done ahead of time - rather like formatting the tape - and the time code stripe will match whatever frame rate the recoding device is set to record at.

G.