Removing chopper noise from videos

[oscillator]

I'm considering using the heli to video some old steam trains, but the sound is almost as important as the image.

One approach is to use a separate mic/recorder located on the train and then sync up the video to the sound later - though I could see applications were the heli noise might still be present or the separate recorder would not be practical.

Since the heli noise is what we call "stationary" noise - meaning its relatively constant over time (i.e. its spectrum does not change significantly over time, unlike speech or music), it is easy to remove the noise from a recording after the fact.

In the past I have done this type of noise removal from recordings using software I coded myself - but this was over 10 years ago. Before I start ripping apart video files and bashing out code, I figured there might be commercial software that does this sort of thing. Does anyone know of readily available (and affordable) commercial software that removes noise from video files?

I must confess I have not played with video editing software recently - so apologies if this is a common feature in all video software today.
Thanks,
Mark

[AZ ChopperCam]

hmm... me thinks you'll need to mic that train.

[sky high]

Hello oscillator. Yes the ability to seperate and add totally different audio tracks with video is a standard feature in nearly all editing software. Once the video file is brought to the timeline, you can then manipulate video and audio seperately. The only way to avoid hearing the helo noise in one take is to have another camera or audio recording device located somewhere where the helo noise is overpowered by the train noise. The other way is to record the train again just for audio which is what film and tv productions do. They would shoot the scene with no audio with the aerials then record the train again just for clean train audio later joining that with the aerials for a perfect mix. Sync doesn't really matter because this is just generic train noise.

If you've ever wondered how the audio for the dialogue of the actors in a crowd scene or high noise environment is always perfect in film or tv, here's how it's done. Whenever you hear dialogue between actors within a crowd scene in a film or tv show, the crowd in the background action is told to mime the action and not really talk but to gesture like they really are talking so they can get perfect dialogue audio of the main actors. Then they just record the background crowd again just for audio having them actually speak and do what a crowd usually does. Like your application, this is done so they can control the levels of each seperate track precisely and get a perfect mix.

[Brady Longmore]

Nice looking Malamute. Looks a lot like mine, but mine has more of a black mask under the eyes.

[mdelzer]

Oscillator,

There are a lot of applications that will do this, unfortunately most that I know are not cheap and usually only come as plugins for Pro Tools. It all depends on how good do you want it. If you want it to sound good enough that no one would ever know then get out the wallet. Anything cheap will leave plenty of artifacts that most listeners will hear. It would be cheaper to buy a sound FX library with train sounds and recreate the sound from scratch.

Mark

[spork]

Mark,

Just a couple observations.

- I would consider trying this with a directional mic at first to see how bad it is.
- I think mic'ing the train separately could work but would tend to reduce the spatial effect very significantly. The train should be louder when it's close to the heli. I don't know if doppler would be an issue at these speeds, but it would be VERY cool if you could hear it.
- You might try Goldwave to do the heli-noise removal. It's fairly full featured, and free. But you'd have to do it as audio only and then put it back in the video - which shouldn't be a problem.

[mdelzer]

Spork,

You are correct on the directional mic, but the weight and actual cost of that mic won't be cheap either, plus those types of mics have phase holes in them that would not fair to well on a heli unless you put it in a cat, but even then it is a big piece to add to a heli. Based on my experience, the easiest thing for me to do would be to recreate it with a sound fx library. It could be recorded with specific field cording equipment for sound fx to get a great sound, but that isn't cheap either.

Mark

[MicroMan]

If youre looking for free software to remove noise, music etc I'd give "Windows Movie Maker" a try. Depending if the video format you recorded in is compatible with the program Id also try "Super C" as well.

[oscillator]

Thanks everyone. If this were a diesel locomotive then re recording the audio would be no problem, but with a steam locomotive the chuffs are synchronized with the rods - and you can watch the plume pulse in sync with the chuff. And then there is the whistle - you will need to pull it exactly the same way (and at the same time) to match the steam coming off. Looks like the choices are 2nd recorder on the train or see what I can do with software and directional mics.

Brady - thanks. She is 3 years old and a total sweet heart (even though she stole a complete medium pizza today - no trace in about 15 seconds! :WOW )

[Cryofix]

Obviously you will know when the train is coming, so setup a directional mic on the ground equal to the position of the heli in the air, this way you can just get the train in sequence, and distance noise will match.

[sky high]

oscillator, sorry I didn't pay attention when I first read your post. Since it does have that stack and make that chugging noise, sync will be important. I don't think you would be able to hear the helo over that noise so if there is a road that runs with the track, you could get a chase car/truck to get some good natural train sounds from a close proximity.

mdelzer, do you actually work in the film or tv industry? If so, I can't believe you would say they don't use the method I described that much. If not, where did you hear that? I currently work mostly in television and have worked on a couple of feature films and that location method is used frequently in both. I am very familiar with ADR and know that is ONLY used to replace audio that was not clearly recorded on location and not as a standard practice. It is also similar to looping which is not something you want to mention around sound mixers on location because it makes them look bad. Neither ADR or looping provides a good result because it can't match the actual location's ambient sound or the scene's mood as originally shot. But, it's definitely cheaper than reshooting the scene.

What I described is used all the time mostly because it's cost effect and it gets the actual location audio so they don't have to use ADR/looping. ADR and looping costs more money in post because it is actually fixing something and they all hate spending more money. Have you ever heard the term, oh we'll fix it in post. That's something else that's not good to say on a set and especially around editors because it's more work for them and like I said earlier, more of an expense to the producers. A great example for having to use ADR/looping is if there is a natural noise like bugs (crickets/locusts) or whatever in the background of a scene that can't be turned off. Have you ever heard of room tone? That is also currently used all the time to get a true sample of the ambient noise of the location. If we are forced to shoot something with intermittent background noise we cannot control, we will record around 30 seconds of that noise so the editors can use it to make it consistent throughout the dialogue. Otherwise, it would be there, then not there throughout the scene. Location crews are paid very well to make great effort get it right on location and not rely on it being fixed in post.

As far as affordable editing software, why would you say there's nothing really available worth using that is affordable? There are a number of software options below $50 including the FREE movie maker mentioned above that will work just fine. He doesn't need something like Pro Tools just to substitute an audio track. :roll:

[DKTek]

Agreed Sky High....although all the stuff I do is MOS. I'm a Wescam Operator/Tech for Film, Video, and other specialty apps. 95% heli shots and the rest are crane, shotmaker, Akela, dolly, etc. Actually, sound guys tend to not like us heli guys unless we are shut down... :lolol

[mdelzer]

Sky high,

:oops:

I should have kept my mouth shut about the production audio portion. All my experience is related to audio editing and Pro Tools, I've also done some field recording for creating sound FX. I'll admit it, I was an a$$ and mis spoke, I apologize and have edited my post.

As for audio editing programs I stand by what my ears tell me. Anything that I would trust removing the heli noise with and not leave artifacts is not cheap. I'm not saying other programs won't work, there just aren't many I would personally use.

Mark

[livesounder]

Oscillator: Unless you plan to fly very close to the engine (within 50' or so), there will be a noticeble time lag for the audio anyway. Potentially enough that it would be very disconcerting.

I suspect you really do want to put a mic on the exterior of the engine, possibly a wireless with the receiver at the video recorder.

[spork]

In baseball, they put a mic at the plate for the bat-crack. And they get pretty excitable about the notion that we want to add 2 frames (1/15th of a second) of video delay to insert our virtual ads - because then the batcrack won't line up with the video.

I find it entertaining because that's about the same delay the pitcher or the guy in the very first row would hear.

[sky high]

DKtech, you are a lucky dog! Do you work with the Wescam cable rigs or nose mount gyro systems? Have you ever worked with Jordan Klein and/or his son Jordan (Jordy)? They are located in Florida and provide alot of specialty camera platforms for features too.

mdelzer, I don't think you should have kept quiet. You just sounded real sure of what you said and it immediately caught my attention because it was a contradiction to what I do all the time. You weren't an ass either. Don't be so hard on yourself. :) :roll: However, ow that you edited your post, my reply won't have context which will make me look like more of an ass than I already am. :mrgreen: As far as the audio replacement, I think we are talking about two different things. I am not talking about removing a noise from a mix, but simply replacing an audio track (helo/train audio mix) in a timeline which is as simple as select>delete, then replace with the new one (clean train audio). If you are talking about doing noise cancellation with wave forms or whatever it is you audio guys do, then yes, that would take some high end software. Since you mentioned Protools, are you an audio mixing engineer? I don't know the intricacies of audio mixing on location or in post but I do know the guys in post don't like it when they don't get clean audio from the field and have to fix something that should have easily been done right in the field. I know enough to get good levels and detect RF hits.

[DKTek]

Yes I have and I travel the world doing what I do. I hate to say it but my ball is usually purple and black. Not my idea! Someone in California decided the colors. I work with all the biggies in the business. Sky High, are you close to Peach Tree Airport. I used to get heli's out of there. Panther Prod. uses us a lot for stock footage.

[spork]

I don't do any sort of professional sound work, but I play with GoldWave for my personal stuff. It's free for personal use, and available by license for professional use. I'd really be curious to know what you guys think of it. Is it just a toy?

[MLaBoyteaux]

I use Goldwave all the time, I think it's a neat tool. I now have Audition from Adobe and I find as I learn it I'm using it more and more, but I still fall back on Goldwave a lot.

I agree about the train sound. I would shoot the video and then try to overlay a second audio track that I would record seperately. I shot some test video yesterday with my E-Raptor and an HC-1. In forward flight, the mic has wind noise. In hover, even with the electric, there are so many different sounds I think it would be a nightmare to try and remove them all. There's the motor, pinion/main gear, chop from the blades that comes and goes, and tail rotor noise.

But, I'm an amateur and I use amateur tools, so my results might vary :D

[GGoodrum]

Is it possible to put a wireless mic on the train itself? You could put the receiver on the heli and plug the output into the camera. No editing required and the sync is perfect. :)

-- Gary

[mdelzer]

Sky high,

I would have left it, but didn't want to give bad information. We definitely were talking about two different processes. I use to be really hardcore into music and audio so I worked as a tech and Pro Tools engineer. That go me into programming Crestron, which is what I do now but I'm still Pro Tools certified in Music and Post for versions 5 and 6.

Adobe audition is pretty good stuff, I haven't used it though since it was Cool Edit and it was pretty much free back then. Digidesign just released a new MBox 2 mini with Pro Tools 7.3 software for only $329 so it's not entirely crazy expensive. It's the plugins that will kill you. At one point Sonic NoNoise was around 2 grand and had to be used with and HD Pro Tools system that cost upwards of 15 grand. Cedar Audio has some good noise products too, but they are not cheap either. Granted all these are for noise removal. Almost any video editing software would let you replace one form of audio with another as Sky high stated.

Mark

[sky high]

Does software called Cakewalk still exist? I heard of that a few years ago too.

[mdelzer]

Yep, Calkwalk is no longer the software name though. Their main offering is Sonar 6. My old boss wrote a user guide for it for Ignition publishing and one of the guys I use to work with did tech support for them.

Mark