General questions about home video editing, noise reduction

[dprocket]

I have a church conference that I video'd a while back. I am making a DVD copy of the event. I have captured the video from my High-8, analog tape to create AVI files. I have then used the simple MyDVD program from Sonic ot make a disc.

The only problem is that the camcorder was sitting in the crowd. In order to hear the speaker clearly, the volume of the TV has to be fairly high. Unfortunately, when the crowd laughs or applauses, it racks the eardrums because the noise is so much louder.

My question is, is there a fairly simple way to edit the audio on these video clips? And if so, what program(s) do I need that will not cost me a fortune? I suspect that with the right software, I can somehow "grab" the crowd noise and "reduce" it, while either enhancing, or keeping the speaker's voice the same.

While I am at it, it would be nice to do away with the "hum" that accompanies my amatuer video recording.

Any ideas or help would be appreciated. Truly, I am a newbie in this area, so I apologize if this is a stupid question, or if I am seeking some "holy grail" in home video editing.

[daamon]

Hi dprocket,

It's not likely to be good news I'm afraid...

It's highly likely (if not definite) that your cam records everything it "hears" in stereo - i.e. 2 channels, one for the left and one for the right.

Every sound that is picked up on each channel will all be bundled into that one channel. This means that splitting out the applause from the speaker is like trying to seperate your vodka from your vodka and coke.

There are free tools, like Audacity, that are very good and can be used to reduce the volume where the clapping occurs - but this will reduce the volume of the entire channel, and so affect the speaker too.

The simplest way to get around this problem in future is to have some kind of microphone (a radio mic would be best) near the speaker - he'll be louder and over the applause as he's closer. This microphone can then either feed into the cam, or onto a separate recording device which can then be downloaded to your computer for combining with the video foorage.

The reason why the pro's can adjust seperate audio levels (speaker vs applause) is that each contributor is recorded in their own seperate channel and mixed as required later on - a bit like deciding how much vodka and how much coke to have before mixing them.

The mixing is done at the very last stage, and the levels of the audio is played with seperately beforehand, and trialled in an editor to make sure the volumes are OK.

Hope that helps...

[Soopafresh]

The simplest way to do this is to download the 30 day eval of Goldwave . You can open up the AVI directly in Goldwave. The effect you want to use is called Dynamic Range Compression (or Compression for short). It'll make the loud parts quieter and the quieter parts louder. You'll recognize the effect - every radio station on Earth uses tons of it.

[edDV]

In the future, use a wireless mic as suggested above. Or, in a pinch stand closer to a PA speaker as you record.

I've attempted a fix many times with a program like abobe premiere that allows both a visble waveform analysis and keyframed volume. Its a highly manual task and takes much trial and error in the difficult parts.

To go a step further, you can export difficult portions of the audio to plug-ins or external audio filter applcations. I've even resorted to drawing voice waveforms with a digital pencil.

[disturbed1]

Nero also has a capable wav editor. Simple normalize will make everything the same volume, increase the speaker's volume, while lower that of the crowd.

If that doesn't work to your liking, Nero, Goldwave, and almost all others, will allow you to zoom into a specific portion of your clip, then lower said volume and EQ it for the selected time period.

Applause, cheers, and normal speaking all have different tones, with a good EQ setting you should get a decent result.

Easy way to remove hum is with an EQ. Unless you need the lower frequencies, which most conferences don't, you can cut the hum by lowering the 120-20hz frequencies with the EQ.

Be careful using a dynamic compressor. 99% of the so called pros that use these, create ill fated effects. How many times have you watched TV, or a movie and had to keep your finger on volume control to constantly adjust the volume? That's the effect of bad sound mixing.

[dprocket]

Thank you for the replys, everyone. It all makes sense, it seems...even though I've never done anything like this before.

Certainly, I did make a mistake by not setting up a mic for the speaker, but what is done is done and hopefully I can use one of these tools to reduce the excess volume in at least some areas.

One other silly questions. Most of the tools recommended (Audacit, Godwave, etc) are "audio" tools. Is there a way for me to put my video (avi files) into these tools? Obviously, my AVI files have audio/video "attached" to them (sorry, not sure of the correct terminology here).

Thanks again for the help, all.

[lordsmurf]

Demux audio/video

[daamon]

Hi dprocket,

Load the AVIs in VirtualDub and the save out the audio as a WAV file.

[KenJ57]

You never said how you captured Hi-8 or what app you usually use to edit. The usual technique is to export your audio track and use a specialized tool to doctor it, then replace the original.

I have successfully used the Audacity program to remove some rather difficult noises from audio by using its' 'Noise Removal' effect. Sample 11 MB wave file here. This effect is very effective to remove camera motor or similar noises. My sample removed an intrusion alarm from the dialog of a cable TV talk show.

It looks like you may have to use a combination of all the techniques presented here to 'resurrect' your audio. By the time you get it just right, you will either be an expert -- or you may well just consider the project too hard for the effort. Good luck! You will probably do better next time you record. -- Ken