Low frequency noise on old AVI files

[RDK45]

Folks...I'm in the process of going through my archives and restoring some old projects (like mid 1980's). I just noticed that the AVI files have a "delayed, low frequency rumble" which seems to be triggered (ie more noticeable) by any foreground narration or folks talking in the AVI video file.

If you listen carefully, it is the person talking, but slowed down.

I DO NOT recall that being an issue when I originally made the file or the resulting DVD's.

As I recall the AVI files were captured via Video Studio using a video capture card and composite output from a VCR player and VHS tapes.

Any ideas as to what is happening here and what I can do about it?.....RDK

[canuck]

"archives and restoring some old projects (like mid 1980's)" ?????

[BrianCee]

I would certainly be interested to know what computer and what software you were using back in the mid 1980's - I had an Amstrad 64K and an Apple 128k but I don't recall any software - seemed we wrote most of what we needed.

[RDK45]

Brian.... , yes I guess my post was not complete. Written in the heat of the moment and obviously without enough thought.

You're right the transfer did not take place in the 80's, the video dates to 1986 to be exact. Back then I had an RCA video camera which took full sized VHS cassettes and did my editing using two VCR's. That changed sometime when I got a "really fast" computer and Ulead VS version 6. Don't recall the year(s), but I have almost every version since then. Thus, I guess, the problem AVI files date to the early 2000's and were transferred from VHS to PC via a video capture card, composite cables and my VCR.

I have tried the problem AVI files on another PC and they do the same thing. Interestingly, it seems, so far, that it is only this one project which is affected. Video Studio x7 says they are "Microsoft AVI files - OpenDML", Video Compression "DV Video Encoder -- type 1" and audio compression "DV Audio -- NTSC".

The problem audio does not happen in the VS x7 editor during preview, but is there when you view the resulting AVI file in Windows Media player. It is not there when you view the resulting MPG file.

OK, is this enough to get the brain cells turning?......RDK

[lata]

Hi

Your files are DV-Avi, the same as recorded by the older Mini-DV Camcorders.
Quality was always good, and using the lossless compression was good to edit.

The rumble sound could have been added during capture but I would expect was on the original VHS tape.

The format is Ntsc, I assume France is Pal at 25fps.
Make sure your project properties are set to use Ntsc

Go to Preferences (F6) set Show Messages when Inserting…..
Start a new project
Insert a Avi to the timeline should show a window to match the project properties.

Rendering your project should use Ntsc, unless you are intending to convert to Pal?
You should use Make Movie Templates Manager to create a suitable template?

It seems strange that the rumble does not show when converting to Mpeg?

Does the rumble disappear if you rendered to “same as first clip” that would effectively create a copy of the original DV-Avi

[RDK45]

Brian and Lala...Hmmmm, this may be an issue with only that one project. As I have sampled some others from about the same time/source and they seem to be ok.

Anyway, I tried your idea of creating a file image copy ("rendering same as first clip"). I did a 7 second clip and the copy has the same sound anomaly issue as the original. However, I noted as I watched and listened to the clip that Windows Media Player ran out to about 13 seconds before it quit, even though the "action" was done at 7 seconds, but the rumble of me talking continued. Note, as before, the MPEG file did not have the extra sound anomalies nor the extra seconds.

Now I'm wondering if it might have something to do with the audio tracks. Is there a way to see the two stereo audio tracks? Clicking on the "sound mixer" icon only shows one wave form.

Yes, this set of videos are NTSC format, but I have others which I checked today, both NTSC and PAL, which do not have the rumble.

I now capture in PAL with my Sony Camcorder, but still render in both PAL and NTSC for family and friends. Wait, I forget that I now capture with my Nikon (MOV which I guess is QuickTime) and with my GoPro which is MPEG4. I suppose my next problem will be with deciding between Lower Field First and Upper Field First......RDK

[Ken Berry]

If it is only one project, I would be tempted to save the entire audio track as a separate new file, then open that in an audio editing program, such as the freeware Audacity. Then I would find a short part of the audio where there is only the hum. In Audacity you can then use that hum to extract it from the entire track. Then reinsert the cleaned audio back in the VS project.

I suppose my next problem will be with deciding between Lower Field First and Upper Field First...

I guess you could always output it as Frame Based (that's fully Progressive in high def terms). That way you won't have to worry about mixing Upper and Lower Field First video, if that is what you intend doing.

[RDK45]

Ken...Thanks for your reply, but the rumble noise I'm experiencing is not 60 cycle or other source buzz/hum which could be filtered out. It is somehow related the foreground narration made at the time the video was taken back in 1986. It manifests itself as a "very slowed down", and thus low frequency, noise which if you listen carefully you can connect that noise with the foreground narration, just delayed by several seconds and lower volume.

I just reviewed the 2006 discussion of Lower Field First, Upper Field First and Frame Based (http://forum.corel.com/EN/viewtopic.php?p=88525). Nice discussion, but it needs to be updated to include comments about newer sources of videos: tablets, smart phones, and normal and DSLR cameras. What are the right settings for these and how does one figure that out?

Thanks again.....RDK

[lata]

Hi
As a general rule……….
All interlaced video, well 99% uses Upper Field, with the exception of DV-Avi, recorded on a Mini DV Camcorder which uses Lower Field.

If you convert Lower Field to Upper Field then you may see jagged edges on vertical edges. More apparent when panning.

Progressive video aka “field based” can be used by HD video.

Most video for the internet would use frame based , WMV for instance would use Progressive (frame based) MPEG4 default templates use frame based.

The golden rule would be to use the same field order as your original video file.
The field order is set when recording the video so a DSLR camera would probably use Frame Based.

Setting Show Messages from the Preferences would match the project properties and correct field order, assuming the video is compliant.
Otherwise right click for properties to view the frame rate.

[Ken Berry]

As for the rumble, even if it is throughout the entire clip, if you can find a little part of the clip where there is only the rumble, then you 'capture' that little bit in Audacity and then it can be used to remove the rumble from the entire clip but leave the rest of the audio intact.