Audacity Forum

Greetings,
I am in the process of transferring hundreds of hours of VHS. I am able to export the Audio from the Video Editor as a WAV and open in Audacity for Post Process cleanup.
Many of these VHS tapes have a what I call "roll in" audio noise/click sound. VHS Video systems back in the day were notorious for such artifacts. As a further example, when recording a live concert and the tape began recording, it didn't track correctly and took time to adjust. This is what produces the sound you will hear in the attachment of this thread. This also occurred if you paused a live recording, then released the Pause button, a "roll in" clicking effect is heard due to the inability to rapidly adjust tracking.

I've tried Hum Removal, Click Fix and Repair. Repair is the only feasible option but with over 100 segments with the Roll In click artifact, this good take hours and hours especially with the max 128 samples permitted per repair of segmented audio.

I've attached an exact example of this issue in WAV format.

NOTE: I would suggest and **caution, when playing this for the first time. Please have your volume set to a very low level then increase as needed. The artifact is a popping noise which is embedded in the original audio track.

Any detailed recommendations or suggestions or help regarding this matter would be most appreciated. Lastly, with all of the Analogue to Digital converters available for such transfers, perhaps this has the potentiality for a new filter creation if none exists.
Cheers
Revup

...I can't listen to your file yet 'cause I'm at work.

Lastly, with all of the Analogue to Digital converters available for such transfers, perhaps this has the potentiality for a new filter creation if none exists.

The problem is A/D converters are supposed to accurately digitize the analog signal.

The other problem is, computer's just aren't that good at differentiating between signal and noise. For example, Audacity's noise reduction effect (filter) needs you to supply a sample of noise-only, and then it only works if you have a constant low-level background noise. And, noise reduction filters sometimes have unwanted side-effects.

Good idea on the noise filter and that filter works fine after testing various intervals. I kept bumping the levels until satisfaction was reached and increased. The final levels were to 30/15/12 respectively. The artifacts have been dissolved. Thanks for the reminder and usage of this filter.

Revup67 wrote: ↑

Thu Oct 08, 2020 9:55 pm

Good idea on the noise filter and that filter works fine after testing various intervals. I kept bumping the levels until satisfaction was reached and increased. The final levels were to 30/15/12 respectively. The artifacts have been dissolved. Thanks for the reminder and usage of this filter.

Hello.

Which values do you use for the parameters "Noise Reduction", "Sensetivity" and "Frequency Smoothing" so that you have noise removing with no artifacts?

so that you have noise removing with no artifacts?

No such thing. Noise Reduction has to rip the sound apart and put it back together again. As the damage increases, the correction has to increase, and the less likely the show will survive with no artifacts.

30/15/12 is a massive correction. I think the default is 12/6/3. Much past about 12/6/6 you can start to hear sound damage.

The Audacity tool used to be called Noise Removal and it didn't work nearly as well as the current Noise Reduction. The name change was because too many people were expecting it to remove all noise to nothing.

~~

I think you're listening to VHS-HiFi kicking in and out.

If everything is working right, a VHS tape will have the conventional, relatively muffled, linear tracks down one edge of the tape, and then a "HiFi" version which is a special, much better quality stereo track embedded in the video. Playback machines look for the HiFi signal and use that for the show. If it can't find one, it defaults to the lower quality linear track. If the tape is damaged, it can switch back and forth and that may be what you have.

Some playback machines have a setting to force linear sound whether the HiFi track is there or not. You may be able to use that to force a lower quality, but still usable track for the first couple of seconds, and then play the tape again in HiFi for the rest. Edit together in Audacity.

Alternately, you may have tape frilling edge damage and that's what the linear track sounds like with no HiFi signal at all.

Koz