Improve audio from VHS - denoise, channel combining?

[apjorz]

I recorded an audio track from a low quality VHS source which I want to use with a DVD quality video track (the movie was not released in that language). I have two questions:

1. Is it theoretically possible to remove some of the background noise, without losing significant quality on the valuable part of the track? I experimented with Audacity's noise removal, but the outcome was always strange and jerky, even at the lowest level. Or am I stuck with that noise, which is also amplified by normalizing the track? (not that I expect any wonders) Should I try different software for denoising?

2. Now for the tricky part: the recorded signal is stereo, but the source material seems to be mono. That means the two channels should be identical, but they are not, just almost :). Sometimes one of the channels is a bit weaker for a few seconds, which is kind of disturbing, especially with headphones

Now it would sound logical to duplicate one of the channels, but the problem is, both channels do that from time to time. So I would end up with an audio track which contains all the errors from one side. Fades on both channels, but less often. I'm not yet sure if I should touch this. I should count the number of times this happens and decide after. And I could manually amplify the concerned parts after duplicating one channel.

But my question still stands: is there a method to somehow preserve whichever of the two signals is stronger, and use that, combining the channels together?


It's also quite ASAP :). Thanks in advance!

[SallyDog]

I recorded an audio track from a low quality VHS source which I want to use with a DVD quality video track (the movie was not released in that language). I have two questions:

1. Is it theoretically possible to remove some of the background noise, without losing significant quality on the valuable part of the track? I experimented with Audacity's noise removal, but the outcome was always strange and jerky, even at the lowest level. Or am I stuck with that noise, which is also amplified by normalizing the track? (not that I expect any wonders) Should I try different software for denoising?

2. Now for the tricky part: the recorded signal is stereo, but the source material seems to be mono. That means the two channels should be identical, but they are not, just almost :). Sometimes one of the channels is a bit weaker for a few seconds, which is kind of disturbing, especially with headphones

Now it would sound logical to duplicate one of the channels, but the problem is, both channels do that from time to time. So I would end up with an audio track which contains all the errors from one side. Fades on both channels, but less often. I'm not yet sure if I should touch this. I should count the number of times this happens and decide after. And I could manually amplify the concerned parts after duplicating one channel.

But my question still stands: is there a method to somehow preserve whichever of the two signals is stronger, and use that, combining the channels together?


It's also quite ASAP :). Thanks in advance!

Just my 2 cents worth, but seems to me that even if you could improve the quality with other software (Soundforge for example), it would be next to impossible to sync the audio back to the video.

[setarip_old]

Hi!but the source material seems to be mono. That means the two channels should be identical, but they are not, just almost . Sometimes one of the channels is a bit weaker for a few secondsThis seems implausible, unless there's some weakness in the connections you've used to capture the audio. You might want to try capturing the audio again...

[Spc01]

What if you convert it to mono?
I think that would eliminate errors...

For the noise try playing with Equalizer a bit maybe you'll cut it off if you have a static noise at the same frequency..

:)

[apjorz]

Hi!This seems implausible, unless there's some weakness in the connections you've used to capture the audio. You might want to try capturing the audio again...

Well the VHS cassette quality is pretty bad (luckily, I don't need the image :). I rented it, since it's unavailable for purchase. The connection should be fine, or at least, I don't know how I could improve it: video player - scart converter - new dualrca/jack cable - audigy4. But I'll recheck anyway.

Thanks for the replies!

[setarip_old]

What's the Title and Region of the DVD and what is the language you are trying to superimpose?

[apjorz]

What's the Title and Region of the DVD and what is the language you are trying to superimpose?

It's "The double life of Veronica" (r2 pal), and the desired language is hungarian (we use pal too). Why do you ask?

[apjorz]

Hi!This seems implausible, unless there's some weakness in the connections you've used to capture the audio. You might want to try capturing the audio again...

You were right, it seems to be the cable (thanks!). It took me a while to figure it out, I had to move it several times to reproduce the effect. This is strange, because I did not touch anything during the recording session. Luckily, I have another cable.

I will still record in stereo, just in case, so if there are differences between the channels, I can notice them easier. But in the end I will use a mono track. Mono mp2 is alright for DVD, isn't it?

Do you know any ideas, guides, faqs etc for syncing the audio and the video together? I suppose it will be more complicated than just selecting the right files in some authoring software.

[SenorKaffee]

According to http://en.wikipedia.org/wiki/DVD-Video#Audio_data one channel (mono) audio is fine.

[apjorz]

According to http://en.wikipedia.org/wiki/DVD-Video#Audio_data one channel (mono) audio is fine.

Thanks, in the meantime i found it too. At first I was a bit puzzled because besweet would not work with a mono wav, but I managed to split the stereo mp2 file with besplit.

[apjorz]

What software would you recommend to join & sync the m2v & mp2 files? A tip for the final authoring software is also welcome - I will have to change/replace the menu.

The goal is a multilingual DVD, so I should also keep chapter information somehow.

Searches did not lead me to a good solution so far, especially for the joining + syncing part.

[setarip_old]

It's "The double life of Veronica" (r2 pal), and the desired language is hungarian (we use pal too). Why do you ask?To see if I had access to the same DVD, or might be able to find more information about available audio tracks for it...

[apjorz]

To see if I had access to the same DVD, or might be able to find more information about available audio tracks for it...

Thank you. So, did you find anything? I guess not, I spoke to the company that released the hungarian version. They never did a dvd release (just vhs), and they don't even own the rights to sell the vhs anymore. They can just rent the few ones they have. What a shame.

I'll probably abandon this thread. I don't think I can improve the noise situation (#1), and question #2 is solved by a new recording session.

Now I'm on to stretch the audio to the correct length (same as the original ac3 stream), because when muxed with the m2v file, it becomes badly out of sync at the end. But this would be off here, so I'll search and eventually post in the appropriate forums.

Thanks for all your help!

[setarip_old]

Thank you. So, did you find anything?As you surmised, unfortunately, no.

I wish you the best of luck trying to synchronize the audio. It might be easier to learn French or Polish ;>}question #2 is solved by a new recording session.Glad to hear my speculation was correct

[apjorz]

As you surmised, unfortunately, no.

I wish you the best of luck trying to synchronize the audio. It might be easier to learn French or Polish ;>}

Thanks, I'll need it! :) I speak french and I have nothing against subtitles (in fact I re-translated the subs to hungarian, because the originals sucked :) ). But it's a very important film for a very important person who knows and loves it in hungarian - therefore, I'm preparing this all-in-one ultimate edition :).

[foxyshadis]

Unfortunately, if you want to step up from Audacity's, the only really good denoisers get quite pricey. ($100+, over $200 for the Sony plugin I like, so glad I wasn't the one to pay for it.) It'd probably be worth experimenting more with Audacity's. Did you read up on how to do it? It's extremely important to do it properly, or you're guaranteed to get lousy bad-mp3 sounding results, since there's zero manual control.

You have to choose an area of the track with absolutely no speech or sound, just dead air and lots of hiss and hum, to create the noiseprint. Then you select the area you want to clean and apply it to that.

VHS is so lousy you can probably just lowpass it to 12 or 14 khz for great quick hiss reduction and not notice.

[apjorz]

Unfortunately, if you want to step up from Audacity's, the only really good denoisers get quite pricey. ($100+, over $200 for the Sony plugin I like, so glad I wasn't the one to pay for it.) It'd probably be worth experimenting more with Audacity's. Did you read up on how to do it? It's extremely important to do it properly, or you're guaranteed to get lousy bad-mp3 sounding results, since there's zero manual control.

You have to choose an area of the track with absolutely no speech or sound, just dead air and lots of hiss and hum, to create the noiseprint. Then you select the area you want to clean and apply it to that.

VHS is so lousy you can probably just lowpass it to 12 or 14 khz for great quick hiss reduction and not notice.

Yes, I know how to use Audacity's noise removal (used it before with success), but as I mentioned, the result was this time always worse than the original signal. I think there is simply too much noise even in the quiet parts, so removing that noise profile wastes the important signals too. But lowpassing seems like a good thing to try! Thanks!

[apjorz]

I think I'll give it a try, but it's VHS after all, so I don't really mind anymore... (still working on it, I had a massive data loss :))

Thanks for your advice, the detailed description, and also welcome to the forums! :)


Yeah, Audacity hasn’t worked for me too...