Why Does Converting VHS to DVD Cause Hiss?

[VideoFanatic]

The WWE doesn't sell wrestling seasons of it's weekly TV show, it only sells Pay Per Views of it's monthly events. So the only way I can watch old seasons is to buy pirated VHS-to-DVD conversions off other people.

All the VHS-to-DVD conversions that I've seen from every seller have a constant hissing noise in the background.

Is hiss unavoidable in VHS-to-DVD conversions or are they just not using the correct equipment and setting the correct audio levels to do the job?

[dragonkeeper]

Pirated is a bad word around here. But to answer your question either they don't know what they are doing or don't care. There are a myriad of reasons there is his in a VCR would produce a hiss. But there is no reason it could not have been cleaned up prior to authoring of a DVD.

[jman98]

Please note that VHS to DVD conversions are almost all done by technical morons. They just hook up any old VCR they have lying around to a DVD recorder and press a button. I bought a couple of such DVDs of Spanish bullfights a few years ago as a surprise gift for my brother and I asked what I thought was a fairly simple question of the seller as to what setting he had used for the length of the DVD recording. For example, he put 2.5 hours on what was clearly a 4 hour setting so there was about 40% wasted empty space on the DVD. I tried to ask only if his DVD recorder had a 3 hour setting and he was just completely unable to comprehend my question. The answer I got out of him something like "I just pushed some buttons. I don't really know what settings were used or how to even check it."

Original VHS audio was pretty low quality and hissy. There were improvements over time, notably hi-fi audio, but the sellers could have very old VCRs. The tapes could have been recorded in the early days (I've got VHS tapes I made in the 1980s that still play) when hiss was normal. Also, some capture devices do a better job than others in dealing with this, but I assume that your sellers fall into the "moron" category I talked about where they barely know enough to do the kind of copying they did of VCR to DVD recorder. Finally, it's worth noting that when VHS tapes were copied to other VHS tapes that this introduced more hiss into the 2nd generation copy, so for all I know they may be working from multi-generational copies. In some music circles certain hard to obtain videos are only available as like 10th generation or worse VHS sources to DVD and what you get is pretty abominable for both video quality and audio, but fans do not have access to anything better and the artist has not chosen to make any better official copies available anywhere.

[VideoFanatic]

Yes I've also come to realize that the people doing the VHS-to-DVD conversions aren't very smart and don't know what they're doing!

I don't think the VHS tapes originally had hiss. The tapes were from 2002. After that everybody seems to have gotten a DVD recorder and they're selling straight-to-DVD instead of VHS-to-DVD. The video quality in the VHS-to-DVD conversions is pretty good even though it's under a layer of compression artefacts so I don't think the VHS sources were multi-generational.

But I'm just trying to figure out if the hiss is caused by the analogue to digital conversion of VHS to DVD as I've read that VHS tapes have inaudible hiss that when converted to digital causes the hiss to become audible. Is this true? There seems to be very little information on the internet about what causes hiss and I can't even find anybody complaining about hiss in VHS-to-DVD conversions which is why I've come here to find out.

If it's possible to convert VHS to DVD without causing hiss, how is this done and what equipment do you need?

[Cornucopia]

A-to-D itself at WORST only adds a tiny incremental amount of either hiss (through dithering) or distortion (through no dithering/quantization). Not even enough for most to even notice unless their speakers are at 11!

Could be they didn't use VHS HiFi audio when they should have.
Could be they had the output & input levels set all wrong.
Could be they tried to do some post filtering and don't know what they're doing and made matters worse.
Lots of reasons, none of them inherent to VHS->DVD.

Scott

[jagabo]

I don't think the VHS tapes originally had hiss. The tapes were from 2002.

VHS Hi-Fi from that time period had two audio tracks. A Lo-Fi mono linear track (with a lot of hiss) and a Hi-Fi stereo audio track written and read by the helical scan heads (much better sound, more like a good cassette deck). It's likely they recorded from the Lo-Fi track instead of the Hi-Fi track when they made the DVDs.

[Hoser Rob]

Whatever noise an ADC adds will generally be dwarfed by the noise already in the analog source.

VHS HiFi was actually a good sounding medium. Surprisingly good. The only problem was that very few of the machines had input level controls, They just used peak limiting on the inputs.

Which kind of negated the virtues,and was why VHS Hifi never really took off with audio enthusiasts. It also means that even if those pirated tapes involved a hifi machine the sound may still not be any good.

You also don't know how many generations those copies are. Maybe several, none of which used VHS hifi.

[yoda313]

If it's possible to convert VHS to DVD without causing hiss, how is this done and what equipment do you need?

Well nobody seems to really be answering this question so I'll take a stab at it.

You'll need to rip (copy) the dvd to your computer. Since this is homemade even older programs like dvd shrink can do it. But you can also use dvdfabdecrypter to do it. EDIT - I realize you are asking how to do this the first time from vhs to dvd but these instructions are how you can do it yourself in post production with the dvd you have on hand right now.

Since this is stereo use virtualdubmpeg2 to open the file. Go to file-save wav to save just the audio to a wav file.

From there use an audio editor that has a de-hiss option. I have an old version of cakewalk pyro (payware) that has a dehiss/noise option that works fairly well. You can also look into the freeware audacity that may have a de-hiss option - don' know for sure though since I have a different program that does it.

You would follow that programs guide to remove the hiss. Remove is kind of a misnomer since at best you are looking to minimize the hiss. I doubt even professional studio equipment would be able to magically eliminate hiss from a source if it was really bad.

You save it as a new file and then you'll need to remux it into the video and author a new dvd. Or you can use a dvd authoring app that can let you replace the existing audio track with the new one (avstodvd is one such freeware program that does that). If you author a new dvd you lose your existing menu unless you have the same authoring program and menu assets that the creator of the dvd used - unlikely to say the least.

I believe if you use ifoedit you can seamlessly incorporate the new audio into the original dvd structure. I'm not sure as I've never really used ifoedit. You can search the forum for info on ifoedit to see if you can - I"m pretty sure you can but I can't guide you on how to do that.

You would take your newly authored dvd folder from either avstodvd, another program or ifoedit and burn it to a dvd with imgburn. Use a quality blank disc like taiyo yuden or verbatim (not the life series).

Edit - the audio needs to be in dvd format which is 48khz and either ac3, mpa (mpeg audio), pcm or dts. Chances are you don't have a dts encoder and don't need to do dts for just stereo - ie overkill since dts is more intended for surround sound than stereo though it can do stereo). PCM (ie wav audio) will be a very large file so it is recommended to just use ac3 since that will work with the most equipment. Edit 2 - I'd recommend using a bitrate of no lower than 384 - max ac3 bitrate for dvd is 448kpbs which I usually use all the time unless I really need to save space - ie the higher the bitrate the more space the audio will take up - but as I said ac3 is a good compromise for compressed audio - good quality at a relatively low space requirement.

Then you should be all set.

But remember this won't be a perfect cure for the hiss. Unless you were able to get a hold of the original video tape and recapture from it directly at best you are reducing the hiss and making it more listenable. You might also be reducing whatever fidelity is already on the video. But if the hiss is that bad that you want to de-hiss it whatever loss in over audio quality you get might be worth it.

Edit - also to do this from the original tape if it had hiss on it you would need some audio equalizer equipment. You'd run the audio out from the vcr to the equalizer and then that audio to the capture device along with the video of course. Than in realtime you'd manipulate the audio from the vcr until you got something that you could tolerate. But as I said either way during capture or post production with software at best you are looking to minimize the hiss not remove it completey.

[JVRaines]

Interesting discussion. I'm guessing holygamer is a young person, which means her/his high-frequency hearing goes close to 20KHz. All magnetic tape audio recordings have hiss, caused by the fact that magnetic particles cannot be made infinitely small. And this is where Ray Dolby made his money: inventing techniques to reduce the hiss. But it's always there.

[VideoFanatic]

Thanks Yoda but I already know how to remove hiss! I was asking if it's possible to convert VHS to DVD without causing hiss! I'm guessing I'll need a TBC but I don't know what else I would need or what software.

[JVRaines]

Padawan-- there's nothing inherent to the process of converting VHS to digital and putting it on a DVD that causes hiss. Some VCRs may have worse audio electronics than others and add more noise, but all the hiss comes from the analog side. A TBC processes video only and won't do a darn thing for your audio.

[VideoFanatic]

I know that but I assume a TBC will be a good quality piece of kit with good audio electronics so it won't add noise!