I often got some wonderful and rare bootlegs from the 'Net. I would like to burn them to CDR, but there are some issues:

1. gaps between mp3s (these I can fix manually and it quite works, shortening every track a few ms tho)

2. AWFUL :eek: artifacts in files. The best (rarity-wise) bootlegs are the worst quality-wise (like Xing-old 96 or sth)

So I would like to know is there any (semi)automatic or manual way to 'smooth out' the artifacts - make them just a bit less annoying... I don't mean reconstructin a transparent or close-to-transparent recording but just to make it quite [more] enjoyable to listen.

Can e.g any winamp DSP plugins help (Enhancer et al.) in this very case?


Thank you for your (hope to be) suggestions
maciey

PS dunno wheteher MP3-Technical is a good place for this thread :confused:

There's really nothing you can do to remove or "soften" the artifacts in a file that's already been encoded. You could maybe try to manually apply some post processing to the worst parts of a file with an audio editor of sorts, but chances are that it won't work very well, at least without significantly changing the sound and making some other aspect worse.

In the end, there just isn't much you can do in those types of situations.

i don't think anything can make xing(old) 96 sound WORSE . Waht postprocessing do You suggest?

Nothing really... Like I was saying, it's not really a viable solution. I don't think it's going to matter what you do because to "cover up" or "soften" the artifacts, the post-processing would have to be very destructive.

For an example of what I was talking about.. suppose you have a file with lots of ringing around 14khz. Well, you could lowpass at 13khz then or something.. and you might not have any more ringing, but now the file sounds muffled. See the problem? Furthermore, most cases wouldn't even really allow something as easy as that because the distortions are often temporal in nature and can be anywhere in the frequency range. You can't easily isolate them.

So basically back to what I was saying, there's really nothing you can do.. certainly nothing automatic, and at best, there's no ideal processing or anything that would "fix" the sound.

There is one thing that could be done -- the file could be decoded to .WAV, then there's probably a lot more flexibility in what could be done with powerful editors like Sound Forge with various plugins. However, at that point it might be a good idea to use a lossless compressor like FLAC if compression is still desired, since transcoding back to MP3 would be a bad idea.

Edit -- maybe someone will eventually write a utility or WinAMP plugin that 'smooths over' known MP3 artifacts like ringing, flanging, etc... it would certainly come in handy for some of the worst stuff... for anyone who's ever had to suffer thru listening to a Blade-encoded MP3 at 160k or below...

The problem [b]is exactly this: how to 'smooth over' ringing, flanging, etc...

--
GCP

for graphics it's quite easy to filter out e.g. JPEG artifacts - thus getting a blurry yet printable pic - so I hoped there are some ways to do similiar to sound - not even to transcode to MP3 back again - just to burn to CD®-Audio

MP3 doesn't suffer from the same blocking JPEG artifacts. But the "ringing" artifacts you see in JPEG are the equivilent of preecho in MP3.

If you want to burn to CD-R as an audio CD, then decode to .WAV first (I suggest the MAD decoder) and look for a good free or shareware .WAV editor -- or pay for a professional one. There's a lot more that can be done once the MP3 is in .WAV format, especially with the pro packages. If this material really is rare & hard to find, then it would be worth it to invest in a quality .wav editor program & learn how to use it.

Edit -- you might consider Cool Edit 2000, available here:

http://www.syntrillium.com/

I agree 100%...



Of course you can always use some sort of .wav editing program to alter the sound of the file, but you aren't going to be able to work at a low enough level, and precisely enough to "smooth out" or "extract" mp3 artifacts. Even if you had the tools to do something like this, how would you define "smoothing out" the artifacts? Especially in regards to sound, this could mean almost anything from lowpassing, to fading something out, to applying some sort of odd effects filter, etc.. all destructive processes which are likely to be nearly just as annoying if not more.



I had a feeling this might have been what you were talking about. Unfortunately, aural media is a completely different beast than visual media, especially in regards to how we interpret what defines an acceptable tradeoff in quality (to compare to a visual example it'd be blurriness vs blocking artifacts). Because of this and due to the nature of errors different audio encoders may produce, it would be a monumental (if not impossible) task to do what it is that you are talking about, effectively.

If you have rining above a certain frequency, you could low pass at that frequency, and then use spectral band replication to approximate what has been lost. If you have audible pre-echo, you could manually change the envelope to remove some of it.

But as Dibrom as said, the result would probably sound better, not worse.

You could just play it back over the same kind of $5 PC speakers that the person who encoded it obviously used!


David.

P.S. - never say something is impossible. I'm sure in (say) 20 years it will be trivial to restore badly encoded audio material to something like respectable quality. Just because the technology doesn't exist now doesn't mean that it will never be invented! The de-clicking of old records was a primative art 20 years ago - now clicks and crackle can be removed without much effort at all.

If you had ringing *at* a certain frequency (say 13 KHz), you could remove all 13 KHz frequency components (or just decrease using equalization) on the .WAV file... that wouldn't sound nearly as bad as lowpassing, especially if you did a bit of boosting other frequencies to compensate.

Another example I can think of is, in Sound Forge there's a "smooth/sharpen" type function that might remove some artifacts (using the 'smooth' function).

As for whether the changes would be more annoying than the original artifacts... that would depend on the listener, i think. Some people who rip vinyl strongly believe in *leaving in* any clicks & pops! And some believe in removing these using click/crackle filters. It just depends.

I found a good way to smoothout the sound.

1.Load your files into nero burning rom.
2.Choose hiss reduction from the filters menu and set them to:
hiss level : -75db (little distortion) -80db (very high distortion)
hiss reduction : 6db
3.Burn the cd.
4.Copy the cd with eac
5.Enhance the sound with DEE http://www.domieszki.com.pl/dee120setup.exe



I've done that with the bootlegs of Vangelis' Blade Runner and this gave very good results.

thanx - I will give it a try as soon as I heve enough time to work with it. btw - do You think that Cool Edit's noise/hiss reduction may work here well too?