Bad mp3s

[tonemgub]

Hi,

Can someone tell me what is wrong with my mp3 files. Every now and again you hear this sudden faulty noise in them. Here is a sample of what I am talking about. http://www.sendspace.com/file/chg0pv

What is this called, and what causes it?

Thanks

[Cobra]

Just a stab in the dark here (as I don't know much about the files or technology) but it sounds like corruption in the file. A part of the file has become damaged and when decoded seems to produce only white noise. Once you're past the bad part, it comes back.

It could be caused by writing it to a format that has no error correction, and bringing it back. Not sure what could do it, really.

Best thing to do is re-rip your CDs. Maybe consider using Vorbis, if you don't use a portable MP3 player or anything. It's higher quality than MP3. CDex supports it (and MP3 if you need that format).

[tonemgub]

Thanks for your reply

I intend to re rip the bad files once I know which ones are bad. I spent the whole weekend copying my cd collection on to my computer. I have hundreds of mp3 files on my computer. When I ripped them I chcecked them briefy to see if they sounded okay and they did. Then I moved on to the next cd. Only now when I listen to the songs the whole way though, do I notice that on some of them the noise occours for a split second.


So what I really want is some program that can detect the bad files, so I don't have to spend days listening to every second of every song to find out if it has bad spots or not. Opening up one of the bad files that I know about, in EAC, the bad spots are clearly visible as a blue line from top to bottom. See where the red arrow is pointing

[bobkart]

That screen says it's looking at a WAV file (sample.wav), not an MP3 file.

[SanderMan]

What audio grabber are you using? I guess you're using burst mode for ripping. You'll then get artifacts like that. I suggest using EAC with secure mode. Errors like that are then a thing of the past. A good site explaining al the options is http://users.pandora.be/satcp/eac-qs-en.htm

Good Luck.


edit: typo

[CrayonEater]

Although it IS likely to be a drive issue, it's also possibly a limitation in MP3 itself. While I did not get a chance to listen to your sample (for some reason the link does not appear on Sendspace), MP3 is a lossy format and certain compromises have to be made in order to get those massive reductions in file size. To some, those compromises ARE noticeable. Try and see if these problems happen in the WAV files before they get converted to MP3. I suggest backing up your CD collection in WAV format anyway and then converting to MP3 if you need compatibility with portable devices because WAV is the original format and is the highest-quality possible. I believe EAC lets you keep both the WAVs and the MP3s. More and more devices are supporting WAV and other lossless formats anyway so you may not need MP3 is a couple of years.

[tonemgub]

Thank you everyone for the replies. I decided to start over again and use EAC this time and will check more carefully for errors. bobkart the screenshot shows a wav because I converted the file to a wav so i could open it in EACs process wav feature.

[bobkart]

I have various standalone command-line-oriented programs that I've written which can deal with WAV files both as input and/or output. For example, one simple one just checks that the WAV file format is correct and also reports the minimum and maximum sample values for each channel (and how many times they occur). So using that technique, one could imagine a program that could tell you if your WAV file is corrupted as is shown in your picture by detecting that the maximum and minimum possible sample values actually appear. Of course I have also seen these values appear in non-corrupted WAV files (clipping). So it would have to be a bit smarter than that if any of your particular tracks do that. But still, it seems feasible to write something that can read a WAV file and detect the kind of corruption present in your example (sample.wav). Perhaps very closely-spaced 100% min/max values.

This replay was to your request for a program that can detect the bad files. You've apparently gotten past the need for such a program since that request, but for future reference, I suggest that such a program could be written in a matter of hours and applied via command script to a large collection of WAV files, and produce some kind of report that indicates which of those files it detected the corruption within.

[TooLFooL]

(for some reason the link does not appear on Sendspace)

its there at the bottom, VERY unnoticable!...