PDA

View Full Version : mp3 degradation over time



elmtree
2005-04-18, 13:09
I've noticed some discussions around the quality of mp3, however I am experiencing something that I've yet to find a duscussion on... It sounds like various tracks within my .mp3 library are degrading over time.
The symptoms are presenting as clicks/pops and sudden bursts of static. The static can be much louder than the output of the rest of the song.
I am running slimserver on a PIII 450 with 256 RAM and an 80GB drive (appx 6000 songs @ 192 or above) and a 12 GB drive for the OS (Win2K Pro). I am currently storing some large mpg files on the music drive as well.
On the other end I have the original slimP3 hardwired.
Between the slimP3 and the server there 2 hubs & and a patch panel.
I have thought that maybe there is too much going on between the server and the head-unit, but the problem appears to present itself on different songs- and once a song is 'infected' the only thing I've been able to do is create new mp3s from the CD.
For the most part, the server is dedicated- though I do use it occassionally to surf the web and check mail through web-mail. Neither of these activities occurs while streaming music.

Any advice is appreciated.
Thx
elm

Jim Dibb
2005-04-18, 13:23
On 4/18/05, elmtree <elmtree.1npaen (AT) no-mx (DOT) forums.slimdevices.com> wrote:
>
> I've noticed some discussions around the quality of mp3, however I am
> experiencing something that I've yet to find a duscussion on... It
> sounds like various tracks within my .mp3 library are degrading over
> time.

You probably haven't found a discussion because it doesn't happen?
Either your system is losing bits or you have something corrupting
your filesystem. Or maybe you're running a re-encoder that's messing
up and corrupting the file. Or your slimp3 is dying.

Try setting all the music files to read-only and see if it keeps happening.

Stephen Ryan
2005-04-18, 13:29
On Mon, 2005-04-18 at 16:09, elmtree wrote:
> I've noticed some discussions around the quality of mp3, however I am
> experiencing something that I've yet to find a duscussion on... It
> sounds like various tracks within my .mp3 library are degrading over
> time.
> The symptoms are presenting as clicks/pops and sudden bursts of static.
> The static can be much louder than the output of the rest of the song.
> I am running slimserver on a PIII 450 with 256 RAM and an 80GB drive
> (appx 6000 songs @ 192 or above) and a 12 GB drive for the OS (Win2K
> Pro). I am currently storing some large mpg files on the music drive as
> well.
> On the other end I have the original slimP3 hardwired.
> Between the slimP3 and the server there 2 hubs & and a patch panel.
> I have thought that maybe there is too much going on between the server
> and the head-unit, but the problem appears to present itself on
> different songs- and once a song is 'infected' the only thing I've been
> able to do is create new mp3s from the CD.
> For the most part, the server is dedicated- though I do use it
> occassionally to surf the web and check mail through web-mail. Neither
> of these activities occurs while streaming music.

That sounds suspiciously like disk corruption to me -- either a bad
drive or a bad driver. In either case, backups are a good idea. The
bursts of static are exactly what you'd get if some bits get scrambled
in the middle of the file; because MP3 is frame-based, it will
eventually get back to uncorrupted frames and get back on track. I'd
recommend using Norton Disk Doctor, but that useless pile of bits just
utterly and absolutely failed to help me in the slightest about an hour
ago[0], so I'm not going to recommend it out of pique. You might have
better luck with it than I've had, though.

[0] "Drive C: is misconfigured. Exiting." Thanks, I knew that. What I
wanted is for NDD to *FIX* it, not just sit and gripe about some
miscellaneous unknown problem. I can't even fix it myself because it
won't tell me what's wrong! Meanwhile, Linux has no problem on the same
hardware... [rant about Windows skipped]
--
Stephen Ryan
Digital Rights Management is bad for all of us:
http://www.bricklin.com/robfuture.htm

John Gorst
2005-04-18, 13:47
elmtree wrote:
> I've noticed some discussions around the quality of mp3, however I am
> experiencing something that I've yet to find a duscussion on... It
> sounds like various tracks within my .mp3 library are degrading over
> time.
> The symptoms are presenting as clicks/pops and sudden bursts of static.
> The static can be much louder than the output of the rest of the song.
> I am running slimserver on a PIII 450 with 256 RAM and an 80GB drive
> (appx 6000 songs @ 192 or above) and a 12 GB drive for the OS (Win2K
> Pro). I am currently storing some large mpg files on the music drive as
> well.
> On the other end I have the original slimP3 hardwired.
> Between the slimP3 and the server there 2 hubs & and a patch panel.
> I have thought that maybe there is too much going on between the server
> and the head-unit, but the problem appears to present itself on
> different songs- and once a song is 'infected' the only thing I've been
> able to do is create new mp3s from the CD.
> For the most part, the server is dedicated- though I do use it
> occassionally to surf the web and check mail through web-mail. Neither
> of these activities occurs while streaming music.

I had a similar problem when i ran a mp3tagger a while back )-:

elmtree
2005-04-18, 15:26
Thanks for the input.
I don't think I've got a Re-encoder running...? Is this something that could be running without me knowing it?

Would MusicMatch be considered an mp3 tagger?

I used MusicMatch to rip all the songs. I have read that there are better tools for the job and frankly I wish I could remember which ones were recommended. Any suggestions?

I also seem to remember that ripping from a particular cd drive wouldn't take care of the problem, but once I switched to my other drive, the songs were better.
Does it make sense that the cd drive would make a difference?

Thanks again,
elm

Christian Pernegger
2005-04-18, 15:44
> The symptoms are presenting as clicks/pops and sudden bursts of static.
> The static can be much louder than the output of the rest of the song.

Assuming that the same songs were fine at one point, something has
corrupted / is corrupting your files. This could be anything hardware
related like a dying disk drive, cable, controller, RAM stick, you
name it. Other likely culprits include software like buggy taggers, or
even players that "clean up" the tags as they go along.

You might want to try generating .par2 files for your important music,
which would allow you to recover from small defects.

More about PAR2: http://parchive.sourceforge.net/

The leading software for Windows is QuickPar (http://www.quickpar.org.uk/).

C.

Simon Still
2005-04-19, 03:41
On 4/18/05, Christian Pernegger <pernegger (AT) gmail (DOT) com> wrote:
> > The symptoms are presenting as clicks/pops and sudden bursts of static.
> > The static can be much louder than the output of the rest of the song.

You're not alone. I noticed a similar problem with my library. I
moved my files to an external drive and swapped out my hard drive for
an ancient one i had hanging around but am still not convinced i've
solved the problem - theres 8k tracks on there so being certain that
i'm not just picking up old corruption is very difficult.

Patrick Dixon
2005-04-19, 04:44
"I used MusicMatch to rip all the songs. I have read that there are better tools for the job and frankly I wish I could remember which ones were recommended. Any suggestions?"

If you're on windows, EAC. There is some help on configuring it on the web (search this forum), so don't give up if it looks too complicated. It rips and then you'd use LAME to compress to MP3. EAC is usually setup to call LAME automatically.

"I also seem to remember that ripping from a particular cd drive wouldn't take care of the problem, but once I switched to my other drive, the songs were better.
Does it make sense that the cd drive would make a difference?"

Yes. Audio CDs don't have all the redundancy and protection that Data CDs do, so if your CD drive's a bit dodgy, and your ripping software doesn't double or treble check everything (as EAC does), you could certainly get inferior results.