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Topic: Struggling to understand why I get bad rips (Read 1855 times) previous topic - next topic
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Struggling to understand why I get bad rips

Hi all--new to the forum (I don't think I've had an account here before), though I've searched here for years to get advice, so thanks for all that you do. Here is the issue that prompted me to register:

I have been using iTunes for daily listening and EAC for archival-quality ripping. Won't get into the reasons but I've always had a lossy library of mp3s and m4as that I play, and a separate archive of .wav files that I don't play. Both iTunes and EAC are installed on my laptop, and both sets of files live on an external USB hard drive. My CD drive is also connected via USB.

Within the last two months I started seeing occasional bad rips in iTunes. Certain tracks wouldn't play and if I looked at the art embedded in them, it would be all scrambled up. Tags would be missing sometimes too, etc. I could delete and re-rip them to fix it, but it started happening often enough to concern me.

After lots of testing this and that, I decided to go nuclear on it yesterday. I replaced 1) the external hard drive, copying all my files over; 2) my music player, switching from iTunes to Musicbee (wanted to get off of iTunes anyway, so I used this as an excuse); and 3) the files I was playing, figuring if I was setting up a new library, I might as well use the .wav files I've already got. I figured one of these 3 things would eliminate the problem, wherever it was.

Well, it didn't. I tried playing an album I ripped earlier this week (to the old drive) and some tracks (.wavs created by EAC, and reported as "accurate") were bad. There were dead spots with no audio, sections with ear-shredding white noise, and a couple files that EAC didn't even recognize as .wavs. Examples of what I mean (shield your eyes from horrible brickwalling):



This suggested to me that the hard drive had been the issue all along, so I re-ripped the bad tracks on this album--but the new files (on a whole new hard drive) also had problems. I ultimately ripped certain songs 3+ times to get good copies. Each time EAC reported my rips as accurate but when I opened them in EAC's editor, they might or might not be any good.

I'm struggling to figure out what to try next. Replace the CD drive? Could it be reporting good rips to EAC but still putting corrupted .wav files on my hard drive? It's obviously not iTunes as that's been eliminated from the process. It's not the hard drive as I've replaced it with a brand new one. I can only figure that it's the CD drive, or the connection between that and the external hard drive, maybe. I don't get why EAC keeps reporting rips as accurate when the files aren't good, but maybe AccurateRip is just working off of data sent back to it by the drive and doesn't look at the actual file created? That's my working hypothesis right now.

Re: Struggling to understand why I get bad rips

Reply #1 –
You will anyway need CUETools: http://cue.tools/wiki/Main_Page
It works on your files. If it verifies an album with AccurateRip, then accurate it is.

Use this on your entire collection first, to see what albums you can safely keep. Re-ripping is not fun.
Oh, and: When you are done,
* use a checksummed lossless format. FLAC. Or anything but ALAC/M4A and the uncompressed WAVE/AIFF ...
* backup. Backup. BACKUP!!

Re: Struggling to understand why I get bad rips

Reply #2 –
AccurateRip can only tell if data was accurately read from CD. It has nothing to do with how data was written to hard drive.
Since data came from CD correctly, problem should be not CD drive or its connection.
If problem is not hard drive itself, it maybe connection between PC and hard drive. Bad cable, insufficient power, bad USB port.

Re: Struggling to understand why I get bad rips

Reply #3 –
Quote from: Bogozo on
AccurateRip can only tell if data was accurately read from CD. It has nothing to do with how data was written to hard drive.
Since data came from CD correctly, problem should be not CD drive or its connection.
If problem is not hard drive itself, it maybe connection between PC and hard drive. Bad cable, insufficient power, bad USB port.

Thanks. I was wondering about the connection as now I am pretty sure it's not the hard drive. Troubleshooting all that may be a real pain as I have one of these dumb modern laptops with no CD drive and almost no USB ports either. The CD drive and hard drive are both plugged into a multi-port USB adapter. Never had issues with this setup until very recently and this config has been how I've done things for at least a few years now. I suppose first I can look at replacing the adapter--I have a few of them, maybe it's acting up.

Re: Struggling to understand why I get bad rips

Reply #4 –
Quote from: Porcus on
You will anyway need CUETools: http://cue.tools/wiki/Main_Page
It works on your files. If it verifies an album with AccurateRip, then accurate it is.

Thank you, I was just wondering how I was going to scan my library for potential problems, other than randomly checking anything I've ripped in the past two months. A tool like this looks a lot better than that, and more comprehensive as well.

Re: Struggling to understand why I get bad rips

Reply #5 –
In addtion to accuraterip;
Use secure mode = ON, Or bust mode + test & copy .

USB adapters / hubs are potentials for problems. (i know as i use old surface pro for media / TV).

Re: Struggling to understand why I get bad rips

Reply #6 –
If it's any help, I find some CD drives better than others, and tracks which fail to rip on one of my external drives invariably rip on an internal drive (YMMV).  When I spotted this had happened (when I played a track and noticed gaps), I scanned my existing library and discovered a number of files were smaller than they should be.  It's not always obvious in EAC's rip log when a track has failed rather than passable.
It's your privilege to disagree, but that doesn't make you right and me wrong.

Re: Struggling to understand why I get bad rips

Reply #7 –
You can rip at least twice in burst mode or using any non secure ripper app you choose.
Then bitcompare audio data of the two rips. That should tell you more or less the reliability of the hardware.
Whatever track doesnt match rip again and compare. If doesn't match still, just listen for audio defects.

Re: Struggling to understand why I get bad rips

Reply #8 –
Quote
here were dead spots with no audio, sections with ear-shredding white noise, and a couple files that EAC didn't even recognize as .wavs
That's VERY LIKELY a hard drive problem.

You can have a fragmented file that's not read (or written) correctly then the white noise could be data from another non-audio file.    I had this problems once...   Sometimes in the middle of a song, there were bits of another song or white noise.      It only happened with a few files (or maybe one long file) but it was pretty obvious what was happening.

...If you have fragments of different files mixed-up, de-fragmenting won't help because the file system is corrupted. and it's too late.

Or if you somehow "lose" one or more bytes the following-data can be "scrambled".    Files are read one byte at a time and there are 8-bits in a byte so the left sample is 2-bytes and the right sample is 2-bytes and everything has to be re-assembled correctly.   

Or the data could simply be corrupted.

If the file header is corrupted (or not written/read correctly) it may not be recognized as a WAV file, or you could get other "weird problems.

With compressed files, compression is very-much like encryption and if the data is not decoded/decompressed correctly it will sound like noise/garbage.

Re: Struggling to understand why I get bad rips

Reply #9 –
Quote from: Porcus on
You will anyway need CUETools: http://cue.tools/wiki/Main_Page
It works on your files. If it verifies an album with AccurateRip, then accurate it is.

Actually ... it seems you have WAVE files? CUETools can convert [to FLAC] conditional upon verifying AccurateRip.
It is a bit too much to say that if it verifies AR, then it is "Accurate": if confidence is 1, then you must assume it matches your own rip, not anyone else's -
- but for the issues you have now, that is just fine.


As for the source of the problem, it is very likely the hard drive yes - but once I experienced the same when the mobo failed USB. That was when Windows had the idea that an NTFS drive had to be an internal drive, and so used deferred/delayed write. Check that you do not have that enabled!

Consequence was that files started to mingle content, like what DVDdoug describes.
As for noise vs dropouts on WAVE vs compressed files: Compressed files appear encrypted yes, so if a single bit is wrong, the consequences are bigger than if a single bit is wrong in a WAVE. But e.g. FLAC can know where "the next 4096 samples begin", and can pick up that mid stream.
Anyway you won't salvage entire files that way - even if it were possible, re-ripping takes shorter time. What saves you time, would be to verify the entire CD against AccurateRip.

Re: Struggling to understand why I get bad rips

Reply #10 –
FWIW, I had bad RAM once which did similar things to my mp3s, my jpgs, etc. I was also confused until I figured it out, put in new RAM and then it was fine.
lame -V 0
 

Re: Struggling to understand why I get bad rips

Reply #11 –
Quote from: dale_cooper on
Quote from: Bogozo on
AccurateRip can only tell if data was accurately read from CD. It has nothing to do with how data was written to hard drive.
Since data came from CD correctly, problem should be not CD drive or its connection.
If problem is not hard drive itself, it maybe connection between PC and hard drive. Bad cable, insufficient power, bad USB port.

Thanks. I was wondering about the connection as now I am pretty sure it's not the hard drive. Troubleshooting all that may be a real pain as I have one of these dumb modern laptops with no CD drive and almost no USB ports either. The CD drive and hard drive are both plugged into a multi-port USB adapter. Never had issues with this setup until very recently and this config has been how I've done things for at least a few years now. I suppose first I can look at replacing the adapter--I have a few of them, maybe it's acting up.

Burn some files  / folders to a cd-r or DVD.  Include a checksum. Utilities like hashcheck shell extension,DVDsig or 7-zip can do it. Verify the checksum stays same on the burned media. Then copy the optical media you created back to a location on the external HDD. Check checksums again.  They should stay unchanged.