Been reading the forums for about a month now and have learned a lot. Just started making the switch from CD playback to using my computer with a dedicated DAC (connected by USB) for music. I have a few questions before I begin ripping my entire cd collection to my HD, mostly related to error checking methods/file verification of flac files.

Is the creation of separate MD5 files for each cd unnecessary since flac already uses crc for error checking? What about the MD5 signature that's stored in the file header? Could someone explain to me how one would go about checking for errors and the error detection process (testing encoded files by decoding). I've been using trader's little helper to test some older flac files (made a few years ago when I didn't have EAC properly configured) and I found more errors than I'd wished to find (this doesn't surprise me however as I was using burst mode and ripping 10 cds a day). Still, after reading some threads here about other ppls. FLAC files becoming corrupt I don't want to take any chances. I also found that a few files had "sector boundary errors". Could someone explain what these are and if they are worth fixing (TLH has the option to do so). Back on the subject of error checking what about using .sfv and parity files? What kind of error checking support do other formats like APE, MP3, MPC offer? Also will editing the tags (metadata) in foobar affect the MD5 file? I plan to keep a backup of my files on an external HD but I'd still like to run some kind of file integrity check on a regular basis for peace of mind.

Should I bother updating old FLAC files to 1.1.4 from say 1.1.2 or 1.1.1? I'm mainly concerned with improving loading/ seek times which are noticeably slower on SOME older flac files (why is this?) and don't care for some of the newer features like adding album art to metadata.

Which encoding level is preferred 0 to 8? I've been using 8 but have wondered if the extra work done encoding to save space may increase the chances of errors.

I've been using secure mode, single file output with cuesheets in EAC and am happy with it. I know that there's currently no AR support using this method (although i think someone here's working on that...) and also no test and copy option in EAC, but I plan to listen closely (twice) to each rip to check for errors. If EAC doesn't report any errors and I don't hear any ticks/pops/skips I will feel I've done enough. Any thoughts? Am I missing anything?


Thanks

I don't know that I can answer all your questions, but here are a few things:

- Ripping in burst mode with an overworked and/or crappy drive has no bearing on the integrity of FLAC files. A junk drive will result in errors in the ripped .wav, which will then be encoded perfectly by FLAC, without errors of it's own. That you found a bunch of corrupt FLACs is disturbing to say the least since it indicates some more serious issues - hard drive failure, RAM flakiness, or some other core hardware issue.

- Updating to the latest FLAC is probably a good idea. I'm not sure about the seek times of older versions, but 1.1.4 does provide significantly better compression rates and is faster too. It's worth it, in my opinion.

- Prefered encoding level is whatever you wish., really. I will say that in my experience with FLAC, I ended up using level 6 since it seemed to be the sweet spot with regards to compression and speed. That being said, 1.1.4 does offer much faster encoding with level 8 as compared to older versions - about twice as fast, in fact. The cruicial point here about encoding level is that it has nothing to do with errors. Unless there is a hardware issue with your system, you will get zero errors regardless of compression level.

- You can still use accuraterip after ripping to an image. Check out Mr. Key's accuraterip script for image + .cue rips. I use it and it's great to have.

Does the accurip script work for an offline computer? I mean has someone compiled all of the crc's into a file I can download?? I know AR has an "offline mode" for those w.out a connection. The computer I rip with is my dedicated audio PC (nothing but audio playback/ ripping prgms.) no internet.

There was an offline database, but it is no longer maintained, also the script mentioned is online only.

That's the md5 for the streaminfo, the music. Your selfmade md5 will include any data added to the file, like padding, tags and cuesheets. But when md5's fail you only ~know~ something has changed, not what, nor can you repair it. That could be done with par2 files, for instance.

You could add more seekpoints, although flac itself adds those every ten seconds. Since I don't cue or rewind often, I set my seekpoints every minute for disc-images.

that option is probably enabling --sector-align