Jessica in San Jose, CA

[newcyberian]

Hi,
My name is Jessica Taylor. I work for a CD duplication plant in San Jose as QA engineer. This is my first job and I need to educate myself. Glad to have stumbled on this site.
At work, I use Gear Mastering Pro and Sonic Studio. I am pretty new to these software so please don't think I am a pro. I work with DDP images from mastering houses and I do know some common problems of CD duplication, or CD replication to be exact.

[brandondrury]

I work for a CD duplication plant in San Jose as QA engineer.

Very interesting! I've never met a person with such a job before.

How often do you have to send CDRs back because they contain too many errors? Just curious. This has happened to me several times.

Brandon

[newcyberian]

Originally Posted by brandondrury

Very interesting! I've never met a person with such a job before.

How often do you have to send CDRs back because they contain too many errors? Just curious. This has happened to me several times.

Brandon

Pretty often. But we can also ask our customers to send us a NERO image, ISO file, or DDP image for small content CD/DVD duplication jobs. If a disc is fully loaded, it will be more reliable to re-send a physical disc. My advise to people who need DVD or CD duplication is to handle the masters with extra care. Gabage in gabage out is the buzz word in our industry. Sometimes we try to do garbage in gospel out by re-authoring the disc. Fixing a broken disc is no fun; we can to it nonetheless sometimes.

[brandondrury]

I had no idea how big of deal the process of burning a mix to a cd before sending it out to the plant was. When I mastered with Eric Conn at Independent Mastering, he was HUGE on his robo expensive "laser etcher". It turned out he was right.

I figured that burning to a name brand CDR @ 2x would be good enough, but in many cases it is not.

Brandon

[newcyberian]

Originally Posted by brandondrury

I had no idea how big of deal the process of burning a mix to a cd before sending it out to the plant was. When I mastered with Eric Conn at Independent Mastering, he was HUGE on his robo expensive "laser etcher". It turned out he was right.

I figured that burning to a name brand CDR @ 2x would be good enough, but in many cases it is not.

Brandon

I was pretty confused at the beginning. I thought by its nature digital data is not supposed to miss by one bit. The good thing is all readers have a checksum protection for reading wrong data. So they are allowed to mis-read data but the checksum will fail the data and it has to be read again. If the failure persists for 8 times or more, we got a coaster. Another good idea is to turn on the verify feature of CD burning software.

[brandondrury]

A buddy of mine learned in his upper level computer program college class that a cd can hold 7 times the data, but all of that is spent towards error correction / redundancy.

Brandon

[thesilentdrummer]

All this talk leads me to a question: when you are done with your mixes, how to you get those to CD?? Is there a special program that prepares your tracks for mastering and/or replication? Or is there just a process that you do??

[brandondrury]

On most projects that have the budget for mastering, I usually just burn a data disc at a very low speed. It's very rare that the mastering guys have trouble with these. I usually prefer to upload the files as it allows me to avoid the cd burning process. The cd that a mastering engineer will send you will be error free if the mastering engineer is good.

When sending a finished cd to a CD Manufacturing place, if you burned yourself, they'll usually find errors on it. The only way around this for me has been with uploading. I wish I had a dollar for everytime I heard a band say "The cd replication place rejected your cd".

Brandon

[thesilentdrummer]

alright, cool. I guess if I ever do something of any magnitude, I'll look for an upload possibility.

[Charlie_M]

Originally Posted by brandondrury

A buddy of mine learned in his upper level computer program college class that a cd can hold 7 times the data, but all of that is spent towards error correction / redundancy.

Brandon

I know people whose entire career is about error detection and correction. Parity is simple and pretty robust, but also somewhat limited in it's ability to correct. My understanding of it is only rather elementary. I'm not really sure what kind of encryption or code is used for CD burning, but in hard drives you can correct and awful lot- on the fly - without the user ever knowing there was a problem. The drive knows though, and keeps track of the location where the error occurred and deals with it appropriately (i.e., now it knows better than to store data in that location, and if the problem seems to be getting worse over time it'll actually send a warning to the OS and says "hey listen bub you better back up this hard drive" and then the OS alerts the user. In fact all throughout the life of a drive it is keeping track of reliability data and will raise a flag when anything looks suspicious.

In a hard drive all this comes with relatively little overhead. Only reason I could think of for having such a low format efficiency with CDs is to put replicates of the data in different physical regions of the disk, so that if you got a scratch near the OD, for example, you'd just go read the copy of the data at the ID. Seems like overkill to me but I guess the main difference is that a CD is something that gets handed and can get scratches which are enormous compared to the size of a track.

Now I'm curious about it...

Charlie