Quote:
Originally Posted by Hase
In dealing with a player's ability to better read a CDR, is the spacing of the pits really an issue? Aren't they all just loaded into a buffer anyway? I am probably missing something, but as long as the laser is actully reading the bits correctly and the buffer never runs flat, isn't the processor receiving the exact same data from a CDR that it would a stamped disk?
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Yes,
IF...
IF the laser is actually reading the bits correctly on the
first pass the buffer should never "run flat" and the data stream should be steady or jitter free.
It's when the laser misreads a bit and has to re-read, and possibly estimate, the data in a given timespan that the data stream to the buffer fluctuates and the potential for jitter and related anomolies is greatest.
Keep in mind that a CD-ROM drive is designed to reread the disc until it gets a correct read based on parity checking. A CD
player is designed to errorcorrect (estimate) all but the worst misreads in a given amount of time.
I realized the strongest evidence that the topic is
possible (again, I am not saying it is probable) is that a copy of a damaged/scuffed CD can play perfectly while the damaged/scuffed original is unplayable (personal experience). Why? The CD player gives up reading the disc after X-passes and "correct" or estimate the data read error, while the computer CD drive attempts to re-read until it gets a correct parity or determines it will never achieve parity.
DVD movies demonstrate this as well since many of the flaws can be SEEN. The player has a time contraint it has to meet, so if it can't read the data, it estimates the picture and goes on. If it didn't, when you watch a movie and it had a misread the picture would freeze instead of just putting up some odd blocks in the picture (and yes I am aware in extreme error conditions, the picture will freeze, but most errors are handled by correction.)