| Quintiano |
28-05-2003 04:50 |
Citaat:
CD-R schreef op 27-05-2003 @ 23:05:
ik gebruik gewoon een winamp plugin ding :)
en dobermann, wat is er zo rampzalig aan een mp3tje geript met een ander programma dan die combi van jou? Die van mij doen het ook gewoon, en dat gaat altijd goed.
Het risico dat er iets misgaat heb je altijd. en om nou alles wat niet is wat gebruikt bagger te noemen is gewoon slecht.
motiveer es waarom mp3tjes die met een ander programma geript zijn zo slecht zijn dan :o
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Het risico dat 't mis gaat met Exact Audio Copy heb je dus *niet*. Ga 't zelf maar vertalen, daar heb ik niet zoveel trek in -->
In secure mode, this program reads every audio sector at least twice. That is one reason why the program is so slow. But by using this technique non-identical sectors are detected. If an error occurs (read or sync error), the program keeps on reading this sector, until eight of 16 retries are identical, but at maximum one, three or five times (according to the error recovery quality) these 16 retries are read. So, in the worst case, bad sectors are read up to 82 times! But this will help the program to obtain best result by comparing all of the retries. If it is not sure that the stream is correct (at least it can be said at approx. 99.5%) the program will tell the user where the (possible) read error occurred. The program also tries to adjust the jitter artefacts that occur on the first block of a track, so that each extraction should be exactly the same. On drives found to have the "accurate stream" feature, this is guaranteed. Of course, this is a little bit more complex, especially with some CD drives which have caching. When these drives cache audio data, every sector read will be read from cache and is identical. I initially implemented two ways of dealing with the caching problem. First there is an extra option for resetting the cache for use the the old secure mode (the one being kept for compatibility reasons). In the current beta version, the cache will still be reset by resetting the drive completely. You might imagine that this would slow down the reading process very badly.
That is why I implemented three new read modes in version 0.85beta. One really fast mode (up to half of maximum speed) is only for non-caching, accurate stream CD-ROM drives. The second one could be used for caching, accurate stream drives and the last one will work with drives that don't have accurate streams, or do caching. The last two will be much slower, when no read errors occur it will usually something around a third to a fourth of the drives maximum speed.
For my testing, I am using a Plextor 14/32 drive that does no caching and a Teac R56S-600 drive that does caching. Furthermore the Plextor 14/32 supports the "accurate stream" feature, so it produces no jitter artifacts on any stream. For more information on this have a look at the table at the end of this document.__
This program is really damn slow in secure mode in comparison with other grabbers, but the program checks every sector over and over to get the correct data with high certainty. If you don't like this feature of EAC and prefer fast copies instead of secure copies, you should use the fast or burst extraction option in the options menu. But of course in fast mode, the program will no longer be able to find read errors. Only if a read error occurs in a sector synchronization area, will a sync error will still be displayed. Fast mode is sector synchronized with 2 blocks of 23 as synchronization blocks. Burst copy is even worse, no synchronization is done, enabling extraction at maximum speed of the drive. No error checking of any kind can be performed. At least I implemented a small help. If the stream ever breaks, it will tell the user in the status report by showing up suspicous positions. Of course this is only heuristic; there needn't be any errors on that positions; moreover there could be errors that are not found at all._
A new option for selecting the error recovery quality will determine how often these blocks of 16 reads will be done before giving up and working with the results obtained so far. For bad CDs, low error recovery quality will be fastest, but high recover quality should give best results. _ Bron: www.exactaudiocopy.de // Technology. |
