Extraction Technology

In secure mode this program either reads every audio sector at least twice or rely on extended error information that some drives are able to return with the audio data. That is one reason why the program is slower than other rippers. 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 selected error recovery quality) these 16 retries are read. So, in the worst case, bad sectors are read up to 82 times! But this effort will help the program to obtain the best result by comparing all of the retries.

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If it is not sure that the audio stream is correct (at least that it can not be said at approx. 99.5%) the program will tell the user where the (possible) read error occurred. The program also tries to correct the jitter artefacts that occur on the first block of a track, so that each extraction should be exactly the same. On drives which have the “accurate stream” feature, this is guaranteed. Of course, this technology is a little bit more complex, especially with some CD drives which implements caching. When drives cache audio data, every sector read will be read from the drives cache and is that way always identical. Basically there are several ways to clear the cache. In newer versions it will overread sectors, so that the cache contains sectors from a position elsewhere on the CD.

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EAC has several secure read modes, depending on the features of the drive. One really fast mode (nearly burst mode speed) is for drives with C2 error pointer support, accurate stream and are non-caching. Another mode (up to half of maximum speed) is for non-caching, accurate stream drives (without C2 support). If caching need to be defeated, the secure mode will be much slower, when no read errors occur it will usually something around a third to a fourth of the drives maximum speed.

This program is really quite 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 are able to use the fast or burst extraction option in the drive 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, a sync error will be displayed. Fast mode is sector synchronized with 2 synchronization blocks of 23 total blocks. Burst copy is even worse, no synchronization is performed at all, enabling extraction at maximum speed of the drive. No error checking of any kind is done. For burst mode there is at least a small indicator of the extracted track quality. If the stream ever breaks, it will tell the user in the status report by showing up suspicous positions. Of course this is only an heuristic; there needn’t be any errors on these positions; moreover there could be errors that are not found at all.