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 Error Bits And Aiff Question??, How does mac use error bits? |
  sam. 5 oct. 2002, 22:08
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#1
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 Newbie Groupe : Members Messages : 3 Inscrit : 05 oct. 02 Lieu : Towson - US Membre no 8,255  |
A CD audio file has about 800 error correcton bits for each 3200 bits of actual data. These are for correcting errors due to poor pressing of the CD, scratches, misreads, etc.
When the mac copies an audio file from a CD using to the hard disk the finder it converts it to an AIFF file. Does it use the error bits to clean up the data, or just store everything, or ignore the error correction data completely. ??? Thanks Oliver Reid 
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dim. 6 oct. 2002, 12:32
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SuperHero  Groupe : Banned Messages : 1,879 Inscrit : 24 févr. 02 Membre no 3,562 |
QUOTE (oreid @ Oct 5 2002, 23:08) When the mac copies an audio file from a CD using to the hard disk the finder it converts it to an AIFF file. Does it use the error bits to clean up the data, or just store everything, or ignore the error correction data completely. ??? When extracting/reading from an Audio CD on your Mac, the same error corrections as in a Hi-Fi CD-Player system occur. Better have a good cd-player. This has to do with the Red Book standard, have a look to http://www.disctronics.co.uk/technology/cd...cs/cd_books.htm for more infos. Bye. |
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dim. 6 oct. 2002, 13:26
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#3
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Newbie Groupe : Members Messages : 3 Inscrit : 05 oct. 02 Lieu : Towson - US Membre no 8,255 |
[When extracting/reading from an Audio CD on your Mac, the same error corrections as in a Hi-Fi CD-Player system occur. Better have a good cd-player.]
This is good news: I called Apple tech support and they did not know. Assuming a source CD that is in good condition, do you have a feel for typically accurate the AIFF is? That is, after the corrections, roughly what % 16-bit samples end up wrong or are skipped and replaced with an interpolated value? Do you get sigificantly better results with certain CD drives or by using a slower copy speed? Is there any Mac program that will tell you how much error correction is done, and how successfully, when the file is extracted? I understand that for windows there is some freeware called "Exact audio copy" that does this, and also slows the drive down and attempts multiples re-reads when it encounters a read error. Any Mac equivalent? Many thanks for the info. Oliver Reid oreid@parkschool.net |
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