Just to ask your question, according to specs:
* According to the ECMA 339, a row of an ECC Block that has at least 1 byte in error constitutes a PI error. If a row of an ECC Block contains more than 5 erroneous bytes, the row is said to be “PI-uncorrectable”.
* The total PI errors within 8 consecutive ECC sectors (PI sum 8) should not be greater than 280. This is, as it were, the error rate of the raw data. The lower it is, the more headroom is available to cope with wear and tear from scratches, marks and ageing due to heat or sunlight.
* The DVD+R specification (ECMA 349) furthermore prescribes that in any ECC Block the number of PI-uncorrectable rows should not exceed 4, after the first, inner parity, error correction (Parity Inner Fails, PIF)
* Errors that can’t be corrected by the second, outer parity, correction are finally the ones that a user will notice as actual data errors. Values greater than zero are not acceptable for the POF (Parity Outer Fails).