Quote:
Originally posted by Upp3rd0G
@BobHere
I assume you are talking about E12 and E22 errors, because an E32 errors flags the whole frame as erroneous.
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Yes and no. I have never been happy with the Exx scheme as it is based on the concept of only 2 corrections in C2 where as C2 can have up to 4 erasure corrections.
That is why I usually just talk about C2 error flags, these flags are used to indicate the validity of each symbol at the output of CIRC (and the thus the validity of each sample) independant of the correction scheme used.
The other issue is that we are interested with the output of CIRC not C2, there is a final interleave stage between C2 and the ATAPI output. This stage spreads the errored samples across different frames (blocks) thus interleaving the errored samples with (hopefully) good samples from the other frames - this allows the relatively benign linear interpolation.
Regards,
Bob
PS.
Usually these Exx measures don't appear at the ATAPI interface (well not using any command I have seen) but are present in a register of the decoder chips that is accessible from a physical line, both Sony and Philips chips have such an output. If you were that interested you could download the data sheets from the Philips site and have a look. It would not be difficult to design a circuit to allow these measures to be monitored by a PC from even cheap standalone HiFi Cd players