DVDs Reed Solomon Outer Parity Interleaving

Hi all,

why are Reed-Solom parity rows beeing interleaved between recording frames according to DVD specification?
To my understanding Reed-Solomon decoding doesn’t care about info or parity byte beeing corrupted.


Interleaving is always used in conjunction with error correction in order to cope with error’s packets. After de-interleaving, packet’s errors are spread among many frames and so error correction is able to correct errors.


Well, RS itself cares about errors wherever they are, including in parity bytes.
If a few parity bytes are corrupted you can ignore them, but your correction
capabilities are weakened. If too many parity bytes are wrong, you can’t know
any more if your data are correct or not, so you have to discard them even if
they are all ok.