[flac-dev] "keep qlp coeff precision such that only 32-bit math is required"
Martijn van Beurden
mvanb1 at gmail.com
Mon Apr 20 10:14:34 PDT 2015
Op 20-04-15 om 18:45 schreef lvqcl:
> Well, the code in process_subframe_() calculates MAX value of
> qlp_coeff_precision,
> while the code in evaluate_lpc_subframe_() adjusts CURRENT
> qlp_coeff_precision.
Yes, but that MAX value is used to loop over the
qlp_coeff_precision values between MIN and MAX. So, if the
qlp_coeff_precision value is limited in the loop but MAX is not
limited, the loop does the exact same thing multiple times: a
waste of time. Therefore, only the MAX should be limited.
I don't think the logic is needed directly after
> min_qlp_coeff_precision = max_qlp_coeff_precision = encoder->protected_->qlp_coeff_precision;
because that value is either chosen by the encoder (it is a
lookup value, and is always small enough not to trigger this,
set in stream_encoder.c around line 700) or it is set through
the encoder, in which case it should probably not be overriden
without notice.
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