[opus] Antw: Re: Antw: Re: Antw: Re: Possible bug in Opus 1.3

Ulrich Windl Ulrich.Windl at rz.uni-regensburg.de
Mon Nov 5 10:41:52 UTC 2018


>>> Jan Stary <hans at stare.cz> schrieb am 05.11.2018 um 11:32 in Nachricht
<20181105103249.GA74867 at www.stare.cz>:
> On Nov 05 11:05:34, hans at stare.cz wrote:
>> > Did you also try to listen at the beginning, shortly before the real tone 
> appears in the audible spectrum? While significantly larger, Opus had 
> produced significant ghost noise (much less than Vorbis did)...
>> 
>> Yes. But given that these are not audible sounds,
>> the various codecs might use various strategies of throwing them away.
>> I have no solid knowledge of what e.g. Ogg vs Opus does, but I would
>> just throw away any frequency below, say, 15 Hz. Maybe they do/don't,
>> and this might be the result.
> 
> Have you also tried creating a swepp only up to those frequencies?
> Say, 1 to 20 Hz? Is the low-freq noise still there?

Not yet; as I said the starting frequency was mainly because of the cleaner mathematics regarding the logarithmic frequency sweep...

> 
> 	Jan
> 
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