[FFmpeg-user] asubboost and asupercut

[Michael Koch]

Am 27.11.2020 um 19:25 schrieb Paul B Mahol:
> On Fri, Nov 27, 2020 at 7:09 PM Michael Koch <astroelectronic at t-online.de>
> wrote:
>
>> Hello,
>>
>> I have a few questions about the asubboost and asupercut filters.
>>
>> -- In asubboost it's not yet clear how the block diagram of the filter
>> looks like. Especially the "decay" and "feedback" options are unclear.
>> What's the input of the the delay line? Before or after the low pass
>> filter? Where does the feedback go to? Before or after the lowpass
>> filter? I have attached a sketch of a possible block diagram, but it's
>> only a wild guess.
>>
> This filter just adds delayed sub frequencies set by cut off frequency back
> to output. Decay sets decay of old sub echo in buffer and feedback sets how
> much
> new sub frequencies are added to the delay buffer.

Sorry, I didn't understand it. I think this filter could be explained 
much better with a block diagram.


>> -- Is it correct that the "slope" parameter effectively changes the
>> cutoff frequency, but doesn't change the steepness (dB / octave) of the
>> filter?
>>
> It changes steepness, not cutoff.

What's the unit of the "slope" option?

Michael