Michael Koch astroelectronic at t-online.de
Thu Oct 1 15:17:37 EEST 2020

Am 01.10.2020 um 14:06 schrieb Michael Koch:
> Am 01.10.2020 um 13:25 schrieb Marco Mircoli:
>> Hello',
>>      I'm a newbie.
>> Just bought a php script that use ffmpeg.
>> it converts to mp3/96Kbps all media uploaded in a unique format.
>> this is the line, and now it normalizes to R128 (thanks Moritz)
>> $shell     = shell_exec("$ffmpeg_b -i $audio_file_full_path -map 
>> 0:a:0 -af
>> loudnorm -b:a 96k $audio_output_mp3 2>&1");
>> I'm wondering if it is possible to include a simple hi-pass filter 
>> (highest
>> db per octave @ 70Hz)
> add  highpass=70,    before  loudnorm
> This filter attenuated 6dB per octave. If you need higher attenuation, 
> you can use several highpass filters, for example 
> highpass=70,highpass=70,highpass=70,loudnorm

Correction: The filter has 12dB per octave.


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