audio normalize

[Daniil V. Kolpakov]

On 04.07.2019 23:44, jdd at dodin.org wrote:
> Le 04/07/2019 à 22:03, Daniil V. Kolpakov a écrit :
> 
>> Edit the project in Kdenlive using unnormalized video clips you have,
>> then render using audio-only profile to a .wav file, then normalize the
>> file using an audio editor (for example the Audacity as suggested), then
>> open up the kdenlive project again, add an empty audio track, put the
>> edited wav to this track right from the beginning of the timeline, then
>> mute or remove original sound track. I do it all the time (although
>> using Ardour not Audacity).
>>
> two things:
> 
> * why use an other editor when kdenlive (seems to) already have the 
> tool, apart if you say the tool is broken

Well it's not broken per se, just incomplete. It's a well known drawback 
that Kdenlive currently lacks a master bus, for example. This means that 
while you can drop a compressor on a track you cannot make it compress 
the mix of, say, a video track with the voice on it plus backing track 
with music, thus you cannot guarantee there is no clipping of the audio 
in the end.

> * there is a much simpler workflow
> 
> when I happen to have a source already cut (for example if I made only 
> short clips), I use this script
> 
> .......................
> #!/bin/bash
> 
> rep="mp4-hd" ;
> mkdir  $rep ;
> 
> for a ; do
>      b=`echo "$a" | cut -d'.' -f1` ;
>      ffmpeg -i $a -af loudnorm -ar 44100 -b:v 12000k -movflags faststart 
> $rep/$b.mp4 ;
> done
> exit
> ........................
> 
> notice the "loudnorm" option.

Again, that depends on the task, it won't help you if you mix the audio 
from the several clips in a complicated way. Also, I'd rather -c:v copy 
for the ffmpeg and do the whatever processing with reencoding of the 
audio before cutting in Kdenlive if the indention would be to cut with 
the video files where audio tracks would be pre-processed somehow.