Re: FFASTrans - FranceBB & Algie Custom Workflows
Posted: Wed Jun 03, 2020 7:04 pm
Well, on ffmpeg I would use something like -c:a pcm_s24le -ar 48000 -af loudnorm=I=-24:LRA=8:tp=-2 however I'm using the default XDCAM block and I didn't want to write a custom ffmpeg block as I wanted to make use of the logic built inside the XDCAM Node made by Steinar, so I kinda had to implement it via Avisynth. Please note that I made it way before the option of doing a loudness correction was introduced inside FFASTrans. Now, in Avisynth, you can do some pretty basic adjustments like Amplify(1.25) or Amplify(0.85) and so on to increase or decrease the volume by a rate factor or AmplidyDB() to increase or decrease it by specifying a value in dB, however this is not what I wanted of course. What I used instead is Normalize() which detects the peak of the audio and performs loudness correction accordingly. Now, one of the things that it's not gonna do is raise the volume, in other words, if it's too high it's gonna lower it down, but if it's too low it won't bring it up, so it's not a totally perfect loudness correction in that sense, however it's generally good enough for general purpose contents that are used for sports events and news. As to movies and other things, they go through the Dolby DP600 instead that performs a real proper loudness correction.
Lastly for -23LUFS you can try with Normalize(0.21) that should do the work. If it's still too low try with (0.20) but it should be fine. Anyway, the ffmpeg one with the audio filter "loudnorm" is more precise than the Avisynth one.
Lastly for -23LUFS you can try with Normalize(0.21) that should do the work. If it's still too low try with (0.20) but it should be fine. Anyway, the ffmpeg one with the audio filter "loudnorm" is more precise than the Avisynth one.