Seeking Guidance on Creating a LUFS Meter

1

I’m a newbie with JUCE. I want to create a lufs meter.

In the process, I found out about LUFSmeter (GitHub - klangfreund/LUFSMeter: An implementation of the loudness measurement algorithm ITU-R BS.1770) but the details on how to execute it are not specified. I also referred to the ‘How_to_set_up_windows_7_for_juce’ document, but I couldn’t proceed in that manner.

Is there anyone who can provide updates or assistance on this?

Thank you.

2

Luckily all information about the protocol is public.
You can find it (at least the core, there are many other resources refining on this) at:
https://www.itu.int/dms_pubrec/itu-r/rec/bs/R-REC-BS.1770-4-201510-I!!PDF-E.pdf.

3

I’m aware that the ITU documents exist. Rather, I’m specifically looking for how to apply the content found on that GitHub to JUCE. If there’s anyone who has recently implemented this, I would appreciate your help.

4

Yeah, I don’t think the project file, referred to in that document, is on the main branch.
On the multiChannelLoudnessBar branch though, there seems to be a project (and a jucer file) that you could try in /projects, that could generate a project you could build.

5

Have you successfully built a peak meter already - if not start there?

1 Like
6

Roughly -

  • Start a JUCE plugin project
  • Write a function called measure(AudioBuffer&) that iterates over the block finding the maximum value(s)
  • Write those to member variables of your audio processor.
  • Start a timer in your plugin editor, use this to trigger a repaint.
  • Draw a rectangle that uses the value from your processor to determine it’s height.
  • Use Decibels class from JUCE to convert to DB so you get a sensible scale.
  • Fuck around for four hours trying to render a nice looking DB scale along side your rectangle where the dashes line up properly with the meter and the font actually looks centred next to the dash
  • Ponder whether you should write the values as negative numbers or assume the user knows that they are all negative. Also be annoyed that the - sign for the negative number aligns badly with the graph.
  • Add in all the nice stuff, peak hold, value read-outs, colours.
  • Discover it crashes in mono or 5.1, fix that.
  • Fret about repaint efficiency. Get confused by how repaint actually works. The optimal solution is to only repaint the changed area of the meter (usually a few pixels).
  • You now have a peak meter - now rewrite your measure function to support LUFS
8 Likes
7

Did autocorrect messed up with your intended verb on item #7 :joy:

8

Thank you everyone for your kind responses. Thanks to you, I feel like I can start off my day on a positive note on the JUCE forum. I will try everything you’ve suggested. Have a great day!

9

I don’t think so :slight_smile: :slight_smile:

10

Well, I personally love that it nicely partakes of the emotions conveyed throughout these otherwise very valuable learning suggestions, though. Definitely makes the journey more appealing and realistic :smiley:

11

Well, I’ve done it a few times now, and it’s always the same trip :slight_smile:

3 Likes
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GitHub - unusual-audio/loudness-meter: Loudness Meter is a juce project using the klangfreund lufs meter