Discussion on Adjusting and Checking Loudness in VPX11
The Peak Meter in the Mixer of VPX is difficult to work with for any accuracy; there is no indication of actual levels other than the blinking or steady lights. Finding peaks and knowing the peak level is difficult to impossible, and there is no indication of the integrated loudness of the entire audio.
Does anyone use any meters to monitor loudness of objects, tracks and master track? If so, which ones? See below for the ones that I have.
What loudness should one use, i.e. EBU R128 (-23 LUFS) for DVD\BR\MP4's for TV, or louder for YouTube (-13 LUFS) and Vimeo?
Other than exporting for use on a TV, exports for YouTube or video have different problems. YouTube normalizes to -13 LUFS, so -23 LUFS would be too quiet and the overall value would likely be raised unless there is clipping.
What should be the True Peak or absolute limit, -1 dB, -3 dB?
We had a detailed discussion on audio in this thread:
I did a project recently that has a lot of narration and background music from various sources, plus some sound effects. The challenge was to:
- Normalize to EBU R128
- Adjust audio clips (narration) to have the same overall level
- Using Ducking (damping) where narration was over music
- Adjust the music to have the same perceived loudness
- Avoid clipping
- Have the loudness from one project to another about the same perceived level on the television so as to not have to make adjustments from one video to another
- Measure the loudness to see the final result.
I didn't have the tools below, so I was making adjustments by eye and ear. The results were mixed.
Here are the two free tools (VST plugins) that I found for measuring and analyzing loudness:
- Melda MLoudnessAnalyzer - comes with the Melda free bundle. The dimensions interface of the free version cannot be modified.
- YouLean Loudness Meter 2 - free version, but there is a paid version with more information, graphing and exporting graphs to a png does not have a watermark.
These are applied using the Mixer and FX on a track.
MLoudnessAnalyzer screen shot on a music part showing that it exceeded the target:
YouLean screen shot on a music part showing that it exceeded the target:
YouLean showing mixed narration then music. The narration was close to the target, but the music went up. The overall integrated level was close to the target, but the music was noticeably louder than the narration, so I should have reduced the volume of the music object:
Below is YouLean with clipping. You can see the red marks at the top and the graph shows time code, not elapsed time. This clip was normalized to EBU R128 and the integrated level shows that it was very close at -22.9 LUFS. This was a relatively quiet clip with some loud noises. Thus, normalizing a clip like this to EBU R128 can cause problems. YouLean shows the problems and where they are.
Both of these tools are interesting and each has some advantages.
YouLean will show where the peak exceeded the target of, say, -1.0 dBFS, and you can see exactly where they are on the timeline. You can easily see which parts exceed the target in the short-term (3s moving measurement) - the red part. The graph is adjustable and you can zoom in on the timeline and slide back and forth using the key graph at the bottom. You can export the graph to a png, but it has a huge water mark. The paid version removes this and there are more features. Note: S = short-term loudness, M = Momentary, T = True Peak. Presets are limited in the free version. The plugin is for analysis only and the output cannot be adjusted.
MLoudnessAnalyzer shows LU - Loudness Units - rather than LUFS. Set the target in LUFS and it is equal to 0 LU. The graph has more things that can be graphed. You see the peaks, not just where the target is exceeded. The free version has presets for YouTube, Spotify and iTunes. There is an auto-gain that will adjust the gain to hit the target, or you can adjust it yourself. Just remember that this is for the entire track, not an object. The width of the graph is limited but has a zoom to show more or less duration. Turn off the left chart and the graph is larger, adjust the zoom level and run again.
Again, these run at track level and in the master track, but not on objects.
Another point on the measurements. The integrated LUFS measurement is gated, such that parts with very low volume are not considered in the calculations.
Damping
I did damping on the music where there was narration, reducing the level by 12 dB. This caused me some additional problems that I am still trying to figure out. I noticed that the difference in the integrated LUFS between the narration and music was not 12 dB or 12 LUFS in some cases. I think that this was because I made some adjustments to object levels after ducking. I didn't have these plugins when I edited the video, unfortunately.
Additional Tools
As noted in the other thread, there is the free Levelator, but it is not a plugin. A similar one that is not free is Auphonic. These would be useful for levelling the narration and require an export of just that part. I haven't tried either.
John CB