On Fri, Mar 07, 2014 at 11:19:28PM +0100, Jaromír Mikeš wrote:
I've just tried r128gain ... works fine
...there are "several presets",
but not possible set "truepeaks" -3dB.
Also not sure how it handle true peaks and RMS (not sure RMS is right term
here).
e.g. If RMS is corrected and gained to -23dB then True peaks are handled
by limiter or just RMS is never raised to True peaks go over -1dB?
I think r128gain is more like a scanner that outputs the statistic to
another processor (in this case sox/ffmpeg). The method used here
("Applying the gain") does not include a limiter in the signal chain.
The TGDB field means the gain needed so that Loudness is same as reference
(-23LUFS). It also outputs TPDB (maximum truepeak).
Since you wanted max true peak at -3dB, for cases where TPDB+TGDB < -3dB
the TGDB should be safe to be applied directly as is (if you want to be sure,
scan one more time after applying gain). For cases where TPDB+TGDB > -3dB
you would need limiter to reduce the peaks. How much limiting should be
applied cannot be determined solely from TGDB or TPDB, so my suggestion is
applying limiter at let's say TPDB-3-TGDB and then run the scan again.
If TPDB+TGDB is still over -3dB then run the limiter again with lower
threshold.
Most materials that have gone through mastering process would likely be
in the first case.
Does the program material should have Loudness exactly at -23LUFS or
the maximum Loudness allowed is at -23LUFS (so program loudness < -23LUFS)?
If it's okay for the Loudness to be less than -23LUFS then you could
skip the limiter and just reduce the gain.