When using loudness normalization (loudnorm) since it oversamples to 192khz to find true peak (still not enough btw, really need 8x or even up to 32x oversampling) the resulting AAC file is at 96khz instead of downsampling back to 48khz. Fix is to set --rate 48000 if loudnorm is used.
Thanks!
PS - it would be really sweet if someone could come up with a multi-pass solution to hit a target range accurately. Loudnorm does a decent job but is still only guessing. Perhaps writing a statistics file on each pass to adjust based on settings would help? Even having 6 passes, it would still complete before the average movie gets encoded
Algorithms to measure audio programme loudness and true-peak audio level (includes multichannel measurement algorithm)
https://www.itu.int/dms_pubrec/itu-r...0-I!!PDF-E.pdf
Loudness standards table
https://youlean.co/loudness-standard...parison-table/