HydrogenAudio

Lossy Audio Compression => AAC => AAC - General => Topic started by: Azevedo on 2014-01-29 21:42:03

Title: aacgain 99dB
Post by: Azevedo on 2014-01-29 21:42:03
Hi,

I'm trying to set all .m4a (and mp3) files in a folder to have ~99dB volume level.

I tried
acgain /c /m 5 "file1.m4a file2.m4a file3.m4a ... "
and
acgain /r /c "file1.m4a file2.m4a file3.m4a ... "

None of them give me 99dB

Is there a trick for that?

Thanks
Title: aacgain 99dB
Post by: DVDdoug on 2014-01-29 23:01:00
I've only used MP3Gain with the GUI, so I'm not sure...

Quote
None of them give me 99dB

What are you getting?  Are you getting 94dB with the /m 5 command?

I belive the default is 89dB, so your command should be /m 10 for an additonal 10dB.



Since you are using the /c command an trying to get 99db, I assume you don't mind distortion as long as it's LOUD?

Title: aacgain 99dB
Post by: Azevedo on 2014-01-30 00:05:59
/m 5

produces from 93 ~ 97dB



/c

yes, i don't mind minor 'cuts' to the sound file
Title: aacgain 99dB
Post by: DVDdoug on 2014-01-30 01:25:52
/m 5

produces from 93 ~ 97dB
Interesting...  I don't know...  The clipping may be throwing-off the calculations.  For example, if you have a normalized (or clipped) file and you apply +6dB of gain, the peaks can't be boosted at all so the average loudness will be boosted by something less than 6db (depending on the amount of clipping).  Or, since clipping adds harmonics, it might sound or measure louder than expected.  But, I'm not sure if the AAC itself is actually clipping even though it may clip when eventually decoded and sent to a DAC.

I don't know about AAC, but MP3 can only be adjusted in 1.5dB increments, so that would account for some of the variation.

Like I said, I've never used AACGain or the command line...  With the MP3Gain GUI (or ReplayGain) and the default 89dB settings, I've never had any trouble.  I just get the 1.5dB increments (with MP3Gain), and sometimes I get a lower level because I use the "Don't Clip" default.
Title: aacgain 99dB
Post by: DVDdoug on 2014-01-30 05:26:32
Just as an experiment, I tried MP3Gain on about 40 files with a  target volume of 99dB, allowing clipping.    The pre-scan showed volumes between 88.5 and 101.8dB.  After applying MP3Gain they were 98.3 to 99.6dB.  So, everything worked as expected and everything accurate is within the 1.5dB adjustment range.    I don't know what's going on with AACGain and your files...