It’s even better if mp3gain actually adds these tags. I’m relatively happy with mAirList treating the REPLAYGAIN_* fields in the same as for other file formats, assuming this is a standard of some sort. In our case the files are used across more than one application, sometimes with differing reference levels. For example it fixes one choice of track/album gain, clipping behaviour and reference level. Modifying the MP3 frames is a clever trick, but not desirable. But this is definitely the desired behaviour for me, and is in-line with the ReplayGain proposal and its implementations with other file formats (eg. It also does not modify the MP3 frames unless I specifically ask for this behaviour (using the “-r” or “-a” flags), so the default it to only apply a playback level in the tag. Perhaps our versions of mp3gain differ here because in my case I do not get the REPLAYGAIN_* fields (I use v1.5.2 by Glen Sawyer) Therefore, when mAirList (or any other MP3 player) loads a file altered by MP3Gain, it will play at the intended, internally altered level and all such files will show up in mAirList with Amplification of 0.0 and this is correct.Īs you have already said that your FLAC files are being handled correctly (and obviously, FLAC uses a different means to set a ‘global’ file gain change which DOES require the use of tags, unlike MP3 files), your only problem might be if you use a tool other than MP3Gain to set the level of your MP3 files. ALL that a player needs to do is to decode and play the file in the normal way, and the level will take care of itself. What this means in practice is that mAirList (or any other MP3 player) should NOT be attempting to change the level of MP3Gain-processed files further by looking for and applying tags, because the level change HAS ALREADY BEEN APPLIED INTERNALLY within the file’s frames. As I said before, I personally use MP3Gain totally without tags, as I do not ever need to be able to undo its changes but it WILL still apply the Global Gain frame changes when I run it. So, the presence or absence of a tag is irrelevant MP3Gain alters MP3 files at a much deeper level which you would not detect, unless you did a frame-by-frame analysis of an MP3 file. I just did a test here on an MP3 file using MP3Gain, and in its standard setup, it writes four APEv2 tags: MP3GAIN_MINMAX and MP3GAIN_UNDO (which are indeed concerned with reversing or undo-ing MP3Gain changes), REPLAYGAIN_TRACK_PEAK, and REPLAYGAIN_TRACK_GAIN.īUT remember that these tags are purely for MP3Gain internal use! Mp3Gain does alter the Global Gain field within each frame in your MP3 file. This was a design decision made in the early 2000s to specifically avoid causing problems or’interfering’ with other tag formats such as ID3v1. Well, I know that MP3Gain writes its ‘undo’ and ‘analysis’ tags in APEv2 format, and always has done. I’ve not yet encountered a tool which puts the information there. MAirList is looking for the gain information in UserTextFrame containing labels REPLAYGAIN_*.
$EYED3 -set-user-text-frame="REPLAYGAIN_TRACK_GAIN:$GAIN dB" "$FILE" > /dev/null Sed -n 's/Recommended "Track" dB change: \(\+\).*/\1/p'`Įcho "$FILE: no gain information in file" >&2 # Copy level information from existing tags into a format which I’ve posed it here in case it is useful to show what’s needed: #!/bin/sh But this is only because these seem to be the standard ones added by other applications.įor information, I made a quick script on Linux to tag the files. It’s a bit of a workaround, it would certainly be more desirable for mAirList to find information in the LAME, APEv2 or ID3v2 tag. mAirList picks up this value and uses it as amplification. I’ve got this working, by copying existing gain information into the ID3v2 tag as a UserTextFrame. $ eyeD3 "50 Cent - Ayo Technology (Clean).mp3"ĥ0 Cent - Ayo Technology (Clean).mp3 # Check using eyeD3 (although it doesn't seem to interrogate the RVA2 frame) Max PCM sample at current gain: 36782.000000 $ mp3gain -s c -s i "50 Cent - Ayo Technology (Clean).mp3" # Check the ID3v2 tag information using mp3gain Can you clarify which tag or field is required? Thanks. I can’t see anything that indicates exactly what tag is required from it though. Thanks for the link to the Foobar information.
So I’m still stuck no MP3 file I’ve tried has been able to modify the amplification value. It seems that the useful gain information goes successfully (look like it’s in an ‘RVA2’ frame), but amplification in mAirList still comes out at 0.0. After some experimentation, I found that later versions of mp3gain have an option to store the data in an ID3v2 tag.
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