Normalize files

[Ducke1001]

In your wiki there is the option -gain to change the volume of a file. But it looks like this option is not implemented, right?

phiola "Deep House Special Mix.mp3" -gain 6 -o test.mp3
#3012 ERROR unknown option '-gain'. Use '-h' for usage info.

It would be great to be able to use this option to normalize the files.

[stsaz]

There are several mistakes here:

• you shoud use convert command when converting files -- by default phiola starts in playback mode
• MP3 encoding is disabled, so -gain with -o .mp3 won't work

So you should use something like this:

phiola convert "Deep House Special Mix.mp3" -gain 6 -o test.ogg

[Ducke1001]

Sorry, I must have mixed that up.
Is it possible to combine gain with convert -copy and overwrite the file?

[stsaz]

Is it possible to combine gain with convert -copy and overwrite the file?

No, because -gain (i.e. changing the volume level of audio samples) must be applied to uncompressed (decoded) audio while -copy switch can only copy compressed (encoded) data. So either you just copy MP3 frames without changing volume, or you decode, apply volume, and then encode again. But keep in mind that re-encoding compressed audio files will slightly decrease original audio quality.

Another approach is to use some ID3v2 tags (e.g. replay gain) that will instruct the decoder to apply volume at runtime. But currently phiola doesn't support that.

[Ducke1001]

Ah, OK. That might be a great feature for the future.

[stsaz]

Support for replay-gain is mentioned in #31, closing this.