i downloaded the program, and just started to experiment with 4 songs. i put the output in the same directory. what happened is that the output file was turned into an aac file. the loudness of the output is also greatly reduced.
with mp3gain, i can put my own target in, even though the default is 89 or, if i recall. so i am wondering if i also have that same option with mp4gain ?
also, i cant imagine anyone wanting this program if it changes their lossless m4a into a lossy aac ? so i am hoping that this is just something i can change somewhere ?
on one song - the m4a is 18.1 mb. the aac is 2.9 mb, even smaller than the mp3 (which is 3.83 mb). on the screen before you click to run, it shows the input format as m4a, and the output format as m4a.
You should ask the company that makes MP4Gain why it works the way that it does.
i was thinking that it was just some mistake i was making. it is a free download, so i dont think any company is gonna spend any time answering questions. thanks for your input
Lossless? Are you dealing with ALAC in mp4?
If it's lossless you can convert it to WAV and use WAVgain and then convert it back.
And even if it is lossy, AAC/M4A is pretty-much immune to accumulated damage from re-compression.
once i convert to wav, i lose my metadata. and i am not sure that a gain on a wav file would stay "gained" when going to another format. or whether itunes would recognize it, or not. various programs seem to use various areas for their tags, and they dont all talk to one another. and it is difficult to even find out what apple does. no one really seems to know the technical details of what soundcheck actually does. and i think that is one of the big reasons why people have so many problems with it.
I take it that you use Windows, since apparently this $40 software is for Windows only.
Foobar2000 can do shift volume by ReplayGain - but cannot it also foobar2000 be set to write Soundcheck tags?
i do have windows, but i think it can bought as a mac version. the options i have been presented with foobar keep me from running itunes. at least that is my understanding