So many years I've used [version 5.666 Pro] it and never spotted that. Because when I got to know about ReplayGain, I also started using Mp3tag for tagging [and so there was no need for me to go to that window in Winamp anymore]
And so, I used Winamp for checking. But for searching I used Foobar 1.3.10. But adding adding two columns to it with
%REPLAYGAIN_ALBUM_GAIN%and
%REPLAYGAIN_TRACK_GAIN%values and running a scan I came up with a clear distinction between files. And here are some statistics, coming out from those almost 200 albums / singles already mentioned by me: 13 albums / singles had ReplayGain attached to them; and all of those with track ReplayGain had also album ReplayGain [so there were not one case of a single file with only track ReplayGain. So that's around 6%, a part rather significant
[Also in Mp3tag you can just add such two columns]
I also was trying to make a tag field [column] showing a value indicating existence of ReplayGain in MP3 files [in both Foobar and Mp3tag] but I could not achieve that
And here is the important part:
"Remove fields except" action in Mp3tag will not wipe out ReplayGain info from MP3s; if that meta data was applied via MP3Gain software to MP3 made with LAME codec
"Remove fields except" action in Mp3tag will wipe out ReplayGain info from FLACs; assuming that "REPLAYGAIN_TRACK_GAIN" and "REPLAYGAIN_ALBUM_GAIN" are the only way of storing that meta data in that format
And also:
Switch Sound File Converter 4.35 and 4dtos Free Audio Converter 3.1 when encoding FLAC to WAV do not take into account ReplayGain [at least in form of "REPLAYGAIN_TRACK_GAIN" and "REPLAYGAIN_ALBUM_GAIN"]. They will produce pure audio with no changes taken from ReplayGain
But Switch Sound File Converter and 4dtos Free Audio Converter will take into account ReplayGain applied via MP3Gain software to LAME coded MP3 file. They will produce permanently damaged WAV files [if that ReplayGain made clippings]
And it seems that also also Sony Sound Forge 11 loads up FLAC files without ReplayGain info, just as Audacity does. So it seems that this is rather universal approach: to leave ReplayGain out of FLAC when it is edited / processed
If someone can debunk those claims, because I misunderstood all those inner workings and made some tests in a wrong way, please tell. Or confirm my statements