The iPod doesn't read tags at all [...snip...] Instead, whatever program you use to send files to the iPod (MM, iTunes, etc.) needs to read all of the tags and store the information in the tags in the iPod database. The iPod then pulls all of the information it needs from the database, not the file itself.

Ah-ha.... Now I get it. MM should document this.

Thanks for your answer....

The iPod doesn't read tags at all (well, it reads lyrics from tags, but that is a separate issue...). Instead, whatever program you use to send files to the iPod (MM, iTunes, etc.) needs to read all of the tags and store the information in the tags in the iPod database. The iPod then pulls all of the information it needs from the database, not the file itself.

Mp3gain uses APE tags, dBpowerAmp and Foobar use one type of ID3 tag (TXXX frames), MM2 uses another type of ID3 tag (RVA2 frames). When MM sends files to an iPod, it uses data in the RVA2 frames. AFAIK, MM is the only commonly used program that is capable of reading and writing RVA2 tags.

I haven't tested what MM3 does, but the use of TXXX frames is becoming rather standard, so hopefully there will be some support for this.

I believe that MM3 does support both album and track gain. In theory either of these values can be converted to a SoundCheck value and stored in the iPod database. Again, I have not tested MM3 enough to know this for sure.

My iPod doesn't recognize the tags inserted by mp3gain, or the tags generated by dbPoweramp Replay gain.

But the iPod does use the tag generated by MM. I can hear it when I turn soundcheck on and off.


According to mp3gain documentation, it uses APE tags to store its stuff.

(from MP3Gain documentation:) MP3Gain stores "Analysis" and "Undo" information in special tags inside the mp3 file itself. These tags are in the APEv2 format. APEv2 tags are carefully designed to not interfere with other tag formats, such as the popular ID3v1 format.

According to dbPoweramp, it uses ID tags:

(from dbPoweramp Music Converter documentation:) ReplayGain values are written to the ID Tags, the audio is untouched.

Leaving me where, exactly??.....


So - I'm hoping that MM3 can put tag information in the same place it does now, so my 80gb iPod will use it. Wherever that place is...

It should be possible for MM3 to analyze an entire album before placing these tags, thus getting the equivalent to album gain, even though the iPod doesn't support it.


I really don't feel so bad being confused by all this. Its clear as mud.....

Ok... what you are seeing is that when you have done the replaygain and see the tags, they are not in a format that MM can read. MM's tags for volume leveling are actually ape tags where replaygain tags like you have are probably id3 tags.

As a result, MM can't handle them, yet (MM3 will).

Now, it sounds like for the MM leveling, you are actually using leveling, which is actually changing the file not just analyzing it. The leveling function does not write a tag, it changes the files volume. As a result, you are hearing the volume leveling on your IPod. However, I doubt that you are able to adjust much, and you probably can't turn it off in MM.

If you ran the analyze function in MM, that would write a tag, but it would be the ape tags I previously mentioned. You could then choose to use the tags in MM without really changing the file (only how you hear the file), but the IPod probably couldn't use those tags, although MM might implement them into the sync.

Supposedly, MM3 will implement the replaygain tags (track and album), which I hope will be in the id3 portion of the file (or with a choice). I've found that some software has trouble with mp3 files with tags in both the ape and id3 header and have thus eliminated them.

As for getting album leveling now, you might have to go to the MM3 alphas to see if it is already implemented. I also think there might be a script that can do the analysis on an album level, but it overwrites any track leveling information (it can only use one or the other).

Erik

OK - I have read some of the other posts, but I still don't get how this all works.

If I use replaygain, I can see (using the dbPoweramp tag editor) that tags have been set in the files. But when I play these files on my iPod, and turn "Sound Check" on or off, I can hear no volume difference. As an experiment, I used replaygain first with 75 and then with 99 db normalization - I still can't hear any difference on my iPod. Same with using the MM player - no differences.

If I use MM to do leveling (but of course, no album leveling - I know...wait for MM3...) I can hear differences on both the iPod and the MM player.

So... is replaygain supposed to work for my iPod?? for the MM player?? How can I get album leveling now???

thnx,