Hello,
I wanted to know if it was possible to export mp3 files (multiple export) without changing metadata. Let me explain, when I do Multiple export, automatically, in the “Artist name” ends the artist’s name last loaded audio file and instead in the field “Title Track” everything ends the song name.
I would avoid this so as not to change the data of my music files (correttmente written!). 
Sorry for my poor English 
As it says in Metadata Editor, only the metadata for the last imported track is stored. You can ask us to add your “vote” for retaining metadata for each imported file if you like.
There are two solutions. Import one file per project by using File > Open… instead of File > Import > Audio… .
Alternatively if Chains let you perform the edits you are trying to make, create a Chain then apply it to selected files. This preserves the metadata tags of each file. It will be more convenient to open Import / Export Preferences and turn off “Show Metadata Editor prior to export step:” then the Chain can run unattended.
Note that re-encoding an MP3 (as Audacity does when exporting) degrades the MP3’s quality. If you just want to trim some of the audio or make volume adjustments, use a direct MP3 editor instead which will avoid re-encoding.
Gale
Hello Gale,
first of all I thank you for your reply and for your help. 
Unfortunately I have many export file and then import it does not suit me one at a time. 
I removed the check from “Show Metadata Editor before export” but I have not figured out how to create the chains that keeps me the metadata of each file tag.
Can you give me an example?
There is a program that improves my quality of audio automatically (and also changed the Kbs but leaving unchanged metadata)?
As you ask for a “vote”?
The instructions are at http://manual.audacityteam.org/man/edit_chains.html. Use File > Edit Chains… . Add available commands to a Chain, then add a final export command to the Chain for the format you want to export to. Then use File > Apply Chain…, select the Chain you created, and choose “Apply to Files…” to select the files to be processed.
Please tell us exactly what edits you are making to these files, then we can advise you better.
A direct MP3 editor does not improve the quality, and it does not lose quality either. But the type of edits that are possible using a direct editor are limited to volume changes and cutting pieces out or pasting pieces in.
We have a “Feature Requests” system where we count “votes” for features that users request. We consider feature requests when looking at features to add or improve. We do not identify anyone personally when we count votes.
Would you like it if Audacity stored metadata per track, so that the metadata for previously imported files is not discarded?
Gale
Yes, i want this. 
I added your “vote”.
Gale
Realistically I don’t see that happening any time soon. Although it sounds like a simple enough idea, it raises countless questions about how to handle the metadata if, for example, audio is copied from one track to another, or if tracks are mixed together, or on “normal” export, or on duplicating all or part of a track …
It would also require a change to the Audacity Project format, which is not a thing to undertake lightly.
Yes you have said that before, and I know you are opposed. It is a complex idea in a multi-track editor. It might even have to be a restricted mode that did not let you exchange audio data between tracks.
Regardless, it is right to count the votes and investigate how other multi-track editors handle this.
A few years ago a developer (not from Audacity) raised this issue on the -devel list in some detail. He did not feel it impractical, as I recall. I think one option discussed was to adapt label tracks/labels to carry metadata, which could then be associated with specific audio tracks.
Gale
I’m not opposed to it if it is done well, but as you say, it is a highly complex feature for a multi-track editor that would require a considerable amount of work for both the developer(s) and for QA. So as to avoid unrealistic expectations, I think it’s only fair to let users know that although we can count their vote for the feature, it’s not likely to happen any time soon.
I agree that if we count votes for feature requests at all, (which we do), then we should count votes for all feature requests.
I don’t know of any multi-track editors that have per-track metadata.
I added a comment about the practical implementation problems to the Feature Requests page.
Gale