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Multiple Metadata when converting .mp3 files

Posted: Sun Apr 24, 2011 6:11 pm
by MWRMWR
1.3 beta under XP (downloaded today) (oh good, I never got asked about the Lame as it was in the right place)

I had a bunch of .mp3 files structured with track number info and was converting to .wav
This worked but I was a bit scared about what was happing witin Audacity with this metadata/
I made sure that I *DID NOT SAVE* changes to the metadate of the input files.

Naive attempt #1
I dragged and dropped 16 .mp3 files into Aud1.3beta - all looked fine at first.
Then I realised the window title was track specific (the first or last in the list I think)
Ah - that means the model of operation is project based I thought so that wrecks my batch-conversions...
I tried export (as .wav) for each track and noticed that they all showed the same metadata
- but so what ? it won't be in the output file; too scary though so I backed out.
then it came to closing and I was asked to save my changed files !... er NO ! don't touch


attempt #2
project-based ...nah, hard work doing 1 at a time

attempt #3
No prob they've provided Export Multiple --- that'll be it 8-)

So I start doing that for a few files and notice that the metadatas are different ..seems good.
close the files ... Save Changes ? er, no thanks.

attempt #4
convert the rest [This export multiple is great]...
hang on, these metadata track numbers don't match what I expected - it is a number withn the set for "this project ?"

Oh well, not my problem; I have the required output files with exactly the required names.

Close down ... Save Changes ? er, no thanks still.

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Maybe the behaviour is all correct by design of Audacity so I would not like to report it as a bug exactly.
Anyone that knows this stuff well though might want to try to reproduce my findings and
to think about recommending some clearer warnings or more specific functionality given the task I had in hand.

Re: Multiple Metadata when converting .mp3 files

Posted: Mon Apr 25, 2011 10:40 am
by steve
Metadata is per project.

When importing files, the metadata will be read from the first file that is imported and that will become the metadata for the project.
When you import a file into an empty project, the current project metadata (if there is any) will be replaced by the metadata that is read from the imported file.

This means that if you are wanting to edit or process a single file, then you will need to import it into an empty project for the metadata to be retained.

Please note that there are thousands of variations of metadata formats, so Audacity is not able to support every metadata feature of every file type for every other program. Audacity supports the most commonly used metadata only. In particular, "Album art" is not supported.

Note also that very few programs support metadata in WAV files.

When using "Export Multiple", you should set the metadata to include only information that applies to all of the tracks, for example, the Album title, but leave song specific information (such as Track title") empty. You can then use your normal media player to add the specific track information and the album information will already be filled in (provided that the player supports the metadata that is supplied by Audacity).