Bit rate for MP3 files

[jch2103]

I've done some more playing with IM's MP3 capabilities. This has mostly reinforced my earlier belief that MP3 tagging by the music industry is even more inconsistent and weird than metadata for images, but I digress.

I can use the MP3 tags provided by ExifTool for information that's available for MP3 tracks. However, I want to access the 'Bit rate' field that's available via the file system (Windows Explorer). This is different from and not necessarily consistent with the various bitrate fields available in the metadata editor. Is this 'Bitrate' field accessible, or is such file system information not available to the metadata panels?

[Mario]

To see all metadata tags available in IMatch for your MP3 files, switch the Metadata Panel into Browser mode.

On my system, the bitrate is always available in:

{File.MD.photools.com::IMatch\30700\id3bitrate\0}

and the corresponding standard tag is named

ID3: Bitrate.

Add it to one of your Metadata Panel layouts to see the info.

Or is this tag not filled for your files?

[jch2103]

Yes, I have no trouble accessing any of the MP3 tags in the meatadata panel. (The specific tags with data depend on the source of the MP3; some of my files have many tags, some have very few.) The issue I found is that the file system (viewed from Windows Explorer) appears to use different tags to display 'Bit Rate' (i.e., doing a right-click in Windows Explorer on the header and choosing 'Bit rate').

Depending on the particular MP3 file, Windows Explorer sometimes shows contents of {File.MD.photools.com::IMatch\30700\id3bitrate\0} (ID3: Bitrate). However, if  Composite\AudioBitrate\AudioBitrate\0 is populated, Windows Explorer shows this information instead. This is based on a quick look at a number of files, so the actual situation with Windows Explorer is probably more complex including whether the MP3 file was encoded with variable bit rate.

So this doesn't look like it's an IMatch issue, but rather part of the confusing world of MP3 meatadata.

[Mario]

"Composite" always means that ExifTool makes up some information from some "other" source.
Ask Phil if you need to know the details.

When I defined the sources for the standard ID:Bitrate  IMatch tag, I based it on:

MPEG::Audio\Bit16-19\AudioBitrate\4
MPEG::Audio\Bit16-19\AudioBitrate\3
MPEG::Audio\Bit16-19\AudioBitrate\2
MPEG::Audio\Bit16-19\AudioBitrate\1
MPEG::Audio\Bit16-19\AudioBitrate\0

which seemed to work best at that time. There are so many variations in ID3 tags, it's best to choose from the tags ExifTool offers whatever works for your files. Sometimes you need to show multiple tags. Or you sit down and clean up the MP3 data in all your files to one common ID3 variation.