FLAC Embedded Album Covers

[TheOldPresbyope]

@leicray

This a moot issue since as you note moOde 6.2 is able to display the previously missing coverart.

However, for the benefit of others, here's what was going on:

• vinyl LPs were digitized using Vinyl Studio.
  
• Vinyl Studio saved the digital tracks as FLAC files, filling in the metadata from lookups on the Internet
  

A file was made available to me. Examining it using the CLI tool metaflac reveals that the Vinyl Studio developers had a curious way of interpreting the FLAC specification. They embedded the downloaded coverart twice

• once among the comments in a FLAC block type VORBIS_COMMENT, with the comment-field name METADATA_BLOCK_PICTURE and base64 encoded image data in the comment-field value (may have been uuencode rather than base64 data, didn't bother to check)
  
• once in a FLAC block type METADATA_BLOCK_PICTURE with jpeg data and appropriate picture metadata.
  

The first embedding is allowed by the permissive FLAC spec but not mentioned. It's bogus as far as the expectations of almost any FLAC-aware software is concerned. The second embedding is explicitly correct per the FLAC spec.

It doesn't take a multiple-transcoding process to "fix" the FLAC file. The CLI tool metaflac can do the surgery required:

Code:

pi@moode:~ $ metaflac --remove-tag=METADATA_BLOCK_PICTURE xxx.flac

et voilà !

Regards,
Kent