Support reading/writing of rating and playcount with ID3 tags

[stuartm]

Primarily this is about maintaining* MythTV metadata, although other apps or hardware can benefit from being able to read this information. MythMusic can also import ratings/play counts from existing POPM tags.

The current implementation inserts the POPM frame with an email address of music@… for identification purposes. There are no immediate plans to allow for another address to be used, I see no justification until we support multiple users in mythmusic. For reading we use the MythTV POPM frame if it exists, otherwise we use the first POPM frame we find. For writing we always use the MythTV frame, since we don't prompt before writing we need to avoid overwriting existing non-myth frames.

The patch is a little rough, but it's limited by the existing architecture.

N.B. The roadmap includes adding file hashing to mythmusic in the same way that is done now for mythvideo, ultimately this will prevent the issue of lost metadata for other tag formats e.g. Flac with Xiph comments.

(*If files are moved or renamed in mythmusic metadata like track ratings, play count and the last play timestamp are lost.)

[kja999]

Hi,

Is there a way to trigger the update of the metadata to the file other than playing it ?

[stuartm]

kja99 can you post your questions to the mythtv-dev mailing list, I'll try to answer them there.

[stuartm]

Updated patch with a few changes, including modtime update

[stuartm]

Unfortunately I forgot to commit this before the feature freeze.

[stuartm]

Milestone 0.25 deleted

[stuartm]

(In [27319]) Allow playcount and rating to be written to and read from ID3 tags meaning they will be preserved even if files are moved. Playcount will be updated each time the file is played. This adds a new setting 'AllowTagWriting' which defaults to off and which must be enabled for this feature to work since some people would prefer MythTV not to alter their tags in any way. Closes #8595