The general rule is that a
NewReleaseMessage must contain the main Release (such as an album) plus one Track Release for each of the primary Resources that make up the Main Release. Thus a ten-track album will lead to a NewReleaseMessage containing eleven Releases.
Track Releases are single-track Releases that are generated to allow "un-bundling". The inclusion of each Track Release does not define whether or not the Track Release is actually available to be un-bundled: that is subject to the Deal information (only those Track Releases for which a
ReleaseDeal is provided may be made available to consumers in accordance with this
Identifying Track Releases
ISRCs are used within a Track Release1 to identify the primary Resource, i.e. the sound recording or music video it contains. ISRCs do not identify the Track Release itself. Track Release identifiers are conveyed using the
ReleaseId composite, which provides a number of options, principally being either:
GRid, which is a standard identifier and has, therefore, a specific tag, or
Some other options are available due to historical practice, but the use of these is not encouraged.
UPC_ISRC as a ProprietaryID for Track Releases
One form of
ProprietaryID that is used in practice is a concatenation of the UPC of the Main Release and the ISRC of the sound recording/music video that is contained within the main Release. The elements should be separated by, for instance, an underscore character.
Unique identification of multiple instances of the same sound recording/music video
In some circumstances a Main Release may contain multiple instances of the same recording identified by the same ISRC. For example this can occur if a lossy compressed and lossless recording are delivered, or in some cases where an original recording and a remastered version are supplied. These should be separately identified. Where GRid is used, each Track Release is a separate release and may be identified using a unique GRid.
Where the proprietary UPC_ISRC is used, and the Main Release contains versions of the same recording having the same ISRC, unique identification of the Track Release can be achieved by appending a _ReleaseReference to the UPC_ISRC identifier.
Pointing from Track Release to Main Release
NewReleaseMessage allows for a Release to "point" to another release using the
RelatedRelease composite. In some cases this has been used to indicate that a Track Release has been ‘un-bundled’ from an album Release. This should, however, only be done if the album release is not the Main Release in the same
Therefore, the Track Release shall not point to the Main Release it comes from if they are both communicated in the same
1 ISRCs are of course also used to identify the primary Resources in the album Release.