I'd like to suggest the addition of Application specific headers to the spec. These are headers that are not part of the specification but may be used by implementations for various purposes. This suggestion is currently included in spec.md:
We have seen the need for application-specific metadata in several places. Examples include #RESOLUTION, #NOTESGAP or the non-standard use of the #VIDEO header by usdb_syncer.
This proposal offers a standardized way for applications to add custom metadata that is unlikely to conflict with future standardized headers or custom headers used by other applications.
In practice USDX-specific headers like #RESOLUTION could continue to exist as, for example, #USDX-RESOLUTION.
Extra info/examples/attachments
This proposal also gives way to a possible standardization process for new headers: If a certain feature is used by an implementation (say via the header #USDX-FOO) and this feature is deemed useful by other applications, these other applications may begin to support their own variant (for example #VOCALUXE-FOO). If a feature becomes popular enough it can be standardized (for example as #FOO) with a clearly defined syntax and behavior. Migration of existing songs that use the prefixed-variants should be simple in most cases.
This kind of prefixing behavior bears some similarity to vendor prefixing in CSS.
The spec currently only says that application specific headers should be prefixed with the application name. A specific format is not suggested (I have been using - to separate the prefix in the examples above). This might be something that should be defined as well.
Suggestion
I'd like to suggest the addition of Application specific headers to the spec. These are headers that are not part of the specification but may be used by implementations for various purposes. This suggestion is currently included in
spec.md:https://github.com/UltraStar-Deluxe/format/blob/23bf9307609f8320b6c6dd13cfef75b95ba33e6e/spec.md?plain=1#L164-L168
Use case
We have seen the need for application-specific metadata in several places. Examples include
#RESOLUTION,#NOTESGAPor the non-standard use of the#VIDEOheader by usdb_syncer. This proposal offers a standardized way for applications to add custom metadata that is unlikely to conflict with future standardized headers or custom headers used by other applications.In practice USDX-specific headers like
#RESOLUTIONcould continue to exist as, for example,#USDX-RESOLUTION.Extra info/examples/attachments
This proposal also gives way to a possible standardization process for new headers: If a certain feature is used by an implementation (say via the header
#USDX-FOO) and this feature is deemed useful by other applications, these other applications may begin to support their own variant (for example#VOCALUXE-FOO). If a feature becomes popular enough it can be standardized (for example as#FOO) with a clearly defined syntax and behavior. Migration of existing songs that use the prefixed-variants should be simple in most cases.This kind of prefixing behavior bears some similarity to vendor prefixing in CSS.
The spec currently only says that application specific headers should be prefixed with the application name. A specific format is not suggested (I have been using
-to separate the prefix in the examples above). This might be something that should be defined as well.