Support v2.3.0/v2.4.0 frame flags

[Zazama]

Example file. The cover image extracted using mp3tag is this file.

I saw that release v0.1.6 was related to ID3 v2.4, but according to @kbuffington, is ID3 v2.4 actually not yet supported?

Originally posted by @hexrcs in #45 (comment)

The APIC frame in this file has n/p indicators set, which breaks the supported header length of node-id3.
See 4.1.2 http://id3.org/id3v2.4.0-structure

[kwisatz]

See #49 which addresses this issue. Although it might not be all that is required, it was enough in our case. Please advise if you'd like us to extend this PR.

[kbuffington]

@kwisatz You might want to try my node-id3 version. It was forked from Zazama's, but then split off because it was a pretty substantial rewrite. It handles TXXX, multi-value TXXX frames, 2.3 and 2.4 ID3 tags, and more.

It's still a WIP because I had to put it on hold for a few months but I'll be getting back to it shortly and finalizing things. It isn't published to NPM yet for that reason (I need to change the name first too!) but it works fine if you just pull the repo and reference the source files.

[artemanufrij]

Hey guys, any updates here?

[Zazama]

A bit late to the party but the most important ones are added to v0.2.0

• Unsychronisation & Data length indicator: d8f4f05
• Extended header: 8c42c6c

Still missing some, so I'll leave this open

[felpsio]

Would be nice to also add Synchronised lyrics/text (SYLT) https://id3.org/id3v2.3.0#sec4.10

[pbricout]

Would be nice to also add Synchronised lyrics/text (SYLT) https://id3.org/id3v2.3.0#sec4.10

@felpsio this has now been done in #122 since version 0.2.4.

[pbricout]

Just a quick implementation note:

• the code should detect which tags are in used and set the version 3/4 according to this, i.e. if no v4 tags are used, the v3 should set is some v4 flags are used, set to v4