Cannot empty or delete VORBIS_COMMENT vendor string

[x0tester0x]

How can I empty or delete VORBIS_COMMENT vendor string while keeping the comments?

METADATA block #1
  type: 4 (VORBIS_COMMENT)
  is last: true
  length: 83
  vendor string: reference libFLAC 1.4.3 20230623
  comments: 1
    comment[0]:

[ktmf01]

metaflac does not offer a way to do this currently.

Why do you want to remove it?

[x0tester0x]

I want to remove it, because i do not want that, when I give files to other people, that they can see which tool I used to create the FLAC. So for example if I rip a bluray with MakeMKV, I want to remove, that in the vendor string they can see MakeMKV.

Can you please implement the feature to delete or empty the vendor string?

[x0tester0x]

This feature is really important for me and I think that this is not a big change and so not much work to implement.
When will this feature be implemented?

[ktmf01]

If you contribute a PR, it could be implemented next week. If not, I won't make any promises. As you can see from the issues list, there are open issues already 5 years old.

[H2Swine]

How can I empty or delete VORBIS_COMMENT vendor string while keeping the comments?

From your question I take it that you know how to remove the VORBIS_COMMENT block entire, so here is a work-around. It will leave a vendor string, but not the right one:

Dump the file(s) into Mp3tag
Ctrl-x the tags away
metaflac --remove --block-type VORBIS_COMMENT
In Mp3tag, hit Ctrl-z to undo.

Mp3tag will write back the tags, but not the correct vendor string - it will it will fill in a vendor string of some reference libflac version.

[x0tester0x]

If you contribute a PR, it could be implemented next week. If not, I won't make any promises. As you can see from the issues list, there are open issues already 5 years old.

I am not very good at C programming... so I think I can only wait until this feature will be implemented

[x0tester0x]

How can I empty or delete VORBIS_COMMENT vendor string while keeping the comments?

From your question I take it that you know how to remove the VORBIS_COMMENT block entire, so here is a work-around. It will leave a vendor string, but not the right one:

Dump the file(s) into Mp3tag Ctrl-x the tags away metaflac --remove --block-type VORBIS_COMMENT In Mp3tag, hit Ctrl-z to undo.

Mp3tag will write back the tags, but not the correct vendor string - it will it will fill in a vendor string of some reference libflac version.

That is not what I want... I want a empty string or delete the vendor string completely

[H2Swine]

Sure I read that. But it will serve this purpose:

that they can see which tool I used to create the FLAC.

If anonymity is what you seek, then replacing it by something common is more efficient than the empty string.

[x0tester0x]

I cannot find in the code where it will write "vendor string: reference libFLAC 1.4.3 20230623".
Can someone show me?

[ktmf01]

Sure. It is right here

flac/src/libFLAC/format.c

Lines 47 to 59 in 31ccd3d

	#if (defined GIT_COMMIT_HASH && defined GIT_COMMIT_DATE)
	# ifdef GIT_COMMIT_TAG
	FLAC_API const char *FLAC__VERSION_STRING = GIT_COMMIT_TAG;
	FLAC_API const char *FLAC__VENDOR_STRING = "reference libFLAC " GIT_COMMIT_TAG " " GIT_COMMIT_DATE;
	# else
	FLAC_API const char *FLAC__VERSION_STRING = "git-" GIT_COMMIT_HASH " " GIT_COMMIT_DATE;
	FLAC_API const char *FLAC__VENDOR_STRING = "reference libFLAC git-" GIT_COMMIT_HASH " " GIT_COMMIT_DATE;
	# endif
	#else
	/* PACKAGE_VERSION should come from configure */
	FLAC_API const char *FLAC__VERSION_STRING = PACKAGE_VERSION;
	FLAC_API const char *FLAC__VENDOR_STRING = "reference libFLAC " PACKAGE_VERSION " 20230623";
	#endif

[x0tester0x]

Ok and where in the metaflac code gets this called?

[ktmf01]

That depends on what action metaflac does, specifically. Taking adding a vorbis comment block when there is none as an example, that would be.

Here:

flac/src/metaflac/operations_shorthand_vorbiscomment.c

Line 63 in 31ccd3d

block = FLAC__metadata_object_new(FLAC__METADATA_TYPE_VORBIS_COMMENT);

Then here:

flac/src/libFLAC/metadata_object.c

Line 468 in 31ccd3d

if (!copy_bytes_(&object->data.vorbis_comment.vendor_string.entry, (const FLAC__byte*)FLAC__VENDOR_STRING, object->data.vorbis_comment.vendor_string.length+1)) {

[x0tester0x]

I changed, as workaround for myself, the variable FLAC__VENDOR_STRING in the code to an empty string and rebuild the metaflac.exe.