Some ID3v2.4.0 frames such as text information frames support multiple strings
separated by the termination code of the character encoding. If the encoding
is $01 UTF-16 with BOM, all strings shall have the same byte order. In the
multi strings written by TagLib, all string elements of such a multi string
have a BOM. However, I have often seen tags where a BOM exists only at the
beginning, i.e. at the start of the first string. In such a case, TagLib will
only return a list with the first string and a second empty string. This
commit will detect such cases and parse the strings without BOM according to
the BOM of the first string.
There are m4a files with regular (non-full) meta atoms. When such
a meta atom is not correctly parsed, the subsequent atoms are not
recognized and offsets will not be adjusted when atoms are added,
which will corrupt the MP4 file.
This change will look behind the meta atom to check if the next
atom follows directly, i.e. without the four bytes with version
and flags as they exist in full atoms. In such a case, these
four bytes will not be skipped.
Witnesses of this strange format specification are
https://leo-van-stee.github.io/https://github.com/axiomatic-systems/Bento4/blob/v1.6.0-639/Source/C%2B%2B/Core/Ap4ContainerAtom.cpp#L60
This changes the modifications from the last commit in order to
achieve the following behavior: MP4::File::save() works in the
same way as before, i.e. it will never shrink the file and will
make space from removed items available as padding in the form of
a "free" atom. To completely remove the "meta" atom from the file,
a new method strip() is introduced, which can be used in the same
way as its MPEG::File::strip() counterpart.
Currently, MP4 tags can only grow. If items are removed, they are
just replaced by padding in the form of "free" atoms. This change
will remove the whole "meta" atom when an MP4 tag without items
is saved. This will make it possible, to bring the file back to
its pristine state without metadata.
The support for MusicBrainz properties is enhanced with "ARTISTS", "ASIN",
"RELEASECOUNTRY", "RELEASESTATUS", "RELEASETYPE", "MUSICBRAINZ_RELEASETRACKID",
"ORIGINALDATE" on APE, ASF, MP4, ID3v2, and Xiph tags.
As described in id3v2.3.0.txt (4.2.1, TCON), multiple genres are
only possible as references to ID3v1 genres with an optional
refinement as a text. When downgrading multiple genres from
ID3v2.4.0, they are now converted to numbers when possible and
the first genre text without ID3v1 reference is added as a
refinement. The keywords RX and CR are supported too.
This incorporates [6ca536b5] (mp4 properties: handle the case when
mp4 file header has zero bitrate) from PR #899 with a more accurate
bitrate calculation and a unit test.
This will allow editing the tags of WAV files which have data
appended at the end. The corresponding unit test checks that the
original contents are still available after editing the metadata
of such files.
This does not put the deprecated marker on methods that will or could resolve
to the same overload, e.g.:
void foo(bool bar = true); // <-- not marked
void foo(Bar bar) // <-- since this will have a default argument in the new version
This uses explicit enums for e.g. the ID3v2 version, making calls more
readable:
file.save(ID3v1 | ID3v2, StripOthers, ID3v2::v4, Duplicate);
Instead of:
file.save(ID3v1 | ID3v2, true, 4, true);
Needs to be ported to other types, per #922
