Instead of writing only the xmp tag for the first found entry
that matches the gstreamer tag, look for all mappings to write
the tag to different schemas.
The rationale here is that some reader application might only
be interested on a particular schema tags, so we should try
to write as many tags for all schemas.
The GstTagXmpWriter interface is to be implemented on elements that
provide xmp serialization. It allows users to select which
xmp schemas should be used on serialization.
API: GstTagXmpWriter
https://bugzilla.gnome.org/show_bug.cgi?id=645167
... as that is the specification and fixes compilation on Cygwin:
gstxmptaag.c: In function 'read_one_tag':
gstxmptag.c:1015: error: array subscript has type 'char'
Variable was being written to and could cause crashes
if multiple elements were parsing xmp at the same time.
Moving it to local scope solves the problem.
Adds mappings from:
GST_TAG_CAPTURING_EXPOSURE_PROGRAM -> ExposureProgram
GST_TAG_CAPTURING_EXPOSURE_MODE -> ExposureMode
GST_TAG_CAPTURING_SCENE_CAPTURE_TYPE -> SceneCaptureType
GST_TAG_CAPTURING_GAIN_ADJUSTMENT -> GainControl
GST_TAG_CAPTURING_WHITE_BALANCE -> WhiteBalance
GST_TAG_CAPTURING_CONTRAST -> Constrast
GST_TAG_CAPTURING_SATURATION -> Saturation
Also renames gst_tag_image_orientation_from_exif_value and
gst_tag_image_orientation_to_exif_value to remove the 'gst'
prefix and not including in the win32 defs.
Tests included.
Makes the xmp helper lib aware that the tags can be simple,
sequences or bags (there is still struct and alt, but those
aren't handled yet). Adding this info makes serialization
and deserialization more consistent.
If we find a bag of tags of type string in the xmp packet, we
should concat them, this is not the ideal approach, but at
least works for now as we don't know what type of tag it
is (simple, structure, seq, alt or bag)
Everything in the xmp helper lib is initiallized once and on a thread
safe way, and after that there are only reads going on, no more
writing. Based on that, drop the locking.
Adds GST_TAG_GEO_LOCATION_MOVEMENT_SPEED,
GST_TAG_GEO_LOCATION_MOVEMENT_DIRECTION and
GST_TAG_GEO_LOCATION_CAPTURE_DIRECTION to xmp
mappings.
Tests included.
Adds a mapping to the _ELEVATION tag, this is a different
mapping as it has to be mapped into exif:GPSAltitude and
exif:GPSAltitudeRef at the same time. So we needed to refactor
a little more to be able to deserialize it properly.
Now, when parsing a xmp buffer into a taglist all tags are
added to a list before being parsed so that when one of the
altitude tags are found the deserialization function can search
for its complementary tag to do the correct parsing
Fixes#613690
When parsing the xmp buffer into the gst taglist store the
found tags into a list to be parsed only after finding all
tags on the buffer. This allows the parser function to search
this list for complimentary tags that should be parsed together
Fixes#613690
This commit is only refactoring, no fetaures added.
Do not store tags in flexible arrays as it doesn't allow us
to use nested flexible arrays. This is going to be needed in the
following commits to map gst tags that are stored into
2 separate tags in xmp (Not that they are alternatives, but
they are complementary).
For example, GST_TAG_ELEVATION is represented in the exif
schema with 2 fields: the absolute altitude and an integer
to indicate if it is above or below sea level.
The previous mappings storage wouldn't allow us to
express it.
Also store a serialization and a deserialization function
for each xmp tag as some of them require some non-trivial
convertion to its string form.
Fixes#613690
I initially looked here because I wanted compiles to not fail with
-Wformat-nonliteral but ended up refactoring the code to make it look
nicer.
As I lack a large collection of XMP tagged files, I only did rough
testing of the code. The testsuite passes though.
XMP metadata can be embedded in many media container formats. Implement own
parser and formatter that can be used to convert between an xpacket and a
GstTagList. Add unit tests.