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public class QuickTimeMetadataLoader {
// Quicktime calendar date/time format is number of seconds since January 1, 1904.
// This converts to UNIX time (66 years + 17 leap days).
public const int64 QUICKTIME_EPOCH_ADJUSTMENT = 2082844800;
private File file = null;
public QuickTimeMetadataLoader(File file) {
this.file = file;
}
public MetadataDateTime? get_creation_date_time() {
var dt = get_creation_date_time_for_quicktime();
if (dt == null) {
return null;
} else {
return new MetadataDateTime(dt);
}
}
public string? get_title() {
// Not supported.
return null;
}
// Checks if the given file is a QuickTime file.
public bool is_supported() {
QuickTimeAtom test = new QuickTimeAtom(file);
bool ret = false;
try {
test.open_file();
test.read_atom();
// Look for the header.
if ("ftyp" == test.get_current_atom_name()) {
ret = true;
} else {
// Some versions of QuickTime don't have
// an ftyp section, so we'll just look
// for the mandatory moov section.
while(true) {
if ("moov" == test.get_current_atom_name()) {
ret = true;
break;
}
test.next_atom();
test.read_atom();
if (test.is_last_atom()) {
break;
}
}
}
} catch (GLib.Error e) {
debug("Error while testing for QuickTime file for %s: %s", file.get_path(), e.message);
}
try {
test.close_file();
} catch (GLib.Error e) {
debug("Error while closing Quicktime file: %s", e.message);
}
return ret;
}
private DateTime? get_creation_date_time_for_quicktime() {
QuickTimeAtom test = new QuickTimeAtom(file);
DateTime? timestamp = null;
try {
test.open_file();
bool done = false;
while(!done) {
// Look for "moov" section.
test.read_atom();
if (test.is_last_atom()) break;
if ("moov" == test.get_current_atom_name()) {
QuickTimeAtom child = test.get_first_child_atom();
while (!done) {
// Look for "mvhd" section, or break if none is found.
child.read_atom();
if (child.is_last_atom() || 0 == child.section_size_remaining()) {
done = true;
break;
}
if ("mvhd" == child.get_current_atom_name()) {
// Skip 4 bytes (version + flags)
child.read_uint32();
// Grab the timestamp.
// Some Android phones package videos recorded with their internal cameras in a 3GP
// container that looks suspiciously like a QuickTime container but really isn't -- for
// the timestamps of these Android 3GP videos are relative to the UNIX epoch
// (January 1, 1970) instead of the QuickTime epoch (January 1, 1904). So, if we detect a
// QuickTime movie with a negative timestamp, we can be pretty sure it isn't a valid
// QuickTime movie that was shot before 1904 but is instead a non-compliant 3GP video
// file. If we detect such a video, we correct its time. See this Redmine ticket
// (https://bugzilla.gnome.org/show_bug.cgi?id=717384) for more information.
if ((child.read_uint32() - QUICKTIME_EPOCH_ADJUSTMENT) < 0) {
timestamp = new DateTime.from_unix_utc(child.read_uint32());
} else {
timestamp = new DateTime.from_unix_utc(child.read_uint32() - QUICKTIME_EPOCH_ADJUSTMENT);
}
done = true;
break;
}
child.next_atom();
}
}
test.next_atom();
}
} catch (GLib.Error e) {
debug("Error while testing for QuickTime file: %s", e.message);
}
try {
test.close_file();
} catch (GLib.Error e) {
debug("Error while closing Quicktime file: %s", e.message);
}
return timestamp;
}
}
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