// There is an issue with Reconyx cameras in how it stores the original 'Date / ime' metadata tag's value
// To get around this, we first try to get that tag's value using the standard method. If it doesn't work,
// we try again using the Reconyx-specific method.
public static bool TryReadDateTimeOriginalFromMetadata(string filePath, out DateTime dateTime)
{
dateTime = DateTime.MinValue;
// Use only on images, as video files don't contain the desired metadata.
try
{
IReadOnlyList <MetadataDirectory> metadataDirectories = null;
// Performance tweaks. Reading in sequential scan, does this speed up? Under the covers, the MetadataExtractor is using a sequential read, allowing skip forward but not random access.
// Exif is small, do we need a big block?
using (FileStream fS = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read, 64, FileOptions.SequentialScan))
{
metadataDirectories = ImageMetadataReader.ReadMetadata(fS);
}
ExifSubIfdDirectory exifSubIfd = metadataDirectories.OfType <ExifSubIfdDirectory>().FirstOrDefault();
if (exifSubIfd == null)
{
return(false);
}
if (exifSubIfd.TryGetDateTime(ExifSubIfdDirectory.TagDateTimeOriginal, out dateTime) == false)
{
// We couldn't read the metadata. In case its a reconyx camera, the fallback is to use the Reconyx-specific metadata using its DateTimeOriginal tag
ReconyxHyperFireMakernoteDirectory reconyxMakernote = metadataDirectories.OfType <ReconyxHyperFireMakernoteDirectory>().FirstOrDefault();
if ((reconyxMakernote == null) || (reconyxMakernote.TryGetDateTime(ReconyxHyperFireMakernoteDirectory.TagDateTimeOriginal, out dateTime) == false))
{
return(false);
}
}
return(true);
}
catch
{
return(false);
}
}
public DateTimeAdjustmentEnum TryReadDateTimeOriginalFromMetadata(string folderPath, TimeZoneInfo imageSetTimeZone)
{
// Use only on images, as video files don't contain the desired metadata.
try
{
IReadOnlyList <MetadataDirectory> metadataDirectories = null;
// PERFORMANCE
// IReadOnlyList<MetadataDirectory> metadataDirectories = ImageMetadataReader.ReadMetadata(this.GetFilePath(folderPath));
// Reading in sequential scan, does this speed up? Under the covers, the MetadataExtractor is using a sequential read, allowing skip forward but not random access.
// Exif is small, do we need a big block?
using (FileStream fS = new FileStream(this.GetFilePath(folderPath), FileMode.Open, FileAccess.Read, FileShare.Read, 64, FileOptions.SequentialScan))
{
metadataDirectories = ImageMetadataReader.ReadMetadata(fS);
}
ExifSubIfdDirectory exifSubIfd = metadataDirectories.OfType <ExifSubIfdDirectory>().FirstOrDefault();
if (exifSubIfd == null)
{
return(DateTimeAdjustmentEnum.MetadataNotUsed);
}
if (exifSubIfd.TryGetDateTime(ExifSubIfdDirectory.TagDateTimeOriginal, out DateTime dateTimeOriginal) == false)
{
// We couldn't read the metadata. In case its a reconyx camera, the fallback is to use the Reconyx-specific metadata
ReconyxHyperFireMakernoteDirectory reconyxMakernote = metadataDirectories.OfType <ReconyxHyperFireMakernoteDirectory>().FirstOrDefault();
if ((reconyxMakernote == null) || (reconyxMakernote.TryGetDateTime(ReconyxHyperFireMakernoteDirectory.TagDateTimeOriginal, out dateTimeOriginal) == false))
{
return(DateTimeAdjustmentEnum.MetadataNotUsed);
}
}
DateTimeOffset exifDateTime = DateTimeHandler.CreateDateTimeOffset(dateTimeOriginal, imageSetTimeZone);
// get the current date time
DateTimeOffset currentDateTime = this.DateTimeIncorporatingOffset;
// measure the extent to which the file time and 'image taken' metadata are consistent
bool dateAdjusted = currentDateTime.Date != exifDateTime.Date;
bool timeAdjusted = currentDateTime.TimeOfDay != exifDateTime.TimeOfDay;
if (dateAdjusted || timeAdjusted)
{
this.SetDateTimeOffset(exifDateTime);
}
// At least with several Bushnell Trophy HD and Aggressor models (119677C, 119775C, 119777C) file times are sometimes
// indicated an hour before the image taken time during standard time. This is not known to occur during daylight
// savings time and does not occur consistently during standard time. It is problematic in the sense time becomes
// scrambled, meaning there's no way to detect and correct cases where an image taken time is incorrect because a
// daylight-standard transition occurred but the camera hadn't yet been serviced to put its clock on the new time,
// and needs to be reported separately as the change of day in images taken just after midnight is not an indicator
// of day-month ordering ambiguity in the image taken metadata.
bool standardTimeAdjustment = exifDateTime - currentDateTime == TimeSpan.FromHours(1);
// snap to metadata time and return the extent of the time adjustment
if (standardTimeAdjustment)
{
return(DateTimeAdjustmentEnum.MetadataDateAndTimeOneHourLater);
}
if (dateAdjusted && timeAdjusted)
{
return(DateTimeAdjustmentEnum.MetadataDateAndTimeUsed);
}
if (dateAdjusted)
{
return(DateTimeAdjustmentEnum.MetadataDateUsed);
}
if (timeAdjusted)
{
return(DateTimeAdjustmentEnum.MetadataTimeUsed);
}
return(DateTimeAdjustmentEnum.SameFileAndMetadataTime);
}
catch
{
return(DateTimeAdjustmentEnum.MetadataNotUsed);
}
}
