saving metadata to a video in savedPhotoAlbum Xcode - ios

Question

When I take a video using UIImagePickerController and save it to SavedPhotosAlbum using
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:(NSURL *)movieURL
completionBlock:^(NSURL *assetURL, NSError *error){
if (error) {
NSLog(#"Save video fail:%#",error);
} else {
NSLog(#"Save video succeed.");
[self getsavedvideo];
}}];
the saved file contains a name and creation date but not the GPS info. I am surprised by this since I am using the built in camera and the imagePicker. Why wouldn't Apple just include the GPS coordinates (even if I had to ask users permission to use location services).
anyway I digress
I have not found anyway to add the GPS coordinates to the video as it is being saved and I haven't been able to find anyway to add the this information in the completionBlock.
If someone knows how please let me know.
So I wrote a bit of code that is called after the video is saved [self getsavedvideo]; above which gets the saved video and I can get the movie name and creation date and it shows there is no location info.
-(void) getsavedvideo;{
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
// Enumerate just the photos and videos group by using ALAssetsGroupSavedPhotos.
[library enumerateGroupsWithTypes:ALAssetsGroupSavedPhotos usingBlock:^(ALAssetsGroup *group, BOOL *stop) {
// Within the group enumeration block, filter to enumerate just photos.
[group setAssetsFilter:[ALAssetsFilter allVideos]];
// Chooses the photo at the last index
[group enumerateAssetsWithOptions:NSEnumerationReverse usingBlock:^(ALAsset *alAsset, NSUInteger index, BOOL *innerStop) {
// The end of the enumeration is signaled by asset == nil.
if (alAsset) {
ALAssetRepresentation *representation = [alAsset defaultRepresentation];
// Stop the enumerations
*stop = YES; *innerStop = YES;
// Do something interesting with the AV asset.
NSString *fileName = [representation filename];
NSDate *myDate = [alAsset valueForProperty:ALAssetPropertyDate];
CLLocation *location = [alAsset valueForProperty:ALAssetPropertyLocation];
NSLog(#"fileName!!!!,%#",fileName);
NSDateFormatter * dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:mad:"dd-MM-yyyy 'at' HH:mm"];
NSLog( #"date for this file is %# %#", [[[alAsset defaultRepresentation] url] absoluteString], [dateFormatter stringFromDate: myDate] );
NSLog (#"locate!!!!%#",location);
} }];
} failureBlock: ^(NSError *error) {
NSLog(#"No groups");}];}
so does anyone know how to append this with the GPS information and save it back to the video's metadata.
I have been wracking my brains out on this for a few days and haven't really found anything helpful.
Plz help

Answer 1

So I figured this out for a device running ios8 or newer anyway.
add this code in the -(void) getsavedvideo that was in the completionBlock above.
Make sure you have
import
if ([PHAsset class]) { // If this class is available, we're running iOS 8
PHFetchOptions *fetchOptions = [PHFetchOptions new];
fetchOptions.sortDescriptors = #[[NSSortDescriptor sortDescriptorWithKey:#"creationDate" ascending:NO]];
fetchOptions.fetchLimit = 1;
PHFetchResult *fetchResult = [PHAsset fetchAssetsWithMediaType:PHAssetMediaTypeVideo options:fetchOptions];
PHAsset *lastImageAsset = [fetchResult lastObject];
[[PHImageManager defaultManager]requestImageForAsset:lastImageAsset targetSize:PHImageManagerMaximumSize contentMode:PHImageContentModeDefault options:nil resultHandler:^(UIImage *result, NSDictionary *info){
if ([info objectForKey:PHImageErrorKey] == nil && ![[info objectForKey:PHImageResultIsDegradedKey] boolValue]) {
NSArray *resources = [PHAssetResource assetResourcesForAsset:lastImageAsset];
NSString *orgFilename = ((PHAssetResource*)resources[0]).originalFilename;
[lastImageAsset requestContentEditingInputWithOptions:nil
completionHandler:^(PHContentEditingInput *contentEditingInput, NSDictionary *info) {
NSURL *imageURL = contentEditingInput.fullSizeImageURL;
NSString *urlstring = [imageURL absoluteString];
NSLog(#"urlstring%#",urlstring);
}];
CLLocationCoordinate2D locationNew = CLLocationCoordinate2DMake( currentLocation.coordinate.latitude, currentLocation.coordinate.longitude) ;
NSDate *nowDate = [NSDate date];
CLLocation *myLocation = [[CLLocation alloc ]initWithCoordinate:locationNew altitude:0.0 horizontalAccuracy:1.0 verticalAccuracy:1.0 timestamp:nowDate];
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
// Create a change request from the asset to be modified.
PHAssetChangeRequest *request = [PHAssetChangeRequest changeRequestForAsset:lastImageAsset];
// Set a property of the request to change the asset itself.
request.location = myLocation;
} completionHandler:^(BOOL success, NSError *error) {
NSLog(#"Finished updating asset. %#", (success ? #"Success." : error));
}];
}
}];
}
else {
//if you aren't running ios8 or newer I haven't found a way to add/change metadata but I will keep looking.So if you leave this blank no new metadata is added.
}
You can add other metadata just create the data in the form needed and then use request.(what you want to change) = new data.
you can check to see if the data already exist and if there is a metadata for it by putting in something like
lastImageAsset (which was the PHAsset fetch result above) and then the property like
NSDate *originalFileDate = [lastImageAsset creationDate]; etc.
there is a list at
https://developer.apple.com/reference/photos/phasset