saving metadata to a video in savedPhotoAlbum Xcode

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