App crash: when writeVideoAtPathToSavedPhotosAlbum using ALAssetsLibrary - ios

Question

We are making a chat app and for video thumbnail we use the following code. But it crashes in random cases.
NSArray *arrjid = [jid componentsSeparatedByString:#"#"];
NSDateFormatter *dateFormatter=[[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyyMMddHHmmss"];
NSString *strdate = [dateFormatter stringFromDate:[NSDate date]];
NSString *strname = [NSString stringWithFormat:#"%#_%#_file.mov",arrjid[0],strdate];
NSString *videoPath = [[NSSearchPathForDirectoriesInDomains(NSCachesDirectory, NSUserDomainMask, YES) objectAtIndex:0] stringByAppendingPathComponent:strname];
[videoData writeToFile:videoPath atomically:YES];
if([[NSFileManager defaultManager] fileExistsAtPath:videoPath])
{
ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library writeVideoAtPathToSavedPhotosAlbum:[NSURL fileURLWithPath:videoPath] completionBlock:^(NSURL *assetURL, NSError *error) {
}];
}
Every time it crashes on the writeVideoAtPathToSavedPhotosAlbum line and it gives only "bad access error".
Does anyone have an idea related to this?

Answer 1

ALAssetsLibrary library method writeVideoAtPathToSavedPhotosAlbum:completionBlock: is deprecated, you can use PHPhotoLibrary instead.
try this
[[PHPhotoLibrary sharedPhotoLibrary] performChanges:^{
[PHAssetChangeRequest creationRequestForAssetFromVideoAtFileURL: yourVideoURlHere];
} completionHandler:^(BOOL success, NSError *error) {
if (success) {
//Do Something
}
}];
Also check if you have Photo Library usage description in info plist with following key
NSPhotoLibraryUsageDescription
UPDATE
For fetching thumbnail from video you can use AVAssetImageGenerator class from AVFoundation framework
- (UIImage *) thumbnailFromVideoAtURL:(NSURL *) contentURL {
AVURLAsset *asset = [[AVURLAsset alloc] initWithURL:contentURL options:nil];
AVAssetImageGenerator *generator = [[AVAssetImageGenerator alloc] initWithAsset:asset];
generator.appliesPreferredTrackTransform = YES;
NSError *err = NULL;
CMTime time = CMTimeMake(1, 60);
CGImageRef imgRef = [generator copyCGImageAtTime:time actualTime:NULL error:&err];
UIImage *thumbnail = [[UIImage alloc] initWithCGImage:imgRef];
CGImageRelease(imgRef);
return thumbnail;
}

Answer 2

Make sure you have permission to save to the photo gallery.
Import the Photos class:
#import <Photos/Photos.h>
Then check for Photo Library Authorization
PHAuthorizationStatus status = [PHPhotoLibrary authorizationStatus];
if (status == PHAuthorizationStatusAuthorized) {
//OK to save your video
[self ContinueDownload];
}
else if (status == PHAuthorizationStatusDenied) {
// Access has been denied.
[self ShowAlert];
}
else if (status == PHAuthorizationStatusNotDetermined) {
// Access has not been determined.
[PHPhotoLibrary requestAuthorization:^(PHAuthorizationStatus status) {
if (status == PHAuthorizationStatusAuthorized) {
//OK to save your video
[self ContinueDownload];
}
else {
// Access has been denied.
[self ShowAlert];
}
}];
}
else if (status == PHAuthorizationStatusRestricted) {
// Restricted access
}
//Show an alert if access is denied
-(void)ShowAlert {
UIAlertController * alert = [UIAlertController
alertControllerWithTitle:#"Gallery Access denied"
message:#"You can grant access in\nSettings/Privacy/Photos\nif you change your mind."
preferredStyle:UIAlertControllerStyleAlert];
UIAlertAction* OKButton = [UIAlertAction
actionWithTitle:#"OK"
style:UIAlertActionStyleDefault
handler:^(UIAlertAction * action) {
//[self dismissViewControllerAnimated:YES completion:nil];
}];
[alert addAction:OKButton];
[self presentViewController:alert animated:YES completion:nil];
}