How to extract images from a video? - ios

Question

can anyone tell me how to extract images from a video? what i ve tried till now is i ve follow these:
Getting iPhone video thumbnails
Getting a thumbnail from a video url or data in iPhone SDK
How do I extract a screenshot from a video in the iPhone SDK?
iPhone Read UIimage (frames) from video with AVFoundation , iphone sdk > 3.0 . Video Thumbnail?
etc. and after that i ve done this:
Source Code:
- (void)viewDidLoad
{
videoPicker = [[UIImagePickerController alloc] init];
[videoPicker setDelegate:self];
videoPicker.sourceType = UIImagePickerControllerSourceTypePhotoLibrary;
NSArray *mediaTypesAllowed = [UIImagePickerController availableMediaTypesForSourceType:UIImagePickerControllerSourceTypePhotoLibrary];
videoPicker.mediaTypes = mediaTypesAllowed;
videoPicker.view.hidden = YES;
}
-(IBAction)imgPickerController
{
[self presentModalViewController:videoPicker animated:YES];
videoPicker.view.hidden = NO;
}
- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary *)info
{
// e.g.
NSString *tempFilePath = [(NSURL *)[info valueForKey:UIImagePickerControllerMediaURL] absoluteString];
NSLog(#"didFinishPickingMediaWithInfo: %#",tempFilePath);
// e.g. /private/var/mobile/Applications/D1E784A4-EC1A-402B-81BF-F36D3A08A332/tmp/capture/capturedvideo.MOV
tempFilePath = [tempFilePath substringFromIndex:16];
NSLog(#"didFinishPickingMediaWithInfo: %#",tempFilePath);
NSLog(#"===Try to save video to camera roll.===");
NSLog(#"UIVideoAtPathIsCompatibleWithSavedPhotosAlbum: %#",UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(tempFilePath)? #"YES":#"NO");
// Check if the video file can be saved to camera roll.
if (UIVideoAtPathIsCompatibleWithSavedPhotosAlbum(tempFilePath))
{
// YES. Copy it to the camera roll.
UISaveVideoAtPathToSavedPhotosAlbum(tempFilePath, self, #selector(video:didFinishSavingWithError:contextInfo:),(__bridge_retained void *)tempFilePath );
}
[self dismissModalViewControllerAnimated:YES];
}
- (void)video:(NSString *)videoPath didFinishSavingWithError:(NSError *)error contextInfo:(NSString *)contextInfo
{
NSLog(#"didFinishSavingWithError--videoPath in camera roll:%#",videoPath);
NSLog(#"didFinishSavingWithError--videoPath in temp directory:%#",contextInfo);
// The thumbnail jpg should located in this directory.
NSString *thumbnailDirectory = [[contextInfo stringByDeletingLastPathComponent] stringByDeletingLastPathComponent];
// Debug info. list all files in the directory of the video file.
// e.g. /private/var/mobile/Applications/D1E784A4-EC1A-402B-81BF-F36D3A08A332/tmp/capture
NSLog(#"%#",[contextInfo stringByDeletingLastPathComponent]);
NSLog(#"%#",[[[NSFileManager defaultManager] contentsOfDirectoryAtPath:[contextInfo stringByDeletingLastPathComponent] error:nil] description]);
// Debug info. list all files in the parent directory of the video file, i.e. the "~/tmp" directory.
// e.g. /private/var/mobile/Applications/D1E784A4-EC1A-402B-81BF-F36D3A08A332/tmp
NSLog(#"%#",thumbnailDirectory);
NSLog(#"%#",[[[NSFileManager defaultManager] contentsOfDirectoryAtPath:thumbnailDirectory error:nil] description]);
///////////////////
// Find the thumbnail for the video just recorded.
NSString *file,*latestFile;
NSDate *latestDate = [NSDate distantPast];
NSDirectoryEnumerator *dirEnum = [[NSFileManager defaultManager] enumeratorAtPath:[[contextInfo stringByDeletingLastPathComponent]stringByDeletingLastPathComponent]];
// Enumerate all files in the ~/tmp directory
while (file = [dirEnum nextObject])
{
// Only check files with jpg extension.
if ([[file pathExtension] isEqualToString: #"jpg"])
{
NSLog(#"***latestDate:%#",latestDate);
NSLog(#"***file name:%#",file);
NSLog(#"***NSFileSize:%#", [[dirEnum fileAttributes] valueForKey:#"NSFileSize"]);
NSLog(#"***NSFileModificationDate:%#", [[dirEnum fileAttributes] valueForKey:#"NSFileModificationDate"]);
// Check if current jpg file is the latest one.
if ([(NSDate *)[[dirEnum fileAttributes] valueForKey:#"NSFileModificationDate"] compare:latestDate] == NSOrderedDescending)
{
latestDate = [[dirEnum fileAttributes] valueForKey:#"NSFileModificationDate"];
latestFile = file;
NSLog(#"***latestFile changed:%#",latestFile);
}
}
}
// The thumbnail path.
latestFile = [NSTemporaryDirectory() stringByAppendingPathComponent:latestFile];
NSLog(#"****** The thumbnail file should be this one:%#",latestFile);
UIImage *img = [[UIImage alloc] initWithContentsOfFile:latestFile];
UIImageView *imgView = [[UIImageView alloc] initWithFrame:CGRectMake(150, 150, 100, 100)];
[imgView setImage:img];
imgView.layer.borderWidth = 2.0;
[self.view addSubview:imgView];
// Your code ...
// Your code ...
// Your code ...
}
After doing all this still i dint reached where i want to reach.i dint get images still.I'm stuck now.Pls anyone help me out!!!Thanks :)

Answer 1

Simple way to extract thumbnails from a movie is to use MPMoviePlayerController class and its - thumbnailImageAtTime:timeOption: method.
For example you've got a filepath url:
NSURL *tempFilePathURL = ...;
MPMoviePlayerController *player = [[MPMoviePlayerController alloc] initWithContentURL: tempFilePathURL];
UIImage *thumbnail = [player thumbnailImageAtTime:THUMBNAIL_TIME timeOption:MPMovieTimeOptionExact];
[player release];
I used it in my code and it worked.

Answer 2

thumbnailImageAtTime:timeOption is depricated since iOS 7.0.
Here is an alternative
+ (UIImage *)extractFirstFrameFromFilepath:(NSString *)filepath
{
AVURLAsset *movieAsset = [[AVURLAsset alloc] initWithURL:[NSURL fileURLWithPath:filepath] options:nil];
AVAssetImageGenerator *assetImageGemerator = [[AVAssetImageGenerator alloc] initWithAsset:movieAsset];
assetImageGemerator.appliesPreferredTrackTransform = YES;
CGImageRef frameRef = [assetImageGemerator copyCGImageAtTime:CMTimeMake(1, 2) actualTime:nil error:nil];
return [[UIImage alloc] initWithCGImage:frameRef];
}

Answer 3

Swift Version
func getThumbOfVideo(fileURL: URL) -> UIImage? {
let movieAsset = AVURLAsset(url: fileURL)
let assetImageGenerator = AVAssetImageGenerator(asset: movieAsset)
assetImageGenerator.appliesPreferredTrackTransform = true
var thumbnail: UIImage?
do {
let cgImage = try assetImageGenerator.copyCGImage(at: CMTimeMake(value: 0, timescale: 1000), actualTime: nil)
thumbnail = UIImage(cgImage: cgImage)
} catch {
print(error)
}
return thumbnail
}
If you need thumbnail array throughout the video then use the following API of AVAssetImageGenerator class
func generateCGImagesAsynchronously(forTimes requestedTimes: [NSValue],
completionHandler handler: #escaping AVAssetImageGeneratorCompletionHandler)
For required thumbnail image resolution set the following property
assetImageGenerator.maximumSize