iphone sdk > 3.0 . Video Thumbnail?

Question

From what i have read apple doesnt expose the api to allow developers to get a thumbnail of a movie using the current sdk.

Can any one share some code as to how they are going about this? I have heard you can access the camera picker view and find the image view just before the ui image picker is closed. This seems kinda ugly.

Also ive considered using ffmpeg to grab a frame out of the movie but wouldnt hava a clue as to how to compile it as a library for the iphone. Any pointers would be greatly appreciated

Answer 1

Hope my code could help you guys. It's ugly. I think apple should open this kind of APIs. Of course, all NSLog() should be removed. It's just for demonstration.

alvin

- (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] retain];
 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:), 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);

 // Your code ...
 // Your code ...
 // Your code ...
}