[group setAssetsFilter:[ALAssetsFilter allVideos]] -- (iPhone,Photo,Videos)

ALAssetsGroupEnumerationResultsBlock assetEnumerator = ^(ALAsset *asset, NSUInteger index, BOOL *stop) {
    if(asset != nil) {
        ALAssetRepresentation* representation = [asset defaultRepresentation];
        NSLog(@"UTI = %@", [representation UTI]);
        NSLog(@"Metadata = %@", [representation metadata]);
    }
};

ALAssetsLibraryGroupsEnumerationResultsBlock assetGroupEnumerator = ^(ALAssetsGroup *group, BOOL *stop) {
    if(group != nil) {
        [group setAssetsFilter:[ALAssetsFilter allVideos]];
        [group enumerateAssetsUsingBlock:assetEnumerator];          
    }
};

ALAssetsLibrary *library = [[ALAssetsLibrary alloc] init];
[library enumerateGroupsWithTypes:ALAssetsGroupAll
                       usingBlock:assetGroupEnumerator
                     failureBlock:^(NSError *error) {
                         NSLog(@"A problem occured. %@", error);
                     }];
[library release];