ALAssetsLibrary *library = [[ALAssetsLibrary alloc]init]; [library enumerateGroupsWithTypes:ALAssetsGroupAlbum usingBlock:^(ALAssetsGroup *group, BOOL *stop) { [group setAssetsFilter:[ALAssetsFilter allVideos]]; if (group.numberOfAssets > 0) { NSIndexSet *videoSet = [NSIndexSet indexSetWithIndexesInRange:NSMakeRange(0, group.numberOfAssets)]; [group enumerateAssetsAtIndexes:videoSet options:0 usingBlock:^(ALAsset *result, NSUInteger index, BOOL *stop) { ALAssetRepresentation *representation = [result defaultRepresentation]; NSString *savingPath = [NSHomeDirectory() stringByAppendingFormat:@"/Documents/%@",representation.filename]; [[NSFileManager defaultManager]createFileAtPath:savingPath contents:nil attributes:nil]; NSFileHandle *writingHandle = [NSFileHandle fileHandleForWritingAtPath:savingPath]; int bufferSize = 1024; uint8_t buffer[bufferSize]; unsigned long long read = 0,length = 0; NSAutoreleasePool *pool = [[NSAutoreleasePool alloc]init]; int n = 0; for (;read < representation.size;) { if (n % 10 == 0) { [pool release]; pool = nil; pool = [[NSAutoreleasePool alloc]init]; } length = [representation getBytes:buffer fromOffset:read length:bufferSize error:nil]; read += length; NSData *fileData = [NSData dataWithBytes:(const void *)buffer length:(NSUInteger)length]; [writingHandle writeData:fileData]; n++; } [writingHandle closeFile]; [pool drain]; }]; } } failureBlock:^(NSError *error) { }];
原文：http://www.cnblogs.com/yan-chao-zhi/p/5263507.html