Read the asset from the Library and get decompresIn the above post the size of the asset file is too big so here is another way to decompress the fileThis is also taken from the stack over flow,http://stackoverflow.com/questions/5687341/iphoneprogrammatically-compressing-recorded-video-to-share- (void)convertVideoToLowQuailtyWithInputURL:(NSURL*)inputURL                                    outputURL:(NSURL*)outputURL                                      handler:(void (^)(AVAssetExportSession*))handler{    [[NSFileManager defaultManager] removeItemAtURL:outputURL error:nil];    AVURLAsset *asset = [AVURLAsset URLAssetWithURL:inputURL options:nil];    AVAssetExportSession *exportSession = [[AVAssetExportSession alloc] initWithAsset:asset presetName:AVAssetExportPresetLowQuality];    exportSession.outputURL = outputURL;    exportSession.outputFileType = AVFileTypeQuickTimeMovie;    [exportSession exportAsynchronouslyWithCompletionHandler:^(void)      {         handler(exportSession);         [exportSession release];     }];}

Export movie/image asset file into the diskThis is taken from the stack overflow and slightly modified - (BOOL) exportDataToURL: (NSString*) filePath error: (NSError**) error andAsset:(ALAsset*)asset{    NSError **errorInternal = nil;    [[NSFileManager defaultManager] createFileAtPath:filePath contents:nil attributes:nil];    NSFileHandle *handle = [NSFileHandle fileHandleForWritingAtPath:filePath];    if (!handle) {        return NO;    }        static const NSUInteger BufferSize = 1024*1024;    ALAssetRepresentation *rep = [asset defaultRepresentation];    uint8_t *buffer = calloc(BufferSize, sizeof(*buffer));    NSUInteger offset = 0, bytesRead = 0;        do {        @try {            bytesRead = [rep getBytes:buffer fromOffset:offset length:BufferSize error:error];            [handle writeData:[NSData dataWithBytesNoCopy:buffer length:bytesRead freeWhenDone:NO]];            offset += bytesRead;        } @catch (NSException *exception) {            free(buffer);                        return NO;        }    } while (bytesRead > 0);        free(buffer);    return YES;}

Read the file from assets-library and write into ur custom fileAlthough u can see many same solutions available same as given below...This method take the Asset and fileName to create that file into the tempdirectory. It returns the path of the tempdirectory/file where it stores the This is the same as reading a file from the Assets library (Photo library). -(NSString*) writeVideoFileIntoTemp:(NSString*)fileName andAsset:(ALAsset*)asset{    NSString * tmpfile = [NSTemporaryDirectory() stringByAppendingPathComponent:fileName];                ALAssetRepresentation * rep = [asset defaultRepresentation];                NSUInteger size = [rep size];        const int bufferSize = 1024*1024; // or use 8192 size as read from other posts                 NSLog(@"Writing to %@",tmpfile);        FILE* f = fopen([tmpfile cStringUsingEncoding:1], "wb+");        if (f == NULL) {            NSLog(@"Can not create tmp file.");            return;        }                Byte * buffer = (Byte*)malloc(bufferSize);        int read = 0, offset = 0, written = 0;        NSError* err;        if (size != 0) {            do {                read = [rep getBytes:buffer                          fromOffset:offset                              length:bufferSize                                error:&err];                written = fwrite(buffer, sizeof(char), read, f);                offset += read;            } while (read != 0);                                }        fclose(f);    return tmpfile;}