- (BOOL) setupRecorder {
    NSError *error = nil;
    if([[NSFileManager defaultManager] fileExistsAtPath:[[self tempFileURL] path]])
        [[NSFileManager defaultManager] removeItemAtURL:[self tempFileURL] error:&error];


    assetWriter = [[AVAssetWriter alloc] initWithURL: [self tempFileURL]
                                            fileType:AVFileTypeQuickTimeMovie
                                               error:&error];
    if (error) {
        NSLog(@"Error creating asset writer: %@", error);
        [assetWriter release];
        return NO;
    }
    // writer

    NSDictionary *videoSettings = [NSDictionary dictionaryWithObjectsAndKeys:
                                   AVVideoCodecH264, AVVideoCodecKey,
                                   [NSNumber numberWithInt:videoWidth], AVVideoWidthKey,
                                   [NSNumber numberWithInt:videoHeight], AVVideoHeightKey,
                                   nil];

    assetWriterInput = [AVAssetWriterInput assetWriterInputWithMediaType:AVMediaTypeVideo
                                                      outputSettings:videoSettings];

    NSDictionary *bufferAttributes = [NSDictionary dictionaryWithObjectsAndKeys:
                                      [NSNumber numberWithInt:kCVPixelFormatType_32BGRA], kCVPixelBufferPixelFormatTypeKey,
                                      nil];

    adaptor = [[AVAssetWriterInputPixelBufferAdaptor alloc] initWithAssetWriterInput:assetWriterInput sourcePixelBufferAttributes:bufferAttributes];
    [adaptor retain];
    assetWriterInput.expectsMediaDataInRealTime = YES;
    [assetWriter addInput:assetWriterInput];

    return YES;
}

- (CVPixelBufferRef) createPixelBufferRef {
    CVPixelBufferPoolRef pixelBufferPool = adaptor.pixelBufferPool;
    CVPixelBufferRef pixelBuffer = NULL;
    CVReturn cvReturn = CVPixelBufferPoolCreatePixelBuffer(NULL, pixelBufferPool, &pixelBuffer);
    if(cvReturn != kCVReturnSuccess)
        NSLog(@"CVPixelBuffePoolCreatePixelBuffer: %d", cvReturn);
    bufferCreatedCount++;
    return pixelBuffer;
}