# OutputFilter An encoder-decoder that writes output data to a stream. ``` class OutputFilter ``` ## Topics ### Initializers Creates an output filter for compressing or decompressing data. [`init(FilterOperation, using: Algorithm, bufferCapacity: Int, writingTo: (Data?) throws -> Void) throws`](/documentation/Compression/OutputFilter/init(_:using:bufferCapacity:writingTo:)) Creates an output filter that can be used to compress or decompress data. ### Instance Methods [`func write(D?) throws`](/documentation/Compression/OutputFilter/write(_:)) Writes data to the output filter. [`func finalize() throws`](/documentation/Compression/OutputFilter/finalize()) Finalizes the stream by flushing all the remaining data in the stream. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)