Current web browsers natively support only a small number of multimedia formats, thus placing barriers to new format adoption and providing challenges to handling legacy formats. We discuss an approach for dynamic construction of multimedia transcoding pipelines with flexible filters and show how this approach can be implemented with WebAssembly. We demonstrate that the integration of a multimedia pipeline into the webpage can be made straightforward by using Web Components, MutationObserver, or ServiceWorker, thereby easily providing for display or playback of data files that are not natively supported by browsers.