Reading ASF Files in DirectShow

For reasons related to backward compatibility, two ASF Reader filters are available for inclusion in a filter graph. To create an application that reads Microsoft® Windows Media™ Format or other ASF files, you will need to understand the difference between the two ASF Readers in order to use the right filter for your requirements.

The default ASF Reader is the filter that is called into the graph automatically when you use methods like IGraphBuilder::RenderFile or IGraphBuilder::AddSourceFilter. This is the filter that is used in Windows Media Player 6.4. This filter is geared toward network playback and provides support for fast forwarding but not rate control.

The new ASF Reader supports the IMediaSeeking::SetRate method. Values of -1 to -10 and 1 to 10 are accepted. To use the new ASF Reader, you must use the COM CoCreateInstance function to instantiate the filter, and call the IFilterGraph::AddFilter method to add it to the graph.

See Also

• ASF Reader Filter