Transcode API

This section describes how to use the transcode API to re-encode media files. The transcode API was introduced in Windows 7.

Transcoding is the conversion of a digital media file from one format to another. The transcode API is designed to be used with the Media Session. It simplifies the use of the Media Session for certain types of transcoding applications:

  • Constant bit rate (CBR) encoding, where the target bit rate is known in advance.
  • At most one audio stream and one video stream.
  • Encoding from and to a file.

Transcode API does not support the following:

  • Variable bit rate (VBR) or multi-pass encoding.
  • Multiple audio streams or multiple video streams.
  • DRM-protected content other than ASF files protected with WMDRM.
  • Live streaming, such as live-to-file streaming or live-to-live streaming.

If your encoding application fits within these constraints, the transcode API a simpler programming model than using the Media Session alone.

In this section

Topic Description
About the Transcode API
Provides a general overview of the transcode API.
Using the Transcode API
Describes how an application uses the transcode API.
Tutorial: Encoding an MP4 File
A step-by-step tutorial that shows how to use the transcode API to encode an MP4 file.
Tutorial: Encoding a WMA File
Shows how to use the transcode API to encode a WMA file. This tutorial modifies the code shown in Tutorial: Encoding an MP4 File, so you should read that tutorial first.


Encoding and File Authoring

Media Foundation: Essential Concepts

Overview of Encoding in Media Foundation