RealAudio content may be created either from previously recorded digital audio files or from an external audio source. Use a sound-editing utility to convert unsupported formats to a supported format. However, you cannot use a mono input file to produce a stereo output file. Video Encoding RealSystem Producer 8.x supports both AVI and QuickTime on Windows. Uncompressed QuickTime only on Linux.
Uncompressed files offer the best results.
RealSystem Producer supports any size image from any video source, but it will automatically crop the height and width to multiples of 4. Input files are also required to be in 24-bit RGB color mode. Encoding from a live source is supported with specific video capture cards. RealNetworks does not specifically recommend any one piece of third party software. However, there are several conversion products available which offer compatibility with RealProducer input formats.