Profiles are presets that specify the parameters that Microsoft Expression Encoder uses to encode your original video, thereby creating a final WMV file that is appropriate for distribution or posting to the web. Those parameters include bit rate, frame rate, video size, and other settings. In the Profile category of the Settings panel, you can choose from profiles included with Expression Encoder. Each of these profiles uses a different bit rate for encoding, and also several other settings. Therefore, you can optimize your media for any number of playback scenarios ranging from high-bit–rate encoding to make playback easier from a local hard disk drive, to low-bit–rate encoding that makes your media usable for playback by users who use only dial-up web access. In general, files encoded with high bit rates are usually meant to be downloaded before playback or played back over a LAN, whereas lower bit rates are more appropriate for web playback.
As you choose your profile, Expression Encoder calculates the total bit rate for your file, and the estimated encoded file size, based on the length of your video and the chosen bit rate. The video part of your file is the most important, so you should set the maximum video bit rate that is appropriate for your file size. Audio can make up a large percentage of final file size, so you should determine your audio requirements accurately before choosing high audio bit rates. For example, if you are encoding a concert video, audio might have to be high quality. However, if you are encoding a news report, you might need only a low audio bit rate that faithfully reproduces voice frequencies, but doesn’t have to reproduce high or low frequencies with great fidelity. Alternatively, if you only want to convert previously-encoded video into a Microsoft Silverlight package and, therefore, do not want to recompress your video, you can choose to use the source profile, thereby bypassing encoding completely.
Because the included profiles are configured for a range of playback scenarios, if you use their default settings to encode your video, they will produce high-quality results. For information about using default profiles, see Define a default profile. However, if you have some experience with and understanding of encoding and want to modify the included profiles, or import your own profiles if you saved them in Windows Encoder, you can do so.