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Preferences : Encoding Options

Choosing "Preferences..." from the File Menu, or clicking "Preferences..." in the MPegger window allows you to specify the encoding options. There are three pages of options. The first page of options looks like this.

1. Layer type This menu contains 5 options: Layer II - Encodes the file as an MPEG Layer II (MP2) file. Layer III Constant Bitrate (CBR) - Encodes the file as an MP3 with a specified amount of data per second. This is the most compatible mode. Layer III Variable Bitrate (VBR) - There are 3 types of VBR encoding: Normal Quality (NQ), Extra Quality (XQ), and High Quality (HQ) See the Appendix for more info on VBR encoding. 2. Source Channels There are 4 options in this menu: Use Left Channel Only - Only encodes audio that is assigned to the left speaker in a file. Use Right Channel Only - Only encodes audio that is assigned to the right speaker in a file. Combine Left and Right Channels - Combines the left and right channels in to one sound. No Source Change - Handles the channels as they are in the source file. 3. Stereo Mode Lets you change how stereo files are handled. There are two options: Stereo - Encodes each channel as a separate stream. For example, if you encode a 128kbps stereo file with this set, it will actually encode two 64kbps streams, one for each channel. Joint Stereo - Looks for similarities and differences in the two channels, and encodes them as one stream. This results in better sound quality, although it may not work with some MP3 players.

4. Mono Bitrate Lets you set the bitrate to encode monaural audio files at. 5. Stereo Bitrate Lets you set the bitrate to encode stereo audio files at. See the Appendix for more info on bitrates. 6. Normalize audio source Some songs are louder than others, and encoding each one the same way means some MP3s will be soft and some will be loud if you listen to different types of music. Normalizing will attempt to make all of the songs approximately the same volume. 7. Low Bitrate Frequency Clamp At low bitrates, audio tends to get sort of a "washy" effect because the encoding routines backfire on themselves. What can also happen is that there may be loud squeaks and such in the encoded file. This option helps to prevent this from happening at low bitrates such as 64 and 32. 8. Encode Mono as Stereo Encodes monaural audio files as stereo. This can reduce the quality of the encoded file, since it now has to process twice as much data in the same space. This option should not be used unless you're sure you want to. 9. Asynchronous IO Using Asynchronous IO allows your computer to continue to work while it is writing to your hard disk. While this may result in slightly quicker encoding, it may not work with some disk drivers.