Encoding Preferences

• Format

  Select the format of the encoded file. AAC is a lossy compressed format, which means you get different sound than what you recorded. You won't be able to hear that difference for the most part, though. Since you get a good tradeoff between sound quality and file size, AAC is a reasonable default choice. MP3 is also a lossy compressed format that is slightly behind AAC in terms of quality. You can share MP3 files more easily with computers not running Mac OS X, however. AIFF and WAV are uncompressed lossless formats that will give you large files but will leave the sound unchanged. Apple Lossless is a compressed lossless format that will give you files that are about half as large as AIFF and WAV.

• Sample Rate

  Choose how many audio samples are recorded every second. The higher the number, the higher the quality, but also higher the resulting file size.

• Stereo Bit Rate

  For lossy compressed formats such as AAC and MP3, this setting determines how much the audio is compressed. With higher numbers you get better quality but also bigger files. 128 kbps is a good default setting, but when recording voice, you can dial down this setting without affecting sound quality much.

• Sample Size

  For lossless formats, this setting controls how much space to use for each sound sample. In 8 bit recordings, each sample can range from a value of -128 to 127 whereas with 16 bit each sample can range from -32768 to 32767, giving you much better sound quality. 16 bit recordings take twice as much space, however.