Include Audio:
Check "include audio on the output" checkbox to include audio on the output Flash.
Format:
WAV PCM
Standard Windows WAV format for non-compressed audio files. Pulse Code Modulation (PCM) is the standard method of digitally encoding audio. It is the basic uncompressed data format used in file types such as Windows .wav.
MP3
MPEG Layer-3 format. Very popular format for keeping of music.
Sampling:
Sampling is also known as audio frequency, number of samples per second. Standard audio cd used 44,100 Hz 128 Kbps Stereo
Bitrate:
This value determines the number of information used to store on the audio. Higher bitrate leads to higher audio quality but also increase in file size. Standard audio cd used 44,100 Hz 128 Kbps Stereo
Channel:
If the stereo checkbox is checked, your output audio will be encoded with 2 channels. If uncheck, it will be encoded as mono, which means single channel. Standard audio cd used 44,100 Hz 128 Kbps Stereo