tracks
tracks.keyAudioTrackName
track
enabled
mixdownEnabled
drc
codecs
codecs.keyAudioCodecName
codec
mixdowns
mixdowns.keyAudioMixdownName
mixdown
sampleRates
sampleRates.keyAudioSampleRateName
sampleRate
bitRates
bitRates.keyAudioBitrateName
bitRate
DRCEnabled
gain
PassThruEnabled
PassThruDisabled
bitrateEnabled
NSIsNotNil
NSIsNotNil