AVEncoderContentSourceKey Declarationlet AVEncoderContentSourceKey: String See AlsoEncoder setting keysAVEncoderASPFrequencyKeyAVEncoderAudioQualityKeyAVEncoderBitDepthHintKeyAVEncoderBitRateKeyAVEncoderBitRatePerChannelKeyAVEncoderBitRateStrategyKeyAVEncoderDynamicRangeControlConfigurationKey