A channel using a non-smooth and steady approximation error, in which the exponential moving average with a variable smoothing factor is used as the midline.
This indicator is compiled as both an MQL5 indicator and an MQL4 indicator, for which the extension of the indicator code should be changed for mq4, place the code in <terminal_data_directory MetaTrader4>\MQL4\Indicators, and compile it using the relevant code editor.
Fig.1. Indicator EMAVFS_channel