The FIRST_LIVE_PROCESS parameter determines whether the start time of the first window is adjusted to always include the first live (non-zero) sample. If the NO (default) option is selected, the first window begins at the time specified by the Window file. If the YES option is chosen and the first live sample precedes the start time of the first window, the first window is extended to include the first live sample. No other window times are changed, including the stop time of the first window. Windows are often modified to fit the requirements of this SFM. The modified windows can be output via the WNDWS output port (see Section 1.8 Quality Control), and should be checked to ensure they properly sample the data.