Add WaterMark(Text) On Video In Asp.net Core Mvc

i want to add watermark on videos in asp.net core,

i use this code :

    NReco.VideoConverter.FFMpegConverter wrap = new FFMpegConverter();
    wrap.Invoke("-i D:\\input.mp4 -i D:\\inputImage.png -filter_complex\"overlay=10:10\" D:\\Output.mp4");     

but show this error, whats, problem ?

TypeLoadException: Could not load type 'System.Web.HttpContext' from assembly 'System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a'.