public static AviSynthScriptBuilder GenerateVideoScript(MediaEncoderSettings settings, string inputFile, bool preview, bool multiThreaded)
        {
            // int CPU = multiThreaded ? Environment.ProcessorCount : 1;
            int CPU = multiThreaded ? settings.Threads : 1;

            if (CPU <= 1)
            {
                multiThreaded = false;
            }
            bool RunMultiProcesses = false;

            if (settings.Deshaker && multiThreaded)
            {
                RunMultiProcesses = true;  // Run through MP_Pipeline
                multiThreaded     = false; // Deshaker doesn't work with MT
                CPU = 1;
            }
            //if (settings.Threads > 0) {
            //    multiThreaded = false;
            //    CPU = 1;
            //}

            settings.CalculateSize();

            // Calculate encoding and final frame rates.
            double ChangeSpeedValue = (settings.ChangeSpeed && settings.CanAlterAudio) ? (double)settings.ChangeSpeedValue / 100 : 1;
            double FrameRateBefore  = settings.SourceFrameRate.Value * ChangeSpeedValue;

            // Generate video script.
            AviSynthScriptBuilder Script = new AviSynthScriptBuilder();
            bool IsYV24 = false;

            Script.AppendLine(); // After clean-up, this adds a line after LoadPlugin commands.
            Script.AddPluginPath();
            if (multiThreaded)
            {
                Script.LoadPluginAvsi("AviSynthMT.avsi");
            }
            if (settings.ConvertToAvi || inputFile.ToLower().EndsWith(".avi"))
            {
                Script.OpenAvi(inputFile, !string.IsNullOrEmpty(settings.SourceAudioFormat));
            }
            else
            {
                Script.OpenDirect(inputFile, !string.IsNullOrEmpty(settings.SourceAudioFormat));
            }
            if (FrameRateBefore != settings.SourceFrameRate)
            {
                Script.AppendLine(CultureInfo.InvariantCulture, "AssumeFPS({0}, true)", FrameRateBefore);
            }
            if (settings.Trim && settings.CanAlterAudio)
            {
                Script.AppendLine("Trim({0}, {1})",
                                  (settings.TrimStart ?? 0) > 0 ? (int)(settings.TrimStart.Value * settings.SourceFrameRate.Value) : 0,
                                  (settings.TrimEnd ?? 0) > 0 && !preview ? (int)(settings.TrimEnd.Value * settings.SourceFrameRate.Value) : 0);
            }

            if (settings.Denoise)
            {
                //Script.LoadPluginDll("MvTools2.dll");
                //Script.LoadPluginDll("MaskTools2.dll");
                //Script.LoadPluginDll("FFT3DFilter.dll");
                //Script.LoadPluginDll("ModPlus.dll");
                //Script.LoadPluginDll("RgTools.dll");
                //Script.LoadPluginDll("DCTFilter.dll");
                //Script.LoadPluginAvsi("mClean.avsi");
                //Script.AppendLine("mClean(rn={0}{1})", 10, IsHD ? ", outbits=16" : "");
                Script.AppendLine(@"MCTemporalDenoise(settings=""{0}""{1})", "medium", settings.Deblock ? ", deblock=true" : "");
            }
            else if (settings.Deblock)
            {
                Script.LoadPluginDll("MaskTools2.dll");
                Script.LoadPluginDll("DCTFilter.dll");
                Script.LoadPluginDll("deblock.dll");
                Script.LoadPluginAvsi("Deblock_QED.avsi");
                Script.AppendLine("Deblock_QED()");
            }

            if (settings.CropSource.HasValue)
            {
                Script.AppendLine("Crop({0}, {1}, -{2}, -{3})", settings.CropSource.Left, settings.CropSource.Top, settings.CropSource.Right, settings.CropSource.Bottom);
            }

            // If possible, KNLMeans will output 16-bit frames before upscaling.
            bool IsHD            = (settings.Dering || settings.Deblock || settings.Degrain || settings.SourceColorMatrix != ColorMatrix.Rec709 || (settings.FrameDouble > 0 && (settings.SuperRes || settings.UpscaleMethod == UpscaleMethods.SuperXbr)));
            bool IsColorMatrixHD = IsHD;
            bool IsChromaFixed   = settings.SourceChromaPlacement == ChromaPlacement.MPEG2;

            if (IsHD)
            {
                //if (!settings.Denoise)
                Script.AppendLine("ConvertBits(16)");
                if (settings.SourceColorMatrix != ColorMatrix.Rec709)
                {
                    Script.AppendLine("[ColorMatrixShader]"); // Placeholder that will be replaced after generating the rest.
                }
            }

            if (settings.FixDoubleFrames)
            {
                Script.LoadPluginDll("FrameRateConverter.dll");
                Script.LoadPluginAvsi("FrameRateConverter.avsi");
                Script.LoadPluginDll("MaskTools2.dll");
                Script.LoadPluginDll("MvTools2.dll");
                Script.AppendLine("InterpolateDoubles(.1)");
            }

            if (settings.Dering)
            {
                Script.LoadPluginAvsi("HQDeringmod.avsi");
                Script.LoadPluginDll("MedianBlur2.dll");
                Script.LoadPluginDll("dfttest.dll");
                Script.LoadPluginDll("RgTools.dll");
                Script.LoadPluginDll("SmoothAdjust.dll");
                Script.AppendLine("HQDeringmod({0})", IsHD ? "lsb_in=true, lsb=true" : "");
            }

            if (settings.Degrain)
            {
                ApplyDegrain(Script, settings, ref IsHD, ref IsYV24);
            }
            if (settings.Deshaker)
            {
                ApplyDeshaker(Script, settings, ref IsHD, ref IsYV24, RunMultiProcesses);
            }

            if (settings.FrameDouble > 0)
            {
                Script.AppendLine(@"ConvertToYUV444({0})",
                                  !IsChromaFixed ? string.Format(@"ChromaInPlacement=""{0}""", settings.SourceChromaPlacement.ToString()) : "");
                IsYV24        = true;
                IsChromaFixed = true;
            }

            string FinalSize = string.Format("fWidth={0}, fHeight={1}",
                                             settings.OutputWidth + settings.CropAfter.Left + settings.CropAfter.Right,
                                             settings.OutputHeight + settings.CropAfter.Top + settings.CropAfter.Bottom);
            string FinalResize = FinalSize;

            if (settings.DownscaleMethod == DownscaleMethods.SSim)
            {
                FinalResize += string.Format(@", fKernel=""SSim"", fB={0}{1}",
                                             settings.SSimStrength / 100, settings.SSimSoft ? ", fC=1" : "");
            }
            else // DownscaleMethod == Bicubic
            {
                FinalResize += string.Format(@", fKernel=""Bicubic"", fB=0, fC=.75");
            }

            if (settings.FrameDouble > 0)
            {
                if (settings.UpscaleMethod == UpscaleMethods.NNedi3)
                {
                    bool IsLastDouble = false;
                    DitherPost(Script, ref IsHD, ref IsYV24, true);

                    Script.LoadPluginDll("nnedi3.dll");
                    Script.LoadPluginAvsi("edi_rpow2.avsi");
                    Script.LoadPluginAvsi("ResizeX.avsi");

                    for (int i = 0; i < settings.FrameDouble; i++)
                    {
                        IsLastDouble = i == settings.FrameDouble - 1;
                        string DoubleScript = string.Format("edi_rpow2(2, nns=4, {0}, Threads=2)",
                                                            IsLastDouble && settings.DownscaleMethod == DownscaleMethods.Bicubic ? @"cshift=""Bicubic"", a1=0, a2=.75, " + FinalSize : @"cshift=""Spline16Resize""");
                        if (settings.SuperRes)
                        {
                            Script.AppendLine(CultureInfo.InvariantCulture, @"SuperRes({0}, {1}, {2}, """"""{3}""""""{4}{5}{6})",
                                              settings.SuperRes3Passes ? (i == 0 && settings.FrameDouble > 1 ? 5 : 3) : 2,
                                              settings.SuperResStrength / 100f, settings.SuperResSoftness / 100f, DoubleScript,
                                              i == 0 ? GetMatrixIn(settings) : "",
                                              IsLastDouble && settings.DownscaleMethod == DownscaleMethods.SSim ? ", " + FinalResize : "",
                                              multiThreaded ? "" : ", Engines=1");
                        }
                        else
                        {
                            Script.AppendLine(DoubleScript);
                            if (IsLastDouble && settings.DownscaleMethod == DownscaleMethods.SSim)
                            {
                                Script.AppendLine("ResizeShader({0}{1})",
                                                  FinalResize.Replace("fWidth=", "").Replace("fHeight=", "").Replace(" f", " "), // Use same string as FinalResize but remove 'f' parameter sufix.
                                                  GetMatrixIn(settings));
                            }
                        }
                    }
                }
                else     // UpscaleMethod == SuperXBR
                {
                    if (settings.SuperRes)
                    {
                        Script.AppendLine(CultureInfo.InvariantCulture, @"SuperResXBR({0}, {1}, {2}{3}, XbrStr={4}, XbrSharp={5}{6}, {7}, FormatOut=""YV12""{8})",
                                          settings.SuperRes3Passes ? (settings.IncreaseFrameRate ? 5 : 3) : 2,
                                          settings.SuperResStrength / 100f, settings.SuperResSoftness / 100f,
                                          settings.FrameDouble > 1 ? ", Factor=" + (1 << settings.FrameDouble).ToString() : "",
                                          settings.SuperXbrStrength / 10f, settings.SuperXbrSharpness / 10f,
                                          GetMatrixIn(settings),
                                          FinalResize,
                                          multiThreaded ? "" : ", Engines=1");
                    }
                    else
                    {
                        Script.AppendLine(@"SuperXBR(Str={0}, Sharp={1}{2}{3}, {4}, FormatOut=""YV12""{5})",
                                          settings.SuperXbrStrength / 10f, settings.SuperXbrSharpness / 10f,
                                          settings.FrameDouble > 1 ? ", Factor=" + (1 << settings.FrameDouble).ToString() : "",
                                          GetMatrixIn(settings),
                                          FinalResize,
                                          multiThreaded ? "" : ", Engines=1");
                    }
                    IsHD   = false;
                    IsYV24 = false;
                }
            }

            if (settings.DownscaleMethod != DownscaleMethods.SSim)
            {
                DitherPost(Script, ref IsHD, ref IsYV24, settings.IncreaseFrameRate);
            }

            string[] ShaderCommands = new string[] { "SuperRes", "SuperXBR", "SuperResXBR", "ResizeShader" };
            if (settings.CropAfter.HasValue || settings.FrameDouble == 0)
            {
                if (settings.CropAfter.HasValue || settings.SourceAspectRatio != 1 || settings.OutputWidth != settings.SourceWidth || settings.OutputHeight != settings.OutputHeight)
                {
                    if (settings.DownscaleMethod == DownscaleMethods.SSim && settings.FrameDouble == 0)
                    {
                        Script.AppendLine("ResizeShader({0}{1})",
                                          FinalResize.Replace("fWidth=", "").Replace("fHeight=", "").Replace(" f", " "), // Use same string as FinalResize but remove 'f' parameter sufix.
                                          GetMatrixIn(settings));
                    }
                    DitherPost(Script, ref IsHD, ref IsYV24, false);

                    if (settings.CropAfter.HasValue || settings.DownscaleMethod == DownscaleMethods.Bicubic)
                    {
                        Script.LoadPluginAvsi("ResizeX.avsi");
                        bool   ApplyResize = settings.FrameDouble == 0 || !Script.ContainsAny(ShaderCommands);
                        string CropFormat  = "ResizeX";
                        CropFormat += settings.CropAfter.HasValue ? "({0}, {1}, {2}, {3}, -{4}, -{5}{6})" : "({0}, {1}{6})";
                        Script.AppendLine(CropFormat, settings.OutputWidth, settings.OutputHeight,
                                          settings.CropAfter.Left, settings.CropAfter.Top, settings.CropAfter.Right, settings.CropAfter.Bottom,
                                          ApplyResize ? @", kernel=""Bicubic"", a1=0, a2=.75" : "");
                    }
                }
            }

            // Use ColorMatrixShader only if it wasn't already applied through any other shader.
            if (Script.ContainsAny(ShaderCommands))
            {
                // ColorMatrix was applied though another shader.
                Script.Replace("[ColorMatrixShader]" + Environment.NewLine, "");
                Script.LoadPluginDll("Shader.dll");
                Script.LoadPluginAvsi("Shader.avsi");
            }
            else
            {
                string ColorMatrixScript = "";
                // Apply color matrix
                if (settings.SourceColorMatrix == ColorMatrix.Pc709)
                {
                    Script.LoadPluginDll("SmoothAdjust.dll");
                    ColorMatrixScript = string.Format(@"ColorYUV(levels=""PC->TV""");
                }
                else if (settings.SourceColorMatrix != ColorMatrix.Rec709)
                {
                    Script.LoadPluginDll("Shader.dll");
                    Script.LoadPluginAvsi("Shader.avsi");
                    ColorMatrixScript = string.Format(@"ResizeShader(Kernel=""ColorMatrix""{0})", GetMatrixIn(settings));
                }
                Script.Replace("[ColorMatrixShader]" + Environment.NewLine, ColorMatrixScript + Environment.NewLine);
            }

            if (settings.IncreaseFrameRate)
            {
                if (IsYV24)
                {
                    Script.AppendLine(@"ConvertToYUV420()");
                    IsYV24 = false;
                }
                DitherPost(Script, ref IsHD, ref IsYV24, true);
                ApplyInterFrame(Script, settings, CPU);
            }

            if (preview)
            {
                if (settings.Crop)
                {
                    Script.AppendLine("AddBorders(2, 2, 2, 2, $FFFFFF)");
                }
                Script.AppendLine(@"ConvertToRGB32(matrix=""Rec709"")");
            }
            if (multiThreaded)
            {
                Script.AppendLine("Prefetch({0})", CPU);
            }

            if (RunMultiProcesses)
            {
                Script.ConvertToMultiProcesses(settings.SourceFrameRate.Value);
            }
            else
            {
                Script.Cleanup();
            }

            return(Script);
        }