public Mp4VideoWriter AddVideo(int width, int height, int fps) { if (writer.Where(_ => _.Codec.Type == AVMediaType.AVMEDIA_TYPE_VIDEO).Count() == 0) { Height = height; Width = width; FPS = fps; var st = writer.AddStream(MediaEncoder.CreateVideoEncode(writer.Format, width, height, fps)); videoIndex = writer.Count() - 1; pixelConverter = new PixelConverter(st.Codec); } return(this); }