I am trying to figure out how to check if a webcam/video capture device is already being used by another application without actually activating it.
My current approach is to use the AForge.NET library and using the .IsRunning property of the VideoCaptureDevice object like this:
var videoDevices = new FilterInfoCollection(FilterCategory.VideoInputDevice);
foreach (FilterInfo videoDevice in videoDevices)
{
VideoCaptureDevice camera new AForge.Video.DirectShow.VideoCaptureDevice(videoDevice.MonikerString);
Debug.Print(camera.IsRunning)
}
I guess the IsRunning property only works on VideoCaptureDevices that have been started using the library and I need lower-level DirectShow access to the device.
While there are many ways to use DirectShow in C#, I have been unable to find a way to check the state even using DirectShow in C++. Is there some magic I need to perform here?
Thanks
Tobias Timpe
I'm not entirely sure if this will be helpful to you, but I found your question because I wanted to write a custom app to control my busylight. This is very much 'Works On My Machine' certified - it's not an attempt to give a general answer. However, I figure it may help you, and possibly the next person who comes across this page while googling...
private static bool IsWebCamInUse()
{
using (var key = Registry.CurrentUser.OpenSubKey(#"SOFTWARE\Microsoft\Windows\CurrentVersion\CapabilityAccessManager\ConsentStore\webcam\NonPackaged"))
{
foreach (var subKeyName in key.GetSubKeyNames())
{
using (var subKey = key.OpenSubKey(subKeyName))
{
if (subKey.GetValueNames().Contains("LastUsedTimeStop"))
{
var endTime = subKey.GetValue("LastUsedTimeStop") is long ? (long) subKey.GetValue("LastUsedTimeStop") : -1;
if (endTime <= 0)
{
return true;
}
}
}
}
}
return false;
}
Related
i am new to WIA. And i have been asked to make scaning service scan faster and duplex. My current service scan one page, then put it in pdf and so on untill there is less then 20 pages(this number just a crutch used before me, will be glad if someone explane how to get "if there is any paper in there" variable). I started to dig and found docs on MSDN describing properties and after found this post describing duplex sanning, but with mysterious 5 in set. After I found this and figured out what i need WIA_DPS_DOCUMENT_HANDLING_SELECT to set to 0x205(FEEDER + DUPLEX + AUTO_ADVANCE). So I tried to setup them like this:
private static void SetProperty(Property property, int value)
{
IProperty x = (IProperty)property;
Object val = value;
x.set_Value(ref val);
}
...some code...
foreach (Property prop in device.Properties)
{
//LOGGER.Warn(prop.Name);
//LOGGER.Warn(prop.PropertyID);
switch ((Int32)prop.PropertyID)
{
// Document Handling Select
case 3088:
SetProperty(prop, 517);
break;
// Pages
case 3096:
SetProperty(prop, 1);
break;
}
}
And it did't worked for me... It just stuck on setting... Can Somebody explain how to setup AUTO_ADVANCE and DUPLEX props? Or maybe "make scanning faster and duplex" need something more then just AUTO_ADVANCE and DUPLEX and my perception about them is wrong? Or I should considering "ISIS / TWAIN (Windows XP / Vista / 7 / 8 / 8.1 / 10)" string in my scan description and use other libraries?
(Window 10, Canon DR-M160||, DR-M160 & DR-M160II Driver for Windows)
and also here is the current fetch function:
public List<ImageFile> FetchImageList()
{
List<ImageFile> imageList = new List<ImageFile>();
//bool hasMorePages = true;
int testcount = 0;
while (testcount >= 0)
{
testcount--;
WIA.Device device = FindDevice(_deviceId);
if (device == null)
{
LOGGER.Warn("Scanner device not found");
return null;
}
// get item
WIA.Item scanItem = device.Items[1] as WIA.Item;
LOGGER.Debug($"ScanItem: {scanItem.ItemID}");
try
{
foreach (Property prop in device.Properties)
{
//LOGGER.Warn(prop.Name);
//LOGGER.Warn(prop.PropertyID);
switch ((Int32)prop.PropertyID)
{
// Document Handling Select
case 3088:
LOGGER.Warn("here");
SetProperty(prop, 517);
LOGGER.Warn("here");
break;
// Pages
case 3096:
SetProperty(prop, 1);
break;
}
}
// scan image
WIA.ICommonDialog wiaCommonDialog = new WIA.CommonDialog();
WIA.ImageFile image = (WIA.ImageFile)scanItem.Transfer(WIA.FormatID.wiaFormatPNG);
imageList.Add(image);
LOGGER.Warn("Front");
//get back side
image = (WIA.ImageFile)scanItem.Transfer(WIA.FormatID.wiaFormatPNG);
imageList.Add(image);
LOGGER.Warn("Back");
}
catch (Exception e)
{
throw (e);
}
}
return imageList;
}
Well... I tried to make duplex scan without AUTO_ADVANCE and got HRESULT: 0x8000FFFF (E_UNEXPECTED) on Transfer call. According to this post(even though that was on Windows 7) I guess there is no way to solve this for me by using WIA, still hope there will other suggestions...
Solved problem
I used saraff.twain and it worked for me:
- git page :https://github.com/saraff-9EB1047A4BEB4cef8506B29BA325BD5A/Saraff.Twain.NET
good library with grate wiki page.(Also have similar library for .net 4.6.1)
When using System.Media, there is something called SystemSounds where you can easily play a couple of operating system sounds:
System.Media.SystemSounds.Asterisk.Play();
System.Media.SystemSounds.Beep.Play();
System.Media.SystemSounds.Exclamation.Play();
System.Media.SystemSounds.Hand.Play();
System.Media.SystemSounds.Question.Play();
Unfortunately, there are only these five options, and in Windows 10, three of them are the same while one of them doesn't even play anything.
What I really want to do is play the Notification sound, as defined in the Sound panel (seen here):
Does anyone know how to do this?
Solution found. Code here:
using System.Media;
using Microsoft.Win32;
public void PlayNotificationSound()
{
bool found = false;
try
{
using (RegistryKey key = Registry.CurrentUser.OpenSubKey(#"AppEvents\Schemes\Apps\.Default\Notification.Default\.Current"))
{
if (key != null)
{
Object o = key.GetValue(null); // pass null to get (Default)
if (o != null)
{
SoundPlayer theSound = new SoundPlayer((String)o);
theSound.Play();
found = true;
}
}
}
}
catch
{ }
if (!found)
SystemSounds.Beep.Play(); // consolation prize
}
You can browse the keys in the registry editor to see the other sounds. Also, this example is coded to work for Windows 10, and I'm not sure what the registry structure is for other versions of Windows, so you'll need to double check what OS the user is using if you're trying to code for multiple platforms.
I am using NAudio for a screen recording software I am designing and I need to know if it's possible to not only control the specific application's volume but also display a VU Meter for the application's sound.
I've Googled all over the place and it seems I can only get a VU Meter for the devices currently on my computer and set the volume for those devices.
Even though I am using NAudio, I am open to other solutions.
I asked the question in more detail after this question. I have since found the answer so I will leave the answer here for those who stumble upon it. Trying to use NAudio & CSCore has gotten me quite familiar with so please ask if you need further assistance.
This block of code uses CSCore and is a modified and commented version of the answer found here:Getting individual windows application current volume output level as visualized in audio Mixer
class PeakClass
{
static int CurrentProcessID = 0000;
private static void Main(string[] args)
{
//Basically gets your default audio device and session attached to it
using (var sessionManager = GetDefaultAudioSessionManager2(DataFlow.Render))
{
using (var sessionEnumerator = sessionManager.GetSessionEnumerator())
{
//This will go through a list of all processes uses the device
//the code got two line above.
foreach (var session in sessionEnumerator)
{
//This block of code will get the peak value(value needed for VU Meter)
//For whatever process you need it for (I believe you can also check by name
//but I found that less reliable)
using (var session2 = session.QueryInterface<AudioSessionControl2>())
{
if(session2.ProcessID == CurrentProcessID)
{
using (var audioMeterInformation = session.QueryInterface<AudioMeterInformation>())
{
Console.WriteLine(audioMeterInformation.GetPeakValue());
}
}
}
//Uncomment this block of code if you need the peak values
//of all the processes
//
//using (var audioMeterInformation = session.QueryInterface<AudioMeterInformation>())
//{
// Console.WriteLine(audioMeterInformation.GetPeakValue());
//}
}
}
}
}
private static AudioSessionManager2 GetDefaultAudioSessionManager2(DataFlow dataFlow)
{
using (var enumerator = new MMDeviceEnumerator())
{
using (var device = enumerator.GetDefaultAudioEndpoint(dataFlow, Role.Multimedia))
{
Console.WriteLine("DefaultDevice: " + device.FriendlyName);
var sessionManager = AudioSessionManager2.FromMMDevice(device);
return sessionManager;
}
}
}
}
The following code block will allow you to change the volume of the device using NAudio
MMDevice VUDevice;
public void SetVolume(float vol)
{
if(vol > 0)
{
VUDevice.AudioEndpointVolume.Mute = false;
VUDevice.AudioEndpointVolume.MasterVolumeLevelScalar = vol;
}
else
{
VUDevice.AudioEndpointVolume.Mute = true;
}
Console.WriteLine(vol);
}
I have code from two different libraries only to answer the question I posted directly which was how to both set the volume and get VU Meter values (peak values). CSCore and NAudio are very similar so most of the code here is interchangeable.
I am new to C# and is currently using COSMOS to make a simple FileSystem for my OS class. Currently I'm trying to implement a "reformat" function that, when the word "reformat" is typed into the console, the OS (emulated via QEMU), partitions the disk. Currently this is my code:
public static void console()
{
while (true)
{
Console.WriteLine("Console: ");
String input = Console.ReadLine();
if (input == "exit")
{
Cosmos.Sys.Deboot.ShutDown();
}
else if (input == "cpumem")
{
Console.WriteLine(Cosmos.Kernel.CPU.AmountOfMemory.ToString());
}
else if (input == "restart")
{
Cosmos.Sys.Deboot.Reboot();
}
else if (input == "devices")
{
var devices = Cosmos.Sys.FileSystem.Disk.Devices.ToArray();
}
else if (input == "reformat")
{
try
{
Partition part = null;
for (int j = 0; j < Cosmos.Hardware.BlockDevice.Devices.Count; j++)
{
if (Cosmos.Hardware.BlockDevice.Devices[j] is Partition)
{
part = (Partition)Cosmos.Hardware.BlockDevice.Devices[j];
}
}
var fs = new Cosmos.Sys.FileSystem.FAT32.FAT32(part);
uint cluster = 100;
fs.Format("newCluster", cluster);
}
catch
{
//Do Something warn user.
}
}
}
}
Most important is this bit:
else if (input == "reformat")
{
try
{
Partition part = null;
for (int j = 0; j < Cosmos.Hardware.BlockDevice.Devices.Count; j++)
{
if (Cosmos.Hardware.BlockDevice.Devices[j] is Partition)
{
part = (Partition)Cosmos.Hardware.BlockDevice.Devices[j];
}
}
var fs = new Cosmos.Sys.FileSystem.FAT32.FAT32(part);
uint cluster = 100;
fs.Format("newCluster", cluster);
}
catch
{
//Do Something warn user.
}
}
Which is analogous to what is located here: http://cosmos-tutorials.webs.com/atafat.html
However, when I run it, I get this error:
I believe this is because I lack this line:
Cosmos.System.Filesystem.FileSystem.AddMapping("C", FATFS);
FATFileList = FATFS.GetRoot();
Located in the link above. Is there any other way to map? Or am I missing something completely? The COSMOS documentation doesn't really tell much, the source code is honestly confusing for a beginner like me as it has no comments whatsoever on how the functions work or what they do. I am using an older version of COSMOS (Milestone 4) as it's the only one that works for Visual Studio C# 2008. Newer versions run only in Visual Studio C# 2010.
Ah, I recognize this... had to debug a similar situation on a Cosmos project I'm working on myself (I'm using the VS2010-compatible Cosmos but the same situation might apply to older versions as well...)
This can happen if you try to call a method on a null object. Type 0x........, Method 0x........ is specifically mentioning the location in the compiled code where the call failed. "Not FOUND!" means that the method it is looking for cannot be found, presumably because you called it on a null reference.
I'm testing with VirtualBox myself, and found that if you're using a brand-new blank hard disk image, there will be no Partitions on it. Thus, the condition will never get satisfied, your Partition will never get set and then Cosmos will try to execute a method on the null Partition!
Look closely at how you set the Partition (it's initialized to null). For starters I would print a simple message each time the "if (block device is partition)" condition is satisfied... I would be willing to bet it will never print.
Hope this helps... I am still learning about Cosmos and custom kernels myself but fixing the null reference in my case solved my occurrence of the problem. If that's the problem, then the next step, of course, is figuring out why you're not getting any Partitions in the first place...
The rest of your code looks fine but I am not sure how you implemented the rest of your classes. Kernel debugging can be a nightmare, good luck to you!
For a programming project I would like to access the temperature readings from my CPU and GPUs. I will be using C#. From various forums I get the impression that there is specific information and developer resources you need in order to access that information for various boards. I have a MSI NF750-G55 board. MSI's website does not have any of the information I am looking for. I tried their tech support and the rep I spoke with stated they do not have any such information. There must be a way to obtain that info.
Any thoughts?
For at least the CPU side of things, you could use WMI.
The namespace\object is root\WMI, MSAcpi_ThermalZoneTemperature
Sample Code:
ManagementObjectSearcher searcher =
new ManagementObjectSearcher("root\\WMI",
"SELECT * FROM MSAcpi_ThermalZoneTemperature");
ManagementObjectCollection collection =
searcher.Get();
foreach(ManagementBaseObject tempObject in collection)
{
Console.WriteLine(tempObject["CurrentTemperature"].ToString());
}
That will give you the temperature in a raw format. You have to convert from there:
kelvin = raw / 10;
celsius = (raw / 10) - 273.15;
fahrenheit = ((raw / 10) - 273.15) * 9 / 5 + 32;
The best way to go for hardware related coding on windows is by using WMI which is a Code Creator tool from Microsoft, the tool will create the code for you based on what you are looking for in hardware related data and what .Net language you want to use.
The supported langauges currently are: C#, Visual Basic, VB Script.
Note that MSAcpi_ThermalZoneTemperature does not give you the temperature of the CPU but rather the temperature of the motherboard. Also, note that most motherboards do not implement this via WMI.
You can give the Open Hardware Monitor a go, although it lacks support for the latest processors.
internal sealed class CpuTemperatureReader : IDisposable
{
private readonly Computer _computer;
public CpuTemperatureReader()
{
_computer = new Computer { CPUEnabled = true };
_computer.Open();
}
public IReadOnlyDictionary<string, float> GetTemperaturesInCelsius()
{
var coreAndTemperature = new Dictionary<string, float>();
foreach (var hardware in _computer.Hardware)
{
hardware.Update(); //use hardware.Name to get CPU model
foreach (var sensor in hardware.Sensors)
{
if (sensor.SensorType == SensorType.Temperature && sensor.Value.HasValue)
coreAndTemperature.Add(sensor.Name, sensor.Value.Value);
}
}
return coreAndTemperature;
}
public void Dispose()
{
try
{
_computer.Close();
}
catch (Exception)
{
//ignore closing errors
}
}
}
Download the zip from the official source, extract and add a reference to OpenHardwareMonitorLib.dll in your project.