I was wondering how I can select the output device for audio in directshow. I am able to get available audio output devices in directshow. But how can I make one of these to be audio output device. Its always going for the default audio device. I want to be able to output audio on my choice of device. I have been struggling through google but couldn't find anything useful. All I could get was this link but it doesn't really solve my problem.
Any help will be really helpful for me.
First off, if you're not using DirectShow .NET (DirectShowLib), get that here: It serves as a (very complete) interface between unmanaged DirectShow and C#
What follows is a pretty simple example of how to play an audio file, to the desired audio device
using DirectShowLib;
private IGraphBuilder m_objFilterGraph = null;
private IBasicAudio m_objBasicAudio = null;
private IMediaControl m_objMediaControl = null;
private void playAudioToDevice(string fName, int devIndex)
{
object source = null;
DsDevice[] devices;
devices = DsDevice.GetDevicesOfCat(FilterCategory.AudioRendererCategory);
DsDevice device = (DsDevice)devices[devIndex];
Guid iid = typeof(IBaseFilter).GUID;
device.Mon.BindToObject(null, null, ref iid, out source);
m_objFilterGraph = (IGraphBuilder)new FilterGraph();
m_objFilterGraph.AddFilter((IBaseFilter)source, "Audio Render");
m_objFilterGraph.RenderFile(fName, "");
m_objBasicAudio = m_objFilterGraph as IBasicAudio;
m_objMediaControl = m_objFilterGraph as IMediaControl;
m_objMediaControl.Run();
}
It is up to user to manage audio devices and choose a primary device (such as via Control Panel applet). You can find ways to switch devices programmatically in Windows XP, however in Vista+ it is impossible without interactive user action by design.
See also Larry's answer here: How to change default sound playback device programmatically?
UPDATE: The mentioned above refers to modifying system configuration trying to alter default audio output device. An application is however not limited to default device only. Instead, it can enumerate available devices (see Using the System Device Enumerator + CLSID_AudioRendererCategory) and then create an instance of renderer for specific device with BindToObject call. From there on, it is a regular filter, just bound internally to device of interest.
Related
I'm making a gym management web app that handles sign-ins. Members have a barcode on a tag that they scan when they arrive to the gym.
I've heard that most barcode scanners simply act as a keyboard. This would require the scanning-in page to be open and in the foreground when a barcode is scanned.
If it's just a keyboard, how would I send the barcode scanner input to a single background process running on the computer, and have it ignore by all processes that may be in focus?
You're right that most scanner can support HID in keyboard emulation, but that's just the start.
If you want to have a bit more control over the data you can use a scanners that support the OPOS driver model.
Take a look at Zebra's Windows SDK to have a overview of the things that you can do. It may be a better solution than try to steal the barcode data coming in the OS as a keyboard entry to the foreground app.
Disclaimer: I work for Zebra Technologies
Other Barcode scanner vendor support a similar driver model.
I found an interesting post with a simple solution:
On the form constructor
InitializeComponent():
this.KeyPress += new System.Windows.Forms.KeyPressEventHandler(this.Form1_KeyPress);
Handler & supporting items:
DateTime _lastKeystroke = new DateTime(0);
List<char> _barcode = new List<char>(10);
private void Form1_KeyPress(object sender, KeyPressEventArgs e)
{
// check timing (keystrokes within 100 ms)
TimeSpan elapsed = (DateTime.Now - _lastKeystroke);
if (elapsed.TotalMilliseconds > 100)
_barcode.Clear();
// record keystroke & timestamp
_barcode.Add(e.KeyChar);
_lastKeystroke = DateTime.Now;
// process barcode
if (e.KeyChar == 13 && _barcode.Count > 0) {
string msg = new String(_barcode.ToArray());
MessageBox.Show(msg);
_barcode.Clear();
}
}
Credits: #ltiong_sh
Original post: Here
Use RawInput API (https://www.codeproject.com/Articles/17123/Using-Raw-Input-from-C-to-handle-multiple-keyboard#_Toc156395975) and check device ID for incoming keystrokes. Different devices have different IDs. You can also block keystrokes from scanner from reaching your application and interfering with input fields.
One thing you might want to add is option for user to identity which device is used as a barcode scanner. I did it by asking user to test-scan barcode with scanner on first application startup or in settings.
Works with any barcode scanner which outputs keystrokes.
I receive over network PCM audio data stream and this part works fine so I am ending up with
DataReader incomming = args.GetDataReader();
byte[] RcvBuffer = new byte[incomming.UnconsumedBufferLength];
incomming.ReadBytes(RcvBuffer);
I have all audio data in buffer.
How I can play this through telephone Speaker ? Can you point me in some direction ?
Thanks
There're many ways to do that.
You can prepend the WAVE header to your data, and use MediaElement for playback, see the documentation for SetSource method.
If however by “telephone speaker” you mean the earphone, then it is only possible if you are creating a VoIP app.
It took a while but I sorted it, maybe someone else will need help in the future.
First Problem - since I just started app development for Windows Phone I have chosen Blank App (Windows Phone) instead Blank App (Windows Phone Silverlight) and I did not have access to many features that are available in Silverlight projects, so my suggestions for beginners: understand what each project is for.
Like Soonts said there are many ways to do this, this is one that I used.
I simplified this code and retyped this so there can be some typos.
using Microsoft.Xna.Framework.Audio;
using System.IO;
1) Create Stream to load your incoming data:
MemoryStream stream = new MemoryStream();
2) Load data from buffer to stream:
stream.Write(RcvBuffer, 0, RcvBuffer.Length);
3) I am using SoundEfect to play this through Loud-Speaker. Sample rate that I use is 8 kHz
SoundEffect sound;
sound = new SoundEffect(stream.toArray(), 8000, AudioChannels.Mono)
sound.Play();
Is there a way to read the info (fps, bitrate, duration, codecs required, etc.) of a media file (avi, mp4, mkv, etc.) on windows using visual studio c++?
I managed to play various files (which I actually don't even want) using directshow (http://msdn.microsoft.com/en-us/library/windows/desktop/dd389098%28v=vs.85%29.aspx) but I don't know how to only get the information from the file.
Edit: I got it working like this...
int height, width, framerate, bitrate;
LARGE_INTEGER duration;
// initialize the COM library
CoInitialize(NULL);
//
IPropertyStore* store = NULL;
SHGetPropertyStoreFromParsingName(L"E:\\test.avi", NULL, GPS_DEFAULT, __uuidof(IPropertyStore), (void**)&store);
PROPVARIANT variant;
store->GetValue(PKEY_Media_Duration, &variant);
duration = variant.hVal;
store->GetValue(PKEY_Video_FrameHeight, &variant);
height = variant.lVal;
store->GetValue(PKEY_Video_FrameWidth, &variant);
width = variant.lVal;
store->GetValue(PKEY_Video_FrameRate, &variant);
framerate = variant.lVal;
store->GetValue(PKEY_Video_TotalBitrate, &variant);
bitrate = variant.lVal;
//
store->Release();
//
CoUninitialize();
You can obtain this information via DirectShow, however if you don't need the playback/streaming pipeline and you are on Windows 7, then you possibly have a better alternate option to get the data from shell properties - those supplying data to display in additional columns of Windows explorer.
SHGetPropertyStoreFromParsingName gets you property store
MSDN entry point for Shell Metadata Providers
Code snippet: How to use the IPropertyStore to obtain Media_Duration?
Have you considered using the MediaInfo SDK? You can get extensive information about all of the audio and video streams available in the container, including codec specifics, as well as everything you were asking about.
Their getting started guide and reference documentation are here:
http://mediaarea.net/en/MediaInfo/Support/SDK/Quick_Start
http://mediaarea.net/en/MediaInfo/Support/SDK/More_Info
Code is available at their SourceForge page here.
I am targeting windows machines. I need to get access to the pointer to the byte array describing the individual streaming frames from an attached usb webcam. I saw the playcap directshow sample from the windows sdk, but I dont see how to get to raw data, frankly, I don't understand how the video actually gets to the window. Since I don't really need anything other than the video capture I would prefer not to use opencv.
Visual Studio 2008 c++
Insert the sample grabber filter. Connect the camera source to the sample grabber and then to the null renderer. The sample grabber is a transform, so you need to feed the output somewhere, but if you don't need to render it, the null renderer is a good choice.
You can configure the sample grabber using ISampleGrabber. You can arrange a callback to your app for each frame, giving you either a pointer to the bits themselves, or a pointer to the IMediaSample object which will also give you the metadata.
You need to implement ISampleGrabberCB on your object, and then you need something like this (pseudo code)
IFilterInfoPtr m_pFilterInfo;
ISampleGrabberPtr m_pGrabber;
m_pGrabber = pFilter;
m_pGrabber->SetBufferSamples(false);
m_pGrabber->SetOneShot(false);
// force to 24-bit mode
AM_MEDIA_TYPE mt;
ZeroMemory(&mt, sizeof(mt));
mt.majortype = MEDIATYPE_Video;
mt.subtype = MEDIASUBTYPE_RGB24;
m_pGrabber->SetMediaType(&mt);
m_pGrabber->SetCallback(this, 0);
// SetCallback increments a refcount on ourselves,
// but we own the grabber so this is recursive
/// -- must addref before SetCallback(NULL)
Release();
Does anyone know of a good repository to get sample code for the BlackBerry? Specifically, samples that will help me learn the mechanics of recording audio, possibly even sampling it and doing some on the fly signal processing on it?
I'd like to read incoming audio, sample by sample if need be, then process it to produce a desired result, in this case a visualizer.
RIM API contains JSR 135 Java Mobile Media API for handling audio & video content.
You correct about mess on BB Knowledge Base. The only way is browse it, hoping they'll not going to change site map again.
It's Developers->Resources->Knowledge Base->Java API's&Samples->Audio&Video
Audio Recording
Basically it's simple to record audio:
create Player with correct audio encoding
get RecordControl
start recording
stop recording
Links:
RIM 4.6.0 API ref: Package javax.microedition.media
How To - Record Audio on a BlackBerry smartphone
How To - Play audio in an application
How To - Support streaming audio to the media application
How To - Specify Audio Path Routing
How To - Obtain the media playback time from a media application
What Is - Supported audio formats
What Is - Media application error codes
Audio Record Sample
Thread with Player, RecordControl and resources is declared:
final class VoiceNotesRecorderThread extends Thread{
private Player _player;
private RecordControl _rcontrol;
private ByteArrayOutputStream _output;
private byte _data[];
VoiceNotesRecorderThread() {}
private int getSize(){
return (_output != null ? _output.size() : 0);
}
private byte[] getVoiceNote(){
return _data;
}
}
On Thread.run() audio recording is started:
public void run() {
try {
// Create a Player that captures live audio.
_player = Manager.createPlayer("capture://audio");
_player.realize();
// Get the RecordControl, set the record stream,
_rcontrol = (RecordControl)_player.getControl("RecordControl");
//Create a ByteArrayOutputStream to capture the audio stream.
_output = new ByteArrayOutputStream();
_rcontrol.setRecordStream(_output);
_rcontrol.startRecord();
_player.start();
} catch (final Exception e) {
UiApplication.getUiApplication().invokeAndWait(new Runnable() {
public void run() {
Dialog.inform(e.toString());
}
});
}
}
And on thread.stop() recording is stopped:
public void stop() {
try {
//Stop recording, capture data from the OutputStream,
//close the OutputStream and player.
_rcontrol.commit();
_data = _output.toByteArray();
_output.close();
_player.close();
} catch (Exception e) {
synchronized (UiApplication.getEventLock()) {
Dialog.inform(e.toString());
}
}
}
Processing and sampling audio stream
In the end of recording you will have output stream filled with data in specific audio format. So to process or sample it you will have to decode this audio stream.
Talking about on the fly processing, that will be more complex. You will have to read output stream during recording without record commiting. So there will be several problems to solve:
synch access to output stream for Recorder and Sampler - threading issue
read the correct amount of audio data - go deep into audio format decode to find out markup rules
Also may be useful:
java.net: Experiments in Streaming Content in Java ME by Vikram Goyal
While not audio specific, this question does have some good "getting started" references.
Writing Blackberry Applications
I spent ages trying to figure this out too. Once you've installed the BlackBerry Component Packs (available from their website), you can find the sample code inside the component pack.
In my case, once I had installed the Component Packs into Eclipse, I found the extracted sample code in this location:
C:\Program
Files\Eclipse\eclipse3.4\plugins\net.rim.eide.componentpack4.5.0_4.5.0.16\components\samples
Unfortunately when I imported all that sample code I had a bunch of compile errors. To workaround that I just deleted the 20% of packages with compile errors.
My next problem was that launching the Simulator always launched the first sample code package (in my case activetextfieldsdemo), I couldn't get it to run just the package I am interested in. Workaround for that was to delete all the packages listed alphabetically before the one I wanted.
Other gotchas:
-Right click on the project in Eclipse and select Activate for BlackBerry
-Choose BlackBerry -> Build Configurations... -> Edit... and select your new project so it builds.
-Make sure you put your BlackBerry source code under a "src" folder in the Eclipse project, otherwise you might hit build issues.