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Play media file, while it is still downloading (Windows Phone)

I would like to know, if there's a way to play a media-file in Windows Phone, while this file is still being downloaded?
At the current time, I have an application with feature, that allows to download and play media files, when they are fully downloaded.
(I've created this feature, using article)
So, in brief, first, the media-file is downloaded from url, then I'm using mediaElement to play it:
mediaElement.source = isolatedStorageFileStream;
After that, I can use this file via my player UI.
However, I prefer to make this feature better - allow to start playing file, while the download is still in progress. In the end, this should look like that: start downloading file, contemporaneously start decrypting this file, contemporaneously allow to play decrypted part of file. Let's forget about decryption so far(I've already written a method for a downloaded file, it should be slightly changed then), the main problem is how to allow two parallel tasks: downloading and playing.
The first question is: "Does MediaElement only allow to set "source" property to only solid(finally downloaded) files or it can use this Stream, during downloading, as well"?
Because, I've found some info, that:
"The MediaElement does not supporting streaming at the moment. It
loads the entire file first before it actually plays it."
, though I'm not sure, that this one refers to Windows Phone, it sounds rather anxiously.
If this cannot be done, what else can I use to work with media-files? I'm not interested in downloading video, let's limit only with mp3 audio files.
Right now, the download process is implemented in this way:
WebClient webClient = new WebClient();
webClient.DownloadProgressChanged += new DownloadProgressChangedEventHandler(webClient_DownloadProgressChanged);
webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
webClient.OpenReadAsync(new Uri(link));
Then in OpenReadCompleted the download file stream is set as source of mediaFile.
mediaFile.SetSource(isolatedStorageFileStream);
After this I can use my media file.
I there a solution for my problem? I'm rather new at Windows Phone threading and streaming and don't know, how to implement such feature.
P.S. Of course, I tried to find a similar question, but failed. If you know one, give me a link, please.
P.P.S. Sorry for my English.

You can only stream it using BackgroundAudioPlayer.

you are trying to read a file that is in use. I don't think is possible.
However:
VideoRecorder works by using filesink and managed to capture, write and display at the same time. would suggest you have a look in that area
How to: Record Video in a Camera Application for Windows Phone
http://msdn.microsoft.com/en-us/library/hh394041(v=vs.92).aspx
FileSink
http://msdn.microsoft.com/en-us/library/system.windows.media.filesink(VS.95).aspx

Is it possible to generate complex tones in C#?

I need to create a sound containing tones of many different frequencies. Is there any way to do this in C#?
The only tone generating methods I've seen so far involve console.beep, which works, but only for pure tones (single frequencies).

The Audiere library makes this extremely easy to do. Here's a nearly complete C# program to generate the DTMF tone for the "1" button:
AudioDevice device = new AudioDevice();
OutputStream tone1a = device.CreateTone(697); // part A of DTMF for "1" button
OutputStream tone1b = device.CreateTone(1209); // part B
tone1a.Volume = 0.25f;
tone1b.Volume = 0.25f;
tone1a.Play();
tone1b.Play();
Thread.Sleep(2000);
// when tone1a stops, you can easily tell that the tone was indeed DTMF
tone1a.Stop();
To use Audiere in C#, the easiest way to get up and running is to use Harald Fielker's C# binding (which he claims works on Mono and VS; I can confirm it works in the both full version of VS2005 and using the separate Express 2008 versions of C# and VC++). You'll need to download the Win32 Audiere DLL, lib, and header (which are all in the same zip) and you'll need to build the C# binding from source using both VC++ and C#.
One of the nice benefits of using Audiere is that the calls are non-blocking. You don't have to wait for tone1a to stop playing before you start tone1b, which is clearly a necessity for playing complex tones. I am not aware of any hard upper limits on how many simultaneous output streams you can use, so it's probably whatever your hardware/OS supports. By the way, Audiere can also play certain audio files (MP3, WAV, AIFF, MOD, S3M, XM, IT by itself; Ogg Vorbis, Flac, Speex with external libraries), not just pure generated tones.
One possible downside is that there is a slightly audible "click" as you start or stop an individual tone; it's not noticeable if you add one tone to an already playing tone. The easiest workaround I've found for that is to slowly ramp the tone's volume up or down when you're turning the tone on or off, respectively. You might have to play around with the ramp speed to get it to sound "just right".
Note that Audiere is LGPL-licensed, and the binding has no license attached to it. You'll have to consult your legal team or try to get a hold of Harald if you want to use his binding in a commercial product; or you could just make your own binding and avoid the hassle.
#Tom: Since there is no specific license attached to Harald's library, I'm not sure what implications would come of hosting it; however, I believe I can at least give you fine detail on exactly how my libaudieresharpglue project is set up.
Using Visual C++ Express 2008, open up bindings/csharp/libaudieresharpglue/vc8.0/libaudieresharpglue.sln. VC++ will automatically convert the solution to a VS9 solution.
In another folder, you should have the Audiere package from Sourceforge. Under your VC++ project properties, go to Configuration Properties > C/C++ > General, and make sure you have path/to/audiere-1.9.4-win32/include in your "Additional Include Directories." Then, in that same window, go to Linker > General and make sure you have /path/to/audiere-1.9.4-win32/lib in your "Additional Library Directories." Then, you should be able to build the project (preferably in Release mode) and this output libaudieresharpglue.dll in your vc8.0/Release folder.
Next, open up Visual C# Express 2008. Open up bindings\csharp\test\vc8.0\AudiereCSharpTest.sln and let it convert the solution. The project should build fine, but then you will get an error when you run it. That's fine; in your csharp/test/vc8.0/bin/Release folder, you need to add both libaudieresharpglue.dll from the VC++ solution and audiere.dll from the package from Sourceforge.
Now, you should be able to build and run AudiereCSharpTest. Note that by default, #define stream_test is not commented out at the top of AudiereTest.cs, and that will reference a file that is not on your hard drive. You can simply comment out that #define and uncomment noise_test or square_test.
That should cover it; if I missed any details, hopefully they are small enough to get by on your own :)

You can always try DirectSound...

I have been looking at NAudio with the view to create a program that emulates feedback whilst playing a backing track. There is a blog post about generating sine waves at specific frequencies, I suspect that this could be adapted to do what you are looking for.

Yes it is possible.
Here is a link to a tutorial on this. but of course this also uses Console.Beep

The MSDN documentation doesn't make it clear if Console.Beep is asynchronous or not. If it is, you can probably fire off as many calls as you need in quick succession and nobody will be the wiser. You'd want to use the version that takes a frequency and a duration, of course.

Essentially, you have to implement your own software synthesizer or find a 3rd party library. See: http://en.wikipedia.org/wiki/Demo_(computer_programming)#Music

Webcam usage in C#

I am making a program in C# to connect to a webcam and do some image manipulation with it.
I have a working application that uses win32 api (avicap32.dll) to connect to the webcam and send messages to it that sends it to the clipboard. The problem is that, while accessible from paint, reading it from the program results in null pointers.
This is the code I use to connect the webcam:
mCapHwnd = capCreateCaptureWindowA("WebCap", 0, 0, 0, 320, 240, 1024, 0);
SendMessage(mCapHwnd, WM_CAP_CONNECT, 0, 0);
SendMessage(mCapHwnd, WM_CAP_SET_PREVIEW, 0, 0);
And this is what I use to copy the image to the clipboard:
SendMessage(mCapHwnd, WM_CAP_GET_FRAME, 0, 0);
SendMessage(mCapHwnd, WM_CAP_COPY, 0, 0);
tempObj = Clipboard.GetDataObject();
tempImg = (System.Drawing.Bitmap)tempObj.GetData(System.Windows.Forms.DataFormats.Bitmap);
There's some error checking which I have removed from the code to make it shorter.

I've recently started doing some hobby work in this area.
We settled on using the OpenCV library with the opencvdotnet wrapper. It supports capturing frames from a webcam:
using (var cv = new OpenCVDotNet.CVCapture(0))
{
var image = cv.CreateCompatibleImage();
// ...
cv.Release();
}
And if you're doing image manipulation, OpenCV's image processing algorithms have been wrapped within the OpenCVDotNet.Algs assembly.
If you decide to go this route be sure to install OpenCV version 1.0 (and install it to "c:\program files\opencv" if you are on Vista 64-bit, or "mklink OpenCV 'c:\program files (x86)\OpenCV`" from the correct directory or else opencvdotnet will not install).

There are really two ways to get camera data into your application, DirectShow and WIA. Microsoft recommends that you use WIA, and the interface for WIA is fairly simple to wrap your brain around. I created and published an open source WIA desktop library based on work I did a while ago.
Now the problem with WIA in some cases is that it's too simple. For example, if you want to adjust camera properties (like frame rate, resolution, etc) then WIA falls down. Microsoft deprecated DirectShow, but they really didn't give us any replacement that has all of its capabilities, and I've found that it continues to work fine on all existing platforms (it's very entrenched, so I can't imagine support going away any time soon).
There is a very good DirectShow library over at SourceForge. The only "problem" with it is it's really complex and that stems from the fact that DShow is just so damned complex and confusing in the first place. There are lots of things that the wrapper can do that just aren't easy to work out, but they do provide samples for a lot of common use cases like showing video or capturing a frame. If you want to add overlays, or insert other filters, it can do it, but be forewarned that it's not at all straightforward.

Take a look at this article:
http://www.codeproject.com/KB/miscctrl/webcam_c_sharp.aspx
It is way too simpler than installing and using OpenCVNetWrapper.

Have you tried Clipboard.GetImage()? You could also try the various Clipboard.Contains*() methods to see what format the data is stored in the clipboard.

OpenCV capture, EMGU capture and all other capture libraries I have tried
all have the same problem: You cannot go higher than 640x480 programatically
(without opening the windows video source window).
I suggest using this (which does work):
https://github.com/ofTheo/videoInput

This was also asked in How to get web cam images in C#? and you might find the following useful (Sorry for spamming, but this really helps answering the question):
I've just released the complete sourcecode of my Windows app CamTimer (written in .NET/C#). Download/view the complete code (with working Webcam examples) at https://github.com/johanssonrobotics/CamTimer
Happy coding!

Can I use MediaPlayer to play sounds from a stream? Or, can I use an URI to access a filestream?

I'm using System.Windows.Media.MediaPlayer to play some sounds, and I would like to load these sounds from a ZIP file. It would be nice to be able to load these files as a stream directly from the zip file instead of having to unzip to a temp directory. However, MediaPlayer.open only accepts an URI.
So, is there a way to create a URI that will reference the contents of a stream? Something like an in-memory localhost? Is there any connector from Stream to URI?

System.Media.SoundPlayer should do what you need (you can skip MediaPlayer and URIs altogether). It has a constructor that takes a stream.

Since you need to support polyphony, one approach is to PInvoke into the waveOutXXXX Windows API in order to play the sounds. Here is a good example of how to do this in C#:
https://www.codeproject.com/KB/audio-video/cswavplay.aspx
This example also has code for reading info like duration, sample rate, bits per sample etc.
If you search, you may find claims that the waveOutXXXX API can only play one sound at a time. This was true in Windows 95/98, but is not true any longer.
By the way, SoundPlayer is probably the most frustrating .NET class. The .Play() method automatically stops playback of any other sound played by your process (it might be any other sound played by any .NET app) before starting, which is why you can't do polyphony with it. It would have taken Microsoft's worst intern less than a minute to add a .DontStopJustPlay() method or a StopFirst bool parameter to the .Play() method. It might have taken him until lunch time to add a Duration property.
Although waveOutXXXX is trickier than you would want from a well-designed modern API (and using it in .NET introduces additional problems), the one unmatched advantage it has is that it's come pre-installed on every single Windows computer since Windows 95, including Windows Mobile devices. Every other option (including MediaPlayer) means somebody will always have to install something.

How can I play compressed sound files in C# in a portable way?

Is there a portable, not patent-restricted way to play compressed sound files in C# / .Net? I want to play short "jingle" sounds on various events occuring in the program.
System.Media.SoundPlayer can handle only WAV, but those are typically to big to embed in a downloadable apllication. MP3 is protected with patents, so even if there was a fully managed decoder/player it wouldn't be free to redistribute. The best format available would seem to be OGG Vorbis, but I had no luck getting any C# Vorbis libraries to work (I managed to extract a raw PCM with csvorbis but I don't know how to play it afterwards).
I neither want to distribute any binaries with my application nor depend on P/Invoke, as the project should run at least on Windows and Linux. I'm fine with bundling .Net assemblies as long as they are license-compatible with GPL.
[this question is a follow up to a mailing list discussion on mono-dev mailing list a year ago]

I finally revisited this topic, and, using help from BrokenGlass on writing WAVE header, updated csvorbis. I've added an OggDecodeStream that can be passed to System.Media.SoundPlayer to simply play any (compatible) Ogg Vorbis stream. Example usage:
using (var file = new FileStream(oggFilename, FileMode.Open, FileAccess.Read))
{
var player = new SoundPlayer(new OggDecodeStream(file));
player.PlaySync();
}
'Compatible' in this case means 'it worked when I tried it out'. The decoder is fully managed, works fine on Microsoft .Net - at the moment, there seems to be a regression in Mono's SoundPlayer that causes distortion.
Outdated:
System.Diagnostics.Process.Start("fullPath.mp3");
I am surprised but the method Dinah mentioned actually works. However, I was thinking about playing short "jingle" sounds on various events occurring in the program, I don't want to launch user's media player each time I need to do a 'ping!' sound.
As for the code project link - this is unfortunately only a P/Invoke wrapper.

I neither want to distribute any
binaries with my application nor
depend on P/Invoke, as the project
should run at least on Windows and
Linux. I'm fine with bundling .Net
assemblies as long as they are
license-compatible with GPL.
Unfortunatly its going to be impossible to avoid distributing binaries, or avoid P/Invoke. The .net class libraries use P/Invoke underneath anyway, the managed code has to communicate with the unmanage operating system API at some point, in order to do anything.
Converting the OGG file to PCM should be possible in Managed code, but because there is no Native Support for Audio in .net, you really have 3 options:
Call an external program to play the sound (as suggested earlier)
P/Invoke a C module to play the sound
P/Invoke the OS APIs to play the sound.
(4.) If you're only running this code on windows you could probably just use DirectShow.
P/Invoke can be used in a cross platform way
http://www.mono-project.com/Interop_with_Native_Libraries#Library_Names
Once you have your PCM data (using a OGG C Lib or Managed Code, something like this http://www.robburke.net/mle/mp3sharp/ of course there are licencing issues with MP3), you will need a way to play it, unfortunatly .net does not provide any direct assess to your sound card or methods to play streaming audio. You could convert the ogg files to PCM at startup, and then use System.Media.SoundPlayer, to play the wav files generated. The current method Microsoft suggests uses P/Invoke to access Sound playing API in the OS http://msdn.microsoft.com/en-us/library/ms229685.aspx
A cross platform API to play PCM sound is OpenAL and you should be able to play (PCM) sound using the c# bindings for OpenAL at www.taoframework.com, you will unfortunatly need to copy a number of DLL and .so files with your application in order for it to work when distributed, but this is, as i've explained earlier unavoidable.

Calling something which is located in 'System.Diagnostics' to play a sound looks like a pretty bad idea to me. Here is what that function is meant for:
//
// Summary:
// Starts a process resource by specifying the name of a document or application
// file and associates the resource with a new System.Diagnostics.Process component.
//
// Parameters:
// fileName:
// The name of a document or application file to run in the process.
//
// Returns:
// A new System.Diagnostics.Process component that is associated with the process
// resource, or null, if no process resource is started (for example, if an
// existing process is reused).
//
// Exceptions:
// System.ComponentModel.Win32Exception:
// There was an error in opening the associated file.
//
// System.ObjectDisposedException:
// The process object has already been disposed.
//
// System.IO.FileNotFoundException:
// The PATH environment variable has a string containing quotes.

i think you should have a look a fmod, which is the mother of all audio api
please feel free to dream about http://www.fmod.org/index.php/download#FMODExProgrammersAPI

The XNA Audio APIs work well in .net/c# applications, and work beautifully for this application. Event-based triggering, along with concurent playback of multiple sounds. Exactly what you want. Oh, and compression as well.

Well, it depends on a patent-related laws in a given country, but there is no way to write a mp3 decoder without violating patents, as far as i know. I think the best cross-platform, open source solution for your problem is GStreamer. It has c# bindings, which evolve rapidly. Using and building GStreamer on Windows is not an easy task however. Here is a good starting point. Banshee project uses this approach, but it is not really usable on windows yet (however, there are some almost-working nightly builds). FMOD is also a good alternative. Unfortunately, it is not open source and i find that its API is somehow C-styled.

There is a pure C# vorbis decoder available that is open source:
http://anonsvn.mono-project.com/viewvc/trunk/csvorbis/

Not sure if this is still relevant. Simplest solution would be to use NAudio, which is a managed open source audio API written in C#. Another thing to try would be utilizing ffmpeg, and creating a process to ffplay.exe (the right binaries are under shared builds).

There is no way for you to do this without using something else for your play handling.
Using the System.Diagnostic will launch an external software and I doubt you want that, right? You just want X sound file to play in the background when Y happens in your program, right?
Voted up because it looks like an interesting question. :D