Develop Reference

Implementing voice chat in ASP.NET

I'm creating a small web chat application using ASP.NET, text chat is almost done using Ajax,SQL Server but now I'm going to create a voice system also. I've googled a lot but with no real luck, what are my options? Silverlight? VoIP? or something else? I've worked a lot with SL, is it my only way of implementing voice chat in web? can I use pure ASP.NET to have voice chat? how can I use TCP/IP for voice communication? is there any online sample showing voice chat or communication?

You can use assembly for voice chat should you want to, but it's very hard. I can't give a good answer without knowing how well you know ASP.NET/C#, but VoIP isn't hard to implement Normally.
Basically, you need a codec on each end, and a protocol to transfer packets - encoded obviously - from one end to the other (Mostly UDP).
Now, When I say Normally I mean in a perfect world where network issues - mostly related to NAT - don't exist.
Also you will need something other than ASP.NET, Like a plugin (Silverlight should do, but something mainstream like flash or java are recommended) to get a bit more control of the client's PC (Microphone, speakers).
I quite doubt you can do this alone, no offence. Therefore I would recommend using a library like SIP Communicator, Here's a Tutorial and Another.

Voice over wifi between android phones in C#

I want to develop an application for voice calls between two android devices on my home network (WiFi). I'm new to programming so don't really know where to begin, I have researched around but cannot find anything that fits what I need to do.
The application has to be written in C# as I have a basic understanding of that language and it's the language I want to expand my knowledge in. I'm using MonoDevelop which allows the creation of android apps through C#.
The call will be peer to peer so very basic and no security or encryption will be necessary in these early stages of development.
All help will really be appreciated!

I'd start with this link at code project:
http://www.codeproject.com/Articles/138484/Simple-SIP-VOIP-based-phone-in-C
You will have to adapt it to android, but again is a probably a good starting point to understand how to do voice over IP.
The big things that may differ on android are:
User interface
method to get microphone input
method to play audio output
access to the IP stack
but the basic (encoding, decoding, etc...) should be there.

how to make call from pc using local landline phone services

I have a desktop application of address diary, developed in C# .Net.
I want to make call from software throw land line phone service,
in my office we have 8 phone lines, so i want to select line before call,
i want to use headphone and mic in place of phone instrument.
how to connect phone lines to pc. i have more then 8 phone lines
is it possible ? if yes then how and which hardware i need for this.

Have you thought of the Skype API: http://developer.skype.com/public/skypekit
or
http://www.twilio.com
Get rid of the landlines and use a service. Much easier in my opinion. Then it would be far more scalable as well.
If you want to go down the telephony services path check out this library: https://github.com/markjulmar/atapi.net/
Hardware for landlines would just include 8 modems and selecting which one to use, before making a call.
I would assume that the atapi library contains functions to select the audio input and output. If not there are plenty of c# libraries for recording audio, in which you could pass the stream through to the library.
I wasn't going to point you down this direction but as per #Saif Khan comment you can use Asterix.
Using Asterix
Step 1 - Get a server install Asterix on it. http://www.asterisk.org. It's open source.
Step 2 - Get supported hardware e.g. http://www.asterisk.org/hardware
Step 3 - Communicate to it with http://sourceforge.net/projects/asterisk-dotnet/ (open source c# to asterisk library.
This maybe overkill for you, I don't know. I suppose I shouldn't assume :)

Since Google Voice is still free in United States and Canada. You can use this Google Voice API in C#.
http://sourceforge.net/projects/gvoicedotnet/

Doesn't want to sound like a noob, but did you try out Windows Dialer? You will need x number of 56k dialup voice modem depending on the no. of connections you have and you want to use.
It should work just fine. Test it out, and if it works well, you can get your app synced with your existing software to export the number to the dialer upon calling. (There is no such functions on the dialer app yet.)

Whats the best C# Way to stream a H.264 Video to another computer/device on a network? Is there a library/API For this? File Sharing?

I am experimenting with C#, and I wanted to create a fun/useful network program. I've programmed for most of my years using C++, C# seems a lot cleaner and easier to program in. I mostly programmed data structures and algorithms. I haven't really touched networking much.
I have video files on my computer that I would like to be able to share/stream/send to other computers on my network. I'm going to eventually expand on it and add a lot of features, but I want to conquer the hardest part first.
Is there a library out that helps with the data management for this?
I see accomplishing this three ways, Idk what's easiest and best.
Maybe using Windows File Sharing (Like how other computers on a network can open videos in a shared folder?)
Streaming the video data to the client computer? Then having their native video program open the data stream? (Buffer-like on youtube?)
Silverlight or some other Library. I can use the built in video player, etc to run it
Features:
I want to allow the client to be able to copy the video tutorial file to their own computer eventually if necessary, so idk. Maybe buffering is the best solution.
Want to allow the client to pause/download the video.
Hopefully I can learn a lot in this project.

You can use Microsoft Expression Encoder SDK to push video stream to a local port, or publish it in Windows or IIS Media Services. Windows Media Player, Silverlight or player-based application can be used for playback on another computer. Also, the are some options for playback on Apple devices. For H.264 support, you would need Pro version of the encoder.
For more information see the SDK documentation on MSDN, and articles Getting started with IIS Live Smooth Streaming and Apple HTTP Live Streaming with IIS Media Services.

You should be able to use vlc to transcode the file (or just stream it) then connect to the stream it produces. I know you're experimenting with C#, but it seems odd to re-invent the wheel, especially when it's such a good one!
I'm sure you'd have some fun automating vlc.

Recording Audio sound on Internet - C# ASP.NET

I want build an application on web which records the audio sound through Mic.
If any one can provide some appropriate approach or some links would be helpful.
also if you can suggest some third party control which is free.
The technology for Implementation - ASP.NET , C#

Since you are looking to use C#, check out Silverlight 4 which added microphone support to Silverlight. Here is a tutorial on accessing the microphone in Silverlight 4. Scratch Audio is a great example of a Silverlight support with microphone support.

javascript does not give mic support. You would have to include another technology to do this.
I know flash supports microsoft input. It might be the best place to start. I don't know if silverlight has these features.
The only other things i can think of would be an activeX control for IE, or a standalone application. Both of these look like much worse approaches

You can use flash to record from microphone and upload it to a server. For the server you can use Red5 which is great open source server.
Here are some examples:
http:// => fms.denniehoopingarner.com/
http:// => mariofalomir.com/blog/?p=101
(Sorry but i can only post 1 hyperlink)