Android Client and Node.js Server

Question

I'm trying to develop a proyect like PTTDroid, I mean a Push-To-Talk or Walkie-Talkie application.

The issue is that in this app you can´t use 3G to access the web, so I've decided to use a Node.js server and implement an Android client to comunicate with it. I tried to do a multiplattform proyect using Phonegap the problem is that for audio record you can't access to buffer, you can only start and stop or pause the recording process but not send data while capturing. So my problem is that is possible to streams audio capture in real time by native Android functions (Audiorecord class) with a Node.js server by Socket.IO or similar?

I discovered this project, Asimi JS, but I don't know if someone else knows a better way to do what I want.

Thank you very much for your help!

Answer 1

It is certainly possible to do it, but a standard NodeJS http server would not be advisable as it uses tcp. You want to use UDP as a transport layer for audio, since it will be faster and the small packet loss that can occur will most likely not be a problem.

To be completely honest with you it sounds like you need to write a few demo applications on the native platforms - so do not use phonegap. You need native platforms in order to access things suchs as the mircrophone and to stream over UDP.

When you have a demo working, you can go on and try with another platform afterwards, but start with a simple setup instead of trying to do it all at once - if it was that easy, someone else would have done it before you.

Let me recommend a simple UDP server in whatever language you are most comfortable with such as (NodeJS, Java, C, C++, C#). Let the UDP server receive and save the content into a file that you can then play back on a desktop computer to verify the result. As a simple client, build one either on Android or iOS, and stream a file that you have already recorded and included in the app. When you have this setup working, you can try to capture the microphone, then do a user interface, then support multiple phones, then build a server which records the conversations, then build a user database, and so on a so forth. But start with a prototype of your main feature.

Answer 2

I've finally discovered and solved my problem (at least that's what I think)...First of all I created a server to send and receive UDP packets by DatagramSocket and after that, to achieve communication between server and client, when I was connected by 3G, I needed to have a static port and IP, that's why my server couldn't connect with the client. With data connection, the user IP and port is not always the same and you have to keep the same socket always opened if you want to send and receive. On the other hand the server has to store the adress and port from the client in the moment of connection.

Thank you very much for your help ExxKA