Android VOIP application - problems establishing a voice(RTP) connection

Budget $250 - $750 USD
Bids 11
Average Bid $1036

I have an Android VOIP application which has problems establishing a voice(RTP) connection. The application actually has two voice connection implementations: a custom one based on Sipdroid and an implementation made using built-in Android RTP API ([url removed, login to view]). And you only need to fix ONE of these.

The first(Sipdroid based) implementation doesn't work reliably - from some reason it occasionally fails to transfer voice (RTP) data between the caller and callee. Plus it rarely succeeds in establishing a connection between the caller and calle if one of them is using a Samsung phone. It appears that UDP hole punching doesn't work very well on Samsung phones. The second ([url removed, login to view]) implementation works almost perfectly. Its sole problem is that it has a terrible 2 - 4 seconds latency. I.e. it takes between 2 and 4 seconds for caller to hear what the calle said and vice versa.

So, long story short I need someone familiar with RTP protocol, Android networking and perhaps VOIP in general to either fix the current code or create a new RTP layer from scratch. If you have ever created a VOIP Android app that uses RTP protocol to transfer voice data you should be capable to fix this. Note that your job on this project is just to take care of RTP related code, everything else is in place and working.

If you don't have experience with this kind of applications don't bother bidding.

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  • digitalhorizuk10 Profile Picture


    London,  United Kingdom

    We can create mobile apps that are high on graphics, those that connect with databases, enterprise systems and websites or simply those that have fun, learning and interaction built in.

    PHP, JSP, Javascript, and J2EE

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    Ghaziabad,  India

    About Us: Over the last 14 years, We have developed a wide range of JAVA/PHP enterprise applications using HMTL/JAVA/PHP SCRIPT/JAVA/JSP/Servlet,Struts and MySQL/SQL Server/Oracle database that run on Apache Tomcat/JBOSS/Weblogic/websphere server including sites for startup companies and small businesses. We have good experience in making Iphone/Android/J2ME native application & phonegap framework app as well.Our core competency lies in complete end-end management of a new website/mobile app development project, and we are seeking opportunities to build websites/mobile app from the ground up for you or your business. We also have experience in the following areas: SQL, Web service, OOP, and software design and testing.I am founder of a small startup after serving many MNC's in past as Architect/Technology Manager.we have 10 developers team at present. Our Skills : Open Source: PHP 5, PHP 4, CGI/Perl (Mod_perl/ ActivePerl/ ePerl), Python. Microsoft Technologies: C#, VB.NET, Visual Studio .Net 2003 / 2005/ 2008, SharePoint services 3.0, ASP, ASP.NET 1.1/ 2.0 / 3.0 / 3.5. Crystal Reports, SQL Reporting, Silverlight. IPhone, Mobile & Handhelds: Apple iPhone development using Xcode and Objective C, Blackberry, Google Android, Microsoft Windows Mobile, J2ME platform CLDC1.1, MIDP1.0, MIDP2.0. Frameworks & CMS: Magento, Joomla, Drupal, WordPress, CakePHP, Zend, Flash & FLEX: Adobe Flash CS4, Adobe Flex, Flash Action scripting (AS 3.0), Flash Gaming, Flash Media Server, Flash Remoting, Rich Internet Applications (RIA), Adobe AIR. User Interface / Graphic Design: Adobe Photoshop, Image Ready, Flash, CorelDraw, Adobe AfterEffects, Fireworks, HTML, XHTML, Dreamweaver. Databases: Oracle, Sybase, MS SQL Server 2000 / SQL 2005 / SQL Regards Ieva Technologies skype :

    PHP, Java, JSP, and Javascript

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    Bangalore,  India

    I am Java/J2EE solution architect with 1o+ year of experience and 2 years experience on Android Platform. I also have experience of creating applications/solutions based on web and integration technologies. I am sufficiently exposed and have working experience in Oracle, Mysql, Sqlserver database and also know C, C++. I have also worked on LAMP technologies.

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    PHP, Javascript, Ввод данных, and Тестир-е / Гарантия кач-ва

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    Ahmedabad,  India

    INTERNET TECHNOLOGIES (WEB Applications) AND MOBILE APPLICATION services provider company. We mean and provide a satisfaction work with quality and enriched services World Wide. Even after completion we provide with other services as in updating debugging future enhancement satisfying our customer. We understand all the business firm of our customer and accordingly we provide our strategy to give the best to our customer. We provide with Development like Web Development and Offshore Software, Outsource Software and Web Development, Opensource Software Development, Rich Web 2.0 Development, Web Development, Web Design, Ecommerce Shopping Cart Solutions, PHP/Ajax/RoR Programming and Mobile Application Development.

    Программирование на С, Java, Javascript, and .NET

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    Ahmedabad,  India

    MobiAppDeveloper is experience and expert development firm who serving the world his dedicating service since 5 years. If you want to develop your app and looking for the best team who not just develop but create the dream into app. We assure you that we will give you excellent service and support. Thanks and Regards,

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    London,  United Kingdom

    PHP, Perl, Java, and Javascript

  • abusayed2004 Profile Picture


    Dhaka,  Bangladesh

    Work 7 years on VoIP, Asterisk, A2billing, Vicidial, And any Asterisk based distro. Vtiger CRM, Open VPN, Cent OS, VoIPSwitch, VOS3000, MVTS with oracle DB, or Mysql Red hat, PHP script writer for IVR and AGI implementation on asterisk , have a good team for support and further development.

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  • baonvdev Profile Picture


    Hanoi,  Vietnam

    More than 3 years' experience in IT industry 3 years working in software development and maintenance with .NET frameworks, Java, MS SQL Server and MongoDB database 1 years as Business Analyst and Technique Leader. Has been in charge of all phases of software development and maintenance life cycle. With high technical, business related, customer dealing skills and excellent English (all skills). I have achieved many awards and 3 certificate of Microsoft at work - Core Responsibilities: - With Development Software: Writing packages, librarys to processing medical image for Fujifilm Medical system Writing packages, librarys for enterprise management system (ERP) Create applications, games on the mobile platform(Windows Phone) - With Development Web: Writing packages, librarys to manage the installation and use of applications on mobile devices in the enterprise Writing packages, librarys for enterprise management system (ERP) Make news websites, e-commerce base on open source platforms (Joomla, OpenCart, DotNetNuke, nopCommerce, etc.) - With Development database: Writing package, stored procedure, function, trigger... Database Enhancement and Maintenance: writing script to create, modify table, view... Database Management. Business Analyst (proposal, business and technical specification) Ticket Management. Standby Support. TECHNICAL SKILLS o Programming languages: C#, Java, MS SQL Server and MongoDB ... o Database Management System: MS SQL Server and MongoDB, MySQL ... o Foreign Language: English o Frameworks/ Platforms: .NET 4.0, MVC3, MVC4, MongoDB, MS SQL o Management skill: Ticket workflow management, team management from 3 to 6 persons, customer relationship... o Operation system: Windows Soft skill: Team building activities, Time management skills EDUCATION o Viet Nam Maritime University- Information Technology faculty - Bachelor of Computer Science. o NetPro academi - Information Technology faculty - Microsoft certificate of achievement. o MCP Certificate Of Service Communication Applications with Microsoft .NET Framework 4 o MCP Certificate Of Web Application with Microsoft .NET Framework 4 o MCP Certificate Of Accessing Data with Microsoft .NET Framework 4 Ps: Employer can goto site and type Transcript ID (1035659) and the Access Code (baonv2109) to see my Microsoft transcript PROFESSIONAL EXPERIENCE ? Project Name: J-iPad (from November-2012 until Now) o Project description: Create a system that allows managers can manage iOS devices and the software running on the device. o Responsibilities: - Customer design document analysis and propose solutions, system development and maintenance. o Technology: - Programming language: Java, MDM server - Database: MS SQL Server 2012 ? Project name: Tomo AWS-5.0 (from July-2012 until November-2012) o Project description: Develop image processing system, support the diagnosis based on the X-ray image processing for customers Fujifilm medical. o Responsibilities: - Develop image process library, moduls display image, moduls manager image of patients - Maintain system and fix bugs. o Technologies: - Programming language: .NET framework(C#) - Database: MS SQL Server 2008 ? Project name: KheCham ERP System (from August-2011 until June-2012) o Project description: Develop and maintain ERP system for Khe Cham Coal Limited Company - Vinacomin. o Responsibilities: - First join the team as senior programmer analyst to analyze, develop software component, unit and integration testing and maintain program running on server. - Database design, database management, maintenance, corrective and enhancement, manage all tickets of software development and maintenance life-cycle: writing proposal, billing to end-customer, business and technical specification, working with stakeholders at all system level such as development, integration, user acceptance and production deployment. o Technology: - Programming language: .NET framework(C#) - Database: MS SQL Server 2008

    Java, Javascript, XML, and .NET

  • tailong1 Profile Picture


    donggang,  China

    Over the last 7 years, I have developed a wide range of websites using HMTL, DHTML, PHP, Joomla, WordPress and MySQL including sites for startup companies and small businesses. My core competency lies in complete end-end management of a new website development project, and I am seeking opportunities to build websites from the ground up for you or your business. I also have some experience in the following areas: MS Office application(Excel, Word, PowerPoint, VBA) , PDF, Font, Photoshop, Python, OOP, and software design and testing.

    PHP, Visual Basic, Графический дизайн, and Управл. проектами