Over the next five years, revenues from the circuit switched voice market are expected to continue to fall.
According to a new report from Juniper Research, the number of mobile video calling users are expected to increase to almost 160 million by 2017.
The increase will be driven by improvements in both user-interface and underlying technology.
According to the report, advertising and freemium models are starting to emerge in the mobile video calling market but revenue generation remains the key challenge for mobile video calling players.
The report, titled Mobile & Tablet Voice & Video Calling - Strategic Opportunities & Business Models 2012-2017, states that freemium models are being explored, but are behind other areas of the broader mobile market, while mobile advertisers have yet to explore the potential of mobile video calling in earnest.
Juniper Research analyst and author of the report, Anthony Cox, said: "Mobile advertising per se is becoming main-stream but the model still needs to be adapted for mobile video calling for meaningful revenues to become available to service providers."
The report finds that specialist mobile VoIP firms are opening their Application Programming Interfaces to third parties, including MNOs, to gain revenues.
According to the report, the arrival of 4G will give further impetus to mobile VoIP take-up but potentially accelerate the decline in overall voice revenues for MNOs.
Advanced IP-based services will develop faster in developed markets due to the direct correlation between 3G and 4G roll-outs and