Voice and Video messaging app - App project

Mobile app project description

We want to develop a voice, text,photo and video messaging app on android.
Key focus is on an intuitive,beautiful yet minimalist UI/UX and great coding for a super-lightweight,robust and scalable app as the target is consumer segment.
Need dev agencies with great UI/UX and design sense along with superb coding skills and expertise in voice and video compression techniques.
App should work seamlessly on low speed/congested networks without draining the battery and with minimal bandwidth consumption.
Preference for dev agencies with deep domain expertise in voice and video messaging space with some established IM apps deployed on the android platform.
Reference apps are Mirage and Samba apps from Israel.
Don't need the reaction capture as in Samba app.
This is an URGENT requirement, so a quicker response will be appreciated.
Thanks