Sinch uses the Opus codec for High-Definition voice. This is a flexible codec which adapts the voice quality to the quality of the network currently used. A good connection results in HD voice quality.
Sinch uses the hardware accelerated H.264 codec for video for both iOS and Android. If this is unavailable, then software H.264 is used.
Visit the In-App Voice Calling product page to learn more about Sinch’s In-App Voice calling products.