There are few guarantees in life, but the Android CTS tests attempt to ensure that all devices correctly perform certain actions. It sounds like what you’re doing makes use of features covered by CTS, so the chances of success are very good, but there can always be exceptions.
For this or any app, it’s good to test on as many different devices as possible.
solved Worrying about the compatibility of Android MediaCodec and MediaMuxer since API-18