Hi, A typical case for PA is to output streams from two or more sinks at the same time. PA provides a special module to handle this case -- module-combine. Let's analyze a case on mobile phone. Mobile phone have two sinks, one sink for embedded speaker, one sink for BT headphone. When call is coming, ringtone should be played. The rule for ringtone is: 1. if no BT headphone, ringtone will out from speaker. 2. if BT headphone is paired, ringtone will out from speaker and BT headphone. At first, BT headphone is not paired, so ringtone will be direct to sink for speaker. Then BT headphone is paired when ringtone is playing, and ringtone should output from speaker and BT. For such situation, module-combine should be used. As we know, after a lot of very complicated steps, ringtone can out from two devices. The issue of above process is : 1. Heavy work Module-combine is complicated and heavy. To make module-combine work correctly, you need to do preparation or initialization before stream flow to dest sinks. In the running stage, module-combine will bring some delay between input streams and dest sinks. 2. Performance & Power module-combine will introduce performance issue and power issue. Performance and power are key concern points for mobile phone. 2. Audio Quality Switching is needed between sinks. Thus the audio quality will be impacted. Is there any good/light method to handle above BT scenario? BR tieg
