Dear Pham
It’s a step about setting audio to recording with R20081
1.You have to open the function on camera site at first (open the function about audio mode and codec type like pic.1)
2.Enter to NVR’s IE interface and chose audio (like pic.2)
3.Chose audio source(when you select audio 1 , it means setting with CH1 (If you want to setting another CH ,you have to choose another audio number),also setting audio mode type and audio in codec type.(like pic.3)
4.After you finish your setting ,you can hear the sound which camera get in live view mode(this step is a way to check camera and NVR can get audio source, but in live view mode you only can hear one CH sound which you select
5.In play back mode chose the video you want to export and chose the function export to USB, after the recording file export to USB ,you can see the video with audio.(video with audio we only support in USB mode at this time)
If still have questions, you can tell me those issue by mail
Thanks for your feedback