I’m sure this is a simple one for you chaps on here. In the past I ran cables from my AV outlets on the rear of the tv to the AV socket on my Nait 5. Worked a treat. Now I have a soundbar connected to the tv via an optical link from tv to bar. Great. However, I have the option of turning the bar off and still using the av function on the Nait but nice connected to the Sony Hard disk recorder. So, I select the Sony hard disk recorder via HDMI cable as the tv input. This means my audio op is via the Nait - but, the video/audio are not synchronised. Any ideas why ??
HDMI exhibits delays through its circuits. The theory is that ARC declares the time taken within a devices internal circuits so that it can be auto compensated for. Don’t think it interops that well. You will need to manually adjust lip sync to bring it in line. The TV or Sony will likely have a function in their menus to do this.
Not sure about your Sony box, but the TV will probably have a lip sync adjustment. The only problem is that this can only increase the delay in the audio signal, so it may or may not help.