This is surprising because samsung says the TV shouldn't be able to do this.
Does anyone know enough about the audio data link/protocols that could tell me if the playbar could be mistaken or if there's a scenario where the playbar is being told it's 5.1 but the audio is actually stereo? Meaning, is there a separation of the label and the actual audio?
Setup: Apple TV 4k connected to my Samsung UN50KU630D TV to HDMI 1 port. Optical audio from TV to my new Playbar.
I've even done a few experiments with the video on my apple tv and the sonos app accurately reports whether the video souce's audio is stereo or DD5.1. The TV even recognizes that my playbar is DD5.1 capable and allows me to select DD5.1 in my expert settings.
When I play movies from Netflix, Amazon Prime, or iTunes that have the 5.1 icon on the video, the Playbar accurately reports DD5.1. When I play YouTube TV (off my Apple TV 4K), which is stereo only, the playbar accurately reports stereo audio.
I've got one of these coming today, b/c I didn't think my tv would be passing DD5.1: AGPtEK 4K x 2K HDMI Audio Extractor Splitter, HDMI to HDMI Audio Converter Adapter Support Ultra HD 4K Toslink Optical Audio Output and 3.5mm Audio with Optical Fiber Cable
Samsung tech support response is below. (*they have my TV model slightly wrong below...I have the UN50KU630D; but they're the same family so I can't imagine the answer would be any different)
Thank you for contacting Samsung. With reference to your email, I see that you would like to know if you can get Dolby digital 5.1 surround sound from the Digital Optical out port of your TV model: UN55KU630DFXZA. I have checked our database, and see that the TV is capable of outputting 5.1 channel sound through the Digital Audio Out port. However, it will output 5.1 channel only in below 3 conditions.
1. When an over the Air Antenna, or cable directly from the wall, or a cable box connected to the Ant IN port of the TV. Only digital stations / signals that are carrying a 5.1 audio signal.
2. When you are using apps(that carry a 5.1 audio track) in Smart Hub from the TV.
3. When steaming media files(that have been encoded with a 5.1 audio codec) from a USB device on the TV.
If you connect any device through HDMI or any other port, in that case, the TV will output 2 channel audio(stereo) through the Optical out port.
Even though HDMI is capable of carrying a 5.1 audio signal because of HDCP (High Density-Bandwidth Content Protection) the TV cannot bypass decoded 5.1 audio content from the HDMI input to the optical output. Because of this 5.1 audio output is not available with the HDMI input.
Best answer by John B