[Toecutter]

I have my firestick  attached to my TV. If I connect the optical out from the TV to my av receiver  will it carry 7.2 surround sound or just stereo? The reason my my TV and firestick are 4k hdr and won't pass through an older avr. 

[WC]

Depends on the TV, but most will only pass through the internal apps and tuner as Dolby Digital surround back through the optical. They will not send out surround from other source inputs. The source inputs are typically limited to stereo on the optical out of the TV. If you want surround your options are get a new AVR, only use the internal apps, or get a 4 k HDMI splitter.

[Toecutter]

Y
Thank you , the issue is i bought a used onkyo reciever.  I was planning on using the arc. It seems the arc hdmi port isnt working the sub port does but its doesn't support arc or hdcp 2.2. I did t pay much for it but it was said to be tested and working.  I'm gonna try and get my money back .

[WGH]

I have my firestick  attached to my TV. If I connect the optical out from the TV to my av receiver will it carry 7.2 surround sound or just stereo?

The answer is that Amazon Firestick will only carry 5.1
https://www.primevideo.com/help/ref=atv_hp_nd_nav?nodeId=GJNRWRVL52FFHJ82


Fire TV/Fire TV Stick

    Streaming Video Quality - up to Ultra HD
    Sound quality - up to 5.1 surround sound, Dolby Atmos
    Closed Captions (Subtitles) - Yes
    Audio Description - Yes
    Live Streaming - Yes (on software version 5.2.6.0 or later)
    Live ad support - Yes
    Ad supported channels - Yes

[Toecutter]

This is from the tech specs of the firestick I have .
"Dolby Atmos, 7.1 surround sound, 2-channel stereo, and HDMI audio pass through up to 5.1. Dolby Atmos is available on select Prime Video, Netflix, and Disney+ titles when connected to compatible equipment."
Not sure if that means it will stream 7.1 on every app or not.

https://www.amazon.com/Fire-TV-Stick-4K-with-Alexa-Voice-Remote/dp/B079QHML21#tech-details_1607977262140

[WGH]

I have not yet seen a movie or program streamed in 7.1 surround sound. I watch a lot in 5.1 Dolby Atmos, usually Netflix, but you need the $17.99/month Netflix Premium subscription (or a friend who has one) and a minimum 3Mb/sec connection. Not all programs have Atmos.

When programs do not have Atmos I use my processor's Dolby Surround setting which upmixes stereo, 5.1 and 7.1 to take full advantage of all speakers in a Dolby Atmos system. Dolby Surround can steer frequency bands individually, producing surround sound with precisely located audio elements and spacious ambience.

Depending on the programs compression codecs I also can use DTS Neural:X which creates separation by placing sounds at different points in the sound field. DTS Neural:X works surprising well to produce 7.1.4 Atmos effects with 5.1 programs, I'm impressed.

DTS Neural:X does not apply to Dolby Atmos, Dolby TrueHD, Dolby Digital Plus sources. Non-Direct mode adapts the audio to your speaker layout if it is different than the content creator's.

[Toecutter]

Gotcha , so to take advantage of 7.1 you need to use a blu-ray ?

[WGH]

I don't have a 4k TV so don't know if HDR 7.1 streaming programs are available, a search doesn't come up with any.

Even the cutting edge, soon to be released (12/15/2020) Tenet in 4K Ultra HD Blu-ray, 2160p HEVC/H.265 HDR10 only has DTS-HD Master Audio 5.1 sound.
https://ultrahd.highdefdigest.com/89968/tenet4kuhdbluray.html

The uncompressed 2160p Tenet is 76.41 GB which is impossible to stream in 2-1/2 hours so quality will take a big hit when it is streamed. Blu-ray will be the only way to see and hear Tenet the way Christopher Nolan intended.