FireTv Stick 4k

[horaciobp]

Dear all,

First of all, I would like to thank you guys for the amazing job, I've been enjoying the IOS and Windows clients a lot. I actually have two questions one regarding the FireStick and the second regarding the windows client.

With the FireStick I've been seeing decode latency of 30ms (1440p/60Hz/HDR on) which adds a lot of input lag, is this normal or there is a way to reduce that? If not does anyone know how much is the decode latency on the Shield (I will then return the firestick and get a shield)?
On my laptop the decode latency is 0.5ms but there is no HDR, any plans to add that to the windows client?

Again thanks for the amazing software.

[horaciobp]

Just to answer my own question, the shield decode time shows as 1ms. It feels way better when playing FPS games (you can feel the aim overshoot with the FireTv 4k).
The FireTv looks ok for slower games and playable for FPS (you can adapt but the lag feeling is always there). The big plus for the FireTv is the support for Dolby Vision, and it may be just my impression, but I feel it looks way better than HDR10.
Another important point is that if you change to H.264 the FireTv decode time is in the 30ms ballpark as well (idk if is using software decode or this is the HW decode time), so there is no way to reduce that, at least for now.
I'm sticking with the shield.

[J4ves]

Were you using an Ethernet cable with the Fire Stick 4K?

[MopheusDG]

Have 2 different fire tv's a 4K and normal Stick (both using WiFi AC) and both have the same issue. I think there's something on the Fire TV's that add too much delay for some reason... I tried on PC and even Android Phone via WiFi with no issues, but Fire TV is a pain for me too. Hope they could find the problem with them....

[horaciobp]

Yes, I was using an Ethernet cable, at the end I returned the Fire Stick and bought the Nvdia Shield.

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs.

[seanocali]

I can confirm this is still happening. I own a dozen Fire TV devices. I tested the latest 4K stick, both Wifi and ethernet using the USB adapter. I also tested the original Fire TV box, the 2nd gen box, the 3rd gen pendant, and a 2nd gen stick. All of them show ~23ms decode time.

Same server, same Moonlight settings, same games, I get under <5ms with an Nvidia Shield.

[cgutman]

It’s a hardware limitation. The Fire TV decoders are slower than modern Exynos and Snapdragon devices.

[seanocali]

It’s a hardware limitation. The Fire TV decoders are slower than modern Exynos and Snapdragon devices.

If that's true then Amazon really screwed themselves as far as Luna is concerned. I'm a little skeptical this is the cause given that the different Fire TV devices have different SoCs with very different performance specs yet they're all 23ms delay both h264 and h265 (when available).

There's also a YouTube video of a guy setting up Moonlight on a Fire Stick and it has a 23ms delay, then there's a jump cut in the vid and it's magically 6ms.

[seanocali]

So I tried just every resolution. 480p/3mbps has the same exact delay (23ms) as 1440p/40mbps. I just don't see how this can be a physical hardware limitation given that fact. Is it possible the Fire OS audio post-processing is causing this?

[cgutman]

The different Fire TV hardware does indeed vary. The early Qualcomm-based Fire TVs have different latency characteristics than the later Rockchip and Amlogic decoders.

HEVC does perform better than H.264 on the pendant Fire TV, which is why Moonlight uses it by default.

Remember that there’s more to hardware than just the physical silicon. The drivers also play a big role. Some drivers support low latency mode (based on profile detection or undocumented OMX/C2 parameters), while others don’t. Some drivers will not produce an output frame until they get some number of additional input frames.

Moonlight tries to patch up the SPS to hit the fast path on drivers/hardware where such optimizations are known (and requests low latency decode using the Android 11 API), but without documentation it’s not possible to do across the board.

[seanocali]

Thanks. Yeah a driver limitation would certainly explain the behavior I've seen.

I'm still flabbergasted by that YouTube video, it's the only thing that gave me hope this could be resolved. I have these things all over the house and they now properly support Xbox/PS4 controllers. Bummer.

[mehditlili]

The different Fire TV hardware does indeed vary. The early Qualcomm-based Fire TVs have different latency characteristics than the later Rockchip and Amlogic decoders.

HEVC does perform better than H.264 on the pendant Fire TV, which is why Moonlight uses it by default.

Remember that there’s more to hardware than just the physical silicon. The drivers also play a big role. Some drivers support low latency mode (based on profile detection or undocumented OMX/C2 parameters), while others don’t. Some drivers will not produce an output frame until they get some number of additional input frames.

Moonlight tries to patch up the SPS to hit the fast path on drivers/hardware where such optimizations are known (and requests low latency decode using the Android 11 API), but without documentation it’s not possible to do across the board.

I am pretty sure Moonlight does stick to H264 on my 4k Fire stick from 2020, whatever option I choose. I am not sure why this happens though. Can anyone try forcing H265 and display the settings overlay during the stream? (My host PC runs on a GTX 1650 so it definitely supports H265)

I also get decoding times around 25ms btw.

[JYAnchang]

The different Fire TV hardware does indeed vary. The early Qualcomm-based Fire TVs have different latency characteristics than the later Rockchip and Amlogic decoders.

HEVC does perform better than H.264 on the pendant Fire TV, which is why Moonlight uses it by default.

Remember that there’s more to hardware than just the physical silicon. The drivers also play a big role. Some drivers support low latency mode (based on profile detection or undocumented OMX/C2 parameters), while others don’t. Some drivers will not produce an output frame until they get some number of additional input frames.

Moonlight tries to patch up the SPS to hit the fast path on drivers/hardware where such optimizations are known (and requests low latency decode using the Android 11 API), but without documentation it’s not possible to do across the board.