Harald To be sure, could you perhaps share the settings of the used Universal Render Pipeline Asset that is assigned at Project Settings - Graphics - Scriptable Render Pipeline Settings.

Sure! Here are the settings I used for my URP Asset during testing:

Then the settings in the Renderer Data Asset are:

Harald Also please check whether under Project Settings - Quality there is no Render Pipeline Asset assigned which overrides the one in the Graphics section.

I assigned the URP Asset to each Render Pipeline Asset slot for each Quality Level in Project Settings - Quality and not in the Project Settings - Graphics since I assumed this would give us greater control to have more complex Render Pipelines for Desktop builds vs Mobile builds. Should I assign it through the Graphics settings instead?

Harald Additionally, could you please share your Material settings you are using at your skeletons? Does the situation change if you are using an unlit URP shader (either Universal Render Pipeline/Spine/Skeleton)?

That was one of the shaders I was attempting to use for this experiment actually. The settings I'm using are:

I'm using the same general settings for the other two skeletons materials as well (one for the Opponent and two for the Player).

Hate to be a bother, but any extra help or information you might be able to offer @Harald ?

A small test showed a rotating capsule was able to hit 60 FPS on this Android TV while using URP. Though the RenderFrame was taking nearly 10 ms

Harald erribly sorry, my mistake, for some reason I incorrectly assumed that the unlit Universal Render Pipeline/Spine/Skeleton shader would render normally with 2D renderer, however it is not finding the respective shader pass and does not render anything at all. We have just pushed a commit to the 4.1 branch which adds an unlit URP 2D shader, available under Universal Render Pipeline/2D/Spine/Skeleton.

A new Spine URP Shaders 4.1 UPM package is available for download here as usual:
https://esotericsoftware.com/spine-unity-download
Please let us know if this improves the situation.

Hey no problem at all! I'm happy to report that after updating the package and then switching the shaders to Universal Render Pipeline/2D/Spine/Skeleton it basically doubles the frame rate from 15 FPS to 30-34 FPS on our Android TV device while profiling a Development Build!

Still not the 60 FPS we had hoped for, but we can probably get away with having a lower FPS for TVs

Thank you and the rest of the Esoteric Software team so much for the help you have provided us! If you ever have any other help, suggestions, improvements or fixes that you think might help us out, we'd love to hear them as well.

For a little bit more info the frame debugger is showing that two of our meshes can't be SRP batched, but I'm not entirely sure why. Could it have something to do with this CBUFFER thing, since I assume the Android TV wouldn't support Vulkan.

The Gfx.WaitForPresentOnGfxThread seems to be quicker on a cyclical pattern as well, which seems odd to me. You can see this on the CPU Usage with these Gfx.PresentFrame spikes as well, taking between 13ms and 28ms to complete, which causes Gfx.WaitForPresentOnGfxThread to fluctuate between 5ms and 22ms.

Anywho, thank you again so much for the help you've already given us and for this un-lit 2d skeleton patch

Harald This is indeed strange. Which Graphics API are you using in your Player settings? You could explicitly set a graphics API like OpenGLES3 instead of "Auto" to be sure which one is used. We will do some more investigations on our end, so far we received the expected SRP batching of skeletons with the new unlit shader on our end when using e.g. OpenGLES3.

I had it set to use Vulkan only, since on Android with Unity only Vulkan supports Dynamic Resolution. Setting it back to only OpenGLES3 causes the spikes above 60 FPS to become more narrow, gaining us about 2 FPS interestingly enough.

Harald Apart from that, I see 29 draw calls in your profiler screenshot, but you mentioned you only have 3 skeletons active. I assume that each of your skeletons is not using a single atlas page texture but multiple. How many are you using per skeleton? While I'm, not sure how you setup the skins of your characters, you could consider either packing combined skins to a single atlas page, or grouping attachment images differently to atlases (or changing draw order, if possible), so that you don't have as many necessary texture switches, like avoiding ABABABA and instead grouping to e.g. AABBBAA which will then result in draw calls ABA.

Is there some more information about this somewhere that I can give to the artists? I'm certain that this is what's happening, as only one of the skeletons has more than one atlas and uses skins (the player spine uses two atlases with several skin variations). In the inspector because of this it creates 29 materials for this one skeleton. But I don't do the art or work with Spine directly myself as the engineer on the team, so I'm not exactly sure how to explain this to the artists or help them solve this issue. Some additional context is that we are also dynamically coloring many of the region and mesh attachments for the player's skeleton as well. Would this, in addition to the second atlas, be causing the ABABABA[...] rendering loop, or is it solely on how the spine itself was created by the artists/how the atlas was exported.

Rendering only the other two skeletons, opponent and crowd, brings us up to 50 FPS as well.

Harald A quick guess is that this could be due to unlucky timing when waiting for VSync, taking a bit longer and then having to wait for the next VSync timepoint.

Unfortunately that couldn't be it, as not only do I have VSync disabled, but both Every VBlank and Every Second VBlank are both ignored on Android, iOS, and tvOS according to the Project Settings window.

Another curiosity is that the crowd skeleton is the only one I can see in the Frame Debugger. No frame that I click on seems to contain the opponent skeleton anywhere that I can see (and it uses an entirely different atlas than the crowd does). This is a screenshot of the frame debugger without the player skeleton rendering:

Harald Very glad to hear that it improved the situation, thanks for the info and for your kind words! Please also be sure to judge the final timings with Development Build disabled.

In testing this I found with all three skeletons the Release Build had no noticeable improvement in FPS over the Development Build oddly enough. Perhaps because this scene and project are so simple?

Harald You can find a short explanation here:
https://esotericsoftware.com/spine-unity#Material-Switching-and-Draw-Calls

Thanks, I'll give this a read through and show it to the artists as well!

Harald What does the current list of materials at your skeleton look like in the Inspector, do you only see two materials alternating many times, or do you see many different materials (e.g. because you're using blend modes at certain slots and slot material overrides)? In any case, grouping attachments (ordering them so that they are in sequence in the draw order) that require the same material would "fuse" two or more draw calls to a single one.

I see the same two materials alternating back and fourth 29 times, which is why I had assumed that this could be part of the issue and that "fusing" these 29 draw calls into 2 or 3 I'd think would get us closer to the 50 FPS with all three skeletons rendering. We also aren't doing any type of blending or anything with these spines, just the "Normal" blending mode.

Harald You might also try if runtime repacking fits all your used attachments into a single atlas texture, see sub-section "Runtime Repacking" here:
https://esotericsoftware.com/spine-unity#Combining-Skins

I can try that out when we start using the skins we've implemented in this test scene, but right now I have only applied a single skin through the SkeletonAnimation inspector window. (I might be doing something wrong too, because a very quick test I threw together to test the Runtime Repacking feature gave me a malformed atlas and several errors in the Console window with the following format:
Graphics.CopyTexture called with region not fitting in source element: trying to copy from region (x:2218, y:1147, width:194, height:136) of mip 0 (size: 2048x2048)

I did set those textures to Read/Write as well, and it didn't improve the situation there.

The script I used for this test was mostly CnP from your Spine Examples for Mix and Match, but here it is anyways in case you spot something I'm doing entirely wrong. My biggest guess as to what I'm doing wrong is that I'm using the wrong material, since the skeleton uses two materials (alternating back and forth 29 times as I mentioned earlier).

using UnityEngine;
using Spine.Unity;
using Spine.Unity.AttachmentTools;

public class DummyRepacker : MonoBehaviour
{
    public SkeletonAnimation Skeleton;

    public Texture2D runtimeAtlas;
    public Material runtimeMaterial;
    
    void Start()
    {
        // Create a repacked skin.
        Spine.Skin repackedSkin = new Spine.Skin("repacked skin");
        Spine.Skin skin = Skeleton.skeleton.Data.FindSkin("male");
        repackedSkin.AddSkin(skin);
        skin = Skeleton.skeleton.Data.FindSkin("male_head_1");
        repackedSkin.AddSkin(skin);

        repackedSkin = repackedSkin.GetRepackedSkin("repacked skin", Skeleton.SkeletonDataAsset.atlasAssets[0].PrimaryMaterial, out runtimeMaterial, out runtimeAtlas);
        Skeleton.skeleton.SetSkin(repackedSkin);

        // Use the repacked skin.
        Skeleton.Skeleton.Skin = repackedSkin;
        Skeleton.Skeleton.SetSlotsToSetupPose();
        Skeleton.AnimationState.Apply(Skeleton.Skeleton); // skeletonMecanim.Update() for SkeletonMecanim

        // You can optionally clear the cache after multiple repack operations.
        AtlasUtilities.ClearCache();
        Resources.UnloadUnusedAssets();
    }
}

Harald That's strange indeed. You could do a test in the Unity Editor and watch the Game view while going back and forth in the draw-call-timeline at the top of the screenshot, then you should see when the crowd appears in the list of draw calls. If the list is completely different, that won't help of course..

Sorry about that, it was just my misunderstanding of how the Frame Debugger is displayed. With both the Crowd and the Scam Caller they get properly rendered with SRP Batch in two draw calls, and if I disable one or the other I see a single draw call in SRP Batch now. So it's only the player spine that isn't getting properly batched, even with OpenGLES3 enabled.

Harald Ok, that at least saves compile time for diffent builds when testing then . A quick guess it that it could be because it's GPU limited and any optimizations would mainly affect performance on the CPU side. Anyway, that's just speculations of course.

Actually that makes a lot of sense, I hadn't thought of that. Because the CPU isn't being hit almost at all with these test I'm running, everything is GPU bound. I'm sure that the Unity Profiler doesn't use hardly any GPU bandwidth at all, and likely just eats up CPU Usage instead.

Harald Thanks for the additional info, that's good news regarding potential improvement, as 29 draw calls for a single skeleton sounds close to worst-case order. Then we would definitely recommend changing draw order or grouping of attachment images to atlas pages.
Harald No need to apologize. That's good to hear at least. Then merging at least some of the player-skeleton's draw calls by avoiding unnecessary atlas page texture switches should improve the situation.

When the artist is ready to make this change for the new player character skeleton, I'll be sure to let you know how much of an improvement, if any, that we see

Harald Did you check whether (apart from "Read/Write Enabled") the other requirements are met? You can find them in the note box listing "Important Note: If repacking fails or creates unexpected results, it is most likely due to any of the following causes:" in the Runtime Repacking section.

If all of these are met, could you perhaps send us a minimal Unity project that still shows this issue? You can send it as a zip package to [contact@esotericsoftware.com](mailto:contact@esotericsoftware.com), briefly mentioning this forum thread URL so that we know the context.

As far as I can tell all of these requirements are met, except that the Player's second atlas isn't a power of two texture. But Unity claims it does default the Texture Import Setting Non-Power of Two to None, so I believe the final requirement is fulfilled there as well. I do say claim, because I cannot actually see the Non-Power of Two setting anywhere on any of the textures I selected, nor in the Project/Unity Settings for defaults.

I'm sending the minimal Unity project over to your support email right now. Thanks again for all your help so far!