Relation between FPS and Game Speed.

[IM0001]

Got streaming up and running between my beast of a gaming rig, and my modest Steam Box on the first try. Wirelessly it actually worked rather well but seemed to top out at around 68Mbit/s. Wired via gigabit I can pull upward toward 450Mbit at 1080P/60.

The one problem I am running into is the speed of the game seems to not properly scale with FPS, or at least is slowing down based on some factor I can't quite identify.

Take Rayman Origins for instance. Wired I can get it to run at 1080P/30FPS maximum it seems (limited by Steam), however the game runs way to slow to be fun. (it is smooth, sound works great, but the gameplay reminds me of multiplayer in the dial up days, you can jump and get a cup of coffee before Rayman lands again but you can see every smooth animation of the process.)

Also tried Risk of Rain which also works great and streams at 1080P/60fps, but again is extremely slow.

Now dropping down to 720P, Rayman Origins and Risk of Rain work at their correct speed even though I can set the FPS to 30 or 60, and the speed remains normal.

I am just wondering if this is a side effect of the Software based Encoding so far or something else as I also have an Nvidia Shield which can stream wirelessly at 60fps or 30fps and all games remain perfectly playable at the speed they were designed for.


For Reference, my system is a 3939K @ 4.6ghz, 32G DDR3 2133, SLI GTX 780's, X-Fi Titanium, Windows 8.1 Pro.

Router between Steam OS and Main System : Netgear WNR3500.

SteamBox is a Zotac H55 with a i3 2100 @ 3.1ghz, GTX 560TI, 4G DDR3.

[IM0001]

Ok. So I am a bit puzzled. Playing any game has the issue of great FPS as per the streaming statistics. (30FPS or 60FPS depending on the game and Res, it locks it in good close to those numbers) However the games themselves are not getting anywhere near that FPS. My main Streaming rig isn't getting loaded at all when streaming while the game being streamed is focused.

Here comes the strange part. If I start the task manager on the Streaming machine and focus on it (or any other application besides the game being streamed, the game itself shoots back up to full speed, however the Streaming performance drops down to 20Fps or less and while the game speed is normal, the streaming slowness makes for a normal feeling of playing at 20FPS like it is supposed to.

So can any Steam dev chime in here and give me a clue as to what is sort of going on? Is it some side affect of the way the streaming processes are handeled, is it something to do with the software encoding for now? Does it have anything to do with Multi Monitor or SLI?

If I could get a clean 60FPS out of my game as well as a close to 60FPS stream, everything would be peachy but at the moment, I am a bit puzzled as to what is going on. There are no performance bottlenecks for a game like Risk of Rain but you can watch the FPS rise and fall as I mess with what program is focused (the game, or anything besides the game on the main streaming PC).

[slouken]

When you switch away from the game, we change from optimized game capture to slow desktop capture. When we're doing game capture we throttle the game to clean divisors of the client refresh rate to make the playback smooth, which is why you'll typically see ~60 FPS or ~30 FPS if that's not possible.

[IM0001]

I see. That makes sense but then leads to the Throttle problem. Streaming at 30/60FPS has no meaning when the game itself is forced way below either number. A forced V-Sync of 30/60FPS I would believe to be a better solution as you want the game to play at full speed, but the graphics to be sent at a similar rate as the stream which makes sense.
Is there any way to override the throttle to test on a per system level?

[slouken]

The FPS reported on the client are the actual FPS of the capture, which in turn is driven by the render rate of the game. If you're seeing 30 FPS, then the game is actually rendering at 30 FPS. You should be able to tell by turning on FRAPS or something similar.

[IM0001]

Risk of Rain has its own FPS counter built in. When the F6 stats for Streaming is on, the streamer says 58ish FPS or pretty darn close to 60 and it stays there solid. Risk of Rain's counter however hovers around the mid 20's. This makes the game run smooth, but much, much slower than it is supposed to.

Doing the focus trick, the game then shoots back up to 60 and stays there, while the streamer drops down to 20FPS and holds there. The game then is fully playable at normal speed, but feels like you are playing at 20FPS.

I will upload a log with both situations in just a sec.

[IM0001]

Here are the two logs. This First one[dl.dropboxusercontent.com] shows the game running at 27FPS as shown in the bottom right. The Streamer says 58.82FPS on the left.


This Second one[dl.dropboxusercontent.com] shows the change when not focused on the main system. The Game itself now reports 60, while the streamer has dropped to 19.61.

[IM0001]

Was wondering if having a multi monitor setup was causing any issues with the capture but disconnecting all monitors except the primary did not change anything.

[IM0001]

Ok that is peculiar. Streaming from my main system to my tablet, a Acer Iconia W500 (C60/Radeon 6290) which has trouble without Hardware Decoding and throws Slow Decode errors which I understand, has an effect again on the render of the host PC. The streamer is set for 720P and 30FPS on the tablet. The streamer shows roughly 30FPS, yet the game this time was forced down to 10FPS on the host PC as shown in the games FPS counter. (And you can really feel it).

[IM0001]

Well how about that, streaming Risk of Rain from my tablet to my main PC, while nearly a futile feat with the speed of encoding, is able to still render the game on the host PC at 27FPS which is near full speed for the tablet. Without streaming the game plays at around 28-30FPS.
The streamer itself reports .97FPS however which I could believe lol.

[IM0001]

Well I believe that is enough testing for one night for me. The tech is amazing and works great for the most part. If I can just get around this slowness issue, I can see myself using this a ton as that was part of the reasoning behind my new Panasonic Plasma purchase right around Christmas and building an ITX Steam Box. My Nvidia Shield right now can also stream most all Steam games at 1080P/60 over a wired network so it fully is possible.

[slouken]

Thanks for the test case, I'll investigate.

[IM0001]

Would you be able to leave a response on your findings here or go to more direct communication? I would be happy to help diagnose this finding directly if you would like. I have a big enough game collection and many more various different hardware configurations to throw at it.

[IM0001]

Ok messed with Streaming a good bit more and I can say that the slowdown doesn't affect all games, only some and a few start out affected but speed up a short bit later. Overall once Hardware Encoding is in I believe things will smooth out even more for 1080P gaming.

Games like Blur, Guacamole, Spelunky, DiveKick, all work and look correct and are fully playable.
A few games didn't work correctly as far as controls are concerned like Ducktails Remastered but I believe that will get fixed in due time.

I still have problems in Risk of Rain and Rayman Origins being way too slow so for some reason it is those two games (the first 2 I tried with streaming actually) that have the issue. Very strange for sure.

[IM0001]

After even more testing. It seems the last few updates have improved streaming for the few games that were having the slowdown issue. Not completely but it is helping. However now the audio quality seems to have been cut in half for all games which is unfortunate. Much lower noticeable bitrate and some static here and there.
Also now with the speed improved a few games show Slow Decode on my i3 2100 cpu in the SteamBox which is understandable. Looking forward to hardware decoding to hopefully improve both Audio and Video.