The "WTF is going on with JXD7800 HDMI Output" Thread

[Joe Sixpack (OP)]

Continued From: http://boards.dingoonity.org/jxd-devices/s7800b-1-6ghz-(tweaked)-minimal-firmware-wfixes-(by-jxd)/msg95246/#msg95246

Ok If you missed it kristianity77 first brought up the problem of jerky frame rates when outputting HDMI on the JXD 7800.

All my testing was done on a December unit, This is one of the newer units that run at 1.4
I was running a repartitioned stock 1.1.4 firmware, with Webclaws 1.6ghz kernel.

First off Mame4droid .37 seems to play fine, Previoulsy I thought there was a problem it turns out it was the video setting, SW Threaded seems to play fine, I tested out narc and mortal kombat narc has some slow downs but it's a CPU intense game, and MK played great.

Previously I had said there was no issue with the *oid emulators.
I was wrong, After more time testing I realize they also suffer from problems, By default auto frame skipping (up to 2 consecutive frames) is turned on, This masks the problem very well.. when turned off problems were apparent on that line of emulators also (or at least nesoid)

Kristianity thought perhaps the HDMI output was taxing the CPU, This doesn't seem to be the case.
I ran Nesoid and Nes.Emu with the US version of Castlevania with 1 core active.
Afterwards I checked CPU times and found NES.EMU ran mostly at 800mhz, while Nesoid ran mostly at 500mhz.
Meaning there was a LOT of CPU headroom left.. so it doesn't appear lack of processing power is the issue here.
-Nesoid-

-Nes.Emu-


These devices should be able to run at 100% with no skip..
For the most part they do when not connected to HDMI.

-Unrelated Side Bug, Skip this section if you want
I did however find a curious problem not related to HDMI.
I was running only 1 core with ondemand governor / performance bias / 85% threshhold with a full speed range 312-1608
Odd thing Is when pressing "right" on the Dpad I would get terrible slow downs a lot of the time.. oddly this clears up when releasing right.
No other button causes this including Up/Down/Left or Analogs, or Touch controls.
The problem goes away if the minimum speed is 816 (almost @ 504), or if you run 2 cores active.
This is kinda weird since we already know neither Nesoid or Nes.emu spend much time above 500-800mhz.
This problem persists regardless of HDMI usage.

I noticed this problem mainly on Nesoid and Retroarch (Nestopia) however it's also present in Nes.emu but much less so.
Of course turning on frame skipping seems to mask this issue fairly effectively.

I don't really know why this happens, I have a few half baked theories but im reminded that the system is littered with joystick error messages if you do Dmesg commands in Terminal which maybe related.

Ok back to the HDMI problem.
I tried a couple android games, Zombiewood and Dead Trigger, Neither game seemed to have issue while on HDMI and if there was a frame drop, it wasn't apparent to me.

Kristianity Had said they have problems with everything on HDMI including OS navigation, While I've not extensively tested that I did'nt notice any problems in this area.

I decided to Try Retroarch, Again I stuck with Castlevania using Nestopia core
Results was the same as Nes.emu and Nesoid, Frame rate drop accompanied by broken audio.
I used the newest Retroarch newly reinstated to Playstore (Jan 14th)

I Remembered retroarch had a setting to calculate refresh rate in settings.
Without HDMI the refresh comes to aprox 60hz.. Which should be what we're looking for.
But WITH HDMI active the story changes, It says display is aprox 40hz
I did the test several times and came back with 39-42hz.. Hmm that's interesting but is the retroarch test accurate?
-NO HDMI-

-HDMI ACTIVE-


I decided to turn on FPS and see what we come up with
I came up with a fairly stable 44fps with HDMI and 60FPS (what we want) Without HDMI
-NO HDMI-

-WITH HDMI-


Well it seems apparent that we're loosing about 1/4th our frame rate, Im still not convinced the refresh rate is really 40hz though.. It could be that the mechanism it uses to calculate is ALSO being affected by the problem at hand.

I am not really sure the cause of this problem, or why only some apps are (obviously) affected.
It could be that there is a slight issue with refresh rates, maybe 40 is'nt accurate but maybe 60 is'nt either.

I suppose it could also be related to the vsync issue on video playback.

Im not sure how the HDMI works on this unit, Normally I'd say the Mali is responsible for this but I believe I had read the CPU core plays a role.. EX: I don't think there are any ARM A8 processor tablets with HDMI, Where as I think this is standard (whether they actually implement it or not on a given device) on A9 CPU's
By the same token there are A8/Mali400 Soc's like the Allwinner A13, So all of this would make me think the GPU is actually not responsible for HDMI output.

If it was I could speculate that maybe the HDMI output was dragging the GPU down but the HDMI is mirrored display not independent so it shouldn't be resource intense.
Of course if it was then I'd expect across the board declines especially in 3d heavy apps, Yet that's not what I see.
Zombiewood and Dead Trigger are both 3d and neither seemed to suffer under HDMI in any obvious way to me.
Yet emulators which probably demand little from the GPU are suffering. 

This makes me think again that it must be a Vsync or Refresh rate problem.
Native android games maybe more adaptive then a emulator.

One last thing about HDMI on the 7800
It seems to be glitchy on it's settings.. Even if you have it unchecked (disabled) in settings.
It will still display a picture if plugged in.

Also when you first plug it in you will get 1080p, Even if you have the resolution set to something else.
I ran 720p because that's my TV's native resolution.. When I plugged it in the only way to get to switch to 720 was to go into settings and select 720 (even if it was already selected).

Has anyone any insight into this problem?
Has anyone gotten the 7800 to work with miracast wirelessly? and how has that worked?

[kristianity77]

If you try android games that dont run at 60fps on the device (ala Dead Trigger)  then it wont be that noticeable over HDMI as I believe software like that will just drop frames rather than "slow down" as an emulator would because you dont have an option in android games to control the frameskip.  On my device also, Dead Trigger seems to play "almost" the same as it does on a tablet, over HDMI.  But its not 60fps on the tablet anyway, and its definitely no more than 30fps over HDMI.  Which therefore could still fall in line with the performance lost in other areas, only not as noticeable.  To put it clearer, Dead trigger on my tablet has a fluctuating framerate of maybe between 30 and 60fps (more towards 30 than 60).  So if the device starts to go screwy anytime anything tries to output more than 42-43fps, its not going to be noticeable as much as this game doesn't hit a framerate this high too often anyway.

If you were to take any android software which DOES run at 60fps on the tablet, IE Rayman Jungle Run, Angry Birds, Temple Run, Pinball Arcade, Jetpack Joyride etc, then the frame rate issue is just as apparent as it is during emulators (only the apps dont slow down, they just become choppy - unlike emulators with zero frameskip)

Its annoying as I first thought it was my device, but having spoken to others as well since this, it seems its all devices.  It pretty much renders HDMI out totally useless.

However, the Retroarch report of 42hz is the same what Im getting when I run the same test and if you were to run an emulator (i did snes9x EX) that has a timer on the screen, then the maths dictates that it is also trying to run at around 42hz!  Interesting.   The way I did this was to use Mario Kart on the tablet, with frameskip of zero and obviously a minute on the track equates to a minute in real time.  However, connected via HDMI with frameskip of zero, then a minute in game time is actually 1 minute 17 seconds (by a stopwatch) which more or less equates to the device running at just above 40hz when outputted to the TV with zero frameskip.  So to me it does seem that that is the problem.  The tablet is effectively only throwing out 40fps over HDMI, with zero frameskip means its always going to run a hell of a lot slower.  Like on my video on the other thread, the graphics aren't choppy with zero frameskip, just a lot slower.  The sound is choppy but that always will be when faced with a 40hz issue.

[Joe Sixpack (OP)]

How do you know what speed those android games run?

why does'nt this effect mame4droid? I tested narc and MK, I don't recall what narc runs at but Mk runs at 53fps.. in the arcade it gave up refresh rate for higher vertical resolution (common in midway games)

It seems to run ok But I guess it could be dropping some frames and me not notice.

I do have pinball arcade I will try this when I get achance.

As for the timing.
Im not convinced this proves it's running at 40hz refresh, I do agree this is a possibility but I also noticed the timing issue on castlevania, (gives 5mins per stage) time came out to roughly 7.5 in real time.
However when think about the frame skipping it makes sense.

If the emulation is running at 44fps instead of 60.. AND we do not allow it to skip frames that means time stretches because the emulator MUST complete every frame, If it can not do this at 100% speed it has no choice but to take longer and there for the time to complete the same amount of time IN GAME is going to be longer in REAL TIME.

This does'nt say that the refresh rate IS NOT 40hz, Only that I don't believe the time discrepancy proves that it is.
I am not really sure what the problem is, Although I bet it's going to require a fix from JXD which we are'nt likely to get it looks like.

Im curious if anyone has noticed this problem using the wireless display option.. I don't know anyone who has a TV with that feature.

[foleyjo]

Have you made sure your tv is in game mode?
Haven't tried it with an android but I know when I worked in tech support for a games copany people would have stuttering issues on PS3 or 360 games with HDMI when there TV wasn't in game mode

[Joe Sixpack (OP)]

I'll have to see if my tv that option.
I don't think this is the problem though because it effects the play speed on the console.
Unless maybe a lot of TV's normally run at 40hz?

They should be running at 60hz minimum (or 50hz PAL)

[kristianity77]

How do you know what speed those android games run?

why does'nt this effect mame4droid? I tested narc and MK, I don't recall what narc runs at but Mk runs at 53fps.. in the arcade it gave up refresh rate for higher vertical resolution (common in midway games)

It seems to run ok But I guess it could be dropping some frames and me not notice.

I do have pinball arcade I will try this when I get achance.

As for the timing.
Im not convinced this proves it's running at 40hz refresh, I do agree this is a possibility but I also noticed the timing issue on castlevania, (gives 5mins per stage) time came out to roughly 7.5 in real time.
However when think about the frame skipping it makes sense.

If the emulation is running at 44fps instead of 60.. AND we do not allow it to skip frames that means time stretches because the emulator MUST complete every frame, If it can not do this at 100% speed it has no choice but to take longer and there for the time to complete the same amount of time IN GAME is going to be longer in REAL TIME.

This does'nt say that the refresh rate IS NOT 40hz, Only that I don't believe the time discrepancy proves that it is.
I am not really sure what the problem is, Although I bet it's going to require a fix from JXD which we are'nt likely to get it looks like.

Im curious if anyone has noticed this problem using the wireless display option.. I don't know anyone who has a TV with that feature.

I dont know what speed they run.  Its very easy to tell however the ones that run at 60 like I mentioned.  And to play the ones i listed on the tablet then go over to HDMI its very noticeable.  What I mean is, is games that dont run fluid on the tablet anyway, you wont notice the difference so much over HDMI.

For what its worth I've just tried mame4droid (37.b5) and the issue is exactly the same. 

Roms tested:

Shinobi, Bomb Jack, Dynamite Dux, Rastan, Strider, Saint Dragon - All games thats run 60fps on tablet with Vysnc on, turn it over to HDMI, same problem, emualtion slows by about a quarter. 

I'm gonna stick my neck out here and say that this quarter slowdown thing is absolutely throughout everything, from the homescreens, to emus, to android games the lot.  If you grab a smooth launcher and flick between homescreens on the tablet then just plug the HDMI cable in and just keep on flicking the homescreens looking at the tablet and not the TV, you can see the difference on the tablet.  It doesn't matter what you run or how you run it, the fluidity of the tablet drops as soon as the HDMI cable goes in, and no matter what program you run, the problem is there.  Its just more noticeable on some apps than others.

Also, regarding framerates you are seeing reported in mame I wouldnt pay much attention to them.  If you use any of the .emu series for example, they will still show 60/60 even through HDMI when its obviously slowing down. 


EDIT:::

Ok, some other things I have now picked up on in testing.  Rayman jungle run.  Everything slows down over HDMI.  Frame rate is less but also, like mario kart, the whole thing has slowed down time wise.  You pull the HDMI cable out, you can see the game speed up.  Put it back in and the game slows down,  Maybe 25%.

Also, go on to the google play store and download a little program called OPENGL FPS Test.

Run it without hdmi, 60fps all the time (its obviously hitting the 60hz ceiling here)

Plug the cable in....bang....41-42fps (this has to be a new ceiling that is set now HDMI is plugged in because its too consisitant with other programs like retroarch etc.  Bare in mind also that this test is so basic, it can run at full speed at 300mhz.  Running at 1.6ghz makes not one jot of difference.)   All its doing is scaling a piece of writing on the screen.  This device for whatever reason, im 100% sure is locked in one way or another to only allow a max of 42fps through HDMI (or some weird 42hz glitch).  You might get certain programs showing an FPS counter as displaying more, but I'll bet my house on the fact that it never is.


EDIT 2:::

Have also just tried another program called Epic Citadel which benchmarks the Unreal Engine on the device. 

Without HDMI, average FPS is 46.1
With HDMI, average FPS is 29.1

I noted all the way through the HDMI test that the FPS counter would not go above the early 40s even though without HDMI, it would hit 60fps in place.  Again, more proof that somehow, the device is locked.  It also shows why the average FPS is only 29.1 through HDMI because the score is lowered due to the inability for the FPS to be higher than 42 at any one point. 

[kristianity77]

Have you made sure your tv is in game mode?
Haven't tried it with an android but I know when I worked in tech support for a games copany people would have stuttering issues on PS3 or 360 games with HDMI when there TV wasn't in game mode

On my TV I can switch on an info page and it will tell me exactly what is being sent to the TV.  If i switch the resolutions or the refresh rate as per options on the S7800, then that is what is being shown on the info screen on my TV.  So it cant be an issue with TV's.  Its got to be the device.

[crispy]

hey joe,
I have tried to use the wifi display on my Samsung smart tv
I tried to play dead trigger and gt racing 2 and both of them were laggy and virtually unplayable

[Joe Sixpack (OP)]

I checked, my TV does not have a "game" setting :/

Tried pinball arcade, you're right there is a little loss of frames there far cry from the emulators and it was still playable.. it took me a few times comparing to make a judgement on it.

But ya was a difference... If the refresh rate IS the problem, we need to first ask.. what is the minimum LCD's will accept? I never seen one listed as less then 60hz(50pal), will they accept lower?

My TV says the signal is 60hz but that may not be accurate I suppose.

Im gonna break out some foreign roms later (Native PAL) and see how they run.

I dont know what speed they run.  Its very easy to tell however the ones that run at 60 like I mentioned.  And to play the ones i listed on the tablet then go over to HDMI its very noticeable.  What I mean is, is games that dont run fluid on the tablet anyway, you wont notice the difference so much over HDMI.

can't speak for you but Dead Trigger plays fairly well on mine so it's not a jerky mess I could'nt tell a difference on HDMI.

For what its worth I've just tried mame4droid (37.b5) and the issue is exactly the same. 

Roms tested:

Shinobi, Bomb Jack, Dynamite Dux, Rastan, Strider, Saint Dragon - All games thats run 60fps on tablet with Vysnc on, turn it over to HDMI, same problem, emualtion slows by about a quarter. 

I tried rastan and vendetta (both 60fps games) While I can't swear it was'nt dropping a frame or two some where it played pretty well, no sound distortion and nothing like seen on other emulators.

I'm gonna stick my neck out here and say that this quarter slowdown thing is absolutely throughout everything, from the homescreens, to emus, to android games the lot.  If you grab a smooth launcher and flick between homescreens on the tablet then just plug the HDMI cable in and just keep on flicking the homescreens looking at the tablet and not the TV, you can see the difference on the tablet.  It doesn't matter what you run or how you run it, the fluidity of the tablet drops as soon as the HDMI cable goes in, and no matter what program you run, the problem is there.  Its just more noticeable on some apps than others.

Maybe you can do a video on the launcher, I use Nova and im not seeing the problem, maybe it's to subtle for me to notice.

Also, regarding framerates you are seeing reported in mame I wouldnt pay much attention to them.  If you use any of the .emu series for example, they will still show 60/60 even through HDMI when its obviously slowing down. 

Is there a show FPS setting in .Emu's? I did'nt see it before..

BTW Try running 0 frame skip in nes.emu and switch video system to PAL
"seems" to play fine, but Pal is 50hz, you'll notice the game runs slower (including tempo of music) this is normal when trying to run a NTSC game as PAL.

EDIT:::

Ok, some other things I have now picked up on in testing.  Rayman jungle run.  Everything slows down over HDMI.  Frame rate is less but also, like mario kart, the whole thing has slowed down time wise.  You pull the HDMI cable out, you can see the game speed up.  Put it back in and the game slows down,  Maybe 25%.

Also, go on to the google play store and download a little program called OPENGL FPS Test.

Run it without hdmi, 60fps all the time (its obviously hitting the 60hz ceiling here)

Plug the cable in....bang....41-42fps (this has to be a new ceiling that is set now HDMI is plugged in because its too consisitant with other programs like retroarch etc.  Bare in mind also that this test is so basic, it can run at full speed at 300mhz.  Running at 1.6ghz makes not one jot of difference.)   All its doing is scaling a piece of writing on the screen.  This device for whatever reason, im 100% sure is locked in one way or another to only allow a max of 42fps through HDMI (or some weird 42hz glitch).  You might get certain programs showing an FPS counter as displaying more, but I'll bet my house on the fact that it never is.


EDIT 2:::

Have also just tried another program called Epic Citadel which benchmarks the Unreal Engine on the device. 

Without HDMI, average FPS is 46.1
With HDMI, average FPS is 29.1

I noted all the way through the HDMI test that the FPS counter would not go above the early 40s even though without HDMI, it would hit 60fps in place.  Again, more proof that somehow, the device is locked.  It also shows why the average FPS is only 29.1 through HDMI because the score is lowered due to the inability for the FPS to be higher than 42 at any one point. 

Im still not sure this is proof the thing is outputting 40-42hz with HDMI.
It could be that, but then again we also know the rk3188 has some sort of Vsync issue on video play back.
This problem might be one and the same.

I don't really know.

Obviously we agree there is some issue with the device the question is what.

hey joe,
I have tried to use the wifi display on my Samsung smart tv
I tried to play dead trigger and gt racing 2 and both of them were laggy and virtually unplayable

When you say unplayable..
Does did you get distorted sound and jerky frame rates? or do you mean there it was smooth but with a delay that made it impossible to control?

[substring]

Just an idea : the HDMI output is progressive, not interlace. It may have something to do with the VSYNC of the TV, and could not be hardware related, but Android dependant. A few tests with some other gaming devices (or maybe even smartphones ?) would confirm that I guess

[crispy]

Hey' sorry I should of explained better
It runs smooth on tablet but when I look at my TV
Its running about 5fps with about a 2sec delay from my tablet
When I went on tube there was still a slight delay but running video was quiet smooth?

[kristianity77]

You can download an app off the play store called FPS Meter which pretty much confirms that there is an underlying issue with the device.  It displays the FPS of your device at all times in the top right hand corner whether your just in the homescreens or any app. 

App is this in case anyone else wants to test their device

https://play.google.com/store/apps/details?id=com.aatt.fpsm&hl=en_GB

Obviously requires root

Using this app whilst its not totally accurate convinces me that this problem is with everything.  Findings below:


General Homescreens

Flicking between 2 homescreens without HDMI plugged allows maximum framerate of 60fps, so smooth transitions as noted previously.

Plugging HDMI and flicking between homescreens offers a maximum framerate of 43fps, never higher.  I can tell this is correct due to performance.

Every...single..app this is exactly the same without compromise.

Snes 9xEx, Nes.emu, GBA.emu, GBC.emu, EPSXE, Drastic DS (All for emulation)  60fps with counter non HDMI, between 40-43 fps with HDMI.

Android Games - Jetpack Joyride, Angry Birds, Basketball Pro, Pinball Arcade, Pool Break Pro, Rayman Jungle Run, Sleepy Jack, Super Stickman Golf 2, Temple Run 1 and 2 - All 60 fps without HDMI, between 40-43 with.  (some games just become choppy, some slow down like emulators, all depends how each individual app is programmed I guess to deal with performance drops.)

Other android apps ive tried as mentioned the difference is less obvious because of lower framerates in the first instance.

Beach Buggy Blitz - HDMI OFF - Fluctuates between 20 and 60 FPS - HDMI ON - Fluctuates between 20 and 42
Dead Trigger - HDMI OFF - Fluctuates between 18 and 60 FPS - HDMI ON - Fluctuates between 17 and 43
Riptide GP2 - HDMI OFF - Fluctuates between 22 and 60 FPS - HDMI ON - Fluctuates between 22 and 42.

The key here is that if a game spends more time hovering below the "magic mark" shall we say of 42-43fps without HDMI, then in practice, over HDMI you wont see much, if any difference as the S7800 would still be fine with this at this point.

There are no apps i found that break this rule.  This device on HDMI has an issue without question. As soon as the HDMI cable is plugged in everything thereafter is plagued by this frame cap or whatever the problem is.  Im 100% certain that the device is still displaying at 60hz and sending out a signal at 60hz however when HDMI is plugged in the fact that everything appears to be locked into the low 40s framerate wise is too much of a coincidence.  And besides, any device actually showing an image at 42hz, even if the screen were capable, would show massive signs of flickering to the human eye.   When you factor in overclocking does nothing, even to an app which runs flawlessly massively underclocked, only adds to the argument.

The differing factor like I've said before between apps working better than others is purely down to how each app is programmed to handle situations which cause slowdowns.  Emulators set to zero frameskip will just slow down to meet the 42-43 fps causing the game to slow whereas most android apps will just skip frames to cater for this, not actually causing programs to slow, just to become more juddery.

Also as mentioned, apps that have fluctuating framerates anyway such as the ones mentioned above, are less noticeable over HDMI because they dont maintain a fluid framerate anyway.

Long story short, HDMI on the S7800 is borked, and unless fixed by JXD, is useless.

[Joe Sixpack (OP)]

hmm I"ll check that out,
Yes unfortunately it seems to universal for it to be a app problem.. It could be hardware but is more likely firmwmare issue.

Unfortunately Skelton said he does'nt think JXD is going to release the source, or any more updates (Moved on to new devices)

So we may very well and truely be screwed on this and other issues.

Although I wouldn't say completely worthless, Yes it's not perfect but with frame skip on most games are still playable albeit not as smoothly they should.

7800 is a device that does a lot of things unfortunately none of them well


EDIT: Oh tried a Pal game, played without sound distortion however I think it was still dropping frames, it's easiest to notice dropped frames when something is scrolling, so I bet it was also running at 44'ish fps.

I'd be curious if someone with a Pal TV has these same issues.
I Tried using a 50hz setting on the 78 and IF my TV was able to understand it, It did'nt say (50hz)
so either the device ddi'nt switch to pal or my tv could'nt handle it and so it did'nt use it.. or 50hz does'nt work on the 78 anyway.. not sure which given that it still displays even when hdmi is turned off and it always reverts to 1080 when first plugged in, i've not much faith in  the settings menu.

Hey' sorry I should of explained better
It runs smooth on tablet but when I look at my TV
Its running about 5fps with about a 2sec delay from my tablet
When I went on tube there was still a slight delay but running video was quiet smooth?

Ok so let me get this straight.
while on wireless display there is a 2second delay from the screen AND the video output is super choppy like 5fps? so it would'nt even be usable for playing movies where a delay would not be a big deal?

[kristianity77]

TV i have accepts a 50hz signal and I've already tried this at the beginning flicking between 50 and 60hz.  The 7800 does appear to make this switch properly as the info on my TV suggests so.  However, it makes sod all difference.

[substring]

It seems the HFMI is handled bu the RK616 chip. So if it's a faulty hardware, any device having that chip would be concerned. Has anyone looked around ? I could only find chinese websites with a "tk616+hdmi" query on google ...

[kristianity77]

I dont think its faulty hardware.  Seems to be consistent with each S7800 that I've come across.  Its highly likely to be a software based problem.  May as well be hardware based though as you can be sure that JXD won't do anything to fix the issue. 

[nicole ridgway]

Hello people...I have bought a HDMI ADAPTER to connect my JXD S7800b in the tv...I tried to, but nothing happens...TV displays: "no signal" and nothing happens...tried to change all the possible resolutions...nothing.
I have WebClaw's firmware installed...

[Joe Sixpack (OP)]

Check to make sure it's seated all the way, the 78's ports are deep.
I had to cut a slice off the rubber molding on mine to get it to full seat.

[nicole ridgway]

Check to make sure it's seated all the way, the 78's ports are deep.
I had to cut a slice off the rubber molding on mine to get it to full seat.

I'll try later in the afternoon...how did you cut that?

[Joe Sixpack (OP)]

Check to make sure it's seated all the way, the 78's ports are deep.
I had to cut a slice off the rubber molding on mine to get it to full seat.

I'll try later in the afternoon...how did you cut that?

Well assuming yours is like mine the molding is rubber just take a sharp knife, I used a mini box cutter.

Do a search for  my posts, I posted a picture at the time.