video / display stuttering discussion?

[mrblack1134]

Hi all,

Got an Imito a couple weeks ago, I really like it, but I'm starting to think there's an issue with the video / display output stuttering (juddering?) in all applications, ie. not being 100% smooth.

I was watching Netflix on the Imito and scenes with lots of motion made it quite obvious. The problem though is it also happens not only on video output, but in rendered content.

Now here is a really simple test you can do and I would REALLY appreciate it if you'd take the 2 minute and do it:

- download angry birds HD (free) from the play store
- start it until it gets to the "PLAY" button (to start a game) -- don't push it
- look at the red angry birds flying in the background, they should be 100% smoothly moving
- here, every 1-2 second they "jerk" or "judder" (ie. skip a few frames), more obvious if they're moving fast, do you see it???

Here's what I've done, and what I'm running:
- Imito MX2, Finless 1.5a 720p rom
- Display output 720p/1080p same thing (in Android display settings)
- TV resolution 1080p x 60hz
- Killed ALL background apps with System Tuner (thought it might be something waking up each second)
- Obviously turned off all TRU-MOTION ie. frame imterpolating crap on TV -- it's as direct as it can be
- Turned off wifi + bluetooth

I don't know what else to try... Please try the Angry Birds Test (as its a simple one) and tell me if you have the same issue! (Imito Mx1 or Mx2)...

Thanks!

[Finless]

OK I understand what your saying but let me explain somthing to you that might put what your seeing into perspective.

All APPs have what are called resource files. These are graphics, etc. The VAST majority of these APPs are made for phone or tablets with say... a max resolution of 1024x768 or there abouts... Oh and let me point out this is why we are now seeing APPs that are called HD version. These are for tablets with much larger resolutions than phones. But even the HD versions I doubt seriously have resources made to 1280x720 let alone 1920x1080.

OK... So please think about what I said above as it will relate to what I am going to tell you.

Now. If the "playing field" was made for say 800x600 and the "bird" or what is called a "sprite" is say 20x20, when you then try to run this on 1920x1080, sure.... the bird is larger but it is NOT made at that resolution nor has resource graphics for it. Same with the background or "playing field". Everything has to be "scaled" for this higher resolution which Android does support.

Now follow me here. If the bird moves across a 800 wide display and it moves one pixel at a time, then the only way to do this on a 1280 display is to move the bird 1280/800 or 1.6 pixels... round that up to 2 pixels! If your running a 1080 kernel than that is 1920 wide and now the bird has to move in incraments of 1920/800 and that is 2.4 pixels round that up to 3. Now even on the 800 screen I doubt the bird only moves one pixel at a time! I bet it might be BEST CASE 1/2 the sprite which lets say is 20 pixels. 20/2 = 10 pixels movements. Using the math above you can see on a larger screen there is NO POSSIBLE WAY to make the translation look "fluid".

Because there are no resources for most of these APPs made for phones, and with the screen resolutions we are using on these TV sticks, you cannot even expect to see graphics work like what you see on smaller screen devices!

I hope that makes sense?

However let me just say this for the long term. It is very clear these TV sticks are going to be BIG BUSINESS! Long term I expect to see APP developers start to make resources that are made for these much higher screen resolutions and not just for phones! An APP can in fact have inside it support for many resolutions and NOT be scaled.. Oh and not just because of the TV sticks either but also because the screens and new IPS screens for tablets are going to be predominately HD resolutions! What I am saying is popular APPs will eventually cater to true HD implementaions and not just low resolutions phones!

Now... let me clearly warn everyone about this convo... Increasing the native resources to higher reslolutions means the GPU has to draw these resources on the screen! MUCH more data and "pixels" to move around! This will require a much faster GPU and processors! So be careful what you wish for.... A game made for 1920x1080 could in fact over burden even our current quad core GPU!

Anyway... did any of this make sense? I think what your seeing is not "lag" but in fact an artifact of scaling up to our higher resolutions and NO ROM can make that better...

Make sense?

Bob

[Finless]

FYI, I think this was a good question and not just for Imito... I am going to move this post to the general Android TV player forum as it relates to ALL APPs tunning on TV players of any kind.


Bob

[mrblack1134]

Anyway... did any of this make sense? I think what your seeing is not "lag" but in fact an artifact fo scaling up to our higher resolutions and NO ROM can make that better...

Make sense?

Bob

Bob,

I read your whole reply and I understand it quite well. I really appreciate your work (seriously, your roms add so much to the experience), and your valuable input.

However I must disagree with your points. It's not the sprite scaling that's causing the problem, but really the video synchronization. I am a programmer myself (that's my dayjob) and I've coded video / game / applications before; this sort of artifact would still appear if the textures were not scaled at all.

The best proof of concept would be to code a simple app that moves a white square on a black background by 1 pixel every 1/60th of a second (ie, the screen runs at 60hz). Since there are no sprites involved (only a perfectly software-rendered square), it should move ultra-smoothly -- I am certain that with the Imito we would see it jerk every second (ie, skip a frame).

Are there any such apps that we could test taht move simple shapes smoothly across the screen? I am new to Android.

Good discussion, thanks for the input.

[Finless]

The best proof of concept would be to code a simple app that moves a white square on a black background by 1 pixel every 1/60th of a second (ie, the screen runs at 60hz). Since there are no sprites involved (only a perfectly software-rendered square), it should move ultra-smoothly -- I am certain that with the Imito we would see it jerk every second (ie, skip a frame).

Are there any such apps that we could test taht move simple shapes smoothly across the screen? I am new to Android.

Good discussion, thanks for the input.

I do not know of an APP that does that but your are correct this would prove if it is a video lag problem or not. I am just telling you my experience with "scaling" of APP resources on the Android platform.

Simple question... Angry birds has a regular and an HD version. Which have you tried? Let me know if you see a difference as I personally have myself. The non-HD version has artifacts like I explained above on these TV sticks.

Bob

[Finless]

Since it seems you know more about what your talking about, my post was for the laman... So maybe we take this to the next level...

Maybe you might remember early days of PC gaming and Nvidia, ATI, and many more that are now gone in the early days... It was all about performance with drawing textures, calculating traingles, Mipmaps, Bumpmaps, etc...

I am going to tell you right now... Android and the current GPUs are like 2001 or there abouts! There is MUCH growth opportunity here like the 2000's with PC gaming and graphics cards!

Also remember the Android OS' largest market is STILL phones! However... that is starting to change rapidly! HDMI support is INFANT right now! So I do not doubt for a minute it is not performing as it should. As I understand Android 4.2 has or will have better support for HDMI output with native support.

Anyway... My point is realize this... We are dealing with an OS that is not tuned to these TV stick devices just yet. Most these ROMs are "ports" of AOSP code made for freakin phones! I do expect to see this change alot this year.

Bob

[mrblack1134]

I do not know of an APP that does that but your are correct this would prove if it is a video lag problem or not. I am just telling you my experience with "scaling" of APP resources on the Android platform.

Simple question... Angry birds has a regular and an HD version. Which have you tried? Let me know if you see a difference as I personally have myself. The non-HD version has artifacts like I explained above on these TV sticks.

Bob

I just tried the HD version of Angry Birds. However, I just ran the Antutu benchmark just now and I could see the frame skipping issue in the 2D display test (harder to see as there's lots of stuff happening). I can also see it in Netflix when the scene moves quickly.

It looks as if it's something deep within the display driver... is it rendering internally not at 60hz and skipping a frame once in a while? (since it has to output at 60hz)? or something weirder than that?

Btw, does the same problem on another display here (a computer monitor); not just on my Samsung LCD TV.

Maybe some of the guys at armtvtech could give us a hand too at nailing down this problem more precisely ...

Thanks bob

[Finless]

Hmmm... maybe I am not as picky as you but I just ran Antutu and on 2D I cannot see any frame skipping?

Now I have recently been studying the HDMI spec. I think many that complain about a TV stick not working on a specific display or TV is a related issue. I think this is why now these TV stick makers are stating things like "supports" HDMI 1.4a, etc...

The HDMI protocal, since it is digital, allows for... lets call it "bad packets" and thus frame skips. I will tell you that the cable provided with my MK808 was total crap! Sometimes my display would be PINK or washed out due to EDID communications on boot and the TV "guessing" at what to sync to.

Before you go too far in troubleshooting... Maybe get a quality HDMI cable or plug the TV stick direct into the TV. Also the power supply is a BIG issues with these devices... In fact if not powered well, the GPU will actually reset!

Then on top of that is the GPU chip quality. My MK808 cannot run ANY of the OC'ed GPU kernels! My GPU is shitty and can not handle it at all... That bums me out of course but it is what it is.... Remember the Intel Celeron CPUs and people wanting the "known" manufacturing locations to make sure they get one that will overclock? Well my MK808 GPU cannot at all even with good cooling....

Just some ideas since we are discussing issues. There are many variables here so we should eliminate what we can. Just a few suggestions which may not even be relevant!

Bob

[fr0d0]

Re: video / display stuttering discussion?

I mentioned Netflix on another thread and someone said it was a known issue on all devices

[mrblack1134]

Just some ideas since we are discussing issues. There are many variables here so we should eliminate what we can. Just a few suggestions which may not even be relevant!

Bob

Bob, thanks again for your input.

Yeah I've orderd a female couple + hdmi cable from monoprice... should receive that next week, I'll see if it makes any difference but I doubt it.

Is there any sort of display driver options configurable at the kernel level on android? (ie. kernel options to the display driver on startup...? I haven't looked through the whole dmesg output yet).

It's interesting to see that fr0d0 has noticed it in netflix too -- it is, indeed, much more obvious in Netflix because (1) it's the single app people are most likely to be staring it at for a while (2) has a lot of panning scenes which make it obvious.

But yeah, you're overall point being that this is the first iteration of those devices and that they're not yet totally ready for prime time is bang on; the Imito is still awesome in its own respect for all the other things. The wifi is a POS (I unsoldered / fiddled with the antenna without success) but that's fixable with a USB wifi or ethernet adapter.

I just wish that this frame skipping "bug" / issue is something fixable -- I would really like this device to replace my WDTV / other media players.

Please keep the ball rolling, I want more people to check this on their setup (ie. the angry birds test that I described), to see if I'm imagining things or not.

[mrblack1134]

*bump*

anyone did the test yet? I actually re-flashed Finless Bob's 1.5a firmware (erased everything), ONLY installed Angry birds, stopped all currently running apps, and same result. Choppy video.

Started Netflix and yeah, same thing again, skips a frame once in a while.

Are all RK3066 based hdmi sticks behaving that way? That really looks like a bug somewhere in the HDMI display drivers...

Thanks

[jukitsu]

I tested this with my iMito mx1 and I can confirm the problem.

I tried directly with my Philips 9705 and the frame skipping is there. I also tested it with my Denon 1909 amp and the problem persist. I noticed the problem in the Angry Birds start screen and also when watching films.

I have disabled additional image processing from the tv and I'm using finless 1.7a rom.

[PoisonWolf]

I couldn't find Angry Birds HD. Only HDs were the space version and that costs $2.99. So I installed regular Angry Birds and started staring at flying birds at 8 AM in the morning after reading your post.

I see the judder that you're talking about, though it's very minor for me (not as obvious unless if I'm staring and fixated on the bird). I'm guessing that the effect may be more prominent on the HD version. Along those lines, did you download the regular version of Angry birds to see if the effect persists? This could tell you whether it's the game issue or if it's the HDMI driver issue. I've watched a lot of movies on this and I have yet to see any judder or anything akin to a pulldown effect during fast scenes. I tried it with Force GPU rendering and without and I still see some bird-flying judder (very minor, again). I suggest trying to use Disabling H/W overlays and Force GPU rendering to see if that makes a difference.

Another game that has fast scenes that you could try is perhaps the beach buggy blitz game that in my mind is essentially a rip off of Temple Run 2 in car format. When I played it via Droidmote on the MK808, I didn't notice any stuttering at 50% graphics under settings.

I'm running a MK808 with 2dark4u's kernel which sports an OC-ed GPU I think and CPU clocks of up to 1.4 ghz. However, Rockchip has been sneaky and has included a build in hard-code to prevent the CPU from ever going up to 1.4 ghz if the governors are interactive or ondemand. So for the most part, the RK3066 will stay at 816 mhz or 1 ghz (more on 816 mhz). Now, if you're on stock kernel, you're likely at a fixed 1ghz. For my power supply, I use a PS Vita charger. Under developer options, I leave Disable H/W overlays checked at all times since battery savings is not an issue. For resolution, I stick to pure 720p as I know RK3066 chips simply cannot handle 1920 x 1032 (48 pixels for status bar) device resolution (I've tried several 1080p kernels and the lag/delay fest difference is horrible and unbearable). For those who use 1080p output resolution but still have a device resolution of 1280 x 672, it is pointless (I've tested it back and forth and there is no discernable difference) and I recommend sticking to 720p to ensure consistent FPS and let your TV do the upscaling.

Just some food for thought, but I'm inclined to think that it's an issue with certain apps and maybe the commands that are called in those apps with regards to how certain things are drawn/refreshed.

If there is a youtube video with fast scenes and HD mode to test this effect on, it would be better and would lend support to my suggestion that it is app-specific.

[nbuuifx]

I noticed this straight away with my mk809 but haven't had time to test or even think about it. I think it occurs all the time but is highlighted with certain movement etc.

I wondered if it was a freq thing 50hz vs 60hz etc?

Or if it was a pal (25fps) /ntsc (29.97fps) /movie (24fps) thing?

Clucthing at straws but I remember some problem with video skipping a frame due to not quite being in the correct mode - but can't remember exactly what the issue was.

This sort of touches on what I was thinking:

http://forum.xbmc.org/showthread.php?tid=130567

That is talking about video and isn't on android, but I wondered if it was something along these lines?

It also mentions a skip every 2 seconds which is what I would say mine was.

[mrblack1134]

I noticed this straight away with my mk809 but haven't had time to test or even think about it. I think it occurs all the time but is highlighted with certain movement etc.

I wondered if it was a freq thing 50hz vs 60hz etc?

Or if it was a pal (25fps) /ntsc (29.97fps) /movie (24fps) thing?

Clucthing at straws but I remember some problem with video skipping a frame due to not quite being in the correct mode - but can't remember exactly what the issue was.

This sort of touches on what I was thinking:

http://forum.xbmc.org/showthread.php?tid=130567

That is talking about video and isn't on android, but I wondered if it was something along these lines?

It also mentions a skip every 2 seconds which is what I would say mine was.

Hey,

I created this thread a few weeks ago; nice to see some activity as the frame skipping is still annoying as hell when watching netflix or doing anything that has smooth panning on iMito.

As I suspected, this is common to most (if not all) rk3066 based android tv-sticks (ie. including the mk's) that have come out in the recent months; most probably a bug/driver issue with rockchip's implementation of vide output.

Do we have the full source for that in the omegamoon/andrewdb kernel sources? (I think so, haven't had much time to look at it though... toddler keeping my busy recently).

I thought of the 29.97 or 24 fps theory before, and it's one of the very logical explanation; say the RK is internally outputting at 24 fps, but the the screen is displaying it at 30fps (it must be since it's 1080p/720p... that's the HDMI standard).

So in effect, the RK isn't outputting frames fast enough for the TV to display. There's always one frame ahead in the output buffer, so it's fine for a while, until the TV is missing an entire frame to display (because it's quicker than the RK) -- that's where we see the frame skip.

The math doesn't really add up for a ~2 seconds interval frame skip (with 24fps we'd see a skipped frame every 4 seconds, and with 29.97 it would be every 1000 seconds)... however there might be other things at play.

Anyways I really wish we can get some help to solve this...