I'd like to get some info on screen latency on the different hpc's (VIDEO)

Since it's my first post here, I'd explain a little.
I am the developer of PocketDVD/Video, and I somehow got affected by long trial sessions with Chris concerning video on HPC's.
He basicaly got me to the point of getting a HPC device, and I decided to go for a NEC MP900. It came in yesterday, and I'm quite happy with it. (working on a review as well for you guys). My original device for Windows CE is an IPAQ running wm2k3, so I got kinda spoiled, but thats not killing the fun.

ANyway, I've been playing with Betaplayer on the NEC, and there is a lot of ghosting going on, even with slowpaced movies.
I'm quite busy on getting some ideas worked out for applications that are just needed, but also on updates for PocketDVD.

If someone has some time, is there a way I could get some information regarding framerates of movies that do not ghost, preferably with the device it's on.

The ghosting seems to be related to the latency of the DSTN screens used on HPC devices, and by pushing more frames per second to the screen, it will result in ghosting. (old frame still shows, while new one is being displayed)

Chris and I found out that a Video Bitrate of around 160kbps can be played good on a StrongArm device (J710/J720) even in full screen.

Any additional information is welcome.

Did some extensive testing on video playback with several devices, mostly using picard's betaplayer. On a handheldpc you're facing three potential bottlenecks: CPU power, graphics engine and slow displays. The latter only occurs with dstn displays - I honestly don't understand why NEC has built a quite modern ce.net device like the 900c with this obsolete technique. Especially considering the fact that NEC at about the same time built the Sigmarion III for NTT DoCoMo, a terrific machine with a marvelous bright and clear tft screen (and by the way definitly running ce.net 4.1, not 4.2 as stated in the device list here).

CPU power is essential for bitrate. A SA-1110 is good enough for about 450kbps video bitrate (I abandoned audio stream in my test clips to get pure video performance results), the PXA255 in Sigmarion III did well up to around 1100kbps (tested with divx 5.1.1, all video clips were 24fps - I'm PAL user - max bitrate means here playback was possible without framedrops). picard's betaplayer is quite optimized for ARM based devices, on MIPS machines the results are below expectation. A NEC VR4122 powered device with 180mhz e.g. drops frames already above 280kbps.

The bigger problem on most devices is graphics engine, especially on machines with more than half vga sized displays. To be more precise: the bus speed between graphics chip and memory is critical. Regardless of bitrate, to playback a fullscreen video the graphics engine has to deal with a lot of data. The Psion Netbook Pro for example has a very slow Epson graphics engine, playback of video clips above ~350x200 results in flickering images. The Book Digital Smartbook G138 on the other hand with its MQ200 chip plays video clips up to ~490x300 even though its StrongARM SA-1110 is much slower than the PXA255 XScale inside the Netbook Pro. The Sigmarion III is the only device I know of capable of playing more or less the same videos I watch on my desktop machine - 720x450 sized clips are no problem at all thanks to an ATI chip with an extra 8megs of video ram.

Back on your ghosty dstn... I have no 900/900c at hand for testing. I know from basic benchmarking the graphics engine is... well, of quite conservative design. Did you do your tests in fullscreen? dstn is really slow, but 12fps should be possible at least. Maybe the ghosts you saw simply came from only partial screen refresh due to an overstrained graphics engine. I''d suggest you encode some test clips in different resolutions, beginning with 200x150 thumbnail size and 12 to 15 frames per sec. Still getting ghost images?

CU
Juergen

Juergen, you are my hero.
How can one person have all these cool HPCs to play with... and I have only one

Sounds like the Sig III is the winner here. Interesting video performance issue with the NBP. Have you tried the Nexio?

Quite simple - I'm still looking for the perfect device. So on the one hand I keep on buying new stuff, on the other hand I don't have the heart to part from any of these nice little gadgets

Haven't done this video testing on Nexio yet. Acquiring the Nexio was a bit of a drama... Got one from ebay about three months ago, but it came here not properly working. The device had a lot of freezes, after a while even a hard reset didn't work. On a Nexio user group I found out the Nexio's hardware has a serious bug: when battery power is totally drained and you switch on the device anyway (as I did immediately after recieving the package) there's a good chance the flash ROM is set to 'write'. In this state several modules of the os cannot work properly resulting in freezes and erratic behaviour. Only chance to correct this is indeed flashing the ROM which users cannot do theirselves, you have to let Samsung support handle this. Samsung here in Germany never ever has heard about a device called 'Nexio' though, nor has Samsung Europe So I landed up at Samsung Hongkong. Those guys now don't accept support issues coming from other countries On the mentioned user group I then found a dealer residing in Hongkong who offered to handle the stuff with Samsung... Now the Nexio is fixed after a long (and quite expensive) journey. Finally got it back about two weeks ago.

Quite a long story just to explain why I didn't find time yet to test Nexio's video performance .

CU
Juergen

Edited by Juergen 2005-02-25 3:29 AM

We will find the perfect device when one heart/mind is content and at peace. ... ok ok ... spare you guys the rheoterics ...

I think the main thingie is the dstn screen that really is crap. I mean, if I was using TFT screens for the past 5~6 yrs, I dun see why 900c or 900 should be released with DSTN. I think what NEC did was to finish off the old stock from the MobilePros. Heck, they even released a 900 with WinCE3.0!! ... so maybe they brought in so much inventory with hopes of making a gazillion but I guess their near $1k release price for the MP700s didn help. So they are clearing old inventory with the MP900s!! ...

just my guess ...

but the bottom line is ... even if someone plug a dstn LCD (can u still find such a thing on the market??) into a desktop blazing at 3.0Ghz, with 128MB ATI video and stuffs, the poor dstn will just have very fancy motion streaks all over the screen!

The very reason I believe why TFT took off was because it improved on the refresh rate and removed the ghosting, making them suitable for gaming. With that, the hordes of gamers will just go for it. Or at least, manufacturers believe they will, and hence ramp up production, dropping price, and even end-users can afford one.

So you still have the Smartbook G138? Can you comment on it in Snappy's "potential owner" thread?
http://www.hpcfactor.com/forums/forums/thread-view.asp?tid=576&posts=26

Why is it not the "perfect" one? Expansion, battery life, size?

It does come close to sub notebook category tho; not a whole lot smaller than an Asus S200 or Lifebook P1000 etc etc

And did you get 4.2 or 4.1? The free 4.2 upgrade was listed on e683.com, but the download speed was rediculously slow, and now the link won't even work anymore

*edit* I just realized you already replied to that thread about the demolux. However I still like to ask the questions above

Edited by takwu 2005-02-25 9:05 PM

No, I don't have the demolux dbook1 anymore. It was a review model, a very early one. It came with CE.NET 4.1 and a couple of programs (MTide's Gemini PIM e.g.) demolux never released with the official image builds.

The 'perfect' device in my eyes would have the size of a pocketpc, nevertheless clamshell of course. The keyboard would be as comfortable as on the Netbook Pro, the screen offering 800x600 or at least 800x480 - transflective tft of course. There have to be at least two card slots, LAN, Wifi and Bluetooth on the other hand already integrated, as are at least two USB host ports. All that at the size of a pocketpc as I said. Did I mention battery lifetime yet? No? Let's see... 20 hours would be sufficient, wouldn't it?
There's nothing 'perfect' in this world, there can't be...

I never got my fingers on a NEC MobilePro 7xx or 900/900c. Is the body really that similar? And the keyboard? In theory it might be possible of course to simply design a new mainboard fitting into an existing shell. But I doubt NEC would had saved much money doing so.
They might have designed the 900/900c to use some things up they still had in stock, true. NEC produces lcd panels on their own, don't they? And maybe they still had a couple of dstn panels nobody else wanted to buy. Could be...

But back on topic - video on a handheld . Did some quick testing with the Nexio - quite disappointing. The graphics engine is similar to Netbook Pro's, video clips above ~350x200 overstrain the graphics capabilities. My guess is most of these graphics solutions for embedded devices are geared to do their job in a pocketpc with a quarter vga resolution - that's the mass market suppliers have to take care of. Using a chip design like this in an actual CE.NET device with xscale and high resolution display is like bundling an up-to-date pentium IV desktop machine with a 19" tft and an old et4000 1mb isa graphics card.

CU
Juergen

Edited by Juergen 2005-02-26 4:42 AM

FYI, back on topic.

I found some interesting info with testing, and bitrate isnt the biggest issue.
On my nec 900, I found that 8 fps (frames per second) gives the best quality with the least amount of ghosting.
I'm currently working on the 1.1 update of PocketDVD/Video and will add a framerate adjuster for different devices.

That's worse than I thought . I have a JVC MP-C33 with dstn display, too, but no noticeable ghosting - at least for my old eyes and for the framerates its old mips processor is able to provide. 1/8 sec is quite a long time and should produce ghost images also in standard operations, e.g. closing message boxes or dialogues. Does it?

CU
Juergen

It sounds worse then it looks though.
due to the screen latency it doesnt look like it's a slideshow, so thats giving it an advantage.
also, since there are less frames per second that need to be rendered, the quality of the actuall movie looks a lot better.

simple example.
25 fps on 200kbps will have 8 kb availiable per frame.
10 fps on 200kbps will have 20kb availiable per frame,
thus on the same bitrate, the picture quality will be a lot more detailed.

hi

Hello. I am ELIZA the computer psychiatrist. What can I do for you?

-Worthless...

Thank goodness! Some help at last!
ELIZA, when I come down first thing in the morning and push the powerbutton, a few moments later, every day the computer beeps at me for no reason!
What does this mean? Does my PC not like me?



Just a reminder to everyone that we're in the final hours of the PocketDVD competition, so for your chance to win a free copy of PocketDVD 1.1 see the information on the home page!

No No No NO NO! Your computer nevers beeps for no reason. What the beep means depends on the beep (long beep, short beep, two beeps, three beeps, one long on short ...) You see, it's all in the beep code. I'd be very surprised if YOUR beep meant that your PC doesn't like you. We all like you, Chris.*, and that includes your PC. Cheers!

Thanks

It beeps like this:
. . . - - - . . .

Perhaps these are one of those thing men aren't supposed to understand, like reading "the signals" made by women. tehe

rofl

Don't forget to enter the competition.