DSTN screens are evil

The Jornada 720 is perfect in every way except for one way... you guessed it... the screen. I watch movies on it, and its terrible at first when you see it blur between frames but you get used to it. If you ever wanted a TFT screen on one, you would have to sacrafice the size, the NEC's have TFTS (i think) but are huge compared to the Jornada.

Nope, my NEC MobilePro 790 has a DSTN... And I think ALL of them did.

The screen on my Psion Netbook Pro is a nice active matrix TFT. Unfortunately, it doesn't have a dedicated video chip to offer accelerated video. I can watch low resolution movies with it using TCPMP set to the GAPI setting (have to install gapi, of course), but I get a nasty clicking noise along with the audio.

I have a spongebob movie on mine using TCMP and GAPI. I wonder what the refresh rates on DSTN's compare to the TFT's. I wonder how many colors a TFT can display too.

What can you do? My 6651s are TFT so great to play videos on. As CBC said, all the MPs are DSTN along with the Js. The TFTs are 65k colors FYI.

It's a reasonable tradeoff IMO for all the other features we get from a hpc.

Edited by wallythacker 2006-03-22 5:35 PM

TFT can display much more colours. DSTN only states 65k colours but it isn't capable of that in practice.

anyway i disagree with the thread title

TFT is the evil, in terms of battery life in a smaller device (the netbook pro could be ok as it has enough room for a nice 11.1V 2400 mAh battery which can easily cope with the large TFT screen)

Cmonex, we are the ones who get 16 hours with wifi.

We would do just fine with a tft screen if we could just get one to plug in...

Whatever happened to the TFT 720 replacement search? Too costly?

TFT's can go up to 32-bit color, assuming the device has vide hardware that supports it. i.e. my Viewpad 100 supports 800x600 at 32bpp (about 4 billion colors). Perhaps you mean the TFT on the 6651 is 65K colors?

And what really got me all bent out of shape is that HP put the same bloody screen on the 728!


Why you ask? Because they had a billion of them left over

Yes, my only hpc TFT units are 65k colors. Of course TFTs are 32 bit capable. Personally, I can't tell the difference between 16 vs. 32 bit color for the most part.

umm... no it is not the exact same screen.

(yes it is dstn but some stuff is different IMO)

Edited by cmonex 2006-03-23 8:50 AM

For most things, you can't see a difference. You really have to be working with high color video or still images to se the difference between 16bpp and 24bpp. But there is definately more 'splotching' (sudden changes in hue/saturation caused by dithering the colors down) in high color photos viewed at 16bpp. The difference between 24bpp and 32bpp is really not visible to me, especially since most digicam photos and videos are 24bpp to begin with.

Hm, my turf I guess.
This is why C:AMIE and I messed around with the J720 to try and get the best possible video working on it.
The "Screenrating" part in DVD Catalyst. The DSTN screen, in combination with the video chip of the Jornada 720 allows for about 8 screen refreshes on the full resolution. (8 FPS) since the resoltion of 640x240 is in an aspect never used for movies, you will usually result in a movie/video that does not fill the full screen. If only part of the screen is displaying a movie, the framerate can go up. (640x240 = 8fps, 320x240=16fps)

The trade-off on frames per second is however made up a bit by having more bps availiable for a frame, resulting in a very good video image during playback.

in detail: the processor of the Jornada 720 can decode video at 160kbps as a maximum. Above that, the playback will suffer because the J cant keep up.

if you have a full screen movie on 640x240 on 8fps, this results in 20kb per frame (160kbps/8fps=20) this compares in quality to a normal movie on 30fps on a bitrate of 600kbps (which is used for most 700mb dvdrips you find on the web)

Yes, the DSTN screen does have it's disadvantages, but in addition, because of the slow responsetime, 8fps does not look completely like a slideshow compared to 8fps on a TFT.

What? There were once a replacement? Wow.

Could someone tell me how a TFT differs from a DSTN? Is it just the refresh rate?