This Is Why We Do Not Have Vga On The Pandora!

[maiden]

"Converting normal TV video signal (PAL or NTSC composite video) to something visible on normal VGA monitor is a complicated task. The difference between PAL/NTSC and VGA is huge. The horizontal refresh rate for VGA is two times faster than PAL/NTSC (15750 Hz for NTSC and 15625 Hz for PAL; > 32 KHz for VGA). Vertical refresh rates of NTSC and VGA are equal (60 Hz for both). PAL uses 50 Hz vertical refresh rate, which most VGA monitors can also handle. VGA monitor wants RGB signals and separate sync signals, where PAL/NTSC composite video has all combines into one signal (composite video).Lots of electronic is needed to do this complicated task. The process needed for conversion is first composite video to RGB conversion and then scanline doubling / scan conversion process. "

try to fit this in the pandora: http://elm-chan.org/works/sc/report.html

for more info please visit: http://www.epanorama.net/links/videocircuits.html

simply put:

Video signal H sync V sync
NTSC 15.734kHz 59.94Hz
VGA 31.469kHz 59.94Hz

15.734 is not equal to 31.469

no flamewar, just information, a.k.a "good to know"
if this makes any offense, please remove this thread.
(sorry, just got angry @ the other thread..)

 

[WizardStan]

One other thing to mention, even if you do convert SVideo to VGA, it's still only a 480i signal. You gain absolutely nothing by doing it.

edit: As opposed to the SVideo to Component adapter I built (splitting SVideo into RGB can be done with about $10 worth of parts, and the timings can be carried) which also has absolutely no gain.
But that wasn't to get any higher resolution: it was so I could plug SVideo things into my projector without running any extra cables

 

[Squidge]

I think a lot of us got angry at the other thread, but some people just don't listen.

It's possible to alter the clocks in software, but it still doesn't provide you with a medium of converting either digital rgb data, or composite/svideo data (the two formats provided by the omap) into analogue vga data without some kind of electronics.

 

[Poem58]

WOW, just read that other thread. AMAZING.
I guess there will be those who are displeased with the inability to output to their favorite choice of equipment but damn.
I guess someone should now start the John Doe pictures of what the Pandora would look like if it had outputs for every conceivable connection!

But hey, I understand the guys frustration. Really how hard could it have been for the team to develop the system to be able to accept original controllers from every system the Pandora could emulate (at least 2 ports each of course, it's more fun to play with friends). Otherwise what's the use of TV out for game play. I mean COME ON NOW!

/sarcasm

Just realized, maybe THAT is what the Pandora cube could be!?!? Pandora emu box with ports for retro controllers!!!

/happy happy foolish stupidity dream

Edit: if the team uses this idea I want one for the idea

 

[Sphinxter]

I thought the whole, 'you guys are too stupid to whip out a VOM and add a couple leads', bit rather hilarious.

 

[josemdark]

What about Displaylink to use higher resolutions?

http://en.wikipedia.org/wiki/DisplayLink

It's source code is implemented in linux (http://en.wikipedia.org/wiki/DisplayLink#Technology (see second paragraph))

EDIT: Look at this http://www.displaylink.com/news/news150509.htm

(If you can't see the image use this url http://img.xataka.com/2008/08/iogear-wireless-usb.jpg )
I found a solution

EDIT2: About the lincense http://www.displaylink.com/news/news150509.htm (LGPL)

 

[WizardStan]

USB VGA adapters have been brought up many times. They probably will work, but it's questionable as to whether they'll work well enough to be of use for anything more than business presentations and such. It's a wait-and-see thing. We won't know for sure until someone tries it.

 

[Enverex]

USB VGA adapters have been brought up many times. They probably will work, but it's questionable as to whether they'll work well enough to be of use for anything more than business presentations and such. It's a wait-and-see thing. We won't know for sure until someone tries it.

Well the Pandora would be pushing ~737MB/s via VGA (pixel quantity (384,000) x bit-depth (32) x refresh rate (60)) so I have no idea how USB and especially not Wireless USB VGA adapters would work (unless I'm screwing up my math here).

 

[lulzfish]

USB VGA adapters have been brought up many times. They probably will work, but it's questionable as to whether they'll work well enough to be of use for anything more than business presentations and such. It's a wait-and-see thing. We won't know for sure until someone tries it.

Well the Pandora would be pushing ~737MB/s via VGA (pixel quantity (384,000) x bit-depth (32) x refresh rate (60)) so I have no idea how USB and especially not Wireless USB VGA adapters would work (unless I'm screwing up my math here).

Can the Pandora's CPU even put out ~737MB/s? Much less over USB.
Edit: That's why it won't work... at 60 fps. Like everyone's said in the other USBVGA threads, it's only good for presentations or maybe (depending on how the VGA adapter updates) text-editing.

 

[WizardStan]

Well the Pandora would be pushing ~737MB/s via VGA (pixel quantity (384,000) x bit-depth (32) x refresh rate (60)) so I have no idea how USB and especially not Wireless USB VGA adapters would work (unless I'm screwing up my math here).

That I can't say for certain. Maybe half bit depth, plus compression, plus some other fancy stuff. I do know they work, I've seen USB->VGA adapters used on desktops, so it is possible, however they do it. It's not great and fast, I don't think you'd be doing any gaming on it outside of solitaire, but it was enough for higher res web browsing that I could see.

 

[Enverex]

USB VGA adapters have been brought up many times. They probably will work, but it's questionable as to whether they'll work well enough to be of use for anything more than business presentations and such. It's a wait-and-see thing. We won't know for sure until someone tries it.

Well the Pandora would be pushing ~737MB/s via VGA (pixel quantity (384,000) x bit-depth (32) x refresh rate (60)) so I have no idea how USB and especially not Wireless USB VGA adapters would work (unless I'm screwing up my math here).

Can the Pandora's CPU even put out ~737MB/s? Much less over USB.
Edit: That's why it won't work... at 60 fps. Like everyone's said in the other USBVGA threads, it's only good for presentations or maybe (depending on how the VGA adapter updates) text-editing.

Yeah, I'd imagine it would completely saturate the system bus at the same time rendering everything unresponsive as hell.

 

[skeezix]

The best post I read all day was the comments... Re announcement email, What font will it be?

*died* *lol*

jeff

 

[rabidpoobear]

Guys, didn't you catch on in the other thread? The guy's name was RedFish!
Get it?
Red fish -> red herring!
it was obviously MWeston trolling us to distract us from the waiting!!
but Trooper didn't check his PMs so he didn't know not to lock the thread.

 

[darkblu]

Well the Pandora would be pushing ~737MB/s via VGA (pixel quantity (384,000) x bit-depth (32) x refresh rate (60)) so I have no idea how USB and especially not Wireless USB VGA adapters would work (unless I'm screwing up my math here).

i'm afraid your are screwing it up. as in 'your math has two errors, and they are not sign inversions':
1. you don't need to send alpha to the VGA - it wouldn't know what to do with it. so in the worst case your pixels will be 24bit, not 32bit.
2. 384,000 x 3 x 60 Hz = 69,120,000, or ~67.5MB/s

if you limit yourself to standard VGA 640x480, above number becomes 307,200 * 3 * 60 = 55,296,000, or ~54MB/s.

that second number might be doable in isochronous usb. iirc, the protocol allows up to 90% user payload over the datalink layer numbers, so it should be about doable.

 

[Loonie]

Wait a minute...

Are you telling me Pandora will not be able to drive a cathode ray tube directly??

 

[rabidpoobear]

Wait a minute...

Are you telling me Pandora will not be able to drive a cathode ray tube directly??

You can wrap wire around it and run obscenely large currents through it, thus creating an electromagnet and biasing all the CRT control units in the room. If you're fast enough with the switch you can interrupt the refresh and draw anything you want on the screens.

 

[Enverex]

Well the Pandora would be pushing ~737MB/s via VGA (pixel quantity (384,000) x bit-depth (32) x refresh rate (60)) so I have no idea how USB and especially not Wireless USB VGA adapters would work (unless I'm screwing up my math here).

i'm afraid your are screwing it up. as in 'your math has two errors, and they are not sign inversions':
1. you don't need to send alpha to the VGA - it wouldn't know what to do with it. so in the worst case your pixels will be 24bit, not 32bit.
2. 384,000 x 3 x 60 Hz = 69,120,000, or ~67.5MB/s

if you limit yourself to standard VGA 640x480, above number becomes 307,200 * 3 * 60 = 55,296,000, or ~54MB/s.

that second number might be doable in isochronous usb. iirc, the protocol allows up to 90% user payload over the datalink layer numbers, so it should be about doable.

I thought that 3BPP and 24bit were more likely (alpha channel did occur to me) so thanks for the correction, this looks like what I was trying to achieve before.

 

[centus]

Wait a minute...

Are you telling me Pandora will not be able to drive a cathode ray tube directly??

Of course it will, through S-Video...
My TV is a CRT TV (I know, I know, time to replace it), and it has an S-Video-in...

 

[WizardStan]

Wait a minute...

Are you telling me Pandora will not be able to drive a cathode ray tube directly??

You can wrap wire around it and run obscenely large currents through it, thus creating an electromagnet and biasing all the CRT control units in the room. If you're fast enough with the switch you can interrupt the refresh and draw anything you want on the screens.

OT: reminds me of an experimental program I once witnessed that drew what effectively looked like static on the screen, but when a radio tuned to the right frequency was brought near it, actually produced music. The drawing was changing the power of the internal magnet in such a way as to actually produce EM radiation at a frequency the radio could pick up on. It was pretty clever in its uselessness.

 

[DAP]

Well the Pandora would be pushing ~737MB/s via VGA (pixel quantity (384,000) x bit-depth (32) x refresh rate (60)) so I have no idea how USB and especially not Wireless USB VGA adapters would work (unless I'm screwing up my math here).

i'm afraid your are screwing it up. as in 'your math has two errors, and they are not sign inversions':
1. you don't need to send alpha to the VGA - it wouldn't know what to do with it. so in the worst case your pixels will be 24bit, not 32bit.
2. 384,000 x 3 x 60 Hz = 69,120,000, or ~67.5MB/s

if you limit yourself to standard VGA 640x480, above number becomes 307,200 * 3 * 60 = 55,296,000, or ~54MB/s.

that second number might be doable in isochronous usb. iirc, the protocol allows up to 90% user payload over the datalink layer numbers, so it should be about doable.

Umm, no. USB can transfer at 480Mb/sec, which at best gets you 48MB/sec, but it is a half duplex shared serial bus. This means that between each block of data, the bus must change direction so the device can send an acknowledge at least back to the master. Also there is other stuff going on on the bus, even if only one device is connected. There is no way you are going to be sending uncompressed VGA data at 60 hz refresh across a USB bus.

The USB VGA video devices have a built in frame buffer. You send commands over USB to draw into the devices frame buffer, and the device takes care of converting that frame buffer into a VGA video signal at 60 Hz.

In any case the Pandora just does not have the horsepower to render games at higher resolution, or upscale standard definition games. A VGA output on the Pandora, no mater how it is implemented would be good for static displays and not much else. It would also increase the cost of the system, use more power, and only a few people would benefit from it.