Vga Or Dvi Out?


narmak

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Will the pandora be able to connect to an external monitor other than a television? The pandora is open source, so i imagine there will be quite a bit more than gaming to do on it, as is the case with the gp2x, and it could be a really compact, low-wattage computer for everyday things like web browsing, email, and coding. Will it be possible to connect the pandora to a higher resolution display?
 

schnitzelboy

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well, no-not to a vga or dvi monitor, but u can use an s-video connector to hook it up to a high-def tv if you'd like!!
 

WizardStan

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schnitzelboy said:
well, no-not to a vga or dvi monitor, but u can use an s-video connector to hook it up to a high-def tv if you'd like!!
This actually begs a few very good questions, now that I think on it. Standard definition North American television is 640x480 of visible space. The actual transmission is 520 lines high, with wide screen sources, such as DVDs, capable of transmitting 720 pixel wide lines with 704 visible. PAL has 625 lines, only 576 of which are visible. I'm not certain about the widths, but I imagine PAL has two different standard widths as well.
"S-video" is just a medium for carrying these standards. So what's the output actually going to be? If we have a 4:3 NTSC screen, can we select 640x480, and the chip will naturally center everything to fit? Or if it tries to output to TV, will it lose the edges because the visible resolution is smaller than the carrier resolution? And if we have a 16:9 TV, can we then also select wide screen to increase the width to 704 pixels? Or must the screen be stretched/letterboxed? Lucky Europeans get an extra 100 pixels horizontal. Which asks the final question: if an application requests a fullscreen 640x480 display, this would fill an NTSC screen perfectly, but if the user is European will the chip automatically letterbox it with 48 empty lines above and below the image, or will it stretch to fit the 576 (or even worse, 625) lines of the PAL television. And vice versa: a european developer makes an app for TV out to PAL at 576 lines, played on an NTSC screen.... where do the extra lines go?
 
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nubie

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WizardStan said:
schnitzelboy said:
well, no-not to a vga or dvi monitor, but u can use an s-video connector to hook it up to a high-def tv if you'd like!!
.... where do the extra lines go?


That is entirely up to your television. The chip should only output actual standard pixel resolutions.

TV's are notorious for being pure Shit http://en.wikipedia.org/wiki/Overscan Even when you are sending a signal of 1280x720 pixels in a digital format to them they insist on stretching the picture off the edges of a physically 1366x768 screen by a few inches, this makes no sense and is pure crap.

The signal (S-Video) is interlaced, I have no reason to believe that TI is implementing the video in a manner that can be exploited to non-standard resolution or progressive scan.

The best video quality you will obtain is on a regular CRT with native S-Video input that has been adjusted in the service menu for accurate geometry and minimal to no overscan. Very close to the best quality can be obtained with a "line doubler" that will output to an HDTV (one that has the ability to turn off overscan and display native pixel resolution) without any scaling, merely doubling every pixel twice and every line twice, thus making the image a very blocky one of double the resolution. But a very sharp image.

The chip being used is a Ti OMAP 3530 http://focus.ti.com/docs/prod/folders/print/omap3530.html :
QUOTE

Display Subsystem

* 2 10-Bit Digital-to-Analog Converters (DACs) Supporting:
o Composite NTSC/PAL Video
o Luma/Chroma Separate Video (S-Video)



The only video output is that supplied by the main chip, there will be no additional chip capable of DVI/HDMI or VGA outputs due to lack of space, cost reasons, and run-time.
 
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WizardStan

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aye, but key point I meant resolved around the differences between PAL and NTSC. The omap outputs either, or both. So how does it resolve the differences? Like I said, an app requests a 640x480 screen: perfectly fills an NTSC screen, but will it stretch on a PAL or letterbox it? Or vice versa, some European developer requests a 768x576, does that get shrunk to fit the NTSC, or cut off? The spec sheet seems to be lacking in this data.
 

Soulkiller

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On commerical consoles the video output hardwre has diffrent PAL and NTSC versions. Thats why you ahve U.S region and EU region consoles, along with games and DVD's that are region specfic as well. I imagined that they would have the same regioning on Pandora as well but since its more of a global oriented project with programmers working from both regions together it might not be that simple. Either they will ahve region specfic Pandoras or will only support one or the other. If we have region specfic Pandoras, programmers that us TV-out might have to release PAL and NTSC versions of their games. But I'm thinking it would be best to just have the region code stored in the firmware or hardware somewhere that can be retreived by the app and then the app can ajust to whatever region its being used with.
 

Tinnus

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Soulkiller said:
On commerical consoles the video output hardwre has diffrent PAL and NTSC versions. Thats why you ahve U.S region and EU region consoles,

Yes.

Soulkiller said:
along with games and DVD's that are region specfic as well.

No. Only difference in games was the output FPS, 50 for PAL and 60 for NTSC because of the refresh frequency of the TVs that were different (because of the power frequency). DVD's are region coded for pure political and economical reasons since the big majority of them are NTSC anyway.
 
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WizardStan

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Chip said:
Read through this thread, then read this post. I think you'll see that this has all been covered in depth already.


Perhaps I'm not seeing it, but those threads discuss why HD and VGA output is impossible. No discussion about the differences between PAL and NTSC TVs. Unless you were address the OP and not me, in which case I withdraw this post.
 
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Chip

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WizardStan said:
Chip said:
Read through this thread, then read this post. I think you'll see that this has all been covered in depth already.


Perhaps I'm not seeing it, but those threads discuss why HD and VGA output is impossible. No discussion about the differences between PAL and NTSC TVs. Unless you were address the OP and not me, in which case I withdraw this post.

I was addressing the topic of the thread: "Vga Or Dvi Out?, will we have the ability to connect to a computer monitor or lcd?".

As for your question... What is your question? If you have a device with an s-video input then the Pandora will be able to output to it. The chipset is capable of both PAL and NTSC output and it will be a trivial matter to specify which format you want.
 
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WizardStan

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Chip said:
As for your question... What is your question? If you have a device with an s-video input then the Pandora will be able to output to it. The chipset is capable of both PAL and NTSC output and it will be a trivial matter to specify which format you want.
SVideo is just a medium though. The analog signal it carries is still either PAL or NTSC, and they are not compatible. PAL has a slightly higher resolution than NTSC. If you write software intending to take advantage of a specific resolution on a TV, and attempt to play it on the other format, will the chip scale the image, or crop/box it as necessary?
Alternative question, the Pandora has a viewable resolution of 800x480 on the LCD, but the NTSC standard has only a max of 704x480 viewable area. If the TV is a direct clone of the screen, where do the extra 96 pixels per row go? Are they cropped, or is it scaled down such that every 8th pixel is removed? PAL, on the other hand, has 576 visible lines, as opposed to the 480. If the Pandora's 800x480 is then cloned directly to the TV, either it will need black bars across the top/bottom or every 6th line will need to be doubled to account for the differences of resolution. And that still doesn't account for the extra width.
This has immediate effects, for example, in a video player with subtitles. If the player knows what the output resolution is, it can produce a font which will be perfectly crisp on the display, assuming the TV is properly tuned. If it gets the resolution wrong, and the OMAP then scales the output to fit, then it's output font will be blurry.
 
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Soulkiller

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Tinnus said:
No. Only difference in games was the output FPS, 50 for PAL and 60 for NTSC because of the refresh frequency of the TVs that were different (because of the power frequency). DVD's are region coded for pure political and economical reasons since the big majority of them are NTSC anyway.
Damn I knew there was something wrong with what I was saying. Guess my asumption was wrong with games. Although I did know their was some kind of video output diffrence. I just assumed this was the resolution for the PAL and NTSC standards. So I'm guessing this means that you just retreive the region code at runtime and have the program adapt appropriatly.

Now my question is, will their be multiple versions of Pandora with diffrent region encodings for diffrent video standards such as NTSC, PAL, and maybe even SECAM?
 
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Snu

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WizardStan said:
schnitzelboy said:
well, no-not to a vga or dvi monitor, but u can use an s-video connector to hook it up to a high-def tv if you'd like!!
This actually begs a few very good questions, now that I think on it. Standard definition North American television is 640x480 of visible space. The actual transmission is 520 lines high, with wide screen sources, such as DVDs, capable of transmitting 720 pixel wide lines with 704 visible. PAL has 625 lines, only 576 of which are visible. I'm not certain about the widths, but I imagine PAL has two different standard widths as well.
"S-video" is just a medium for carrying these standards. So what's the output actually going to be? If we have a 4:3 NTSC screen, can we select 640x480, and the chip will naturally center everything to fit? Or if it tries to output to TV, will it lose the edges because the visible resolution is smaller than the carrier resolution? And if we have a 16:9 TV, can we then also select wide screen to increase the width to 704 pixels? Or must the screen be stretched/letterboxed? Lucky Europeans get an extra 100 pixels horizontal. Which asks the final question: if an application requests a fullscreen 640x480 display, this would fill an NTSC screen perfectly, but if the user is European will the chip automatically letterbox it with 48 empty lines above and below the image, or will it stretch to fit the 576 (or even worse, 625) lines of the PAL television. And vice versa: a european developer makes an app for TV out to PAL at 576 lines, played on an NTSC screen.... where do the extra lines go?

actually, ntsc standard is 720x486 visible (the extra lines up to 525 are broadcast related stuff), and svideo is 700x486 visible, tho the aspect ratio of both is 4:3...
bear in mind that this is analog, not digital, and while tv's have a set number of vertical refresh lines, the horizontal refresh is flexible, data may be lost, and these are transmission maximums only, and svideo can probably simply transmit at 640 horizontal rez anyway.
the issue tho is still the vertical lines, and framerate.
pal has a lower framerate - 50i versus 60i (which in the computer world is equivalent to 25p versus 30p, so no, running a game at over 30fps through an svideo signal wont make a difference).
in my opinion, possible issues with resolution differences are outweighed by the possible issues with framerate differences...
 
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Nilsiboy

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I'm pretty sure that the OMAP can output BOTH NTSC and PAL signals... Firstly because it isn't that hard, apparently - My MacBook's GMA950 can do both, as can the PS3 (at least the European 60GB one can, haven't had experience with any others - if you stick an NTSC game in that, you get NTSC output).
And secondly, why would TI want to make two different versions of the same SoC just because of TV region?
 

nubie

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Nilsiboy said:
I'm pretty sure that the OMAP can output BOTH NTSC and PAL signals... Firstly because it isn't that hard, apparently - My MacBook's GMA950 can do both, as can the PS3 (at least the European 60GB one can, haven't had experience with any others - if you stick an NTSC game in that, you get NTSC output).
And secondly, why would TI want to make two different versions of the same SoC just because of TV region?
I thought I answered his question, as with most species, variations within a species are often greater than that between species.

AKA TV's will show whatever the hell they want, most games have a huge border of extra space (on some the border is even grey or pink!?!), although many TV's I see are so over-scanned that they cut off menus placed very far from the actual edge.

Rest assured that the differences between PAL and NTSC will be trivial compared to the overscan on 95% of televisions.

The answer is that nobody knows how it will work yet, I don't know what kind of control is available, and I just hope that the scaling will be easily selectable and the code will find its way into all apps (we can only hope, as the video out cord will be in the box for all units, so there is no reason that support should be difficult to come by).

Personally I adjust my TV through the service menu (in much the same fashion as a CRT monitor), thus I don't really have to worry about anything being over-scanned off the edge.
 
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WizardStan

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Nilsiboy said:
I'm pretty sure that the OMAP can output BOTH NTSC and PAL signals...
Aye, it can, and as I keep saying, that there is the problem. How smart is the chip when handling cross region code?

nubie said:
The answer is that nobody knows how it will work yet, I don't know what kind of control is available, and I just hope that the scaling will be easily selectable and the code will find its way into all apps (we can only hope, as the video out cord will be in the box for all units, so there is no reason that support should be difficult to come by).
That's the answer that I'm concluding too. There's this chip that does TV output, and no one actually knows how it will work, how it handles cross region code, what adjustments will need to be made in software. I suppose we could take a wait and see attitude, as you seem to have, but it is a little irksome. What if it really is no good? What if the OMAP always does some sort of weird scaling that results in lost image and distortion that would normally be fine for video, but not for other tasks?
 
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