Custom TV-out Cable Pre-orders (Split from other topic)

[peca]

@WizardStan: I checked by ohm-meter already and seems to be OK. I'll check again. Thank for a clue.


@Norl: Sorry, I don't know - maybe someone else could answer this.

 

[Lewbio]

My Pandora will probably be some time away yet, will email for another update again a week or 2 >_>


I'm not too clued up in how the pandora sends out the tv signal. By the looks of it, it mirrors whatever is on the screen as far as I know. I thought that there should be some mechanism that turned the pandora screen off once you have it connected to a tv, and maybe be able to output to tv at a different resolution. Not sure what resolution the s-video/rca is limited to though.

 

[WizardStan]

I'm not too clued up in how the pandora sends out the tv signal. By the looks of it, it mirrors whatever is on the screen as far as I know. I thought that there should be some mechanism that turned the pandora screen off once you have it connected to a tv, and maybe be able to output to tv at a different resolution. Not sure what resolution the s-video/rca is limited to though.

S-video is limited to 720x480, or 562 depending on region, in contrast to the Pandora's 800x480. This is a TV limit, not a Pandora limit.


TV out is actually its own frame buffer: while the default is to simply clone the screen, it is entirely possible to have it output an entirely different display. It is also possible to turn off the screen while TV out is active; the same shut-off command is called when you close the lid.

 

[monty]

... and maybe be able to output to tv at a different resolution. Not sure what resolution the s-video/rca is limited to though.

S-video is limited to 720x480, or 562 depending on region, in contrast to the Pandora's 800x480. This is a TV limit, not a Pandora limit ...

TV signal is analogue and therefore has no strictly definable horizontal resolution. It has lines (for PAL it is 625, of which 576 are visible), but no columns. So in theory, sure, it can match the aspect ratio of the Pandora simply by squeezing more information onto each of the lines and getting stretched when in the television; exactly the same as what already happens to get 16:9 out of a standard originally designed for 4:3; exactly the same as how widescreen is achieved on film (compressed by camera lens, uncompressed by projector lens). This just depends on the software and is not limited by the cable type or, as long as your set gives you the option to adjust the picture, the TV.

 

[WizardStan]

TV signal is analogue and therefore has no strictly definable horizontal resolution. It has lines (for PAL it is 625, of which 576 are visible), but no columns. So in theory, sure, it can match the aspect ratio of the Pandora simply by squeezing more information onto each of the lines and getting stretched when in the television;

Exactly why I said it was a TV limit and not a Pandora one. If you find a TV with an analog input that displays more, you can by all means go ahead and display more. Keep in mind, however, that every HDTV I've encountered uses 720 samples per line when upscaling, so even though the TV itself could display more, it doesn't use more from the analog signal. To the best of my knowledge there is no TV that displays more than 720 samples per line, and some will even display fewer. I'd love to hear otherwise, however.

 

[dgame]

...


For those who don't know - composite output is connected to tv-out-1 pin (luminance) and in this state gives black and white picture only. For colour picture we need new kernel. So - I should get BW picture on composite, not colour.


...

Hi peca,


I stand correctable, but doesn’t the TV OUT 2 ( C ) [Chrominance] need to be connected to the TV OUT 1 (L) [Luminance] with a 470pF capacitor and then to the center of the composite jack in order to get a color picture?


Like in this diagram below:

Chrominance (chroma or C for short) is the signal used in video systems to convey the color information of the picture, separately from the accompanying luma signal . . . In video, luma, sometimes called luminance, represents the brightness in an image (the "black and white" or achromatic portion of the image). Luma is typically paired with chroma.

Seems as if you only use luminance you would only get black and white?

 

[slaeshjag]

Yes, but the TV-out port is capable of outputting composite on the luminance pin, it just need the software to tell it to do that.

 

[Morn]

In the meantime (until kernel is updated) one can use S-Video with a simple adapter

which is simple implementation of dgame's diagram

 

[peca]

@dgame: Yes it is possible, but as slaeshjag and Morn says


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Some news. I'm messing with cables. Friend with big plasma screen is on holidays but I realize that we have a projector (beamer ) in my work. So I tried and it provide nice picture even from cable 3 meters long. Sharp BW from composite and clear colour from S-Video. Projector is some cheap Acer. My TV at home is some cheap crap - some cheap brand for cash & carry storehouse. It could mean that picture on some old TV set wouldn't be good. It may be due to good or bad input filters on one or another device. Don't know.


I'm starting building cables. In PM I'll rather inform about this anyone that wishes cable longer then 1 meter to be sure that he/she take this. 1 meter and shorter works good even on my TV.


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One other thing - I realize that I'm not test audio input yet. I'll must find out some script that redirect EXT port audio input to Pandora's speaker for testing this. I rather test it this way than only measure by ohmmeter.


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edit: Added some pictures They are yellowish due to projecting on yellow wall.





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edit2: Oh, about PM. I'm probably forgot to reply someone. Don't be frustrated. I'm registering orders. I'm just unsure if I'm reply to all or not. Anyway - as I'll be ready to send some, I'll reply to ask address and money.

 

[MarioPandio]

Thanks for your VGA feeback earlier Peca and sorry to hear of the initial cable issues but it sounds like things are getting sorted. Looks great on the beamer

 

[dgame]

In the meantime (until kernel is updated) one can use S-Video with a simple adapter

which is simple implementation of dgame's diagram

I made a TV-out cable by soldering a female S-Video cable to the tiny EXT connector. h34r:


Tested on a Sony PVM 1944Q CRT Monitor. B)


Using the S-Video the TV Out picture is beautiful!


When using an S-video to composite adapter like the one Morn showed above, the picture looks grainy and bad. It could be the adapter though. Need to get a 470pF capacitor to make an S-video to composite adapter in order to test further.

 

[Prometheus]

When using an S-video to composite adapter like the one Morn showed above, the picture looks grainy and bad. It could be the adapter though. Need to get a 470pF capacitor to make an S-video to composite adapter in order to test further.

Isn't composite supposed to look like that, though?

 

[slaeshjag]

It's not a fault, it's just a modern -> retro image adapter!

 

[Link]

Looks great on the beamer

+1

 

[mcobit]

For compositeaoutput on the cable directly you have to put a 470pF capacitor in the C line and wire C and Y together afterwards. The you'll get a colored Composite out.


Have a look here:





or here:


http://de.wikipedia.org/w/index.php?title=Datei:S-video-composite-adapter.svg&filetimestamp=20051006154953


Edit: OOOOps, didn't see the previews posts

 

[peca]

I'm preparing to update initial post and add some informations.


I still can't believe that it take so long to build one cable. I was start at 20 (8 PM) and was done at midnight. I'll must find some speed-up without quality lose. :-/

 

[mcobit]

Practice is always your friend.


Also you can pack worksteps into batches, like:


First solder all wires to all the breakoutboards, then solder all the boards to the extconnectors, then solder all the other connectors.


Also you can prepare all the cables first, with stripping the ends and pretinning. Maybe this can be done by some other person in parralel.

 

[peca]

Practice is always your friend.


Also you can pack worksteps into batches, like:


First solder all wires to all the breakoutboards, then solder all the boards to the extconnectors, then solder all the other connectors.


Also you can prepare all the cables first, with stripping the ends and pretinning. Maybe this can be done by some other person in parralel.

Yes, this is what I have on mind. Although there is no companion for help (if I'm not going to employ my child - for clearance: I'm not ).

 

[Sugarfix]

if I'm not going to employ my child - for clearance: I'm not

Do child slave labour laws apply to family members? <_<

 

[peca]

I'm not dead still working on cables. I have done a few of them ready for shipping. Now I'm building 10 in one small batch - this should be hopefully done by weekend. Then I'll ship them and I'll have done all for those who already paid - so your money are not stolen but I didn't realize how much work it will be. Actually it is not hard work - it is rather time consuming.