Video Cable/connector

[rv6502]

I'm certain there's a very good reason for not having used it (no room for signal traces?, only composite video possible and not s-video?, cost?) I'm just curious about it.

why not have used a TRRS plug for a video out / headphone combo plug using "standard" camcorder cable?

http://images.google.ca/images?hl=en&q=camcorder%20cable

the video and right audio signals would be interchanged (unless some extra circuit swaps them) but the cable would be cheap and easy to find.

I tried searching the forum but couldn't find anything on the topic, sorry if its been answered already.

 

[WizardStan]

The "video" port isn't really a video port, it's an auxiliary port. Video/audio are just two of the things it has on it. I forget all what's actually out of it, but it's 14 pins and every one is used. Or it was 13 pins and one guide pin. Or something, my memory is fuzzy.
Point being that there's a lot of hackability on that port, and it was easier to put everything (including video and audio) on that single port than to make two separate ports. Or so is my understanding.

 

[Squidge]

The "video" port also contains digital i/o, power, uart, and other stuff. Headphones and Mic are on a seperate connector I think (or were once).

Besides, the video output is S-Video, not composite.

 

[rv6502]

The "video" port also contains digital i/o, power, uart, and other stuff. Headphones and Mic are on a seperate connector I think (or were once).

Besides, the video output is S-Video, not composite.

to get composite from s-video you just mix both luma and chroma signals by connecting the wires.
(with an optional ~3.5Mhz lowpass filter on the luma feed before mixing)

 

[Vorporeal]

Of course, but he's just saying that the specific output type is S-Video, not composite, and that if you want composite, you'll have to get it from the S-Video connector.

 

[Squidge]

Yes, thanks Vorporeal, much better to put the better resolution one first and let the customer downgrade it if they wish than the later and be stuck with it.

The cable Stephane mentions is a 4-conductor cable. Left/right audio, Composite & Ground. Since the Pandora supports S-Video we would either have to downgrade it to composite or use a 5-conductor cable. If your going to go custom, might as well throw other stuff on it at the same time.

 

[rv6502]

Yes, thanks Vorporeal, much better to put the better resolution one first and let the customer downgrade it if they wish than the later and be stuck with it.

The cable Stephane mentions is a 4-conductor cable. Left/right audio, Composite & Ground. Since the Pandora supports S-Video we would either have to downgrade it to composite or use a 5-conductor cable. If your going to go custom, might as well throw other stuff on it at the same time.

I'm curious how much would it raise the price to have both the custom connector with extra stuff (which is really nice to have), and the TRRS plug (replacing the TRS headphone one while still being compatible).

if the OMAP3 hardware support mixing both signals internally with a software control to switch between separate (luma, chroma) and (luma+chroma) on one of the pins, all we'd need is an extra trace (or wire) and a TRRS plug.

otherwise we'd need a video amp circuit to mix both signals for the "headphone" plug while keeping them separate on the custom plug, so in this case it would be a bit more work and more expensive.

I'm not complaining or critiquing, or trying to "MEE HAZ GRATE AIDEEAH" :rolleyes:
I take s-video over composite anytime, I got a Commodore 1702 video monitor for my consoles (a-ma-zing video quality, you can count the pixels, a 2000$ TV isn't even close, larger, but not sharper, at least for non-HD analog signals)

its just very convenient to be able to plug a normal cable, camcorders even output the video on the first ring so you can use a stereo audio cable as video+mono if you don't have a camcorder cable handy.
but that would require a signal switch to be able to use headphones, having video on the sleeve would keep compatibility even tho the video signal will be on wrong RCA plug color.

putting aside probably having to go thru CE/FCC again for just that modification, what would the extra cost be if it was added to Pandora 1.01 ?
if a problem is discovered with the board, or cost savings, etc, it could be nice to add if feasible.

I already ordered the custom cable and if I ever lose it and can't get another one for some reason I'll just void the (likely expired) warranty and replace the headphone plug myself and run wires with a switch

or by then order a Pandora 2 with another custom cable...
the more reason to hack a TRRS plug on the old Pandora just for the heck of it then

 

[gahndalf]

I would imagine the hardware change you are suggesting is cheap. (a few dollars)
But it would not happen! I want a headphone jack so i can use my pandora as an MP3 player!
I think what you should look into is if this is a mod that a user can do and if the driver will be in the Pandora or need to be created etc..

 

[x86Daddy]

I would imagine the hardware change you are suggesting is cheap. (a few dollars)
But it would not happen! I want a headphone jack so i can use my pandora as an MP3 player!
I think what you should look into is if this is a mod that a user can do and if the driver will be in the Pandora or need to be created etc..

Nice thing about a jack like that is that you *can* use it with headphones / purely audio output, or with another cable for video+audio... The later Nokia NSeries phones like N95, N85, etc... have this feature; I use it often. It is very very convenient. I know I'd be happy to see this feature in the Pandora, or as a documented user-mod down the road.

 

[WizardStan]

The headphone jack is already a TRRS. It has microphone on it as well. To do what you're suggestion, they'd have to switch to a TRRRS (TRRRRS?), or add a second TRRS. In both cases you're looking at user confusion (which plug goes where?) but in the first you've also got the problem of needing a custom cable anyway (how many TRRRS cables have you seen?) so you may as well go with the auxiliary port idea they did use.

Edit: not to mention that headphone output isn't the same as line level output that you're getting out of the AUX port.

 

[x86Daddy]

The headphone jack is already a TRRS. It has microphone on it as well. To do what you're suggestion, they'd have to switch to a TRRRS (TRRRRS?), or add a second TRRS. In both cases you're looking at user confusion (which plug goes where?) but in the first you've also got the problem of needing a custom cable anyway (how many TRRRS cables have you seen?) so you may as well go with the auxiliary port idea they did use.

Edit: not to mention that headphone output isn't the same as line level output that you're getting out of the AUX port.

Oh yeah... My old Zaurus's audio jack was of this nature, and I forgot about it from the Pandora specs. That said, the Nokia phones have something in software to handle this as well... same 4 pins, but on device insertion (or set up as an "always use this" profile) they ask what you plugged in: headset, headphones, TV-out cable, something else... For those with a modern Nokia with 3.5mm jack, visit Settings-->General-->Enhancement to see the options. I'm guessing the user's choice at that point digitally changes which lines route to the 4 pins... and that's likely some proprietary and/or patented chip/code/hardware paradigm. :-(

 

[rv6502]

The headphone jack is already a TRRS. It has microphone on it as well. To do what you're suggestion, they'd have to switch to a TRRRS (TRRRRS?), or add a second TRRS. In both cases you're looking at user confusion (which plug goes where?) but in the first you've also got the problem of needing a custom cable anyway (how many TRRRS cables have you seen?) so you may as well go with the auxiliary port idea they did use.

Edit: not to mention that headphone output isn't the same as line level output that you're getting out of the AUX port.

nice, I did not know the plug was TRRS and already had the mic input.

makes it easier to do a hardware mod: 1 trace cut on the mic signal, wire a hardware switch and a few thin wires.
you could switch between mic+audio and video+audio, you're unlikely to be using both at the same time ...
(pandora karaoke machine? :blink: )

the headphone output might not be at the same level as line output, but that's nothing that cant be adjusted using the internal mixer or the hardware volume knob.
people plug headphones in line output, and audio amplifiers into headphone outputs all the time.

 

[peca]

makes it easier to do a hardware mod: 1 trace cut on the mic signal, wire a hardware switch and a few thin wires.
you could switch between mic+audio and video+audio,...

Ahm, are you kidding? If not, try learn something about signals, frequencies and so. You can't use just some thin wires and switch, or you kill video signal (mic probably suffer on quality only).

 

[rabidpoobear]

makes it easier to do a hardware mod: 1 trace cut on the mic signal, wire a hardware switch and a few thin wires.
you could switch between mic+audio and video+audio,...

Ahm, are you kidding? If not, try learn something about signals, frequencies and so. You can't use just some thin wires and switch, or you kill video signal (mic probably suffer on quality only).

Maybe you could explain why this wouldn't work? It seems to me composite video is a fairly low-level signal so it shouldn't need very thick wire to run it.

 

[Squidge]

True, I've run composite video down thin headphone cable before (it was the only cable I had and even then it was a svidoeo->composite converter).

However, inside Pandora you might get far more interference with thin wire.

Just try it and see if the results are acceptable for you.

 

[Enverex]

So what can that port be used for? Is there going to be some sort of "breakout" cable available that gives you the S-Video, Mic, Headphones at the same time? Or can it only do one at once? Also I saw mention of Digital I/O on that port, does that mean the port can also be used for digital output? (for connecting the Pandora up to a Dolby/DTS decoder and using digital passthrough, etc.).

 

[peca]

I'm not either electronic engineer nor skilled hobbyist so I may be wrong, but Composite signal is something that I never put on some thin wire. Not to mention that there is no composite available in Pandora. There is S-Video on Ext-Out. So you need find traces with chroma and luma and merge them to composite. AFAIK this kind of signal needs shielding. And HF signals, which I guess composite signal is, can't be switched just by some unshielded switch.

Pandora have 14pin port. You can buy video out cable that have S-Video, composite and audio line out and line in. I don't se any reason for modding Pandora to have video on front audio jack instead of mic (or switchable with mic). If moding is so risky and you need some other cable for connecting to TV (projector).

 

[WizardStan]

So what can that port be used for? Is there going to be some sort of "breakout" cable available that gives you the S-Video, Mic, Headphones at the same time? Or can it only do one at once? Also I saw mention of Digital I/O on that port, does that mean the port can also be used for digital output? (for connecting the Pandora up to a Dolby/DTS decoder and using digital passthrough, etc.).

The digital I/O that was mentioned is things like RS232 and i2c, and other computer type communications, not digital audio. Although you could theoretically write an audio driver to dump the digital output onto the RS232 line, and then run that into a DTS decoder somehow. It wouldn't be terribly difficult, but not easy either.

 

[Kimundi]

Let me just Quote myself here:

The Ext-Connector has 14 Pins:

2 Stereo Audio Line In
2 Stereo Audio Line Out
2 Video (S-Video or Composite)
6 Serial Interfaces
1 Ground
1 Power (2.8V, for example to power a adapterchip)

The Audio Line In and Out are independend from the Speakers/Microphone, and the Tv-Out can either use 1 Pin for Composite Out or 2 Pins for S-Video out. And It can run at Pal/NTsc, so there should be no problems connecting it to any TV