Welcome to the MacNN Forums.

If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below.

You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Notebooks > Mini DisplayPort Hacking

Mini DisplayPort Hacking
Thread Tools
Fresh-Faced Recruit
Join Date: Nov 2008
Status: Offline
Reply With Quote
Nov 1, 2008, 02:32 PM
 
Do displayport & mini-displayport have identical wiring? Would it be feasible to take this displayport/hdmi adapter and just chop the cable in half and splice in the tail of one of Apple's mini-displayport adapters?
     
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Nov 1, 2008, 03:37 PM
 
It's the same pin count (20 pins), but Mini DisplayPort is proprietary to Apple so it's possible they changed the purpose of some of the pins.
     
Professional Poster
Join Date: Jan 2003
Status: Offline
Reply With Quote
Nov 1, 2008, 04:02 PM
 
yep, as stated, you'd better get the pin-out diagram.
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 2, 2008, 10:31 AM
 
Are you trying to go Mini DisplayPort to HDMI? If so, why bother with the diagrams and splicing? Just get 2 cables: (1) Mini DisplayPort to DVI and (2) DVI-D to HDMI. However, if you you like splicing and diagrams, then by all means, go for it. Were you gonna splice the tail of the $99 adapter?

If instead you intended Mini DisplayPort to DisplayPort, may I ask why?
10.7.1 on Mac Pro 8x2.8
     
Posting Junkie
Join Date: Jun 2002
Location: Calgary
Status: Offline
Reply With Quote
Nov 2, 2008, 10:45 AM
 
Originally Posted by Ted L. Nancy View Post
Are you trying to go Mini DisplayPort to HDMI? If so, why bother with the diagrams and splicing? Just get 2 cables: (1) Mini DisplayPort to DVI and (2) DVI-D to HDMI. However, if you you like splicing and diagrams, then by all means, go for it. Were you gonna splice the tail of the $99 adapter?

If instead you intended Mini DisplayPort to DisplayPort, may I ask why?
In both cases, the answer may be that Apple seriously overcharges for it's display adapters.
     
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Nov 2, 2008, 11:14 AM
 
Originally Posted by Ted L. Nancy View Post
Are you trying to go Mini DisplayPort to HDMI? If so, why bother with the diagrams and splicing? Just get 2 cables: (1) Mini DisplayPort to DVI and (2) DVI-D to HDMI.
To connect to an HDTV with audio?
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 2, 2008, 01:26 PM
 
Originally Posted by Wiskedjak View Post
In both cases, the answer may be that Apple seriously overcharges for it's display adapters.
I thought that at first, but then I don't understand why the OP wants buy one of those expensive cables only to cut into it.
10.7.1 on Mac Pro 8x2.8
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 2, 2008, 01:44 PM
 
Originally Posted by mduell View Post
To connect to an HDTV with audio?
I thought this at first as well. But, ummmm... are talking cutting into the Mini DisplayPort AND an audio cable, or trying to take advantage of the Mini DisplayPort's (purported) audio capabilities?

In either case, if you MUST transmit your audio over the video cable, I would definitely wait for Apple or a third-party manufacturer to release a Mini DP ->HDMI. (If audio is in fact possible over the Mini DisplayPort, it is only matter of time before this type of connector is released. Then you wouldn't have to buy and destroy a Mini DisplayPort connector prematurely. Also, the advantages of outputting audio and video via the same cable are, IMO, not worth it right now given the available standards for doing so.)
10.7.1 on Mac Pro 8x2.8
     
Yortuk  (op)
Fresh-Faced Recruit
Join Date: Nov 2008
Status: Offline
Reply With Quote
Nov 2, 2008, 01:54 PM
 
Originally Posted by Ted L. Nancy View Post
Are you trying to go Mini DisplayPort to HDMI? If so, why bother with the diagrams and splicing? Just get 2 cables: (1) Mini DisplayPort to DVI and (2) DVI-D to HDMI.
DVI doesn't do audio. Although I just read a claim on some blog that Apple doesn't route audio to the mini-DisplayPort anyway. Would be nice to be able to confirm one way or the other.

Were you gonna splice the tail of the $99 adapter?
No, I just need the mini-DisplayPort end, so I'd use one of the "cheaper" adapters.
     
Yortuk  (op)
Fresh-Faced Recruit
Join Date: Nov 2008
Status: Offline
Reply With Quote
Nov 2, 2008, 02:04 PM
 
Originally Posted by Ted L. Nancy View Post
In either case, if you MUST transmit your audio over the video cable
It's not that I must, it's just that it would be nice to have one fewer cables to mess with every time I hookup my laptop. I assume there will be proper adapters in time, but that means I either have to wait, or waste money on an interim solution. I guess I'm kind of annoyed that Apple didn't offer a proper variety of adapters from the outset.
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 2, 2008, 02:04 PM
 
Originally Posted by Yortuk View Post
DVI doesn't do audio. Although I just read a claim on some blog that Apple doesn't route audio to the mini-DisplayPort anyway. Would be nice to be able to confirm one way or the other.



No, I just need the mini-DisplayPort end, so I'd use one of the "cheaper" adapters.
Good to hear from you, Yortuk. I think the consensus is that Apple does route audio through the Mini DP (why wouldn't they, right?), but I, among many others, would like a definite, widespread confirmation of this.

I would nonetheless recommend, as a practical measure, doing a MiniDP/DVI/HDMI video cable and then taking advantage of that optical out.
10.7.1 on Mac Pro 8x2.8
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 2, 2008, 02:05 PM
 
Originally Posted by Yortuk View Post
I guess I'm kind of annoyed that Apple didn't offer a proper variety of adapters from the outset.
I hear ya!
10.7.1 on Mac Pro 8x2.8
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 2, 2008, 02:16 PM
 
Oh, and by the way, since the HDMI Mafia requires companies to pay fees for offering HDMI on their products (hence the dawn of the free DP standard) you can understand the hesitation on the part of Apple in not supporting HDMI.

Nonetheless, given the number of people who benefit from HDMI at this point, I hope Apple will at least offer an adapter. If not, you'll definitely find it with a third party soon (monoprice, are you listening?).
10.7.1 on Mac Pro 8x2.8
     
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Nov 2, 2008, 02:56 PM
 
Now that I think about it, DisplayPort only passes through HDMI, so I doubt you're going to get audio from a hacked miniDP-HDMI cable.

Originally Posted by Ted L. Nancy View Post
Oh, and by the way, since the HDMI Mafia requires companies to pay fees for offering HDMI on their products (hence the dawn of the free DP standard) you can understand the hesitation on the part of Apple in not supporting HDMI.
The HDMI licensing fee is only $10k/year plus 5 cents/unit, but HDMI only supports single link DVI so Apple had to move to DisplayPort to maintain support for their 30" display.
     
Posting Junkie
Join Date: Nov 2000
Location: in front of my Mac
Status: Offline
Reply With Quote
Nov 3, 2008, 04:26 AM
 
Originally Posted by Ted L. Nancy View Post
Oh, and by the way, since the HDMI Mafia requires companies to pay fees for offering HDMI on their products (hence the dawn of the free DP standard) you can understand the hesitation on the part of Apple in not supporting HDMI.
From what we've previously seen it's a pretty safe bet that while HDMI will be found on most new TVs, projectors, etc. DP will become the interface of choice on computers. For video-out on computers DP offers clear advantages over HDMI. And actually most if not all involved industries wouldn't mind if TVs and computers didn't use the same interface.
     
Fresh-Faced Recruit
Join Date: Aug 2000
Location: Edmonton, Alberta, Canada
Status: Offline
Reply With Quote
Nov 10, 2008, 10:16 PM
 
I got a full set of drawings for the mini displayport connectors from Molex when I emailed them and asked when they will have these connectors available for purchase.

Some information I got from them. The connector is not propriatary. At least it will not be because it will be included as part of version 1.2 of the Displayport specification when it eventually gets published by VESA. So Apple is jumping the gun on the standard but it's coming.

Molex will not be selling the discreet connectors until the standard is out. At least that was the plan. Requests for parts from their distributors and large customers may change their plans if there is enough demand to release early. For now the only way to get a mini displayport to standard sized displayport connector would be to hack apart an Apple adaptor and make it yourself. This might be risky if Apple doesn't use all the required connector pins in their cable you will be screwed.

I posted the drawings on a temporary web page:
http://www.test.upcraft.com/



     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 10, 2008, 10:57 PM
 
Originally Posted by que_ball View Post
The connector is not propriatary.
Awesome. Can you confirm where you heard this? -Ted
10.7.1 on Mac Pro 8x2.8
     
Fresh-Faced Recruit
Join Date: Aug 2000
Location: Edmonton, Alberta, Canada
Status: Offline
Reply With Quote
Nov 10, 2008, 11:49 PM
 
Originally Posted by Ted L. Nancy View Post
Awesome. Can you confirm where you heard this? -Ted
The drawings I posted are easy enough to read. The company name on them is Molex.

They are a member of the displayport committee at Vesa and deeply involved in the development of the standard. They are also the company manufacturing the connectors on the motherboard of the new Apple Laptops and the plugs that apple assembles in their conversion cables.

Specifically I was told by someone directly at Molex. I went to their homepage and choose contact us and send an email to the canadian contact address requesting information and this is what they sent back. I have no special relationship with the company, they were just very helpful in answering my questions. I was hoping to buy the plug parts. I was asking what the part numbers were so I could go to my local electronics supplier and have him order them. In answering my inquiry they sent the drawings and told me they were not manufacturing these parts for general sales yet until the standard is finalized or at least published in draft format. The person I was talking to said it was his opinion that they may change plans if a large number of requests for preliminary spec parts come in as a result of Apple releasing product ahead of the published specs.

Not much more to say about it. The drawings have the pin descriptions which match the full sized displayport connectors so a direct conversion cable is trivial assuming you can get your hands on the connectors. Exact same electrical signal just on a smaller connector.

So for the other questions raised by the new port (HDMI adapter, SVIDEO, component, composite video, etc) I guess you can find out if those things are possible on a full sized displayport card and the same will be true for the mini version.
     
Posting Junkie
Join Date: Nov 2000
Location: in front of my Mac
Status: Offline
Reply With Quote
Nov 11, 2008, 02:48 AM
 
Originally Posted by que_ball View Post
Some information I got from them. The connector is not propriatary. At least it will not be because it will be included as part of version 1.2 of the Displayport specification when it eventually gets published by VESA. So Apple is jumping the gun on the standard but it's coming.
Thanks a bunch for those drawings. Excellent material.

I'm glad you were able to get independent information regarding MDP not being proprietary. I don't know who started this nonsense about MDP being Apple's proprietary thing. It's quite obviously not. My guess is a few people saw a new connector nobody else but Apple was currently using and figured this was ADC all over again. But as others here already knew and you have now been able to confirm independently MDP will be finalized in the updated DP specs.

I think this should give some more reassurance that the move to DP/MDP was a good idea. It's not the first time Apple is just plain early. But eventually DP/MDP will become the prevalent display bus. And that is totally independent of where HDMI is going.
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 11, 2008, 12:22 PM
 
Great news, that it's a non-proprietary connector. I'm sure the PC world has been looking for a compact connector for laptops, too.

P.S. There is a dual-link version of HDMI, but I've never seen it in use. I wouldn't be surprised if it never sees the light of day, if DP can do the same thing over a gorgeous tiny connector.
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 11, 2008, 12:23 PM
 
P.P.S. Am I the only one to notice that all the recent connector types (USB, FireWire, HDMI, DP) all seem inspired by the pinless plugs Nintendo introduced with the GameBoy back in, what, 1989?
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 11, 2008, 04:00 PM
 
Originally Posted by tooki View Post
P.S. There is a dual-link version of HDMI, but I've never seen it in use. I wouldn't be surprised if it never sees the light of day, if DP can do the same thing over a gorgeous tiny connector.
I've seen DVI --> HDMI cables where the DVI end seemed to sport a full set of dual-link pins, but I always assumed that those were just dead pins.

Does HDMI have some extra pins or pin spots that I don't know about?
10.7.1 on Mac Pro 8x2.8
     
Mac Enthusiast
Join Date: May 2008
Location: Thousand Oaks, CA
Status: Offline
Reply With Quote
Nov 11, 2008, 04:02 PM
 
Originally Posted by tooki View Post
P.P.S. Am I the only one to notice that all the recent connector types (USB, FireWire, HDMI, DP) all seem inspired by the pinless plugs Nintendo introduced with the GameBoy back in, what, 1989?
Which is good, because it is a real nuisance when you jam a plug in at the wrong angle and bend pins...
10.7.1 on Mac Pro 8x2.8
     
tuc
Fresh-Faced Recruit
Join Date: Aug 2003
Status: Offline
Reply With Quote
Nov 11, 2008, 04:12 PM
 
Originally Posted by Yortuk View Post
No, I just need the mini-DisplayPort end, so I'd use one of the "cheaper" adapters.
Be careful, as I would guess that Apple's "cheaper " mini-DisplayPort adapters don't have the
full complement of conductors. This is just speculation on my part, but if you were creating the
adapters, wouldn't you just use the few conductors that you need?
     
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Nov 11, 2008, 07:17 PM
 
Originally Posted by Simon View Post
I'm glad you were able to get independent information regarding MDP not being proprietary. I don't know who started this nonsense about MDP being Apple's proprietary thing. It's quite obviously not.
How is a connector that's not defined by any published standard not proprietary? Can you name any other connector that's not proprietary and not covered by a published standard?

I'm happy to hear rumors that Apple is moving toward standardization, but there's no guarantee they'll get it with VESA.
     
Fresh-Faced Recruit
Join Date: Aug 2000
Location: Edmonton, Alberta, Canada
Status: Offline
Reply With Quote
Nov 11, 2008, 11:54 PM
 
Originally Posted by mduell View Post
How is a connector that's not defined by any published standard not proprietary? Can you name any other connector that's not proprietary and not covered by a published standard?

I'm happy to hear rumors that Apple is moving toward standardization, but there's no guarantee they'll get it with VESA.
You are absolutely correct. Until they actually publish the standard it is de jure proprietary. There is no guarantee that when the members of the DisplayPort committee get together to vote on the next revision of the standard that they will pass the design of the display port connector that Apple is using.

No company has released or even announced any Mini displayport product outside of Apple. The information I got from Molex is the only third party information I have ever found. Lets hope it catches on.
     
Posting Junkie
Join Date: Nov 2000
Location: in front of my Mac
Status: Offline
Reply With Quote
Nov 12, 2008, 02:36 AM
 
Apple has learned a lot from ADC. They have no intention to make MDP proprietary. You can rest assured that MDP will be in the next version of the DP specs. Open to everybody. When it comes to MDP Apple might be early, but they're right. And I'm very confident that will prevail.
( Last edited by Simon; Nov 12, 2008 at 02:48 AM. )
     
Mac Enthusiast
Join Date: Feb 2006
Status: Offline
Reply With Quote
Nov 12, 2008, 03:14 AM
 
P.P.S. Am I the only one to notice that all the recent connector types (USB, FireWire, HDMI, DP) all seem inspired by the pinless plugs Nintendo introduced with the GameBoy back in, what, 1989?
The AppleJack connector used on the Pippin was the first "make before break" connector, and came out in 1995. The original GameBoy had a game link connector, but it was little more than an audio interface (using the same hardware).

So, no, they are not.
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 12, 2008, 10:26 AM
 
Uhhh, the GameBoy connector most certainly is not an audio plug. Maybe you're thinking of the TI-Link plug on TI's graphing calculators, which is a 2.5mm miniplug?

The GameBoy Game Link looks like a cross between a FireWire plug and a USB plug. Look at it (courtesy Wikipedia):

That is a modern connector, but in 1989.
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 12, 2008, 10:30 AM
 
Originally Posted by Ted L. Nancy View Post
I've seen DVI --> HDMI cables where the DVI end seemed to sport a full set of dual-link pins, but I always assumed that those were just dead pins.

Does HDMI have some extra pins or pin spots that I don't know about?
Dual-link HDMI has a larger plug that apparently has never been implemented in an actual product. See http://en.wikipedia.org/wiki/HDMI#Connectors

As for fully-populated DVI plugs, that's really common in connectors, as I suspect it's often cheaper for a cable maker to just buy a ton of fully-pinned connectors and wire them as needed than to buy many different variants.
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 12, 2008, 10:38 AM
 
Originally Posted by tuc View Post
Be careful, as I would guess that Apple's "cheaper " mini-DisplayPort adapters don't have the
full complement of conductors. This is just speculation on my part, but if you were creating the
adapters, wouldn't you just use the few conductors that you need?
Not likely. There really aren't any spare conductors to save on. As I understand it, DP has a limited number of conductors, which are configured to carry different types of signals. That is, the same conductors carry DP, DVI/HDMI, or VGA signals, depending on what the sense pins in the adapter tell it to output. DP has enough conductors ("lanes") to carry the following:
  • DisplayPort signal (up to 2560x1600px)
  • Single-link DVI/HDMI (up to 1920x1200px)
  • VGA
  • Component video
A signal from the display or adapter tells the graphics card which signal to output over the connector.

What it does not have enough conductors for is to do multiple signal types at once (which is what "dumb" adapters would need), nor to do dual-link DVI.

That's why the single-link DVI adapter is cheap (all it's doing is telling the graphics card to output DVI, and then physically adapting the plugs), while the dual-link DVI adapter is expensive (it's having the graphics card output DP signals, and then it's converting those outside the computer to a DVI signal).
     
Fresh-Faced Recruit
Join Date: Nov 2008
Status: Offline
Reply With Quote
Nov 12, 2008, 02:28 PM
 
Originally Posted by que_ball View Post
I got a full set of drawings for the mini displayport connectors from Molex when I emailed them and asked when they will have these connectors available for purchase.

...
That's great --- thanks for posting the drawing. Is there any way to tell from this drawing whether miniDP carries, or can carry, audio?

--Paul
     
Fresh-Faced Recruit
Join Date: Aug 2000
Location: Edmonton, Alberta, Canada
Status: Offline
Reply With Quote
Nov 12, 2008, 03:14 PM
 
Originally Posted by paulgg View Post
That's great --- thanks for posting the drawing. Is there any way to tell from this drawing whether miniDP carries, or can carry, audio?

--Paul
You would need to purchase a copy of the Displayport standard documents from VESA.org for that kind of information. The drawing only shows the size, position and name of the pins, nothing about the signal protocol.
     
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Nov 12, 2008, 07:50 PM
 
Originally Posted by paulgg View Post
That's great --- thanks for posting the drawing. Is there any way to tell from this drawing whether miniDP carries, or can carry, audio?
Originally Posted by que_ball View Post
You would need to purchase a copy of the Displayport standard documents from VESA.org for that kind of information. The drawing only shows the size, position and name of the pins, nothing about the signal protocol.
The DisplayPort 1.1a standard is free from vesa.org, but of course it doesn't cover the non-standard Mini DisplayPort. According to the Wikipedia, Mini DisplayPort has the same number of pins as DisplayPort, but Apple may have repurposed some of them. The auxiliary channel in DisplayPort is only good for 1Mbps, (the following is speculation) so Apple may have had to use the standard audio channel pins for high speed USB (with USB speakers/mic/hub in the display).
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 12, 2008, 08:14 PM
 
Uhhh, why would Apple had to have repurposed pins? The LED Cinema Display uses a USB plug to the Mac in addition to mini-DP, plus offers a MagSafe plug to power the laptop.
     
Moderator
Join Date: May 2001
Location: Hilbert space
Status: Offline
Reply With Quote
Nov 13, 2008, 07:23 AM
 
Originally Posted by mduell View Post
How is a connector that's not defined by any published standard not proprietary? Can you name any other connector that's not proprietary and not covered by a published standard?
Well, 82.011n was also used before the standard was officially released (and yes, there were some incompatibilities of early `pre-n' devices).
I don't suffer from insanity, I enjoy every minute of it.
     
Fresh-Faced Recruit
Join Date: Nov 2008
Location: UK
Status: Offline
Reply With Quote
Nov 13, 2008, 08:52 AM
 
Hello from the other side of the pond... I've been eagerly searching forums for anyone who's tried making a DIY Mini-DP to (either regular DisplayPort or) HDMI cable, to answer the million dollar question: Can a mini-DisplayPort to HDMI cable carry audio and video?

So far has anyone found, seen, heard of or even taken the plunge themselves and snipped/soldered a pair of cables together? You can get displayport-to-HDMI cables (not sure I'm allowed to post links, but a quick google brought one up) so splicing a mini-DP plug from one of Apple's adapters (anyone got a spare?) shouldn't be too hard to do, if mini-DP and DP are pin/level compatible.

I've read in a couple of places that Apple's mini-displayport-compatible 24" LED Cinema screen (which has sound and a USB hub, yet only power, mini-DP and USB cables) drops the audio when you unplug the USB. And will play audio even if you unplug the DP cable... so I'm not terribly confident an AV mini-DP to HDMI is going to be possible, and I'm a bit nervous about buying 2 quite pricy cables to test it out. But logically, if mini-DP adheres to the DP spec (all signs point to this at the moment), it would be quite a brave move for Apple to decide to send audio over a seperate cable to their own monitors... I suppose I'm so impressed with the MacBook, I don't want to beleive Apple has intentionally made life a little tiny bit harder for us!

In the mean-time, if I pluck up the cash for the extra cables I might just knock up a frankenstein mini-DP to HDMI cable and will post the results back here But until then, it'll just have to put up with yet more cables and adapters

Cheers,
Colin
     
Fresh-Faced Recruit
Join Date: Nov 2008
Status: Offline
Reply With Quote
Nov 13, 2008, 04:58 PM
 
Hi Colin,

I hope you do get around to build such a cable. : - )

Regarding the audio on the new 24" LED Cinema dispaly being via USB, and the indication that the miniDP is to VESA standards, it seems that even if audio is routed via USB when driving the 24" LED Cinema display, there is no reason for audio not to be also carried via the miniDP; it might take a 3rd party hack/utility, though. I'm feeling optimistic that Apple would allow both video and audio out from the miniDP.
     
Posting Junkie
Join Date: Oct 2005
Location: Houston, TX
Status: Offline
Reply With Quote
Nov 13, 2008, 06:52 PM
 
Originally Posted by tooki View Post
Uhhh, why would Apple had to have repurposed pins? The LED Cinema Display uses a USB plug to the Mac in addition to mini-DP, plus offers a MagSafe plug to power the laptop.
You're right, I missed that.

Originally Posted by OreoCookie View Post
Well, 82.011n was also used before the standard was officially released (and yes, there were some incompatibilities of early `pre-n' devices).
But the drafts were published and available, a very different situation from what we have with Mini DisplayPort; also note that my question was regarding connectors, not other types of standards (a bit pedantic).

Originally Posted by colinrocks View Post
Hello from the other side of the pond... I've been eagerly searching forums for anyone who's tried making a DIY Mini-DP to (either regular DisplayPort or) HDMI cable, to answer the million dollar question: Can a mini-DisplayPort to HDMI cable carry audio and video?

So far has anyone found, seen, heard of or even taken the plunge themselves and snipped/soldered a pair of cables together? You can get displayport-to-HDMI cables (not sure I'm allowed to post links, but a quick google brought one up) so splicing a mini-DP plug from one of Apple's adapters (anyone got a spare?) shouldn't be too hard to do, if mini-DP and DP are pin/level compatible.

I've read in a couple of places that Apple's mini-displayport-compatible 24" LED Cinema screen (which has sound and a USB hub, yet only power, mini-DP and USB cables) drops the audio when you unplug the USB. And will play audio even if you unplug the DP cable... so I'm not terribly confident an AV mini-DP to HDMI is going to be possible, and I'm a bit nervous about buying 2 quite pricy cables to test it out. But logically, if mini-DP adheres to the DP spec (all signs point to this at the moment), it would be quite a brave move for Apple to decide to send audio over a seperate cable to their own monitors... I suppose I'm so impressed with the MacBook, I don't want to beleive Apple has intentionally made life a little tiny bit harder for us!

In the mean-time, if I pluck up the cash for the extra cables I might just knock up a frankenstein mini-DP to HDMI cable and will post the results back here But until then, it'll just have to put up with yet more cables and adapters
If you have a device that outputs an HDMI (audio+video) signal via a Mini DisplayPort connector, I have little doubt that that you could pass it through a MDP connector. But I don't see any evidence that Apple has included HDMI audio output in the MDP-equipped products.

Originally Posted by paulgg View Post
Regarding the audio on the new 24" LED Cinema dispaly being via USB, and the indication that the miniDP is to VESA standards, it seems that even if audio is routed via USB when driving the 24" LED Cinema display, there is no reason for audio not to be also carried via the miniDP; it might take a 3rd party hack/utility, though. I'm feeling optimistic that Apple would allow both video and audio out from the miniDP.
Note that I missed that USB was a separate connector; I have no reason to believe the audio channels have been repurposed except for colinrocks' unsourced comment above (the webcam and microphone are almostly certainly both routed via USB, since the audio and video channels are one way).
     
tuc
Fresh-Faced Recruit
Join Date: Aug 2003
Status: Offline
Reply With Quote
Nov 14, 2008, 02:22 AM
 
Originally Posted by tooki View Post
Not likely. There really aren't any spare conductors to save on. As I understand it, DP has a limited number of conductors, which are configured to carry different types of signals. That is, the same conductors carry DP, DVI/HDMI, or VGA signals, depending on what the sense pins in the adapter tell it to output. DP has enough conductors ("lanes") to carry the following:
  • DisplayPort signal (up to 2560x1600px)
  • Single-link DVI/HDMI (up to 1920x1200px)
  • VGA
  • Component video
A signal from the display or adapter tells the graphics card which signal to output over the connector.

What it does not have enough conductors for is to do multiple signal types at once (which is what "dumb" adapters would need), nor to do dual-link DVI.

That's why the single-link DVI adapter is cheap (all it's doing is telling the graphics card to output DVI, and then physically adapting the plugs), while the dual-link DVI adapter is expensive (it's having the graphics card output DP signals, and then it's converting those outside the computer to a DVI signal).
I pretty much agree with everything you say, but I still think
there may be less than 20 conductors in Apple's cheap adapters.

VGA needs at most 13 conductors.
DVI needs at most 19 conductors (DVI-D single-link).
Svideo+composite needs 6 conductors, plus a few for sense.

(Last I checked, Apple doesn't have an adapter with component.)
     
Posting Junkie
Join Date: Dec 2000
Status: Offline
Reply With Quote
Nov 14, 2008, 02:28 AM
 
Originally Posted by tuc View Post
(Last I checked, Apple doesn't have an adapter with component.)
Would it be possible to connect a generic VGA-to-component adapter to the Apple MiniDP-to-VGA adapter? VGA and component are both just analog signals, right?

Ticking sound coming from a .pkg package? Don't let the .bom go off! Inspect it first with Pacifist. Macworld - five mice!
     
Fresh-Faced Recruit
Join Date: Nov 2008
Location: UK
Status: Offline
Reply With Quote
Nov 14, 2008, 05:41 AM
 
Originally Posted by paulgg View Post
Regarding the audio on the new 24" LED Cinema dispaly being via USB, and the indication that the miniDP is to VESA standards, it seems that even if audio is routed via USB when driving the 24" LED Cinema display, there is no reason for audio not to be also carried via the miniDP; it might take a 3rd party hack/utility, though. I'm feeling optimistic that Apple would allow both video and audio out from the miniDP.
Hi paulgg,

Good point... maybe Apple reasoned that peripheral functions such as USB, webcam and audio should be grouped together and kept seperate from the video stream, hence they bundled the audio connectivity in with the USB cable... perhaps to allow users with DVI ports to use a DVI-to-miniDP adapter for video and still get audio functionality too. Actually, because mini-DP is backwards compatible with DVI, I'll bet they just used a DP-to-DVI bridge in the screen hardware. It'd reduce manufacturing costs, and because the screen has a DVI-capable native resolution and a USB hub, there's no need to support any of the additional features of DP, but you can bet Apple will want to start selling screens with miniDP connectors to help raise the profile of the new plug.

Back to the macbook, if they used an existing DP chip to drive the mini-dp connector, audio integration should be possible at a hardware level, which then only requires software or firmware support. If Apple doesn't provide this out of the box, it might be possible for a software hack to unlock it, but that's WAY beyond my skillset!

Splicing a 20-cable adapter is a little closer to my comfort zone... and a step in the right direction. I'm going to keep scouting around for cheaper mini-DP connectors for a few days, just in case someone else has started knocking out replicas - if anyone spots one please get in touch!

Hi mduell, sorry for not quoting my sources, I wasn't sure if posting links was suitable (some forums don't like it), but if you want some background reading, googling for "mini displayport" and "Audio via USB" brings up a macrumors forum page where someone apparently tried unplugging the mini-DP on his new 24" cinema display, and the audio continued uninterrupted. It's not exactly concrete evidence, but it's early days yet! I can't find the page where someone tried unplugging the USB only (it was in an Apple store, IIRC), but if I come accross it I'll let you know.

CharlesS - yeah that should work, I don't know of any VGA connectors that don't carry RGB component, though I should imagine when mini-DP connectors start being produced by 3rd parties you'll probably be able to get a direct mini-DP to component adapter quite cheaply.

Cheers,
Colin
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 14, 2008, 07:11 PM
 
Originally Posted by CharlesS View Post
Would it be possible to connect a generic VGA-to-component adapter to the Apple MiniDP-to-VGA adapter? VGA and component are both just analog signals, right?
Well, they are both analog, but I'd hardly call it "just analog". An analog signal can be arranged a bazillion different ways, and VGA and Component do things differently, mostly in terms of the color spaces used.

VGA is RGB video plus discrete horizontal and vertical sync, supporting a wild array (essentially unlimited) of resolutions in various aspect ratios.

Component video carries YPbPr video, with the sync on the luma channel (it's actually extremely similar to the L*a*b color space's color representation). Though the component video connectors are typically red, green, and blue, they are not RGB video signals! Also the number of supported modes is strictly limited to a number of specific resolutions, refresh rates, scanning technique (interlaced or progressive), and aspect ratios.

So circuitry to convert between them is somewhat complex. The color space conversion isn't too hard, but forcing the VGA output of the computer to something compatible is a crapshoot at best. The alternative is to have the adapter re-scale the video, but that entails quality loss and much increased cost.
     
Admin Emeritus
Join Date: Oct 1999
Location: Zurich, Switzerland
Status: Offline
Reply With Quote
Nov 14, 2008, 07:20 PM
 
Originally Posted by tuc View Post
I pretty much agree with everything you say, but I still think
there may be less than 20 conductors in Apple's cheap adapters.

VGA needs at most 13 conductors.
DVI needs at most 19 conductors (DVI-D single-link).
Svideo+composite needs 6 conductors, plus a few for sense.
On previous models, where Apple used mini-VGA, mini-DVI and micro-DVI connectors, the miniature plug has always been fully populated.

The cost savings from leaving out a few pins just can't be big enough to justify the cost of managing a larger number of different components. I'm also not sure that modern plugs can even handle missing pins -- they may be essential to mechanical stability, since screws are gone.
     
tuc
Fresh-Faced Recruit
Join Date: Aug 2003
Status: Offline
Reply With Quote
Nov 16, 2008, 12:39 AM
 
Originally Posted by tooki View Post
On previous models, where Apple used mini-VGA, mini-DVI and micro-DVI connectors, the miniature plug has always been fully populated.

The cost savings from leaving out a few pins just can't be big enough to justify the cost of managing a larger number of different components. I'm also not sure that modern plugs can even handle missing pins -- they may be essential to mechanical stability, since screws are gone.
All the pins are all there, or at least that's my assumption.

The question is how many conductors does the cable have that is connected to those pins.

The suggestion was to cut the cable in the middle and use the existing conductors, right? It may be possible to hack off everything except the connector and connect new conductors to it, but I'm not sure how.
     
tuc
Fresh-Faced Recruit
Join Date: Aug 2003
Status: Offline
Reply With Quote
Nov 16, 2008, 12:46 AM
 
Originally Posted by colinrocks View Post
Actually, because mini-DP is backwards compatible with DVI, I'll bet they just used a DP-to-DVI bridge in the screen hardware. It'd reduce manufacturing costs, and because the screen has a DVI-capable native resolution
First of all, I wouldn't say that mini-DP is backwards compatible with DVI, at least not in the sense that HMDI is. The signaling is completely different. When using Apple's $30 miniDP-to-DVI adapter it's not really DP anymore--it's just DVI using a funny port.

Second, I doubt they used a DP-to-DVI bridge in the screen hardware. One of the points of DP is that it is easier for the screen to decode than DVI or VGA. Even if DP fails in the consumer marketplace, expect virtually all internal screens (think laptops and iMacs) to use DP internally before too long.
     
Fresh-Faced Recruit
Join Date: Nov 2008
Location: UK
Status: Offline
Reply With Quote
Nov 17, 2008, 06:28 AM
 
Originally Posted by tuc View Post
First of all, I wouldn't say that mini-DP is backwards compatible with DVI, at least not in the sense that HMDI is. The signaling is completely different. When using Apple's $30 miniDP-to-DVI adapter it's not really DP anymore--it's just DVI using a funny port.
Oops, you're right, sorry, I had my wires crossed there (no pun intended) and mixed up DP and HDMI... DP is substantially different to HDMI and DVI, and not directly compatible at all - my mistake.

Originally Posted by tuc View Post
Second, I doubt they used a DP-to-DVI bridge in the screen hardware. One of the points of DP is that it is easier for the screen to decode than DVI or VGA. Even if DP fails in the consumer marketplace, expect virtually all internal screens (think laptops and iMacs) to use DP internally before too long.
Yeah, for some reason I had it in my head that DP was more compatible with DVI than it is, hence didn't think of the cost of the DP-to-DVI bridge, which changes things somewhat. A DP-only chip would likely be cheaper to produce than a DP-to-DVI bridge and DVI controller.

Maybe they used USB audio to leave room for potential DVI-to-DP adapters then? Though that'd still need the serial comms to micropacket comms conversion, and isn't likely to be an easy adapter to make.

Hmm, it's getting harder to remain optimistic that the miniDP can carry audio.

Originally Posted by tooki
Well, they are both analog, but I'd hardly call it "just analog". An analog signal can be arranged a bazillion different ways, and VGA and Component do things differently, mostly in terms of the color spaces used.
Tooki - I think Charles was just asking if the VGA from a miniDP-to-VGA adapter would be suitable for a VGA-to-component adapter... your post was excellent but has left me wondering if back-to-back miniDP-VGA-component adapters would work... I think they should, shouldn't they?

Originally Posted by tuc
All the pins are all there, or at least that's my assumption.
Yep, I've just got the miniDP-DVI adapter, and the pins are all there but the cable is very thin, especially for 20 internal lines and (I'd assume) shielding. I've not been able to take a knife to it just yet, running PlexApp in full 1:1 1080p on my 37" LCD is simply gorgeous, and I'm going to cry if I butcher the adapter and it doesn't work! Incidently, if anyone's searching for it, an aluminium unibody 13" MacBook, with Apple's mini DisplayPort to DVI adapter and a cheap DVI to HDMI cable, plugged into a Philips 37PFL9632 37" LCD works no problem, straight out of the box. 1080p was detected and switched to, without any need for screen res hacks/software, though minor fiddling was required to disable various LCD features to get the best image.

Ok, back to the potential cable surgery... Looking at the DVI spec, I think there could be as few as 11 lines in the adapter for a single DVI-D, (pins 1, 2, 6, 7, 9, 10, 16, 17, 18, 23, 24) - does that sound likely? Or even possible? I might be able to crack the casing for the DVI plug to non-destructively check how many wires are at the DVI end, I'll have a look tonight.

Cheers,
Colin

PS - just seen on macrumours people have been hassling Apple to find out if MiniDP carries audio... Apple apparently say "yes"! And 3rd party MiniDP plugs will be out in Jan '09 from monoprice too, according to another poster :-D
( Last edited by colinrocks; Nov 17, 2008 at 06:40 AM. Reason: adding info)
     
Fresh-Faced Recruit
Join Date: May 2008
Status: Offline
Reply With Quote
Nov 18, 2008, 01:06 AM
 
Originally Posted by colinrocks View Post
PS - just seen on macrumours people have been hassling Apple to find out if MiniDP carries audio... Apple apparently say "yes"! And 3rd party MiniDP plugs will be out in Jan '09 from monoprice too, according to another poster :-D
Can you provide a link to that thread on macrumors?
     
Fresh-Faced Recruit
Join Date: Nov 2008
Location: UK
Status: Offline
Reply With Quote
Nov 18, 2008, 04:54 AM
 
Originally Posted by Mackan View Post
Can you provide a link to that thread on macrumors?
Assuming links are OK - http://forums.macrumors.com/showthre...=582590&page=2 (post 42)

Still nothing confirmed though.

I've not yet had a closer look at my miniDP-DVI adapter yet, but the diminuitive diameter of the cable makes me think there are less than 20 conductors in there... especially as it's only a single-DVI adapter. It looks positive from the monoprice comments in the above thread that we'll have 3rd party plugs by January, so we'll no doubt see 3rd party adapters in the next 2-3 months... I'm tempted to wait it out, and live with the extra wires for the time being. Sorry guys!

Cheers,
Colin
     
Posting Junkie
Join Date: Nov 2000
Location: in front of my Mac
Status: Offline
Reply With Quote
Nov 18, 2008, 05:34 AM
 
I'm not sure I understand why the MDP->DVI adapter should have 20 signal lines. Single DVI-D requires 17 signal lines, right?

     
 
Thread Tools
Forum Links
Forum Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On
Top
Privacy Policy
All times are GMT -4. The time now is 04:29 PM.
All contents of these forums © 1995-2014 MacNN. All rights reserved.
Branding + Design: www.gesamtbild.com
vBulletin v.3.8.8 © 2000-2014, Jelsoft Enterprises Ltd., Content Relevant URLs by vBSEO 3.3.2