
Use your iDevice as an extra display for your Mac - bauerpl
http://www.duetdisplay.com
======
drinchev
I wonder how they achieve "Zero lag". I've been using similar software (
AirDisplay [1] ) and the lagging is awful.

You have to be certified hardware manufacturer if you want to use the USB
connection to transmit any data between the iPad and your Mac [2]. So my bet
is they either use WiFi ( which can roughly get 60fps on retina resolution )
or Bluetooth 4. In both cases I think the refresh rate would not satisfy in a
lot of cases, e.g. playing a YouTube video through their software on the iPad.

1: [https://avatron.com/applications/air-
display/](https://avatron.com/applications/air-display/) 2:
[https://avatron.com/support/faq-air-display/#toggle-
id-13](https://avatron.com/support/faq-air-display/#toggle-id-13)

EDIT:

I've found more information on their facebook page [3]

> To setup, download and open duet on your Mac (for free) and on iOS.

> Connect your device using a lightning or 30 pin cable. Done.

> No need to worry about firewall settings, Wi-Fi speed or your 802.11n
> network.

> Duet is secure, simple, and allows you to use your iOS and OS X devices in
> harmony.

So I guess I was wrong with my bets. Maybe they got a hardware manufacturer
license from Apple. Anyway launch is on 16th, so let's see.

3:
[https://www.facebook.com/duetdisplay/info?tab=page_info](https://www.facebook.com/duetdisplay/info?tab=page_info)

~~~
supercoder
My guess would be they're just using the shared documents area .

There's a number of libraries on the desktop that let you access an API to
write to the shared documents area. I'd guess they'd just be piping a mp4 feed
to this and the iOS would just be reading from there.

~~~
ejstronge
Is there any chance this approach could eventually be used on a Linux distro
or Windows?

~~~
kevin_thibedeau
The technology already exists in X11. The problem is getting devices to act as
display servers.

~~~
ejstronge
I haven't seen examples of folks trying to use iPads (for example) as X11
displays, likely because it's outside my area of expertise. Do you know of any
examples?

~~~
aaronem
iSSH includes an X11 display server, and I've had reasonable success using it
with clients on an assortment of architectures, including a Tru64 VM running
Open Genera. I wouldn't expect it to work well with something like video
playback unless you've got a very fast and uncongested wireless network (or
possibly a Lightning-to-Ethernet adapter, if such things exist), but if you
don't need that kind of sustained responsiveness, it's at least worth a try.

~~~
ejstronge
I think the original product link isn't using wireless but instead depends on
a wired connection. I've heard about using X11 over the internet but I'm
worried that the lag would make this approach more annoying than effective.

It would be great to have a wired connection option on other operating systems
besides the Mac.

------
alexggordon
I've been beta testing duet for about a month now. As a person that travels a
lot, it's awesome. The developers have done an incredible job, and have been
very responsive in fixing the bugs I've reported to them.

However, a couple of things to note. Firstly, this is lag free, but still not
something you should play videos on. I'm not sure what the framerate is, but
I'd be surprised if it's over 30fps. I believe this is probably a result of
using USB.

Secondly, I never thought I'd say this, but retina is not your friend. On the
new iPads, the OS X menu bar is _maybe_ a centimeter tall. Obviously, you can
change the resolution, but I like hi-res, and you just see so little when you
bump it up (keep in mind the new iPad is only 1024 by 768).

The app is the best it can be, but what I'd emphasize is that most people
should really get a second monitor, if that's what they're looking for. I
understand you could save some money, but iPads just don't offer enough real
estate.

Again, kudos to the devs for doing a great job on the app though.

~~~
TazeTSchnitzel
They claim 60fps with no lag.

~~~
mistercow
That figure could refer to "typical" usage, where most of the screen doesn't
have to update.

------
shurcooL
This isn't the first app that lets you do this, is it? It might be better (or
worse) in performance, but the functionality has already been made available
in the past, right? Just want to check.

Also, this is neat but I wish it were integrated into OS X + iOS as part of
AirPlay. I love AirPlay and want to see it expand to cover all possible
permutations (iOS -> OS X screen/audio/both sharing, as well as OS X -> iOS
screen/audio/both sharing). That would go well under the Continuity moniker
and is something Apple can do well thanks to their control.

Hopefully it's one of the minor new features in next Apple OS updates.

~~~
jakejake
I've used an app called Air Display to do the same thing for quite a while,
but instead of USB it connects over WiFi - which is convenient, but the
refresh rate is slow. I used it mainly to have my chat client on a 3rd screen.

------
leehro
This is really interesting technically, a couple tidbits I dug up looking in
the mac app bundle:

1\. There are a couple of OpenGL shaders in the bundle for converting the
screen image to HDTV color space/format (420v.fgsh) and some kind of
passthrough.

2\. They appear to be using x264 to encode the screen with defaults of
1280x720, 1000kbit, superfast preset. (Defaults.plist)

So on the mac side, they're definitely capturing the screen and sending a
streaming video. Not surprising, but the curious part is how they manage to
get the iPad to stream in that data over USB. I suppose something like HTTP
Live Streaming[1] could work. Place small files into the device's Documents
area, and they get streamed. It would be awesome if something else was going
on here - like a named pipe.

1\.
[https://developer.apple.com/streaming/](https://developer.apple.com/streaming/)

~~~
spdustin
My guess is it's using Apple's version of RNDIS ... iPad becomes a network
peer of the Mac and streams video over that network.

But I don't believe that API is public, so I can't know for sure...

------
jscheel
I know this is nit-picky, but Duet is not "the first app that allows you to
use your iDevice as an extra display". It's not even the second. There's an
opportunity here for better copy to differentiate themselves.

Also, I've always thought this would reduce the life of your ipad. Has anyone
noticed this?

~~~
knd775
How? Like the display burning out or something? Maybe something battery
related?

~~~
jscheel
Battery is definitely a concern, though it probably doesn't matter since it
will be plugged up. The screen dimming might be a concern for me as well.
Honestly though, now that I think about it, I've never been worried about that
with my laptop, so I probably shouldn't care about it with my ipad.

------
Doctor_Fegg
Best part of this: "All iPads."

My iPad 1 is pretty much a paperweight these days (I know, I know, never buy
the first version of anything Apple). This could be a great new use for it.

~~~
happyscrappy
Seriously. I was going to give away my first gen ipad but due to being so
outdated it seemed more of an imposition than a gift.

~~~
dagw
What's wrong with it? I have a first gen iPad and it still works fine. In fact
I almost wish it would die already so that I would have a valid excuse to buy
a new one.

~~~
oneeyedpigeon
Did you upgrade iOS to version 5? I did, and it's never been the same since. I
can now barely use the web browser without it crashing. Some domains are
totally unusable; appears to be related to javascript use. Low-impact sites,
such as HN, are OK. Other apps (such as the app store and many games) are very
prone to crashing, too. There's very little I can use it for now without
getting frustrated and giving up.

~~~
acomjean
I have the same experience. I wish I could get a better web browser for it. my
ipad 1 is just a video player/ book reader at this point (which isn't bad,
just not grat)

------
blaze33
> the first app that allows you to use your iDevice as an extra display for
> your Mac

I stumbled upon iDisplay.com the other day. Can't recommend anything though,
I'm not an apple user, I was looking for ways to replicate my android phone
display in my desktop Linux.

~~~
teddythetwig
Did you find anything worth using for your use case?

~~~
blaze33
Not really: I tried android-screencast [1] but had to root my phone, the
framerate was terrible, lots of crashes, touch gestures not really satisfying.

The other option was using genymotion, works well, but some apps can't be
installed multiple times (whatsapp I'm looking at you).

If anyone knows a better way to do so, thank you in advance!

[1]
[https://code.google.com/p/androidscreencast/](https://code.google.com/p/androidscreencast/)

~~~
alexhektor
[http://web.airdroid.com/](http://web.airdroid.com/) maybe? Lots of drawbacks,
though, and not 1:1 mirroring I believe, so may not fit your needs. But seems
to support whatsapp via screen mirroring + custom keyboard (probably?).
Haven't tested since I'm currently on iOS.

------
Kluny
Here's the bit I was looking for:
[http://www.duetdisplay.com/#compatibility](http://www.duetdisplay.com/#compatibility)

Compatible with all iPads, nice! I have an old iPad 1 lying around that runs
very few of the apps I would like to use with it (Office suite and VLC,
mostly), so I've been looking for a way to repurpose it, and this might be it.

~~~
metanoia
Looks like they changed it to "All iPad hardware with iOS 6 and above". Which
means no iPad 1. :(

------
ripitrust
OK Guys After I installed and launched this MacOS app , it drastically slowed
down my chrome and increased the chrome cpu usage. I am guessing something
wrong with the duet app display driver.

so if anyone having the same problem like mine, please go to finder, search
for "duetdisplay.kext" kernal extension, delete it and reboot your Mac. It
should go back to normal.

------
furyg3
If it is really real-time this will be interesting. In combination with
SideCar you could have a nice mobile dual-screen setup.

[http://www.cultofmac.com/247700/sidecar-hangs-your-ipad-
from...](http://www.cultofmac.com/247700/sidecar-hangs-your-ipad-from-your-
macbook-screen/)

------
wodenokoto
The iAccessories pictured looks really beautiful. Anyone know what brand it
is?

~~~
ashaiber
Amusingly, these are sold by Evernote:
[https://www.evernote.com/market/feature/pfeiffer](https://www.evernote.com/market/feature/pfeiffer)

------
some1else
Screen emulation:

iDisplay: [http://www.getidisplay.com/](http://www.getidisplay.com/)

AirDisplay: [https://avatron.com/applications/air-
display/](https://avatron.com/applications/air-display/)

iDevice preview:

LiveView:
[http://www.zambetti.com/projects/liveview/](http://www.zambetti.com/projects/liveview/)

Skala (Pre)view:
[http://bjango.com/mac/skalapreview/](http://bjango.com/mac/skalapreview/)

------
rayiner
If you want a proper external monitor to go with your laptop, invest in
something like this:
[http://www.bhphotovideo.com/c/product/1021217-REG/asus_mb168...](http://www.bhphotovideo.com/c/product/1021217-REG/asus_mb168b_15_6_led_lcd.html).

~~~
gsands
+1 for linking to the lowest price I can find for it on the web (199 vs
Amazon's 266).

------
sathomasga
Well, the app is obviously working for some folks, but in my case it's junk.
13" MBA 2012 OS X 10.10.1 connecting with iPad Mini Retina or iPhone 5s (both
iOS 8.1.2) using genuine Apple Lightning cable and direction connection (i.e.
no USB hub). Most of the time the iOS app never gets beyond the "Connect to
Mac" stage, even though the screen flashes on the Mac indicating new display
hardware is available. Sometimes the iOS app gets to the "Launching Duet…" and
hangs. Rarely, the iOS app actually becomes a display; however, when that
happens my mouse is frozen (in a "stuttering" sort of way). Waste of good
money for me.

------
tluyben2
I have been testing this as well; it is really great for travelling. I put my
air 2 on high res and find myself hardly using my normal screen anymore. There
are a few bugs but those will be gone soon I reckon; the creators respond fast
to mail.

------
petercooper
_Duet is the first app that allows you to use your iDevice as an extra display
for your Mac._

What am I missing about this sentence that seems to make "the first" false in
the face of things like Air Display?

~~~
hboon
It's tethered using lightning cable.

------
mark_l_watson
Wrong. I have been using my iPad as an extra display for my MacBook Air for
about 2 1/2 years using the AirDisplay (getairdisplay.com).

It is odd that this company would place a large lie as the first readable
text.

~~~
sigjuice
You did not read the whole sentence.

Duet is the first app that allows you to use your iDevice as an extra display
for your Mac using the Lightning or 30-pin cable.

This app uses a cable. All the other apps use wifi.

~~~
mattdw
They have obviously changed the copy in the last few hours. The second half of
that sentence ("Using…") was not there earlier.

~~~
sigjuice
You are right. My apologies.

[https://web.archive.org/web/20141215154238/http://www.duetdi...](https://web.archive.org/web/20141215154238/http://www.duetdisplay.com/)

------
elyrly
I'm happy this application made its way onto Hacker News. First heard it from
a founding team member and thought the use-case is immense.

------
RBerenguel
I've occasionally used AirDisplay when doing minor HTML/CSS stuff (browser on
iPad, emacs with impatient-mode on Mac) and it's useful, nice, but when doing
heavier lifting lag kills it. I'll definitely be getting it tomorrow, and look
forward seeing if I get to use it more or "as often as I did."

------
MagicWishMonkey
It would be neat if they could figure out a way to let you use an iMac screen
as a secondary monitor for a mbp.

~~~
eurleif
This is already built-in:
[http://support.apple.com/kb/PH14264](http://support.apple.com/kb/PH14264)

~~~
MagicWishMonkey
Woah, do you know if this works with the new retina display iMacs?

~~~
mkhalil
I'm here to confirm to you that it doesn't. Sorry buddy, wish it did myself.
5K is out of reach for most MBP's (if not all).

~~~
MagicWishMonkey
That's a bummer, it would be worth buying a new iMac for the screen alone.

------
NietTim
I've been using Air Display for a long time for when I'm on the go. Does
anybody have experience with both and which is better? Never really had
problems with Air Display - if you don't expect it to work as a full external
display. However lag has always been very manageable for me

~~~
darylteo
Product launches tomorrow, so hardly any comparisons can be made. It seems to
be promising - wired connection means higher bandwidth and improved latency.
Supposedly can do Retina resolutions at 60hz.

~~~
NietTim
I see now, I should have been reading better - my bad. I also read in this
thread that Air Display had some troubles with Yosemite, but I haven't updated
on my work machine yet so I hadn't seen these problems.

Streaming over USB seems promising though, I needed to plug in my iPad for the
battery.

------
Cthulhu_
So uh, why is the marketing being done today when the release is tomorrow?
I'll probably have forgotten about it by then. I wouldn't mind it though, the
other ones (using wifi streaming) never really worked for me. And I wonder why
this isn't a default feature in iOS / OSX.

~~~
petercooper
_So uh, why is the marketing being done today when the release is tomorrow?_

They want your email, Twitter following, and other things that are more useful
over time than your casual perusal after launch.

~~~
memeplex
Actually a bit simpler, Business Insider released the article to fill their
timeline not Duet's launch date. The app is still awaiting review and with the
app store being so busy this season it's hard to give a hard date. Expected to
be released later this week.

------
ripitrust
I've actually just downloaded their MacOS App and tried to install and launch
it.

It now basically does nothing just blinking in the statues bar.

But I observe sudden CPU usage surge of this app from the activity monitor,
not sure whether it is because of not pairing an iOS app or not

And also, my chrome feels significantly lagged.

~~~
igrekel
mhm in my case once I opened the App it just disappeared. It moved itself to
the Application directory, can't say I like this.

~~~
ripitrust
will it slow something down?

------
patman81
I would love to use this to share my Macbook screen on an iPad with a client.
One screen seems to small for more than two people to share. Perhaps I could
even connect multiple iPads for small presentations without a projector. All
running in mirror mode.

------
RankingMember
Anything like this available for Windows? Wouldn't be bad for an email/IM
screen.

~~~
tmuir
Any VNC app allows you to view and control your screen. I like RealVNC. The
corresponding app on Android and iOS is called VNC Viewer. There are several
companies/projects that offer this functionality.

~~~
RankingMember
I meant adding the iPad as an additional screen (with additional desktop
space) for a Windows machine.

------
aselzer
The line "An additional display increases productivity by up to 48%." is
particularily funny.

I wonder how they "measured" this. A Macbook Air 11" \+ extra display is quite
different from a Macbook Pro 15" \+ extra display.

~~~
bboreham
"up to".

------
larryy
So where is it?!? It's the 16th and nowhere to be seen. BusinessInsider.com is
now saying the 17th. I also wonder why they removed the Mac app from
duetdisplay.com.

------
darylteo
Wonder how much bandwidth is required to drive this... My USB3.0 port is taken
by an SSD hosting virtual machines, the other is hooked to a powered hub.

~~~
dan1234
Assuming the video stream is compressed (MP4?) it shouldn't take too much.
We're pretty used to streaming HD over the internet, so even USB2 should be
able to handle it.

------
iamhenry
I signed up for the newsletter and the download button appeared but it just
hangs there and I can't download the app. How do I download the app?

------
joshcrowder
This looks cool - I'd definitely use it for emails. Has it not been done
already though?

I have a question about the image - whats the stand used for the iPad?

~~~
simi_
[https://www.twelvesouth.com/product/compass2](https://www.twelvesouth.com/product/compass2)

12 south are pretty nice, but my wife had a bad experience with their
SurfacePad iPhone case (really awesome case, but the leather wears heavily
after 1-2 months)

~~~
jrockway
Isn't the point of leather that it wears?

------
edcastro
Am I a little too slow here or they just launched the Mac app without the iOS
counterpart? Can't find it on App Store.

~~~
cstuder
You're too fast, the release date for the iOS app is 16th december.

~~~
edcastro
Ah. I see. Got a little confused because the Mac app is already available, so
I thought it was just a matter of old sign up form not removed from site yet.

------
jimmyrocks
I'd really like this to work with my old iMac G5. It has a great monitor, but
I struggle to find uses for it.

------
maaaats
Do I need an iDevice to view the video as well? Wont play here, would be
interested to see more how this works.

~~~
paraserv
You don't need an iOS device to watch the website's ad. It's an embedded
YouTube video. Here's the direct link:
[https://www.youtube.com/watch?v=mVYimOiEya8](https://www.youtube.com/watch?v=mVYimOiEya8)

------
DanielShir
Finally, something to do with my 1st generation iPad.

~~~
NietTim
You could have used Air Display :) I do really like this use though, never
thought of using my old iPad as a permanent extra display.

------
kelsol
Fantastic! Been wanting this for, like, ever

------
DaveSapien
is it out yet?

------
PinguTS
It is called AirDisplay and available since years:
[https://avatron.com/applications/air-
display/](https://avatron.com/applications/air-display/)

I think there was/is also another App available doing it.

~~~
shadowmint
...and then yosemite came out, the the fps dropped from 25 to 2, and everyone
stopped using it.

The same goes for DisplayPad.

The key here is that this is not a wifi streamcast.

