First confimed Miracast compatible devices announced... no Nexus 7, yet.

e.mote · Nov 5, 2012

>Does anybody know if the S3 has the capability of connection to a Widi adapter

AFAIK Samsung toys use AllShare, Sammy's version of DLNA, a different media-sharing standard. The S3 does have dual-band wifi. Edit: Galaxy S3 is Miracast-certified.

The only HDMI adapter known to support Miracast/WiDi 3.5 thus far is the NetGear PTV3000. No doubt there'll be others, but that's it for now. Note that earlier versions of PTV adapters CANNOT be upgraded to WiDi 3.5 (and thus won't suport Miracast), according to NetGear.

>Or does it do audio (music) to receivers as well?

From its lit, Miracast is intended for video. That doesn't necessarily exclude audio receivers, but I think most of the work will be directed to getting content onto TVs.

>There is nothing in the Miracast whitepaper that specifies that the wifi needs 5GHz.

Yes, it's a personal assessment, based on experience that sustained HD streaming within 2.4GHz band is usually problematic. Those who've done wireless HTPC setups can attest to same.

As mentioned elsewhere, Miracast can involve two streams, one inbound and one outbound, which at least doubles the bandwidth req. Couple this with wifi performance which can fluctuate widely depending on environment and equipment used, and it's pretty much a lock that no vendor in its right mind would dare to certify 2.4GHz-only devices for Miracast. Certification is a form of guarantee, and there is no way it can guarantee that 2.4GHz will work for all the myriad situations possible.

sark666 · Nov 5, 2012

As mentioned elsewhere, Miracast can involve two streams, one inbound and one outbound, which at least doubles the bandwidth req. Couple this with wifi performance which can fluctuate widely depending on environment and equipment used, and it's pretty much a lock that no vendor in its right mind would dare to certify 2.4GHz-only devices for Miracast. Certification is a form of guarantee, and there is no way it can guarantee that 2.4GHz will work for all the myriad situations possible.

I didn't see that mentioned, how would two streams be involved? I thought just out to the hdmi device. Your sobering logic is dashing my hopes of using this with my n7. I still have a modicum of hope but we'll see. At the least I could see custom roms enabling it.

Also, and this would be really pushing it, how does miracast deal with framerate? Does it always try to achieve 30 fps regardless of source material? If one is playing a movie that is 24 fps then it could be dedicating more bandwidth per frame instead of up converting to 30 and potentially causing tearing/vsync issues. And what I mean by pushing it is regarding games (which yes I have low expectations just because of latency). But does it attempt to go higher than 30? If the network can handle more than 30 fps does it attempt to go higher or is it locked. Makes me also wonder about resolution flexibility. As in lowering output res to achieve higher fps.

SS2006 · Nov 5, 2012

e.mote, i believe allshare cast is samsungs name for 'miracast'

thier allshare cast dongle (that connects to the TV) should work with any miracast device

e.mote · Nov 6, 2012

>how would two streams be involved?

The prevailing use-case will be video streamed from online via Hulu/NetFlix/etc. Content would be composed on the mobile device, encoded in real-time, and re-sent via Miracast link to TV. From the whitepaper, one topology shows that content can be directed from router to TV, but I'm not sure how that would work.

>how does miracast deal with framerate?

From the whitepaper, Mira supports a variety of resolutions and framerates. Max is 60fps, or 30fps at 1080p. For the other questions, your guess is as good as mine, as nobody has yet seen Miracast in action under 4.2. The Nvidia demo showed basic display mirroring, but the TI demo (some months ago) showed that you can do other things while Miracast streams a video in the background. The cynic in me votes for the lowest common denominator, which is display mirroring.

>e.mote, i believe allshare cast is samsungs name for 'miracast'

Thanks, I can't find a reference indicating AllShare Cast being same as Miracast, but they sound similar enough. One interesting user comment on Amazon was that the ASC dongle doesn't work with rooted phones, and you have to use some app to work around it. It may well be the same for Miracast, as content protection is one of Miracast's features, and excluding rooted devices could be one of its functions. DRM content playback could get interesting.

XDA has a good review thread for the AllShare Cast dongle:

http://xdaforums.com/showthread.php?t=1872278

andy o · Nov 6, 2012

Anyone knows if there is an audio-only implementation of Miracast as well? I imagine it being used more than video mirroring, for music.

lobotomik · Nov 6, 2012

e.mote;33734920 >Or does it do audio (music) to receivers as well? From its lit said:
As for audio-only, the Miracast FAQ explicitly excludes it. It only covers video-only and video+audio.

As for problems with the 2.4Ghz band, bear in mind that it will be a point-to-point connection, with no access points mediating. The distance should be very few meters, and signal strength extremely good, so the throughput should be close to maximum, which is 54 Mbps for single channel. You need around 5mbps for downstreaming x264 HD video, so there is a wide safety margin even if your neighbor has his TV hanging back to back to yours.

e.mote · Nov 6, 2012

>As for problems with the 2.4Ghz band, bear in mind that it will be a point-to-point connection, with no access points mediating. The distance should be very few meters, and signal strength extremely good

You may want to peruse the posted thread of the AllShare Cast dongle review. That would show you the difference between "should" and "is," especially when it comes to bleeding edge equipment. Keep in mind that S3 wifi is dual-band, a far cry from N7's 1x1 2.4GHz radio.

>so the throughput should be close to maximum, which is 54 Mbps for single channel.

Quoting theoretical specs like this tells me that you have no real-life experience with wireless connectivity and its limitations. It's not just a matter of bandwidth wrt 2.4GHz. Depending on your location, it may be heavily congested (eg apartments, dorms), with no space for a clear channel. Somebody turns on the microwave, or uses one of any number of 2.4GHz remote devices, and the link is toast.

I'll say it again: There is no way anybody can guarantee smooth, uninterrupted 720p streaming in 2.4GHz. That said, I hope you're right and I'm wrong, and N7 owners will get a new feature for their use. But you should temper your optimism by looking at the travails of the S3 owners as a probable foretaste of what's to come.

http://xdaforums.com/showthread.php?t=1872278

costipl · Nov 6, 2012

lobotomik said:
As for audio-only, the Miracast FAQ explicitly excludes it. It only covers video-only and video+audio.

As for problems with the 2.4Ghz band, bear in mind that it will be a point-to-point connection, with no access points mediating. The distance should be very few meters, and signal strength extremely good, so the throughput should be close to maximum, which is 54 Mbps for single channel. You need around 5mbps for downstreaming x264 HD video, so there is a wide safety margin even if your neighbor has his TV hanging back to back to yours.

You seem to forget that you can use 802.11n in 2.4 GHz band, achieving 300 Mbit/s.

Wysyłane z mojego Nexus 7 za pomocą Tapatalk 2

NotablyNice · Nov 6, 2012

e.mote said:
>As for problems with the 2.4Ghz band, bear in mind that it will be a point-to-point connection, with no access points mediating. The distance should be very few meters, and signal strength extremely good

You may want to peruse the posted thread of the AllShare Cast dongle review. That would show you the difference between "should" and "is," especially when it comes to bleeding edge equipment. Keep in mind that S3 wifi is dual-band, a far cry from N7's 1x1 2.4GHz radio.

>so the throughput should be close to maximum, which is 54 Mbps for single channel.

Quoting theoretical specs like this tells me that you have no real-life experience with wireless connectivity and its limitations. It's not just a matter of bandwidth wrt 2.4GHz. Depending on your location, it may be heavily congested (eg apartments, dorms), with no space for a clear channel. Somebody turns on the microwave, or uses one of any number of 2.4GHz remote devices, and the link is toast.

I'll say it again: There is no way anybody can guarantee smooth, uninterrupted 720p streaming in 2.4GHz. That said, I hope you're right and I'm wrong, and N7 owners will get a new feature for their use. But you should temper your optimism by looking at the travails of the S3 owners as a probable foretaste of what's to come.

http://xdaforums.com/showthread.php?t=1872278

So completely wrong it's funny. Uninterrupted streaming of 720p over 2.4ghz wireless N is more than possible as I do it every damn day. Yes your speed is important but latency is what matters

musabbir · Nov 6, 2012

Does anybody know if all widi receivers will be able to receive Miracast signal from the tablets/phones? My LG smart tv has WiDI, just wondering if that will work.

ave_nue · Nov 6, 2012

musabbir said:
Does anybody know if all widi receivers will be able to receive Miracast signal from the tablets/phones? My LG smart tv has WiDI, just wondering if that will work.

The LG Smart TV with Intel WiDi (firmware) would need to be upgraded to the Intel WiDi 3.5 release or higher which Intel said will be Miracast certified.

lobotomik · Nov 7, 2012

e.mote said:
You may want to peruse the posted thread of the AllShare Cast dongle review. That would show you the difference between "should" and "is," especially when it comes to bleeding edge equipment. Keep in mind that S3 wifi is dual-band, a far cry from N7's 1x1 2.4GHz radio.

>so the throughput should be close to maximum, which is 54 Mbps for single channel.

Quoting theoretical specs like this tells me that you have no real-life experience with wireless connectivity and its limitations. It's not just a matter of bandwidth wrt 2.4GHz. Depending on your location, it may be heavily congested (eg apartments, dorms), with no space for a clear channel. Somebody turns on the microwave, or uses one of any number of 2.4GHz remote devices, and the link is toast.

I'll say it again: There is no way anybody can guarantee smooth, uninterrupted 720p streaming in 2.4GHz. That said, I hope you're right and I'm wrong, and N7 owners will get a new feature for their use. But you should temper your optimism by looking at the travails of the S3 owners as a probable foretaste of what's to come.
]

Thanks for the pointer to the thread. I have not read the whole thing, but it seems like the software is a POS, as should be expected with no kind of certification. It also seems like it works OK when it works.

As for my lack of experience, it is your (rude) supposition. Anyway, your words tell me you have no deep knowledge of digital radio links and spread spectrum modulations. It is not the same to go to a router and back, possibly through walls, than having a direct link only 10 feet long. The attenuation of your signal on the short haul will be possibly hundreds of time smaller, so your signal will be far stronger than the competing interference, and this will give you a far larger share of the bandwith, so to say. Surely, you won't get the 54mbps single-channel top speed, but the data rate will be much better than through a remote access point, with less latency and a more resilient connection.

As for smooth 720p on 2.4Ghz, maybe Apple does not guarantee it, but it happily sells it, wrapped in hyperbole as usual, as Airplay. And going through access points, BTW, although they are planning to Invent and introduce a Revolutionary direct Airplay connection very soon now.

Still, it remains to be seen whether Google does implement it in the N7. I'd say yes, because it is free, it will work fine in many or most cases, it is a nice marketing point and, it will open the market for movie rentals from Google Play (who will pay 4€ more than once to watch a movie all by himself on a 7" screen?), and yes, because I feel optimistic.

e.mote · Nov 7, 2012

>software is a POS, as should be expected with no kind of certification

Galaxy S3 is one of two phones that were announced to be Miracast-certified. The AllShare Cast dongle is also from Samsung, so all the "it shoulda work" tickboxes are checked.

Some of the problems in the S3 thread are likely from user ignorance of the underlying tech, eg lag. Because the display image has to be encoded in real-time at 720p@60fps, then system load would likely be a factor, regardless of hardware encoding. Disconnection issue is probably from firmware not being fully baked. That it only works on stock ROM is probably due to Miracast's content protection. All these apply to N7, assuming the optimistic case that it gets Mira in stock update, plus jumping through 2.4GHz hurdle. Otherwise, custom ROM'ers will need to figure it out.

>As for smooth 720p on 2.4Ghz, maybe Apple does not guarantee it, but it happily sells it, wrapped in hyperbole as usual, as Airplay.

All of the iPads and iPhones have been dual-band, albeit single-stream (I'm unsure about the latest iterations). While it's fashionable to do the Apple-hate song and dance on an Android forum, Apple should be thanked for being first with Airplay. Without Airplay, Miracast would not exist, because it's a direct response to Apple's. In fact, we can say the same about the iPad. Credit where it is due.

One hopes that Goog's implementation of Miracast in 4.2 will be more stable than Sammy's attempt. But I recall Goog's same attempt with Miracast's predecessor, Wifi Direct, which was half-baked and never worked with anything. I'm starting to think that Miracast's omission from N10 specs was intentional. Encoding 2560x1600 at 30fps in real-time is no cupcake, and pushing 1080p uninterrupted through wifi will be a major challenge, noobs' claims of "sufficient bandwidth" notwithstanding.

jonmorris · Nov 7, 2012

AirPlay Mirroring is fine for watching movies, or looking at pictures - or anything that doesn't involve any user interaction... but Apple should stop advertising/implying you can use it to connect your Mac to a monitor/TV wirelessly as the lag is such that it's unusable - unless you're happy to move the mouse, wait, type a few characters, wait..

I didn't buy an Apple TV box for this feature, but I was really looking forward to being able to sit in the living room and have my MBA on my TV - then use the wireless keyboard/trackpad. It didn't quite work out and I'm left feeling disappointed, just as I have been with many Apple features of late (Siri, Maps etc)

Finally, I am not convinced Miracast wouldn't exist without AirPlay. I heard about the concept long before Apple launched it, so all it did was get something workable (sort of) to market sooner.

e.mote · Nov 7, 2012

>but Apple should stop advertising/implying you can use it to connect your Mac to a monitor/TV wirelessly as the lag is such that it's unusable

There will always be lag, because the image needs to be encoded to H.264 (and decoded). Lag then is a function of processor, specifically the hardware dedicated to H.264 encoding. Intel promises 60ms latency for the latest WiDi and Ivy Bridge (250ms for Sandy Bridge). Those are marketing claims, so one expects real-world use would be somewhat worse. But sure, (fast) typing and twitch games are where lag would impact the most.

Since it's an inherent limitation of the tech, I think there'll always be lag until there is a more robust solution (eg WiGig, WirelessHD, et al) where 1080p can be sent uncompressed.

>I heard about the concept long before Apple launched it, so all it did was get something workable (sort of) to market sooner.

There've been several proprietary attempts at getting video to the TV over wifi, but Apple's was the first that's workable for mobile devices and not just laptops/PCs. Miracast was billed the wifi industry's answer to AirPlay.

jonmorris · Nov 7, 2012

But surely it will be better as it's direct from device to TV? As against going via your router that is doing a load of other things (or certainly might be, as is the case of my home set up which has 20+ connected devices).

I accept I'm probably the exception to the rule, on account of my job requiring the use of multiple devices. However, I can see that this technology could be very useful in a business scenario, where the Apple system will suffer even more. If Apple is doing to launch AirPlay Direct then it sort of proves that it hasn't 'invented' the perfect solution for others to copy.

e.mote · Nov 7, 2012

>But surely it will be better as it's direct from device to TV?...If Apple is doing to launch AirPlay Direct then it sort of proves that it hasn't 'invented' the perfect solution for others to copy.

Sure, Apple doesn't "invent" much, and its solutions are oftentimes a work-in-progress. Tech is more about iterative improvements than revolutionary jumps. But Apple should get credit for pushing the envelop, and being generally better in its executions than its competitors. One such illustration would be to juxtapose AirPlay's track record against Samsung's AllShare Cast (from the mentioned review thread).

Yes, Maps was a rare flop, and Siri is still an experiment. But here, too, one can argue that Siri was the inspirational impetus for Google Now.

>I can see that this technology could be very useful in a business scenario

As said previously, I see Miracast or any wifi-based to-TV scheme as an interim solution, because it usurps most of the device's wireless bandwidth and precludes other uses. It would be suitable on a provisional basis, but I can't see being adopted for enterprise use. Miracast as it stands is a black box, where channel/bandwidth/etc are all auto-configured. For business use, bandwidth management & config would be essential.

[BTW, the Netgear PTV3000 does have a web interface at 192.168.3.1, but it's for firmware update only.]

WiGig and its ilk have been a long time coming, but the surge in tablet market should provide some impetus for faster adoption. Dell will have WiGig in one of its coming ultrabooks. One hopes that Apple will get WiGig rolling for iProducts--likely under the AirPlay brand--as it alone has the clout to push for any tech adoption by its sheer market size in mobile. Then, the rest of the industry will follow along, if only to keep up with Apple.

jonmorris · Nov 7, 2012

e.mote said:
>But here, too, one can argue that Siri was the inspirational impetus for Google Now.

You could, but it would be totally wrong.

Sure, Samsung's S Voice is a rip off in terms of design and presentation, but Google had most of what Siri does available before - just in a terribly disjointed way. It had the off-board voice processing for one. In any case, Apple bought the Siri tech and had it not done so, Siri would have been available to ALL Apple users and probably other platforms as well.

Google Now is way more than simply asking questions; it provides information based on what you do normally, from searching to places you go, to upcoming appointments and things Google learns - like where you work. If you say what teams you support, it will keep you updated on that and much more.

Apple will no doubt reinvent it, as Google has clearly done a poor job of explaining what Google Now is - or indeed how its voice stuff worked before.

What next, Apple invented pull down notifications, picture phonebooks, SMS...?

lobotomik · Nov 8, 2012

e.mote said:
All of the iPads and iPhones have been dual-band, albeit single-stream (I'm unsure about the latest iterations). While it's fashionable to do the Apple-hate song and dance on an Android forum, Apple should be thanked for being first with Airplay. Without Airplay, Miracast would not exist, because it's a direct response to Apple's. In fact, we can say the same about the iPad. Credit where it is due.
...
I'm starting to think that Miracast's omission from N10 specs was intentional. Encoding 2560x1600 at 30fps in real-time is no cupcake, and pushing 1080p uninterrupted through wifi will be a major challenge, noobs' claims of "sufficient bandwidth" notwithstanding.

Not most iPhones, anyway. And in all cases it goes through an access point, which in the vast majority of cases will be a cheap single-band ADSL router provided by the ADSL provider.

As for credit where it is due, I think even wi-fi.org says quite literally that Miracast is like an Airplay but for everyone. Anyway, I don't give a damn about credit to Apple -- they already grab more than their fair share.

Encoding a computer screen showing computer data at a high resolution is not much of a job, because mostly everything is clean and static and needs no updates. Movies won't be over HD resolution. And yes, fast-acton full-screen games might pixelate occasionally, as digital TV does when it runs out of bits.

kenyee · Nov 8, 2012

jonmorris said:
AirPlay Mirroring is fine for watching movies, or looking at pictures - or anything that doesn't involve any user interaction... but Apple should stop advertising/implying you can use it to connect your Mac to a monitor/TV wirelessly as the lag is such that it's unusable - unless you're happy to move the mouse, wait, type a few characters, wait..

Same issue w/ the HTC OneX's wireless solution...lag..enough that it's unusable for gaming. That's why I wish the N7 had MHL support.

First confimed Miracast compatible devices announced... no Nexus 7, yet.

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