Miracast是众多无线显示标准之一。如果您有Miracast设备和显示器，则可以将视频信号从一个设备发送到另一个设备，而无需一根长的HDMI电缆。
听起来不错吧？问题是，在实践中，Miracast正在与许多其他看似相似的标准竞争。这意味着很多用户不确定他们是否可以使用Miracast，或者它是否是正确的无线显示技术。
什么是 Miracast？(What Is Miracast?)
Miracast是WiFi 联盟(WiFi Alliance)定义的标准，这意味着它的核心是使用WiFi 技术(WiFi technology)。具体来说，它使用WiFi Direct，它在两个设备之间创建 WiFi 连接，而不需要路由器或其他接入点来扮演中间人的角色。
通过该无线连接，视频数据以H.264 格式(H.264 format)发送。这是当今最常见的高清视频编码标准。Miracast官方支持高达 1080p 的分辨率，也称为“全高清”。在声音方面，该标准也支持 5.1环绕声(Surround Sound)。
如果范围内有Miracast显示器，您所要做的就是选择它作为显示器并将您的媒体投射到它。Miracast的美妙之处在于，任何两个经过认证的设备都将处理连接的所有底层细节，您可以继续工作或娱乐。
Miracast 的竞争对手是谁？(Who Are Miracast’s Competitors?)
Miracast于 2012 年发布，但如今有很多替代技术。两个最著名的替代品是Google Cast和Apple 的 Airplay(Apple’s Airplay)。还有英特尔的WiDi（无线显示）标准，它为 VR（(Wireless Display)虚拟现实(Virtual Reality)）等低延迟应用提供了具有潜力的性能。这些标准不可互操作。换句话说，您的Miracast设备不会与Apple Airplay设备通信。
可悲的是，在Miracast推出多年后，我们似乎仍然没有特别接近拥有单一的通用标准或无线显示技术。
谁支持 Miracast？(Who Supports Miracast?)
要使设备与Miracast一起使用，它需要正确的硬件和软件。因此，尽管您可能拥有运行兼容操作系统的设备，但您还需要在引擎盖下安装合适的芯片才能使其正常工作。
Miracast支持自 8.1 版以来已内置到Windows中，并且(Windows)Windows 10仍然支持Miracast作为施法者和接收者。
在计算世界的Apple方面，您不会找到任何Miracast支持。macOS 和iOS使用Airplay作为唯一的内置选择。多年来有一些软件变通方法，但根据我们的经验，这些方法不可靠且性能不佳。
Linux支持确实存在，但其背后似乎没有任何驱动开发。MiracleCast和适用于Linux的(Linux)无线显示软件(Wireless Display Software)是这里经常引用的两个选项。
Android用户也喜忧参半。有一段时间，MiraCast支持已融入Android本身，但从Android 6.0开始，这种支持就消失了。但是，个别Android设备制造商可以选择将Miracast硬件和软件支持直接放回这些设备中。
因此，如果您想知道您的Android设备是否可以使用MiraCast显示器，您必须查看该特定机器的文档。
Miracast 设备(Miracast Devices)
MiraCast设备是什么类型的设备？原则上，任何可以生成视频的设备都可能配备MiraCast技术。在实践中，这几乎是您所期望的。平板电脑、智能手机、笔记本电脑、台式机和其他常见计算设备也可以通过Miracast 认证(Miracast-certified)。
有时可以稍后通过软件更新添加对Miracast的支持，但这取决于硬件制造商。(Miracast)
Miracast 加密狗(Miracast Dongles)
如果您的显示器没有内置MiraCast支持怎么办？(MiraCast)好消息是，这是一个非常容易解决的问题，而且不需要购买全新的显示器。您需要做的就是购买MiraCast加密狗并将其插入显示器上的一个HDMI端口。
这样做的真正好处是您可以随身携带加密狗，这样您就可以将它连接到目的地的任何显示器。例如，当您想要进行演示时，您可以将它连接到公司的投影仪，并且由于MiraCast使用直接连接，您不必担心使用本地无线网络。
Miracast 显示器(Miracast Displays)
有些显示器内置有MiraCast硬件。(MiraCast)这意味着您无需执行任何特殊操作即可从Miracast设备投射图像。在Miracast显示器附近时，它应显示在源设备上的可用投射目标列表中。
MiraCast 软件接收器(MiraCast Software Receivers)
获得Miracast设备认证意味着手头拥有正确的硬件和软件资源，但这并不意味着MiraCast解决方案始终与特定硬件相关联。
最好的例子可能是用于 PC 的 Airserver Universal(Airserver Universal for PC) ，这是一款出色的软件，可作为MiraCast、Google Cast和Apple AirPlay的通用接收器。这意味着您可以在笔记本电脑上安装软件，将其连接到投影仪或其他大型显示器，并镜像人们出现的任何设备。
MiraCast 安全吗？(Is MiraCast Secure?)
相当安全——实际上与WiFi一样安全。这是因为MiraCast使用与现代WiFi相同的(WiFi)安全协议(security protocols)。这使得某人不太可能有能力远程窥探传输。
对于 99% 的用户来说， MiraCast(MiraCast)内置的安全性很好。但是，如果您使用它向DARPA(DARPA)展示绝密计划，您可能只想使用HDMI电缆。
Miracast 的缺点(The Downsides Of Miracast)
MiraCast是一种非常可靠且易于使用的屏幕镜像技术，但它确实有一些严重的缺点。一方面，该标准没有指定任何类型的最小延迟标准。这意味着，如果您的应用程序（例如游戏或交互式演示）需要低延迟级别，则无法保证您的特定MiraCast设置足够好。
MiraCast也不支持纯音频应用程序，因此您不能只将音乐或其他声音信息发送到MiraCast接收器。由于现在大多数东西都有蓝牙，所以这并不重要。但是，这是一个值得了解的限制。
MiraCast的另一个主要缺点是您只能使用它来镜像设备屏幕。例如，使用AirPlay，您可以让无线显示器充当第二个显示器而不是镜子。从生产力的角度和演示的角度来看，这都是有用的。
Miracast 重要吗？(Does Miracast Matter?)
当Miracast首次发布时，它感觉颇具革命性，但事实是Miracast已被AirPlay和Google Cast所取代。由于移动设备世界已经在 iOS 和Android之间彻底分裂，因此对(Android)Miracast的支持似乎有点乏善可陈。
如果您碰巧拥有Miracast设备并拥有显示器，那么利用它并没有错。然而，除非Miracast获得大幅升级，否则也没有特别的理由寻求这项技术。
HDG Explains : What Is Miracast?
Miracast is one of a number of wireless diѕplay standards. If you have a Miracаst device and display, you cаn send a video signal from one to the other, wіthout the need for a long HDMI cable.
Sounds pretty good right? The problem is that, in practice, Miracast is in competition with lots of other seemingly similar standards. This means that plenty of users are unsure of whether they can use Miracast or if it’s even the right wireless display technology to use.
What Is Miracast?
Miracast is a standard defined by the WiFi Alliance, which means that at its core, it uses WiFi technology. Specifically, it uses WiFi Direct, which creates a WiFi connection between two devices without the need for a router or other access point to play the part of middleman.
Over that wireless connection video data is sent in the H.264 format. That’s the most common HD video encoding standard today. Officially, Miracast supports resolutions up to 1080p, also known as “Full HD”. In terms of sound, the standard supports 5.1 Surround Sound as well.
If there’s a Miracast display in range, all you have to do is select it as a display and cast your media to it. The beauty of Miracast is that any two certified devices will handle all the under-the-hood details of the connection and you can just get on with your work or entertainment.
Who Are Miracast’s Competitors?
Miracast was released in 2012, but today there are plenty of alternative technologies. The two best known alternatives are Google Cast and Apple’s Airplay. There’s also Intel’s WiDi (Wireless Display) standard, which offers performance with potential for low-latency applications like VR (Virtual Reality). These standards are not interoperable. In other words, your Miracast device is not going to talk to an Apple Airplay device.
Sadly, years after Miracast was launched, we still don’t seem particularly close to having a single universal standard or wireless display technology.
Who Supports Miracast?
For a device to work with Miracast, it needs both the right hardware and software. So, although you may have a device that runs a compatible operating system, you also need the right silicon under the hood for it to work.
Miracast support has been built into Windows since version 8.1 and Windows 10 still supports Miracast as both caster and receiver.
On the Apple side of the computing world, you won’t find any Miracast support. macOS and iOS uses Airplay as the only baked-in choice. There have been a few software workarounds over the years,but in our experience these have been unreliable and performed poorly.
Linux support does exist, but there doesn’t seem to be any driven development behind it. MiracleCast and Wireless Display Software for Linux are the two oft-cited options here.
Android users get a mixed bag as well. For a time, MiraCast support was baked into Android itself, but from Android 6.0 onwards that support is gone. However, individual Android device makers can choose to put Miracast hardware and software support right back into those devices.
So if you want to know if your Android device will work with a MiraCast display, you’ll have to look at the documentation for that specific machine.
Miracast Devices
What sorts of devices are MiraCast devices? In principle any device that can generate video could potentially be equipped with MiraCast technology. In practice, it’s pretty much what you’d expect. Tablets, smartphones, laptops, desktops and other common computing devices can also be Miracast-certified.
Sometimes support for Miracast can be added via a software update later, but that would be up to the hardware manufacturer.
Miracast Dongles
What if you have a display that doesn’t have MiraCast support built in? The good news is that this is a pretty simple issue to solve and it doesn’t involve buying an entirely new display. All you need to do is purchase a MiraCast dongle and plug it into one of the HDMI ports on your display.
The really nice thing about this is that you can take your dongle with you, so that you can connect it to any displays at your destination. For example, you could hook it up to the company projector when you want to do a presentation and since MiraCast uses a direct connection you don’t have to worry about using the local wireless network.
Miracast Displays
Some displays have MiraCast hardware built right into them. This means you don’t have to do anything special in order to cast the image from a Miracast device. When in the vicinity of a Miracast display, it should show up in the list of available casting targets on the source device.
MiraCast Software Receivers
To be certified as a Miracast device means having both the right hardware and software resources on hand, but that doesn’t mean MiraCast solutions are always tied to specific hardware.
The best example of this is probably Airserver Universal for PC, an amazing piece of software that acts as a universal receiver for MiraCast, Google Cast and Apple AirPlay. That means you can install the software on a laptop, connect it to a projector or other large display, and mirror just about any device people show up with.
Is MiraCast Secure?
Pretty secure – about as secure as WiFi in fact. That’s because MiraCast uses the same security protocols as modern WiFi. This makes it pretty unlikely that someone will have the ability to snoop on the transmission remotely.
For 99% of all users the security built into MiraCast is just fine. If, however, you’re using it to present top secret plans to DARPA you may want to simply use an HDMI cable.
The Downsides Of Miracast
MiraCast is a pretty solid and simple to use screen-mirroring technology, but it does have a few serious downsides. For one thing, the standard doesn’t specify any sort of minimum latency standard. This means that if you have an application (such as a game or interactive demo) that needs low latency levels, there’s no guarantee your specific MiraCast setup will be good enough.
MiraCast also doesn’t have any support for audio-only applications either, so you can’t just send music or other sound information to a MiraCast receiver. Since most everything has Bluetooth these days, it doesn’t matter all that much. However, it’s a limitation worth knowing about.
The other major downside of MiraCast is that you can only use it to mirror a device screen. With AirPlay, for example, you can have the wireless display act as a second monitor rather than a mirror. This is useful both from a productivity point of view and from a presentation point of view.
Does Miracast Matter?
When Miracast was first released it felt rather revolutionary, but the fact is that Miracast has been overtaken by both AirPlay and Google Cast. Since the mobile device world has been so thoroughly split between iOS and Android, it seems that support for Miracast is a little lackluster.
If you already happen to own a Miracast device and have a display, there’s nothing wrong in taking advantage of it. However, unless Miracast receives a substantial upgrade, there’s no particular reason to seek this technology out either.
