Remote display technology lets users fully experience cloud content04 Jul 2012 | Raj Pawate
Mobility is of paramount importance for many of the devices that access the cloud, such as smartphones, tablets, and the new thinner and lighter laptops. Users of these devices simply want to carry the cloud in a pocket or purse. But that means small display screens and few, if any, hardwired connectors that could link to another device like one of the many large-screen LCD monitors that are becoming more and more ubiquitous as their prices drop. Remote display technology also bridges this gap so that content from the cloud can be experienced to its fullest.
Pick your cloud
Most often the concept of cloud computing conjures up an image of one amorphous yet monolithic entity labeled "THE CLOUD." In fact, this is a rather simplistic and not completely accurate conception of something that is multifaceted and varied. Most people interact with at least three different sorts of clouds over the course of a typical day, as shown in Figure 1. Each different segments of cloud computing has its own distinct set of needs for remote display technology.
First, there's the "infotainment cloud," which is made up of the readily accessible, public websites on the Internet. These sites can be accessed by anyone. Much of their content is free and unrestricted, or it can be accessed for a small fee. YouTube, Facebook, Netflix, the news outlets and other types of sites make up the infotainment cloud.
A different sort of cloud is the "work cloud," a private cloud that typically serves the employees of a business organization. Since at least some of the information shared among the members of an organization is sensitive or confidential, access to work clouds is limited to the people who have a right to know the information contained on this cloud. Access is restricted and the content is secured against hacking, tampering and theft.
The last type of cloud is the "home cloud." This is where an individual's or a family's personal content is stored, accessed, shared and experienced. Devices connected to this cloud can include one or more desktops, smartphones, tablets, TVs and home entertainment centers. Today, most home clouds have some type of security safeguards, which, at the very least, are intended to protect the content and devices on the home cloud from viruses and other types of malware. Home clouds also have secure access, limiting access to only family members while preventing a neighbor from viewing personal content.
Serving the clouds
Easily accessing any of these clouds and seamlessly moving from one to the other is a key user experience requirement. Remote display technology is flexible enough to serve all of the many different use cases.
In an infotainment or home cloud use case, content consisting of movies, photographs or music can be stored on a large desktop, but the cloud offers flexibility for experiencing this content on a number of different devices, such as a large TV, home entertainment system, tablet and smartphone. For example, a movie might best be shared with several people by mirroring it on a large-screen high-definition (HD) LCD display as it is streaming from the cloud to a laptop, tablet or smartphone. Music might also be mirrored from an MP3 player connected to the cloud to a home entertainment center.
Work clouds in medical facilities, retail stores, insurance companies or financial institutions often have very different manifestations of remote display technology. For example, a retail store could employ remote display technology to implement a network of large-screen LCD displays throughout the stores for advertising purposes. A central server could remotely display advertising videos or still images on the displays. In an office setting or school, a network projector could wirelessly mirror presentation slides or other materials from a tablet or laptop to a display screen or LCD display in the room.
Another business use case might involve many thin client terminals each made up of a display, keyboard and mouse, and all connected by remote display technology to a central server on a work cloud where applications and data would be stored. All processing would be done in the server to reduce procurement and maintenance costs, ensure data security and privacy, and simplify asset management for the IT department.
The processing stack
Remote display technology involves a "source" and a "sink." Sometimes the terms "transmitter" or "sender" are used for the source device, and the term "receiver" is used for the sink device. Examples of a source include a desktop PC, laptop, smartphone and tablet, while examples of a sink include a TV, home audio entertainment system, monitor and tablet.
The processing stack in the source device encodes the video, audio and graphics on the source screen, optionally encrypts it, multiplexes audio with video, packetizes and transports the data over a wired or wireless connection to a sink device, where the opposite of this process is performed in order to display the screen or information. As straightforward as this process may seem, it presents a number of technical challenges.
For example, the processing power needed to accomplish complex coding and decoding algorithms in real time is significant. Retrofitting large-screen LCDs for remote display will involve connecting a device to the display through its HDMI port. Ideally, this remote display connector device will be small and unobtrusive, probably the size of a thumb drive or dongle.
The development of certain standards such as the H.264 coder/decoder (codec) has helped in this regard, but several proprietary codecs are still prevalent in the marketplace. While H.264 was developed primarily for video, it might not work well for compressing text and graphics. However, H.264 is everywhere and is particularly critical because it enables high-definition video at lower bit rates.
Additionally, power consumption becomes an important design consideration. For instance, a group of thin clients connected to a central server by remote display technology might be powered by power-over-Ethernet (POE), requiring very low power consumption by the client. In another use case, the sink may need to be powered off of a USB or a battery.
Right core for right chore
What are the different types of content? And where are they used? We can classify content into four major types or categories: (1) documents such as Microsoft Word and PowerPoint as well as Adobe PDF files; (2) media such as video and audio files; (3) games and (4) web content. As we discussed before, there are several different types of algorithms for encoding content on the source side.
Some algorithms are lossy codecs, and some are loss-less; each offers its own benefits depending on the type of content displayed. These range from JPEG to H.264 to proprietary codecs. For example, using a lossy codec like H.264 for encoding documents might result in artifacts.
Several different standard bodies have addressed these needs from different perspectives. The Digital Living Network Alliance (DLNA), Wi-Fi Alliance's Wi-Fi Display (WFD) and Wireless Gigabit Alliance's WiGig are some examples of how the industry is addressing this need to wirelessly display content. DLNA was primarily formulated for streaming video and audio and supports a large number of codecs. Interoperability continues to be a challenge, and it is not well suited for displaying webpages.
WFD is much simpler and hopefully will address the interoperability issue. It is well suited for displaying webpages because what you see on the screen of a source device is what you see on the display connected to the sink device. Ultimately, for the best user experience, some or all of these different types of codecs might need to be invoked in the source-sink solution.
Another challenge will be the simplicity of the wireless communications connection. Any of several wireless technologies like Near Field Communications (NFC), Wi-Fi or one of the new variants of Wi-Fi, such as Wi-Fi Direct, could be implemented at the transport/physical layer in this stack, but what will be essential to widespread adoption will be how easily, seamlessly and quickly a wireless connection can be established.
A connectivity link that is time-consuming or technically challenging to set up could become an insurmountable obstacle to rapid adoption. Technologies like NFC simplify setting up this connection and enable two devices to exchange information without human intervention. Setting up a connection can be as easy as tapping the source device to the sink.
The underlying factors for remote display technology are finally converging. Wireless connectivity and Wi-Fi bandwidth continue to rise, costs continue to decline and newer standards, like Wi-Fi Direct and Wi-Fi Display, from the Wi-Fi Alliance standard body help drive new use cases. Video compression standards like H.264 and H.265 provide high quality video compression at HD resolutions and at bitrates sustainable on wireless links.
The demand for thin, small devices such as smartphones and tablets has driven away familiar connectors like VGA and HDMI, pushing the need for an alternative wireless connectivity solution. Finally companies like Texas Instruments Incorporated (TI) are building system-on-chips (SoCs) such as the DaVinci� DM81xx video processor generation that pack the processing power of a full desktop, run on a battery and at are offered cost-points that enable solutions that consumers can easily afford.
TI is helping original equipment manufacturers develop these implementations with several reference design kits (RDKs). Check out TI's Content Sharing RDK to enable sharing content with the infotainment and home clouds, as well as TI's Thin Client RDK, which adds access to the work cloud.
About the author
Basavaraj (Raj) Pawate is a Distinguished Member of the Technical Staff at Texas Instruments Incorporated (TI). He has held several leadership positions for TI in North America, Japan and India. His responsibilities have included individual research, initiating R&D programs, establishing product development groups, outsourcing and creating reference designs, helping customers go to production, and being CTO of emerging markets.
Share this page with your friends
5,000 Panasonic workers to lose jobs
Jobs from Panasonic's auto and industrial division, will be cut based on new business strategy...