I have been doing a lot of work with video containers recently, especially figuring out interoperability between iOS/Android and optimizing progressive playback. In particular it seems Android devices fail to perform progressive playback on certain files while iOS and VLC succeed:
Why ?
As usual understanding things to the deep down proved extremely worthy.
Analysis
A movie file is called a container. There are several kind of containers but the most common on mobile platforms are:
Apple's MOV/Quicktime.
MP4: design is based on MOV.
3GP: design is also based on MOV.
Within the container, datas are organized as "ATOM"s. As you can see in the drawing on the left a typical movie container features four atoms:
ftyp atom: The magic number part of the file. The body of this atom also contains the branding and version of the container format. With quicktime/MOV it is always "qt ".
moov atom: The metadatas, containing codec description used in the mdata atom. It also contains sub-atoms "stco" and "co64" which are absolute pointers to keyframes in the mdata atom.
wide atom: A dirty hack explained later.
mdata atom: The interleaved compressed audio and video streams. Account for 95% of the file size. Most of the time codecs used are H.263 for video and AAC for audio.
Note : Why is the wide atom a dirty hack ? Because its only purpose in life is to be overwritten: Atom size are coded on 4 bytes. Hence an mdata atom maximum size is 4GB. To allow itself to grow further the mdata atom header can be moved up by 8 bytes thanks to the padding and a special atom header can be used in order to code its size on 8 bytes instead of 4.... and raise the limit from 4 GigaBytes to 9 ExaBytes.
Now when a file like this is accessed over HTTP, the player performs progressive playback as follow:
Receives the "ftyp" atom and check that the container format, version and branding are supported.
Receives the "moov" atom, check that the required codec are available and use the "stco" sub-atoms to start decoding the video and audio streams.
Receives the "mdat" atom, buffer the content and make it available so codec can decompress it.
Since the "ftyp" and "moov" are a few KB, progressive playback can start within a few seconds.
Problem
In order to start playing a movie file right away its metadata contained in the "moov" atom is paramount to the player. If the movie file atoms are ordered as previously described everything work as expected...but most video editors (ffmpeg, quicktime, flash video) generate atoms in the wrong order (as seen on the right): With the "moov" atom last.
If you try to load a file structured like this on an Android device over the internet, you get an error message like this:
Progressive playback is not possible and you have to download the entire file before you can start watching the video. But if we try to open this file with an iOS device or VLC they are able to start playback within seconds:
How ?
The answer is pretty obvious and can be observed via WireShark:
iOS and VLC open a second HTTP connection to the server using the not so well known "Range" HTTP header:
The first HTTP request features a "Range: bytes=0-" HTTP header field. So the movie is downloaded from the start.
As soon the the player detects a "mdat" atom without the "moov" atom it opens a second connection with a "Range: bytes=4726467-" HTTP header field. This skip most of the file up to the end and retrieve the "moov" atom.
Thanks to the second connection, the "moov" atom is retrieved faster and progressive playback can start right away without waiting for the entire file to be downloaded.
Solution
Android videoplayer elect NOT to open a second connection but wait for the entire file to download. The only solution is to fix those files and reorder the atoms inside. This can be done:
Apple kicked off this winter’s iOS 5 Tech Talk World Tour last week in Berlin. I was lucky enough to get a seat and I’d like to tell you a bit about the sessions I attended for those who weren’t there.
First up after the kickoff session was Mark Kawano, Apple’s User Experience Evangelist. He talked aboutiPhone and iPad User Interface Design, in particular:
Understanding what makes the iPhone and iPad so special is essential to designing a great user experience. Learn best practices for optimizing your app’s user interface for the unique characteristics of iOS devices.
Great Apps Tell a Story
Mark opened his talk by reminding the audience to strive to build a truly great app. Great apps like djay or The Early Edition 2 define a new benchmark for their genre. The attention to detail that went into such apps helps them to remain successful on the App Store over a long period of time. And looking at how relatively small the teams behind those highly successful apps often are, there is no reason why any one of us couldn’t build a truly great app, too.
One common theme of great apps is that they tell a story. In fact, telling a great story should be your main goal during the design of your app. Your app’s story should drive most if not all of your design decisions. The story answers questions like:
What will your app do?
Who are the users?
Where will they use it?
Concrete Advice
Mark continued with some concrete steps you should follow while designing your app, always driven by the story you have defined.
1. Define Your App’s Style
Ask yourself two questions in this section:
What type of app are you building?
Depending on where you place your app on this line, you should tend to make your app more or less visually rich and immersive, and make different tradeoffs between stunning looks that may be lots of fun but a bit harder to use and a UI that is optimized for usefulness, efficiency and reliability (no surprises). Sounds like common sense, and it probably is.
A not so obvious insight is that you can (and should) make a different decision for each screen of your app. If your app exposes different characteristics on its different screens, you should optimize each screen for its intended purpose. Take Apple’s Photos app on the iPhone as an example: the albums navigation is a plain table view that looks rather boring but is efficient in letting you find the photos you’re looking for. Once you have selected a photo for viewing, the app turns into a totally immersive experience, hiding all navigation controls.
What kind of content does your app have?
The design of your app’s UI should be heavily influenced by the type and amount of content you want to display.
Photos and Videos: should always be shown full screen (at least on second tap); let the content shine; hide all UI controls; reduce color in the UI to focus on the content; should be able to swipe between fullscreen items.
Large data sets: focus on legibility: align text at common edges; when displaying data fields,right-align the label and left-align the content (as in the iPhone’s Contacts app); use one typeface only, with subtle shading and size differences to visualize importance; minimum font size should be 13 pt for short and rather unimportant snippets, 15 pt for normal body text; make navigation easy; have great visual design.
Minimal data: make it graphically rich; use realism where appropriate. (An example of this type of app is the iPhone’s Compass app: it only displays a single piece of information; another example would be a thermometer app that only displays the today’s current, highest and lowest temperature.)
Games: graphics must be beautiful; be consistent: menu screens should look just as good as the actual gameplay; use playful typography: Helvetica is probably not the font you want to use in a game; customize the Game Center UI to make it fit with the rest of your game’s appearance.
General Tips
Customize your UI for both iPhone and iPad: the iPad version should not just be a blown-up version of your iPhone UI. Make use of the bigger screen and display more information per screen.
Use the new appearance customization APIs in iOS 5: just because you use the standard UIKit controls doesn’t mean you can’t make your app graphically rich.
Read the Human Interface Guidelines, which have been heavily updated for iOS 5. Mark stressed that he understands the HIG as being more of a cookbook than a checklist. He encouraged the audience to try to understand the concepts and ideas that stand behind the rules in the HIG and then adhere to these ideas rather than following every rule to the letter.
2. Design for Touch
Tap Targets
Everybody who has used an iOS device knows that the finger is a vastly different input device than a mouse or trackpad. Not only is a touchscreen a more direct form of interacting with an app, our fingertips are also a lot less accurate than a mouse pointer that can be positioned with pixel precision.
Mark recommends that tap targets should be at least 44 × 44 pt in size and have adequate spacing between them. If in doubt, have a look at Apple’s Calculator app on the iPhone to check how big a fingertip-sized control should be.
Gestures
Just as important as tapping are gestures. Your app should support all of the common gestures that users have learned to rely on as long as they make sense in the context of your app. Gestures include:
Swiping. A swipe must feel like direct manipulation of the objects on the screen. Responsiveness is therefore extremely important. You should provide visual indicators (such as a UIPageControl) to show the user between how many items she can swipe. To avoid confusion, it is important that the items she can swipe between are all on the same hierarchical level. When swiping between photos in an album, don’t include a screen showing a list of all albums.
Scrolling. Scroll bars are hidden most of the time so it is important to show the user that the content is scrollable. For example, Apple always makes sure in its own apps that table views include a partly visible row at the bottom of the screen. The clipped content tells the user that there is more to discover. Another subtle indicator is flashing the scroll indicators briefly when a scrollable view appears on screen.
One drawback of gestures is that all but the most trivial gestures are not easily discoverable. It is important to not hide key functionality behind gestures. Your app should also offer a more discoverable method (e.g., a button) to achieve the same thing.
Touch-centric UIs
If you want a real challenge and make a great jump towards a great app, you should try to create a totallytouch-centric UI. Move away from buttons and other controls (which are, after all, just layers of abstraction) and try to design a way for users to interact directly with your content. In the best case, your app does not even have a UI anymore!
As examples of apps that made great progress in this regard, Mark cited Push Pop Press’s Our Choice (for making the entire UI go away) and Visible Market’s StockTouch (for introducing a completely fresh way of visualizing and interacting with stock market data).
3. Use Animation
Animations are more than just eye candy. If properly used, they really help a user understand what’s going on in your app. Smooth Transitions between screens make it easier for users to keep track of where they are in the hierarchy of screens. Users know that a right-to-left transition means they moved down in the navigation hierarchy as opposed to going back up. A zoom transition from thumbnail size to full screen when the user taps a photo shows him direcly what’s happening.
Animations can also be used with the all-important task of responding to touch input immediately:Imagine your user taps a row in a table view that causes your app to download additional data to display on a detail screen. It is important to immediately do the transition animation to the detail view and show the animated activity indicator even if you can’t display any new content until the download has finished. Nothing would be more jarring to the user than giving him the feeling that your app did not react to his touch input.
A third important use of animations is to provide feedback in certain situations, for example if the app has entered a new mode. A good example of this is the wiggle animation in Springboard when the app icons are ready to be moved.
4. Focus!
This is really important to make your app as good as possible: Determine your app’s essential features and concentrate on those! There is always time to add more features later (when your users have told you which ones they really want). In the initial design and development phase, your time is best invested by polishing a limited feature set to perfection.
The example to follow here is Ben Zotto’s iPad appPenultimate, an app that launched on the iPad App Store on day one with a pretty limited featureset but highly polished UI. Largely due to its great design, Penultimate has always been high in the App Store charts, giving the developer time to add highly requested features one by one.
5. Prototype and Iterate
In all likelihood, you will not arrive at the perfect design with your first attempt. Nor with the second or third. This is a process that takes time, and you should constantly prototype and iterate to make sure your design feels right. Don’t worry too much about the tools to use for this process. Any tool you feel comfortable with that allows you to make quick changes is great. Mark mentioned that internally at Apple, many love Keynote for building quick click prototypes, especially for its great built-in animations. For the more code-oriented designers, Xcode’s new Storyboarding feature might be the way to go.
Mark stressed the importance of testing your UI on an actual device. Nicholas Zambetti’s free LiveViewapp is his tool of choice to quickly bring a design mockup from your computer screen onto a device screen.
6. Have a Great App Icon
Your app’s icon is the first thing a potential customer notices about your app. And after they have bought it, the icon will be a constant companion and your app’s main identifier on a crowded Springboard. So make sure it’s great!
Mark offered a nice little tip to test the recognizability of your icon. Place it into a folder in Springboard. If it can still be recognized easily among other icons in the folder, chances are it is also very recognizable at a larger size.
Is It Apple Quality?
Finally, this is the question you should ask yourself constantly: Is my app Apple Quality? Remember, there is no reason why your app shouldn’t be as good as Apple’s own iOS apps. So if your answer to the question is no, you should probably work harder on your app’s design.
If you are programmer or actually if you at least have some basic coding skills, you’ll find this article useful. For example just look at this page source – without highlighting that whole code is just a bunch of plain black text and it is really hard to find specific things if everything looks the same. Thankfully there are many highlighting scripts available, for example Notepad++ also supports and highlights different code snippets. These code syntax highlighters actually are doing mainly the same thing, but with more options, big coding language support, better integration – really in our days you just need to choose one – there are too many tools available anyway.
Use these syntax highlighters in daily coding or just in cases where you are sharing code with friends, want to add that code in your blog post (by the way there is SyntaxHighlighter WordPress plugin available too) or just want to rapidly read and maintain it – use online syntax highlighters in that case and pick your favorite one from this article!
I definitely think this syntax highlighter tool should be your choice – this tool is supported very well and offers many options, extensions and integrations with other programs and platforms, but however I want to offer you other tools too to choose from.
SyntaxHighlighter is here to help a developer/coder to post code snippets online with ease and have it look pretty. It’s 100% Java Script based and it doesn’t care what you have on your server.
The idea behind SyntaxHighlighter is to allow insertion of colored code snippets on a web page without relying on any server side scripts. SyntaxHighlighter isn’t for those looking for ability to edit highlighted code.
Extensions & Integration – check out this page too, because you can find there WordPress extensions, Ruby on Rail plugins and much more integration extensions, should be handy!
GeSHi supports PHP5 and Windows, and has even been used to highlight code on ASP pages, it really supports and highlights almost every coding language, you should check out his website to read more – very powerful tool!
GeSHi aims to be a simple but powerful highlighting class, with the following goals:
Doesn’t get any easier than this to create a web page from your source code. This online highlighter tool offers many coding languages you can choose to highlight together with several options, you can check/uncheck before highlighting code:
A Javascript module and CSS file that allows syntax highlighting of source code snippets in an html page.
The comments in prettify.js are authoritative but the lexer should work on a number of languages including C and friends, Java, Python, Bash, SQL, HTML, XML, CSS, Javascript, and Makefiles. It works passably on Ruby, PHP, VB, and Awk and a decent subset of Perl and Ruby, but, because of commenting conventions, doesn’t work on Smalltalk, or CAML-like languages.
Features:
Works on HTML pages
Works even if code contains embedded links, line numbers, etc.
Simple API : include some JS&CSS and add an onload handler.
Lightweights : small download and does not block page from loading while running.
Customizable styles via CSS.
Supports all C-like, Bash-like, and XML-like languages. No need to specify the language
Extensible language handlers for other languages. You can specify the language.
Pygments is a generic syntax highlighter for general use in all kinds of software such as forum systems, wikis or other applications that need to prettify source code.
Highlight.js highlights syntax in code examples on blogs, forums and in fact on any web pages. It’s very easy to use because it works automatically: finds blocks of code, detects a language, highlights it.
This program supports following languages – 1C, AVR Assembler, Apache, Axapta, Bash, C#, C++, CSS, DOS .bat, Delphi, Django, HTML, XML, Ini, Java, Javascript, Lisp, MEL (Maya Embedded Language), PHP, Perl, Python, Python profile, RenderMan (RIB, RSL), Ruby, SQL, Smalltalk, VBScript, diff.
Web-based image editors have several advantages to its desktop counterparts. The most obvious benefit is that they allow you to work on any computer (that has a browser). In most cases, you can save your work online, avoid having to install desktop software, and interface with other web based services such as Flickr or Picasa. This article shares 6 of the finest, free online image editors that are capable alternatives to desktop applications like Adobe Photoshop and GIMP.
Pixlr is a very robust, Flash-based image editor that shares a similar user interface to Adobe Photoshop. The Pixlr API – which is still in its early stages of development – opens up possibilities of mash-ups an integration of Pixlr into your blog, web application, or website. It has a smart Wand tool to help you automatically select similar and adjacent pixels (which is equivalent to Photoshop’s Magic Wand tool).
Splashup is feature-packed online image editor that integrates with popular photo sharing services like Flickr, Picasa, and Facebook – allowing you to access your photos remotely. Some of the cool features that Splashup has are layers with blending modes, the ability to interface and capture images from your web cam, and a nice variety of filters and layer effects.
Phoenix, a powerful web-based image editor by Aviary, rivals the capabilities of desktop image editing applications. Check out this list of tutorials to fully appreciate the potential of this excellent image editor. You have to sign-up for an account to access Phoenix, but it only takes a few seconds and also gives you access to other Aviary tools and services such as Peacock ("Visual Laboratory") and Toucan (color and swatch tool).
If you’re looking for an application to meet your simple photo-editing needs, check out pixer.us – a free, web-based photo editor. It has an intuitively simple interface and useful photo-editing features like cropping, resizing, and rotating. It also has some color adjustment options such as Saturation, Brightness, and Contrast adjustments. You can save your work as one of the four popular digital image files (PNG, JPG, GIF, or BMP).
FotoFlexer is a free, web-based photo editor that has tons of features but is still simple to use. Check out FotoFlexer’s demo page to see some of the useful capabilities of the application. FotoFlexer certainly does an excellent job for common photo-editing needs such as cropping, resizing, and rotating. It also integrates with popular web services such as Flickr, Picasa, Photobucket, Facebook, MySpace andmore.
SUMO Paint is a free, online image editor that allows you to edit and create images. It has a Shape tool that gives you the ability to draw unique shapes, a Brush tool with a surprisingly high-quality set of brushes, a Transform tool to help you scale, move, and rotate objects, and much more.
What’s your favorite?
Is your favorite web-based image editor not on the list? Share it with us in the comments, along with your experience and why you like it over other web-based image editors.
Soon after the hackers made first successful attempts of porting Siri to iPhone 4, iPod Touch & 3GS, it was obvious that more is coming.
After a sufficient amount of reverse engineering, enough understanding has been made regarding the Siri Protocol. To tap the app communication with the cloud, hackers setup a rogue DNS server that manipulates and tracks the interactions.
Siri communicates with server at port 443, to a server at 17.174.4.4 which is nothing but https://guzzoni.apple.com. The connection, obviously, is over https that uses SSL certificates to verify if the domain and the client are both authentic. Hackers managed to create custom SSL certification authority, added it to their iPhone 4S, then used it to sign their own certificate for a fake “guzzoni.apple.com”. This proved to be successful – Siri was happily sending commands to a faked HTTPS sever, which, as stated before, can be replicated again and again. Using this data, they managed to understand the data thats transmitted for every command.
Siri’s protocol is opaque. Let’s have a look at a Siri HTTP request. The request’s body is binary but headers look like this:
The request is using a custom “ACE” method, instead of a more usual GET.
The url requested is “/ace”
The Content-Length is nearly 2GB. Which is obviously not conforming to the HTTP standard.
X-Ace-host is some form of GUID. After trying with several iPhone 4Ses, it seems to be tied to the actual device (pretty much like an UDID).
Siri Body payload (binary data)
When Siri binary data is looked in a hex editor, you would notice that it starts with 0xAACCEE. Oh, seems like header ! Unfortunately, nothing after that is readable coz its compressed using zlib.
To be more precise this AACCEE header in the request body is 3 bytes, but actual data payload starts after 4th byte. Unzipping data after 4th byte yields actual data that is sent over the network. Unzipped data still has some binary artifacts plus some human readable text in form of bplist00 i.e. data is some binary plist.
Here is the description of the payload chunks:
Chunks starting with 0x020000xxxx are “plist” packets, xxxx being the size of the binary plist data that follows the header.
Chunks starting with 0x030000xxxx are “ping” packets, sent by the iPhone to Siri’s servers to keep the connection alive. Here xx is the ping sequence number.
Chunks starting with 0x040000xxxx are “pong” packets, sent by Siri’s server as a reply to ping packets. Without surprise, xx is the pong sequence number.
Deciphering the content of binary plists: Its easy, you can do it on Mac OS X with the “plutil” command-line tool. Or in ruby with the CFPropertyList gem on any platform.
How iPhone 4S talks with apple Servers:
The audio data: The iPhone 4S sends raw audio data compressed using the popular VoIP codex Speex audio.
Signature: The iPhone 4S sends identifiers everywhere. So if you want to use Siri on another device, you still need the identfier of at least one iPhone 4S. You would need one of the tools from below tool chain to extract that. But beware, Apple could blacklist an identifier.
The actual content: The protocol is actually very, very network chatty. Your iPhone sends a tons of things to Apple’s servers. And those servers reply an incredible amount of informations. For example, when you’re using text-to-speech, Apple’s server even reply a confidence score and the timestamp of each word.
Writing your own Siri-based Application for Android, iOS
You can download Applidium’s tool chain and get started with your own app that’s Siri enabled.
The future of wireless is very blurry to most users and most can’t figure out what should they buy today to be future proof.
Bluetooth has long been limited to short range P2p connections or short range networks and Wifi had gained popularity for its better throughput for infrastructure toplogies and have failed to be a p2p media. This is set to change with next verisons of Bluetooth and Wifi.
Bluetooth 4.0 vs. Wi-Fi Direct
Both of these new specifications are promising learning from each others mistakes from past. Both have grown up to to make it easier for you to quickly transfer pictures, files and other data between two wireless devices such as your smartphone and laptop without the need for a dedicated device for Wi-Fi.
The Wi-Fi Direct & Bluetooth 4.0 specs confirm that they would gaurantee fast data transfers over long distances between two devices. Wi-Fi Direct promises regular Wi-Fi speeds of up to 250 Mbps, yet,easier to configure than previous ad-hoc modes.
Backward compatibility
Wi-Fi Direct devices will be able to communicate with legacy Wi-Fi devices. That means if your next laptop has a Wi-Fi Direct chip, you will be able to create a device-to-device connection with your old wireless printer or wireless digital picture frame.
Bluetooth 4.0 includes a power-saving feature called “low-energy technology.” Actually, Bluetooth 4.0 is three Bluetooth specs in one. Bluetooth 4.0 not only uses the new low-energy technology, but also relies on high-speed data transfers introduced in Bluetooth 3.0 and so-called classic Bluetooth technology found in older Bluetooth specifications. However, the worst part is that Bluetooth 4.0′s low-energy technology is not compatible with existing Bluetooth devices, which in all ways is weird.
However, the rescue is in hands of manufacturers who could incorporate low-energy technology into a newer device using Bluetooth 2.1 or Bluetooth 3.0.
Speed
Wi-Fi Direct goes up to 250Mbps, while Bluetooth 4.0 would provide up to 25Mbps (similar to Bluetooth 3.0).
Network Range:
Wi-Fi Direct devices can reach each other at a maximum distance of 656 feet (more than two football fields) away. So, practically, even if it is half of that, it would connect all your devices across home, no matter how big is your place.
Bluetooth 4.0′s maximum range is not dependent on the specification, but on the capabilities of the Bluetooth device. So as per manufacturers, a distance of at least 200 feet for a Bluetooth 4.0 device is something we would expect.
Power consumption:
Both claim to be of low power, but the question is how low?
The Bluetooth 4.0 uses the new low-energy technology (PDF) feature. What this means is that it can run for a year using a coin cell battery alone. However, such power mangement is only applicable when transferring short bursts of data. And not to forget, it would work with newer devices only.
The Wi-Fi Alliance says Wi-Fi Direct devices can support the WMM Power Save program that promises to improve a device’s battery life by 15 to 40 percent over current 802.11n popular wifi standard. That means it would still consume 100mW or so.
Security
Wifi & bluetooth have suffered poor security in the past, but this is going to change with taping inherent security. Bluetooth 4.0 uses AES 128-bit encryption, while Wi-Fi Direct relies on WPA2 security, an AES 256-bit encryption. Both look great on this.
Availability
Bluetooth 4.0 products should start hitting the market before the end of the year or early 2011. But it looks like Wi-Fi Direct may be first out the gate. The Wi-Fi Alliance recently announced that five wireless networking PC cards from Atheros, Broadcom, Intel, Ralink and Realtek are Wi-Fi Direct ready and should be available before the end of the year.
DLNA® and Wi-Fi Direct Make It Easier Than Ever for Consumers to Connect Devices
PORTLAND, Ore., Nov. 15, 2011 /PRNewswire/ -- The Digital Living Network Alliance® (DLNA®) today announced that Wi-Fi CERTIFIED Wi-Fi Direct has been incorporated into its Interoperability Guidelines. Wi-Fi Direct is a certification by the Wi-Fi Alliance® for products that are capable of device-to-device connections without the presence of a traditional home, office or hotspot network. Through incorporation into the DLNA Interoperability Guidelines, Wi-Fi Direct will expand on the existing Wi-Fi CERTIFIED devices supported by DLNA to enhance wireless connectivity for consumers globally.
"Wi-Fi Direct meets an important need for today's consumers to enjoy seamless product interoperability," said Nidhish Parikh, chairman and president of DLNA. "DLNA has supported Wi-Fi CERTIFIED devices since 2005 and the inclusion of Wi-Fi Direct in our Interoperability Guidelines is a logical extension of our relationship with the Wi-Fi Alliance. We continue to advance the connected home by providing consumers with new, innovative ways to connect and enjoy their digital content."
ABI Research recently examined key market and technology trends for the integration of home networking capability in mobile devices and expects DLNA Certified® and Wi-Fi CERTIFIED Wi-Fi Direct smartphones to grow strongly through 2016. The firm stated that both will help consumers when connecting devices at home and will bring wireless technology further into the mainstream market.
"Worldwide demand for interoperable, security-protected Wi-Fi® products has grown exponentially in recent years, and the device-to-device usages enabled by Wi-Fi Direct are fundamental to digital home usages for Wi-Fi," said Edgar Figueroa, CEO of Wi-Fi Alliance. "Wi-Fi continues to evolve and to enhance the connected consumer experience. The incorporation of Wi-Fi Direct into the DLNA Interoperability Guidelines will aid the proliferation of Wi-Fi Direct in today's connected home."
DLNA and the Wi-Fi Alliance are also jointly distributing a holiday edition Gadget Guide (http://www.nxtbook.com/nxtbooks/wifi/gadgetguide_dlnawfa) which highlights great DLNA Certified® and Wi-Fi CERTIFIED gift ideas available today for consumer purchase. The 2011 Wi-Fi® and DLNA® Gadget Guide: Holiday Edition is available now.
About DLNA
Members of Digital Living Network Alliance (DLNA) share a vision of an interoperable network of personal computers (PC), consumer electronics (CE), mobile devices and service providers in and beyond the home, enabling a seamless environment for sharing and growing new digital media and content services. Founded in 2003, the group established and maintains a platform of interoperability based on open and established industry standards that, when used by manufacturers will support the sharing of media through wired or wireless networks. More than 200 multi-industry companies from around the world have joined DLNA, committing the time and resources necessary to achieve their vision. DLNA's Promoter Members include: ACCESS, AT&T, AwoX, Broadcom, CableLabs, Cisco, Comcast, DIRECTV, DTS, Dolby Laboratories, Ericsson, HP, Huawei, Intel, LG, Microsoft, Motorola, Nokia, Panasonic, PROMISE Technology, Qualcomm, Samsung, Sharp, Sony, Technicolor and Verizon. Additional information about the Alliance, its participating companies and membership benefits is available at www.dlna.org or find the Alliance on Facebook at www.facebook.com/dlnacertified or on Twitter at @DLNA.
About the Wi-Fi Alliance
The Wi-Fi Alliance is a global non-profit industry association of hundreds of leading companies devoted to seamless connectivity. With technology development, market building, and regulatory programs, the Wi-Fi Alliance has enabled widespread adoption of Wi-Fi worldwide.
The Wi-Fi CERTIFIED program was launched in March 2000. It provides a widely-recognized designation of interoperability and quality and it helps to ensure that Wi-Fi enabled products deliver the best user experience. The Wi-Fi Alliance has completed more than 11,000 product certifications, encouraging the expanded use of Wi-Fi products and services in new and established markets.
Wi-Fi®, Wi-Fi Alliance®, WMM®, Wi-Fi Protected Access® (WPA), the Wi-Fi CERTIFIED logo, the Wi-Fi logo, the Wi-Fi ZONE logo and the Wi-Fi Protected Setup logo are registered trademarks of the Wi-Fi Alliance. Wi-Fi CERTIFIED, Wi-Fi Direct, Wi-Fi Protected Setup, Wi-Fi Multimedia, WPA2 and the Wi-Fi Alliance logo are trademarks of the Wi-Fi Alliance. Additional details on the Wi-Fi Alliance and Wi-Fi CERTIFIED Wi-Fi Direct can be found at http://www.wi-fi.org/Wi-Fi_Direct.php. Follow Wi-Fi Alliance on Twitter @wifialliance.
On wireless computer networks, ad-hoc mode is a method for wireless devices to directly communicate with each other. Operating in ad-hoc mode allows all wireless devices within range of each other to discover and communicate in peer-to-peer fashion without involving central access points (including those built in to broadband wireless routers).
To set up an ad-hoc wireless network, each wireless adapter must be configured for ad-hoc mode versus the alternative infrastructure mode. In addition, all wireless adapters on the ad-hoc network must use the same SSID and the same channel number.
A movie file is called a container. There are several kind of containers but the most common on mobile platforms are:
In order to start playing a movie file right away its metadata contained in the "
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