*Autobahn HD for OS X coming soon . . .

At Swarmcast, our focus has always been to provide the best online video user experiences while solving the economics of video delivery. It is thus with great pride that we unveil the beta release of Autobahn HD for Flash.

The demand for high quality online video is undeniable. However, content providers are being held back by available players and delivery methods that lack the flexibility and expressive power to support innovative and profitable business models for online video.

Autobahn HD for Flash is the first ever FREE video player platform to feature network acceleration, protect against rebuffering, and ensure that every viewer receives the best video quality, every time.

Developers can get the open code to create or customize their own embeddable, full-screen video player. The Flash platform combined with Autobahn HD will always deliver the best possible user experience.

Developers - get the player source code

To learn more about how Autobahn HD for Flash works, see the posts below.

To support you in showcasing high quality video on your site, for a limited time we’re offering a risk-free hosting trial. That’s right – you use our player or integrate Autobahn HD into your Flash player, and we’ll foot the bill for delivery from several of the top CDNs in the world. You are not required to use our delivery for Autobahn HD, but many CDNs are always faster than one, so why not give it a try.

Please join me in spreading the word about Autobahn HD. I can’t wait to see what new experiences we can bring to online video.

Best,

Justin Chapweske

CEO and Founder

Developers - get the player source code

Today Swarmcast proudly launched Autobahn HD for Flash®, a unique technology that combines the ubiquitous Flash® platform with network acceleration technology and adaptive bitrate streaming to ensure the best possible video quality for every viewer. In this series of postings I’m going to go through the exact steps necessary to get your high quality content delivered through Autobahn HD and things are going to get quite technical pretty quickly, but first let’s look at just what we mean when we say “adaptive bitrate streaming”.

For years Swarmcast has been providing network acceleration technologies which allow Internet users to view high quality content wherever they get an Internet connection. However, “high quality” is a moving target and bitrates are constantly growing. When encoding video content for online delivery providers have had three suboptimal options: select the least acceptable bitrate viewable by all of the target audience, pick a high bitrate knowing that only a fraction of the target audience can view it, or offer multiple bitrates and put the selection decision on an end user who may not know Kbps from kibble.

Selecting the right bitrate is made harder because the bandwidth available to end users is far from constant. It varies depending what else they’re doing with their computer, changes as a result of the actions of other computers on their network, and is even sensitive to radio interference if they’re using wireless. Picking the right initial bitrate is hard for you, the provider, or them, the user; being certain that the bitrate will be the correct one throughout playback is impossible.

Adaptive Bitrate Streaming eliminates the necessity if picking a bit rate. Your content gets encoded at multiple bitrates, and your viewers seamlessly switch from one to another during playback according to their available bandwidth. Viewers won’t see rebuffering caused by too high a bitrate, and they won’t watch grainy video when they could be watching your higher quality encodings.

Our Adaptive Bitrate Streaming is the only system that works without requiring a custom media player, file format, and media server. Everything is standard Adobe® Flash® served from any HTTP server. In the next post we’ll look at the steps necessary to make your content available for Adaptive Bitrate Streaming through Autobahn.

Developers - get the player source code

Autobahn HD for Flash® plays standard video encodings using the standard Flash® player from a standard web server. To enable the Adaptive Bitrate Streaming for your content you’ll need to provide some metadata to allow Autobahn to find and choose among the alternate encodings. Before we launch into creating those let’s look at the various moving parts:

Flash Player: Adobe’s Flash® player is available for easy installation as a plug-in for all major browsers on all major platforms.

Flash Encoded Video: Video content stored in Adobe’s FLV format with the .flv extension. Autobahn HD’s Adaptive Bitrate Streaming currently supports both VP6 and Sorensen codecs with more coming soon. All your standard tools for creating FLV files work great with Autobahn HD.

Autobahn HD: Swarmcast’s client side plugin adds Acceleration, Adaptive Bitrate Streaming, and Playback Skip-Ahead to the Flash video experience.

Autobahn HD Player for Flash: Our Flash based video player uses Autobahn HD to provide robust playback with enhanced features. It can be used as a basis for your own player or as an example of how your Flash player can take advantage of the advances made possible using Autobahn HD.

Media Group Descriptor: An XML document that describes all the available encodings for a piece of content (the media group), their bitrates, and the location of each one’s Swarmcast Media Metadata file.

Swarmcast Media Metadata: A file with the .smm extension that provides information about a specific video file necessary to switch into that encoded video during playback and is created using the Swarmcast Media Indexer.

Swarmcast Media Indexer: Provided by Swarmcast the tool creates Swarmcast Media Metadata files from encoded videos.

Web Server: All the encoded videos, Media Group Descriptors, and Swarmcast Media Metadata files need to be hosted on a standard HTTP server such as Apache or IIS. There’s no custom server side software or configuration required at all. If you’re looking for help hosting your HD files economically contact us and we can help you out.

Whew. That might seem like a lot of required components, but most of them you already have the rest are easily created using free tools Swarmcast provides.

Now, let’s take a look at the steps required to make your video available through Autobahn HD. They might seem involved at first, but fear not, nothing below is outside the comfort zone of any web developer worth his or her salt.

Step 1: Create multiple FLV encodings of your video asset and upload them to your web server.

Step 2: Create a Swarmcast Media Metadata file for each of your encodings and upload them to your web server.

Step 3: Use the Swarmcast Player Wizard to create a Media Group Descriptor and Embed/Object tag and place it on your web page.

We’ll take a look at each of those steps in detail subsequent postings.

Developers - get the player source code

The Adaptive Bitrate Streaming enabled by Autobahn HD makes sure viewers always see the best available encoding for their current network conditions. It doesn’t, however, do real-time transcoding on the fly. Instead it relies on multiple encodings of the same content, collectively called a Media Group.

When assembling a media group start with the highest bitrate you’re able to support with your source content and willing to support on your playback site. Using Adobe or third party tools create a FLV video using VP6 or Sorensen encoding with the desired audio and video bitrates. Continue by creating additional encodings of the same video, decreasing the video bitrate by 200 or 300 Kbps each step. Bitrates should be even multiples of 100 Kbps.

It’s best to leave the audio bitrate the same across all the encodings as viewers notice shifts in audio quality much more than those in video quality. As you decrease the video bitrate you may find it necessary to decrease the frame size/resolution in pixels to maintain an acceptable viewing experience. It is helpful but not required that filenames of the various encodings be identical but for the bitrate and possibly screen resolution. Whether you include the bitrate in the filename or opt not to, do make sure you note the exact bitrate in kilobits per second for each file as they’ll be required later.

For example, if you have a source video named ElephantsDream.mov with a bitrate of 5Mbps and you would like the highest bitrate available for viewing to be 1.5 Mbps you would use your transcoding tool to produce the following files:

• ElephantsDreamAbbr_1280x720_vp6_1400Kbps.flv
• ElephantsDreamAbbr_1280x720_vp6_1200Kbps.flv
• ElephantsDreamAbbr_1280x720_vp6_800Kbps.flv
• ElephantsDreamAbbr_320x180_vp6_500Kbps.flv

With each containing the same content at the bitrate and resolution indicated in the filename.Once you’ve created the components of your Media Group upload them to your standard Web Server — there is no need for custom server software or configuration. Acceleration is only possible if your server supports HTTP Range: requests, which is standard for all modern HTTP servers.

With the files uploaded make note of the URLs where each file can be accessed as determined by your web server’s hostname and configuration. In our example the four files identified above correspond to these URLs:

• http://showcase.swarmcast.com/ElephantsDreamAbbr_1280x720_vp6_1400Kbps.flv
• http://showcase.swarmcast.com/ElephantsDreamAbbr_1280x720_vp6_1200Kbps.flv
• http://showcase.swarmcast.com/ElephantsDreamAbbr_1280x720_vp6_800Kbps.flv
• http://showcase.swarmcast.com/ElephantsDreamAbbr_320x180_vp6_500Kbps.flv

All of the files referenced above can be found in the archive at http://showcase.swarmcast.com/AutobahnAdaptiveBitrateStreamingExample.zip.Next: Step 2: Create a Swarmcast Media Metadata file for each of your encodings and upload them to your web server.

Developers - get the player source code

In the previous post we learned how to create multiple encodings of our Elephants Dream video to provide playback options for Adaptive Bitrate Streaming. In this step we’ll learn how to create the Swarmcast Media Metadata files necessary for Autobahn HD to allow switching amongst the videos during playback.

Begin by downloading the Swarmcast Media Indexer tool. Within the Swarmcast Media Indexer archive you’ll find a Java application and within the directory or folder named bin the generateSwarmcastMediaMetadata.cmd and generateSwarmcastMediaMetadata command line scripts necessary to run the application on Windows and UNIX-like operating systems, respectively.

On either platform the script takes a single argument, the filepath to the FLV file to be indexed. Upon completion of the Swarmcast Media Indexer invocation a Swarmcast Media Metadata file with the same name as the input FLV and the “.smm” extension will be present on disk. Running the Swarmcast Media Indexer with the “-h” option will display full command line help.

For example, an invocation of the command: “generateSwarmcastMediaMetadata ElephantsDreamAbbr_1280x720_vp6_1400Kbps.flv” will create a Swarmcast Metadata Metadata file named “ElephantsDreamAbbr_1280x720_vp6_1400Kbps.smm“. The resulting file is much smaller than the original FLV because it contains only select information about the original file.

Once you have created a Swarmcast Media Metadata file for each of the FLV files in the Media Group upload them to your web server and make note of their corresponding URLs. It is customary to place them in the same folder on the same server as the FLV files, but it is not required. All of the files referenced above can be found in the archive at http://showcase.swarmcast.com/AutobahnAdaptiveBitrateStreamingExample.zip. So long as the Swarmcast Media Metadata files are available at known web addresses you’re ready for the next step: Using the Swarmcast Player Wizard.

Developers - get the player source code

In Step 1 you created multiple encodings of your content for Adaptive Bitrate Streaming, and in Step 2 you created the Swarmcast Media Metadata files necessary to allow real-time switching amongst them. In this Step we’ll tie the various components of our Media Group together by creating a Media Group Descriptor using the Swarmcast Player Wizard and playing it with the

The Swarmcast Player Wizard is an online tool which creates both the Media Group Descriptor XML documents and the HTML snippets used to embed the Autobahn HD Player on any web page. The Swarmcast Player Wizard can be found at http://getautobahn.com/developers/wizard and is shown in the image below.

Each horizontal line in the “Setup Videos” step, corresponds to one of the videos created in Step 1 of this tutorial. The “Video URL” column is the web address of one of the FLV encoded videos. The “Bitrate (Kbps)” column is the combined audio and video bitrate you selected while encoding each video, and the “SMM URL” is the web address of the Swarmcast Media Metadata file corresponding to the FLV in column one, as generated in Step 2. More lines can be obtained by clicking the ‘Add Video’ button. One video must have its ‘Default’ checkbox checked indicated it’s the video that will be shown to viewers without Autobahn HD. It is recommended that you make your lowest bitrate video the default. After completing the “Setup Videos” form click the “Next” button in the bottom right.

You’ll now see your Media Group Descriptor file in a scrollable text box. Copy it to clip board or download it using the provided buttons. If you’ve copied the descriptor to your clipboard paste it into a new text document and save it with an appropriate name for your Media Group, for our example we’ll use ElephantsDreamAbbr.xml. Once you have your Media Group Descriptor on disk you’ll need to upload it to your web server. Put the URL for the resulting file, in our example http://showcase.swarmcast.com/ElephantsDreamAbbr.xml, into the “Media Group URL” input field and click “Next”.

Step 3 of 4 allows you provide some basic parameters that affect the appearance of the embedded Swarmcast HD Player. All fields, excepting width and height, are optional. The “Autoplay” check box specifies whether or not the embedded video should begin playing as soon as the user arrives at the page. The “Image URL” field provides the location of a static image to display when the video is not playing. Any provided “Caption Text” is displayed as a title for the video. The “Background Color” hex triplet is used to allow the embedded Autobahn HD Player to blend into the web page onto which it is placed.

After filling out the appearance and behavior settings in step 3 and clicking “Next” the Object/Embed tags are displayed in the scrolling text box. These tags can be copied and pasted into most any web page to embed a full featured Autobahn HD Player with Adaptive Bitrate Streaming. If you prefer the SWFObject option at the top my be selected to provide embeddable javascript code that is more flexible than the Object/Embed tags but cannot be embedded into web pages without also being able to modify the page’s <head> tag. All of the files referenced above can be found in the archive at http://showcase.swarmcast.com/AutobahnAdaptiveBitrateStreamingExample.zip.

It should be noted that the Adaptive Bitrate Streaming and other features of Autobahn HD are not limited to use within the Autobahn HD Player. In the future we’ll be posting a series of entries showing how Autobahn HD’s Adaptive Bitrate Streaming can be included in the Flash based Media Player of your own authoring.