Creating and Serving Content for Mobile Players

Mobile Players such as the Audible Player by Audible, Inc. are an important new class of consumer products that can be used to access and playback RealAudio files. With these new products, you can take audio content in RealAudio format that has been downloaded to a client computer and transfer them to a hand-held Mobile Player that can then playback the content at your convenience. RealEncoder, RealPublisher, and RealServer support the creation and serving of content to Mobile Players such as the Audible Player.

Encoded files can be easily created using the RealEncoder or RealPublisher. These files can then be linked using .ram files on a Web page. When the user clicks on such a link, the RealAudio file is downloaded to the client computer using TCP at a rate faster than the streaming bit-rate. The rate at which this data transfer takes place is configurable by the RealServer administrator.

There are three steps to implementing Mobile Player support:

  1. Encode audio content.
  2. Create the .ram file to use on your Web site.
  3. Configure the RealServer to allow Mobile Player support. (This step need only be done once.)

Encoding Content for Mobile Download

In RealEncoder or RealPublisher, click the Mobile Playback checkbox and encode audio files as usual. The Audible Player supports only the 6.5 Kbps voice codec that is available as part of the RealEncoder and RealPublisher products. Currently, (and in the near future) Mobile Players can only decode and play RealAudio files or .rm files with only-audio data.

If you are using the command-line encoder, you will need to use the /P option. Valid arguments for /P are "0" (disabled) and "1" (enabled).

You can also use the rmedit tool to modify a pre-existing .rm file created using RealEncoder 5.0 and enable it for Mobile Playback. See the RealAudio and RealVideo Content Creation Guide for more information on encoding files with these options.

Creating .ram Files for Mobile Download

To make content downloadable for Mobile Playback, you will need to create a .ram file on your Web server that points to the encoded .rm file and contains the "mobileplayback" .ram file tag. Once the appropriate .rm file has been created you can create a .ram file that contains an entry of the form:

pnm://my.server.com/basepath/file.rm?mobileplayback="1"

where my.server.com is the name of the machine that is running your RealServer, basepath is the location on the machine that contains your .rm files and file.rm is the name of the file you want to make available for Mobile Download. You can also add other .ram file tags such as starttime and endtime to the entry. In addition, you can also create .ram files with multiple URLs as before. With multiple Mobile Download enabled URLs, the files are downloaded in succession to the client computer. If you insert URLs without the mobileplayback .ram file tag, these URLs are streamed to the client player instead of being downloaded.

Leaving the mobileplayback tag out of the .ram file enables you to make the same .rm file streamable (instead of downloadable) to the client computer.

Configuring Servers for Mobile Download

Add the MobilePlaybackOversendRate configuration setting to the server.cfg file. For information on how to do this, see Editing the Configuration File.

The syntax for this variable is as follows:

MobilePlaybackOversendRate

The multiple of the streaming rate that is used to determine the effective bit rate at which the server transfers files to Mobile Playback enabled RealPlayers via TCP. The file is sent via TCP at the effective bit rate or the network bandwidth, whichever is lower.
Default value 10
Range of values 1-100

Syntax
MobilePlaybackOversendRate <number>
Example

To serve 6.5 Kbps encoded files at 19.5 Kbps:

MobilePlaybackOversendRate 3

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