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Khronos offers APIs for mobile TV, audio software

Posted: 25 Jan 2011 ?? ?Print Version ?Bookmark and Share

Keywords:mobile TV API? audio API? Open Max AL 1.1? OpenSL ES 1.1?

The Khronos Group recently launched three new APIs designed to fast track the development of mobile software for audio and digital TV.

The newest interfaces underscore mobile developers' anticipation of a mobile digital TV comeback. They also point to Google's continued push to make Android the leading open alternative to closed mobile platforms from Apple, Microsoft and Research in Motion. Google contributed to the API development while the three companies did not.

Khronos released OpenMax AL 1.1, a broad C language API for mobile systems, as well as an extension to that API targeted at digital TV. In addition, it released OpenSL ES 1.1, an audio API enabling a broad range of features including 3D sound.

"There are a lot of APIs out there that are hardware or software-framework specific, and it can quickly become difficult for application developers to wade through the maze of differences," said Yeshwant Muthusamy, chairman of the Open Max AL group and a technical manager of mobile media in Nokia's architecture group.

"These new APIs try to cut through the clutter so developers can focus on use cases rather than hardware or software platforms without sacrificing the performance of hardware acceleration," Muthusamy said. "We are not bringing brand new functionality, but offering functionality in a single API that is easier to use," he added

Muthusamy understands the frustrations. For its part, Nokia supports Symbian, MeeGo and its Series S40 software platforms on its handsets, and has been rumored to be considering supporting Android and Windows Phone 7.

"We have a lot of confidence in all three [platforms Nokia current supports]," he said. As for Android and Windows 7, he said "they are all good platforms, but I have no information [on whether Nokia will use them]."

A number of mainly chip and systems companies also interested in reducing software support hassles participated in defining the APIs. They include AMD, Creative, Ericsson, Google, Nokia, Nvidia, Qualcomm and SRS Labs Inc.

The APIs are available on the Khronos Web site. SRS is demonstrating working software based on the audio API.

Inside the new APIs >
The Open Max AL API for C language programming on mobile devices comes in two flavors. One profile is for playback devices only, and one is for devices that can play back and record audio, pictures and video.

An extension to the API for digital TV allows programmers to write apps that can run on any mobile TV device whether the device implements mobile TV standards from Europe (DVB-H), South Korea (DMB), Japan (ISDB) or elsewhere.

"As far as I know there isn't a single native API agnostic of all these standards," said Nokia's Muthusamy.

The Java mobile TV API (JSR 272) can run on top of the Khronos API. It requires a Java virtual machine, but the OpenMax AL APIs do not.

In the past, developers lacked a single API for creating a mobile video app on any handset or OS, said Erik Noreke, chairman of the OpenSL ES working group and an independent standards consultant.

"Phone makers had to come up with their own apps and end users had limited choices," said Noreke. "This API opens things up for third parties to write one app for mobile TV, streaming or local media and have it in various flavors for different systems and markets," he said.

Mobile TV has seen better days. After hype that it might be the next big thing in handsets, both Crown Castle and Qualcomm tried and failed to launch mobile TV services in the U.S. Some terrestrial broadcasters are now rolling out mobile TV services using a version of the ATSC standard.

"Based on what I saw at CES, I would say mobile TV is making a comeback," said Muthusamy. "The [handset] hardware is finally beginning to catch up and though you still have a question of bandwidth with 4G networks, that problem is looking smaller," he said.

"There have been chicken-and-egg problems getting all the content and technology pieces together," he added. "But we think mobile TV is not done yet, it just needs to have all the pieces fall into place," he said.

The Khronos API supports broadcast, unicast and multicast video delivery. It defines software objects for video sources, data sources and electronic program guides. It also defines an optional but recommended EPG manager.

The OpenSL ES 1.1 API supports playback of audio content including PCM audio, MIDI ring tones and user interface sounds. It handles audio controls including equalization and 3D effects. It also supports LED and vibrator controls as options.

More specifically, the API supports buffer queues, content pipes, dynamic sources and sinks and metadata for streaming playback. It comes in three profiles, one for playback controls on phones, one for music controls and one for gaming audio.

Android version 2.3 already supports OpenSL ES. SRS showed its 3D audio software running under the new API.

Rick Merritt
EE Times

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