MPEG-4 Analysis

VLab is considering the implementation of the MPEG 4 standard as a component of the Viewer software, to deliver media.  The MPEG 4 standard has a tool set that includes capabilities that are complementary to VLab's research.  MPEG 4 provides a media architecture that compresses and transmits media, as object types.   The design of VPS just happens to align very well with the design of MPEG 4's multistream architecture.

MPEG-4 provides support for arbitrarily shaped video, the mesh distortion of video, and the integration of three dimensional objects with video.  It provides tools for working with meta-content, including integrating Java.  MPEG 4 is robust in error prone environments such as with multicasting.  It is scalable with fine granularity in its content, spatial resolution, and quality.  MPEG 4 provides the ability to efficiently code multiple views of a scene, exploiting redundancies in the multiple views. This may include a prioritization of objects within the scene.  It also provides structures for return channel data. This architecture is suited to multicast and the multiplexing of media streams.  It is probable that VLab will implement the selective and predictive multicast streaming of media data using the MPEG 4 standard.

What follows are notes that help to define the directions of MPEG 4 companies, and that highlight certain features as they relate to prioritized wide data streaming.
 

High Resolution

2netFX is a company developed by TeraLogic and 3Com, they have developed the multicasting of HDTV over IP, and make use of MPEG 4 as a multicast solution.

Hardware

Vbrick provides a single channel MPEG 4 appliance, this relates with VLab's plans to provide a rackmount appliance for multiple video inputs, for the encoding of immersive environments. This product configuration begins to approach the 180 input head end transcoding systems provided by LSI logic .

Panoramic

Companies supporting MPEG 4 as a streaming solution, may be able to support similar applications that require the multicasting of interactive wide image field video. One such company is iVAST. This company has a player that will support arbitrarily sized and shaped video, as well as ad serving, accounting, e-commence, and digital rights management. Envivo also supports the MPEG 4 main profile, and offers an API. As they provide the MPEG 4 decoder for Real Video, and Real Video supports Be Here's panoramic video environment, this combination is the most likely to develop into a competitive product offering.

Resolution is an important aspect of visual profiles. Resolution is defined by the Common Image Format. The specification defines the maximum number of 16x16-pixel macro-blocks allowed, 4CIF has 1620. 16x16 blocks can be organized into any shape, and any profile compliant player must be able to decode them, although they may display strangely if the output resolution on either axis is greater than what the device supports. So, for QCIF, instead of 176x144-pixel files, you could deliver a 256x96-pixel. The main profile CIF supports 1920 x 1088and any 16 block subset of that.

Low Bandwidth

Tobagi is a company making use of MPEG 4, that is focused on streaming video over wireless. The GMV Network Distributed Media Frameworkª (DMF) is an open standard that supports multicast streaming and reflecting of MPEG 4, primarily for wireless devices. The Wireless companies are oriented to a different product space, though they do provide video optimized for low bandwidth clients

There are also several companies that have developed a suite of video multicasting tools that will logically extent to include MPEG4. Ligos provides serverless streaming video and stream management software. 3CX, with the IXJET Streaming Server, may develop towards MPEG 4 though they are ensconced in the Windows architecture. Kasenna features a server and media management software that supports MPEG 4 through QuickTime.

Profiles

This next portion draws text from a review of MPEG 4 players, by DV magazine:

The Internet Streaming Media Alliance (www.isma.tv)-is a consortium of companies including Apple, Cisco, IBM, Kasenna, Philips, and Sun has created what may become an important standard for MPEG 4 use. Real Networks licenses its MPEG 4 playback from Envivio, which is an ISMA member.

Advanced Simple Profile is a superset of Simple Profile, so it can play all Simple Profile content. Advanced Simple Profile adds a number of enhancements to support better visual quality. These enhancements include B-frames, Global Motion Compensation (GMC), and quarter-pixel motion estimation (compared with half-pixel motion estimation in Simple Profile). Interlaced content is supported at Advanced Simple Level 3 and above. Advanced Simple Level 3 is the video Profile for ISMA Profile 1.

Advanced Simple Profile will likely become the first mainstream MPEG 4 visual Profile for desktop computers, set-top boxes, and other high-power devices.

Simple Scalable Profile adds a single enhancement layer that lets a server dynamically reduce bitrate by lowering image quality, frame rate, and/or resolution. PacketVideo is the only company currently shipping a Simple Scalable Profile authoring tool and player.

Main Profile is targeted at interactive broadcasting, and therefore supports interlaced video.

When broadcasters talk about "the interactive future with MPEG 4," they are referring to the Main Profile. Envivio and iVast have encoding tools and players that support Main Profile's advanced features.