White Papers%5coptibase H

Danna Bethlehem

H.264: The New MPEG Standard

MPEG-4 OVERVIEW

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H.264: MAKING MPEG-4 BETTER

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H.264 PROFILES

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OPTIBASE’S H.264 OFFERINGS

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KEY FEATURES

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MPEG-4 Overview MPEG-4 (ISO14496) is an ISO/IEC standard developed by MPEG (Moving Picture Experts Group). The first version of the MPEG-4 standard was finalized in October 1998 and became an international standard at the beginning of 1999. Although defined as one standard, MPEG-4 is actually a set of compression/decompression formats and streaming technologies that address the need for distributing rich interactive media over narrow and broadband networks. Since the first MPEG-4 standard was finalized in 1999, there have been several efforts on the part of other standards bodies to further improve and enhance the existing MPEG-4 standard. One of these efforts has led to a new MPEG-4 based video compression standard known as H.264 (also known as MPEG-4 Part 10, MPEG-4 AVC, MPEG-4 JVT or H.26L (L standing for Long). Finalization of the H.264 standard was approved by a joint team of experts from the ITU ((International Telecommunications Union) and the ISO (International Standards Organization). The combined team is known as the Joint Video Team or JVT. The video compression standard, which the JVT is working on, will be recommended by the ITU in an ITU-T recommendation and will be approved by the ISO as an international ISO standard.

H.264: Making MPEG-4 Better The original MPEG-4 standard was designed to address the following issues: •

Interoperability. The standard is not specific to any one platform but is designed for all platforms.

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Transport Independence. MPEG-4 leaves the choice of transport mechanism up to the service provider. This allows MPEG-4 to be used in a wide range of networking environments.

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Compression and Transmission of Rich Media. MPEG-4 has been designed for the low and mid bit-rate compression and transmission of rich media streams.

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Interactivity. MPEG-4 allows content authors and viewers to influence how they interact with a stream.

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Scalability. MPEG-4 allows for flexibility in the way multimedia streams are decoded. Decoding bit rate and resolution of content is adapted to the networking environment and display device. This quality is necessary when transmitting rich media over heterogeneous networks, as well as for applications where the receiver is

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not capable of displaying the full resolution or full quality images. •

Profiles. MPEG-4 offers different technology profiles for different applications. In this way, service providers need not use the entire set of technologies, but only the subset that suits their applications needs.

The JVT has set out several enhancements, which it wishes to achieve in the H.264 standard. These are: •

To simplify the design using well-known building blocks

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To improve the compression performance and reach a 50% or greater bit rate savings from H.263v2 or MPEG-4 Advanced Simple Profile at all bit rates

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Support a flexible application that is appropriate to a variety of services, including low delay (e.g., no B pictures) for real-time conversational services and higher delay appropriate for storage or sever-based streaming applications.

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Ensure network friendliness through ease of packetization, information priority control and application to video streaming services.

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Ensure error resilience through packet loss resilience and mobile channel corruption resilience.

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Full specification of decoding by resolving the mismatch problem (e.g., integer transform, VQ,)

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Performance improvements at higher bitrates

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File storage support that includes simple stream exchange, http streaming service, random access and multiple streams with transitions.1

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Terms of Reference for Joint Video (JVT) Activities, as published on the ITU’s website at http://www.itu.int/ITU-T/studygroups/com16/jvt/

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H.264 Profiles Video In contrast to MPEG-4 with its many profiles, H.264 has three profiles, as outlined below: Profile

Target Application

Decoder Complexity over MPEG-2

Estimated Improved Efficiency over MPEG-2

Baseline Profile

Low delay, video phone,

2.5 times more complex

1.5 times better

Extended Profile

mobile, streaming

3.5 times more complex

1.75 times better

Main Profile

Interlaced video applications, broadcast, packaged media

4 times more complex

2.0 times better2

Audio MPEG-4 uses a compression format known as AAC (Advanced Audio Coding). To give an idea on AAC’s efficiency: In contrast to MPEG-1 Layer 2 which produces near CD quality at 128kbit/s/channel, AAC can produce the same results at 64kb/s/channel. AAC supports coding 5.1 and 7.1-channel surround sound effectively. AAC has recently been extended with a technique called Spectral Bandwidth Replication, which significantly improves bandwidth savings for applications like Internet Audio and digital broadcast. AAC with SBR, which is also known as “High Efficiency AAC”, can deliver high quality stereo audio at 48kbit/s. AAC Features: •

Multichannel Support: In addition to mono and stereo, AAC supports various surround sound configurations (e.g. 5.1 or 7.1 channels), up to 48 audio channels.

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Low Computational Complexity: Most AAC encoder implementations are real-time capable.

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Wide Application Range: AAC supports a large set of audio sample rates, ranging from 8 kHz up to 96 kHz, making it ideal for high quality audio in many applications with limited channel or memory capacities.

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As published on the MP4 (MPEG Industry Forum) at http://www.m4if.org/public/documents/vault/m4-out-30035.pdf

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Optibase’s H.264 Offerings Optibase's MPEG-4 AVC/H.264 encoding module enables live encoding and transcoding of next generation CODECs with Optibase's MGW IPTV platforms. The MPEG-4 AVC module is a high-performance real-time encoder that can process any analog, digital or DVB (MPEG-2) video input into MPEG-4 AVC. This module is part of a system specifically designed to address applications where high availability, full redundancy and no single point of failure are all crucial parameters. Key Features Codec Flexibility Each MPEG-4 module utilizes a strong set of on-board state-of-the-art DSP processors with the ability to encode and multiplex video and audio streams based on the MPEG-4 AVC/H.264 industry standard. The MPEG-4 module is software upgradeable to other next generation algorithms such as VC1. MPEG-2 DVB-ASI Transcoding Service providers that already support MPEG-2 signals from satellite TV feeds can now process these same channels into MPEG-4 AVC without changing their existing head-end infrastructure. The MPEG-4 AVC module has on-board transcoding capabilities and requires no additional video decoding or processing components. Carrier-grade Design Each module in Optibase's IPTV platforms is a stand-alone unit, controlled through a dual-star IP backplane and totally independent from other encoding modules. A realtime operating system controls each module separately, assuring constant streaming of live TV content. Modules can be configured to 1+1 and N+K redundancy according to application demands. All parts are hot swappable and support hot-standby redundancy. Main and Baseline Profile Through its ability to encode Baseline and Main profiles, the same MPEG-4 AVC module can address low resolution and low bit-rate applications. The Baseline profile provides very low latency (mandatory for military and surveillance applications) and dramatically low video bitrates (ideal for mobile and PC streaming).

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