finalised until three years after the publication of the standard) and the nature of these terms has led some commentators to predict that MPEG-4 Visual will not ‘capture’ the market for its target applications. At the same time, it is widely agreed that there is a requirement to find a successor to the popular (but rather old) technology of MPEG-2. Some developers may opt for H.264 and bypass MPEG-4 Visual completely but despite its clear performance advantages (see Chapter 7), H.264 is the less mature of the two standards. There is a continuing debate about whether proprietary CODECs (for example, Microsoft’s Windows Media Player 9 [3]) may offer a better solution than the standards. Developers of proprietary CODECs are not constrained by the tightly-regulated standardisation process and can (arguably) upgrade their technology and respond to industry requirements faster than standards-based vendors. However, reliance on a single supplier (or at least a single primary licensor) is seen by some as a significant disadvantage of proprietary solutions.

8.6 FUTURE DIRECTIONS

Guessing the future commercial and technical evolution of multimedia applications is a notoriously inexact science. For example, videoconferencing (now a mature technology by most standards) is yet to be as widely-adopted as has been predicted; many of the innovative tools that were introduced with the MPEG-4 Visual standard five years ago have yet to make any commercial impact. However, some predictions about the short, medium and long-term development of the technologies described in this book are presented here (many of which may be proved incorrect by the time this book is published!).

In the short term, publication of Recommendation H.264/MPEG-4 Part 10 is likely to be followed by amendment(s) to correct omissions and inaccuracies. A number of ongoing initiatives aim to standardise further transport and storage of MPEG-4 and H.264 coded video data (for example, file and optical disk storage and transport over IP networks). Following the extended (and arguably damaging) delay in agreeing licensing terms for MPEG-4 Visual, it is hoped that terms for H.264 will be finalised shortly after publication of the Standard (hopefully with confirmation of the royalty-free status of the Baseline profile). The ongoing debate about which of the current standard and proprietary coding technologies is the ‘best’ is likely to be resolved in the near future. The main contenders appear to be MPEG-4 Visual, H.264 and Microsoft’s proprietary Windows Media 9 (‘Corona’) format [3].

In the medium term, expect to see new Profiles for H.264 adding support for further applications (for example, Studio and/or Digital Cinema coding) and improved coding performance (probably at the cost of increased processing requirements). For example, there is currently a call for proposals to extend the sample depth supported by the standard to more than eight bits per pixel and to include support for higher chrominance quality (4:2:2 and 4:4:4) [4]. It is difficult to see how MPEG-4 Visual can develop much further, now that the more efficient H.264 is available. The ‘winner’ of the coding technology debate will begin to replace MPEG-2 and H.263 in existing applications such as television broadcasting, home video, videoconferencing and video streaming. Some early mobile video services are based on MPEG-4 Visual but as these services become ubiquitous, H.264 may become a more favoured technology because of its better performance at low bitrates. Widespread adoption of mobile video is likely to lead to new, innovative applications and services as users begin to engage with the technology and adapt it to suit their lifestyles.

In the longer term, expect to see the emergence of new video coding standards as processor performance continues to improve and previously impractical algorithms become feasible in commercial applications. Video coding research continues to be extremely active and there are a number of promising approaches that may finally replace the long-standing DPCM/DCT coding paradigm. These include (among others) model-based, mesh-based and wavelet-based video compression. It has been argued that the DPCM/DCT model has had 15 years of continuous development and is near its performance limit, whereas other techniques offer the possibility of greater potential performance (however, this argument has been circulating for a number of years now and DPCM/DCT is not yet dead!) It is possible that some of the more esoteric features of MPEG-4 Visual (e.g. object-based and mesh-based coding) may re-emerge in future standards alongside improved coding technology. It could be said that these tools are ahead of their time at present and may have more chance of commercial success if and when real application needs become apparent.

8.7 CONCLUSIONS

Years of effort by many hundreds of researchers and developers have led to the standardisation of MPEG-4 Visual and H.264/MPEG-4 Part 10/AVC. The standards are impressive achievements, each in a different way. MPEG-4 Visual adopts an imaginative and far-sighted approach to video compression and many of its features and tools are perhaps still ahead of their time. H.264 has taken a more pragmatic, focused approach to addressing the problems and needs of current and emerging multimedia applications. This book has attempted to explain the fundamentals of both standards and to put them in the context of the goals of the standardisation groups and the ever-changing market. The answer to the much-asked question, ‘which standard is best for my application’, is not yet clear, although there are indications that H.264 may become the technical leader that will drive the next generation of digital video applications. However, before staking a reputation or a product development strategy on the likely outcome of the ‘MPEG-4 vs. H.264’ debate, it is worth remembering a similar debate from the distant past: VHS vs. Betamax.

8.8 REFERENCES

1.MPEG LA, http://www.mpegla.com.

2.Iain E G Richardson, ‘Video Codec Design’, John Wiley & Sons, 2002

3.Microsoft Windows Media 9 Series, http://www.microsoft.com/windows/windowsmedia/.

4.ISO/IEC JTC1/SC29/WG11 N5523, Call for Proposals for Extended Sample Bit Depth and Chroma Format Support in the Advanced Video Coding Standard, March 2003.