International organisation for standardisation

18.5MPEG Media Transport (MMT)

According to N10496 issued at the 87th meeting, there is a need for a transport and file format friendly stream format. Error resilience of current MPEG streams might not be optimal. The potential gains of joint optimization of coding and transport are not known. Conversions between different transport mechanisms like from MPEG-2 Transport Stream to MPEG Program Stream are not straight forward or defined. Furthermore, MPEG does not provide any hint on how to adapt content to different networks. Information provided in NAL unit headers is not used optimally in real world implementations. However, previous attempts outside of MPEG showed that MPEG-2 Transport is difficult to replace. Hence, special care has to be taken in order to assure that MMT will find a place in the commercial market.
The area of work for MMT (Figure 6) might include adaptive progressive transport (download/stream), cross layer optimization, hybrid delivery and conversational services. It is foreseen that MMT will also provide adaptive streaming support for mp4 files.

Figure 6 - Networks of interest in the context of MPEG Media Transport

DVB, 3GPP and OIPF indicated interest in the work area. New services in the area of MMT are expected towards the end of 2010. Hence, MPEG expects to issue a Call for Proposals in April of 2010 with a due date in July of 2010.
A second workshop on MMT (N11060 Workshop on MMT (MPEG Modern Transport) – Call for Contributions) with 90 attendees took place at this 91^st meeting. Eight presentations focused mainly on application scenarios, adaptive progressive download and cross layer design. N11200 2nd MMT Workshop in Kyoto: Presentations includes the program and the presentations of the workshop. Main conclusions of the work shop were: Uni- and bidirectional channels have to be considered; buffer sizes and management are not as important as in MPEG-2 development times; requirements are not yet fully understood due to the potentially diverse application scenarios. Initial design goals for an architecture were discussed. These include compatibility and efficiency which is measured in terms of rate, functionality and quality. At this point, a choice of three architectures with different implications is considered (Figure 7, Figure 8, Figure 9).
A set of documents required for the Call for Proposals in April was prepared: N11223 Draft Requirements for MMT (Modern Media Transport), N11224 Draft Call for Proposals on MMT, N11225 Draft Modern Media Transport (MMT) Context and Objectives, N11226 Draft use cases for MMT. They are still in a draft status and require significant work until the next meeting. Until the 92^nd meeting work on MMT is carried out within the File Format Adhoc group.
MPEG is considering combining the upcoming standards for HVC, Audio and MMT into one package.

Figure 7 - Potential architecture for MMT over TCP/UDP and http/RTP