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New contribution spec for MXF files gets AMWA approval

The Advanced Media Workflow Association (AMWA) has released specifications for what it calls a “vendor-neutral subset” of the MXF file format to use for delivery of finished programming from program producers and program distributors to broadcast stations.

The new Application AS-11, MXF Program Contribution (AS-11) joins the growing list of AMWA Application Specifications that provide constrained versions of MXF standards. The group said the overall goal is to improve interoperability between equipment from different vendors.

The Application Specification was developed by the AMWA to meet a specific need from broadcasters in the UK. Under the auspices of the Digital Production Partnership (DPP), which includes BBC, ITV and Channel 4, with representation from other broadcasters and independent partners, the Partnership needed a common program delivery specification for program material delivered as files.

Kevin Burrows, Chief Technology Officer for Broadcast and Distribution at Channel 4 (and chairman of the DPP Technical Standards Group) said they were looking for a file format that they could use as a program delivery specification that would deliver good quality.

“We looked at existing formats and found that the AMWA AS-03 was the closest match to our requirements. However we needed a higher bit rate than the 50Mbps limit of AS-03, and support for the AVC-Intra 100 video codec. We worked with the AMWA to develop a new Application Specification that would meet our needs, and the fruits of this work is the AS-11 specification.”

The AMWA has developed AS-11 to be similar to the existing AS-03, MXF Program Delivery, but extended it to include high definition AVC-Intra 100. AS-11 also includes explicit support for standard definition D-10 video with AES3 audio (compliant with SMPTE ST 386).

AS-11 defines a minimal core metadata set required in all AS-11 files, a program segmentation metadata scheme, and allows for the inclusion of custom shim-specific metadata in the MXF file. Such shims will complement the broadcaster’s technical delivery specification.

Working with the new AS-11 format, the DPP is also developing a desktop application that will allow production companies to add AS-11 metadata to files. It is anticipated that vendors will add native support for the Specification in future software releases.

Brad Gilmer, Executive Director of the AMWA, said, “We believe that work such as AS-11 goes a long way to improving interoperability, both at the metadata and video/audio level. This interoperability is becoming increasingly important as broadcasters and facilities transition to truly tapeless workflows.”