News Production & Post

AMWA releases AS-11: MXF for Contribution

20 February 2012

The Advanced Media Workflow Association (AMWA) has released AS-11: MXF for Contribution, supported by Kevin Burrows (pictured), DPP. AS-11 specifies a vendor-neutral subset of the MXF file format to use for delivery of finished programming from programme producers and programme distributors to broadcast stations. AS-11 joins the growing list of AMWA Application Specifications that provide constrained versions of MXF standards, with the aim of improving interoperability between equipment from different vendors. The Application Specification was developed by the AMWA to meet a specific need from leading UK broadcasters. Under the auspices of the Digital Production Partnership (DPP), which includes the BBC, ITV andChannel 4, with representation from other broadcasters and independent partners, the Partnership needed a common programme delivery specification for programme material delivered as files. Kevin Burrows, chief technology officer — broadcast and distribution, Channel 4, and chairman of the DPP Technical Standards group explained: “We were looking for a file format that we could use as a programme delivery specification which would be of good enough 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 50Mb/s 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 Programme Delivery, but extended 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 programme 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. Acknowledging that AS-11 is a new 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. “This is a great example of the AWMA working with users to create a Specification in a short timescale,” said Brad Gilmer, executive director of the AMWA. “The DPP and the AMWA adopted a pragmatic approach, and used existing MXF standards to create AS-11 in a timely manner to meet the pressing operational needs of the DPP. The AMWA is pleased to have worked with the DPP to develop this important Application Specification.” Gilmer continued: "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."

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