Today’s guest post is from Kate Murray, Digital Projects Coordinator in the Digital Collections Management and Services Division at the Library of Congress.
The Federal Agencies Digital Guidelines Initiative (FADGI) AudioVisual working group is pleased to announce new resources to support diverse digital preservation workflows using the open source FFV1 video encoding. FADGI, through its membership in SMPTE (Society of Motion Picture and Television Engineers), sponsored the development of mapping FFV1 into MXF along with a variety of sample files for testing and research.
FFV1, standardized by IETF (Internet Engineering Task Force) as RFC 9043: FFV1 Video Coding Format Versions 0, 1, and 3 in August 2021, is designed to support a wide range of lossless intra-frame video applications such as long-term audiovisual preservation, scientific imaging, screen recording, and other video encoding scenarios that seek to avoid the generational loss of lossy video encodings.
MXF, short for the Material Exchange Format, is standardized by SMPTE in SMPTE ST 377-1 and related documents. FADGI previously sponsored SMPTE RDD 48 which specifies a vendor-neutral subset of the MXF file format for the long-term archiving and preservation of moving image and other audiovisual content, including all forms of ancillary data, together with associated materials. Among other features, RDD 48 defines a means for the carriage and labeling of multiple timecodes and audio tracks; the handling of captions, subtitles, and Timed Text; a minimal core metadata set; program segmentation metadata; and embedded content integrity data.
RDD 48 Amendment 1 adds a “mapping” of FFV1 to the MXF Generic Container for the first time. In this sense, a mapping is basically instructions for encoders and decoders to understand how to interpret the video essence content within the file. RDD 48 already spells out these instructions for lossy or lossless JPEG2000 and uncompressed video. Part of this mapping includes defining ULs or Universal Labels for specific points of metadata and registering these labels for global use. Examples of these labels define the video essence as frame-wrapped or clip-wrapped, the version of FFV1, and the maximum bitrate. Although these labels are defined within the RDD 48 framework, users of any flavor of MXF can make use of the ULs to create, validate or otherwise use the FFV1 encoding within an MXF wrapper.
To support testing and development for additional tools for FFV1 in MXF, FADGI sponsored a set of sample files created by Oliver Morgan of Metaglue. These sample files represent a variety of components including a variety of constructions including standard definition (SD) and high definition (HD); interlaced and progressive; and a range of frame rates, all with timecode, captions and CRC fixity data. The files have valid UL and descriptor content based on RDD 48 Amd 1.
FADGI’s free, open source application embARC (metadata embedded for archival content) that enables users to audit, validate and correct embedded metadata is using RDD 48 Amd 1 and the sample files to expand to include FFV1 in MXF. embARC, which currently supports DPX and uncompressed and JPEG video in MXF, is developed and maintained by AVP and PortalMedia.
RDD 48 Amd 1, like the main RDD 48 document, carries a Creative Commons Attribution-Share Alike 4.0 International License (CC BY-SA 4.0). The sample files are in the public domain with rights free imagery data. All products are available at no cost from FADGI.