Archival Video Formats According to the Library of Congress

Archival video formats can be a confusing and complicated matter. We get questions frequently asking what formats we recommend for media preservation. One great resource we’ve found is The Library of Congress's Recommended Formats Statement (RFS). This yearly document outlines the preferred formats for the long-term preservation of video content and provides guidance on the selection and use of formats.

The Recommended Formats Statement identifies three categories of video formats: preferred, acceptable, and proxy. Preferred formats are those that are recommended for the long-term preservation of video content due to their stability and ability to withstand technological changes. Acceptable formats are those that may be used for preservation, but are not as reliable or robust as preferred formats. Proxy formats are those that are not recommended for preservation, but may be used for accessing the media when the archival formats are too large or otherwise inaccessible.

The Recommended Formats Statement recommends the use of uncompressed or lightly compressed formats such as IMF, XDCAM HD or higher, and ProRes 422 HQ or higher. These formats provide a high level of image quality and are designed to withstand technological changes.

MPEG-2 is also listed as a recommended format, but only because it has historically been used as a delivery format for digital video used in TV broadcast. We don’t recommend the use of MPEG-2 for any new material that is being created or archived.

For acceptable formats, the Recommended Formats Statement only outlines FFV1, which is a relatively new format that is quickly gaining traction in the archiving community. The Library of Congress expresses concerns over the support for timecode and closed captions alongside FFV1 video. However, it’s worth noting that FFV1 is lossless, while XDCAM and ProRes are not. This means that there are certain circumstances where FFV1 could be the better option.

Proxy formats, such as H.264, are not recommended for preservation due to their higher levels of compression. However, H.264 and similar formats may be used for accessing the material when an archival format is too large or difficult to work with directly.

At Archival Works, we recommend FFV1 for most analog video tape transfers. When closed captions are needed, we suggest either keeping captions in an additional file alongside the FFV1 file, or using ProRes if additional files are not an option.

It’s also worth noting that several formats are noticeably absent from the Recommended Formats Statement. Specifically, all versions of DV are not listed. The DV family of codecs is used by many video transfer companies due to how easy it is to work with. However, DV is largely considered to be obsolete, is poor quality, and the files are fairly bloated. Even the higher quality DV50 is a poor option when you consider modern alternatives such as ProRes or FFV1. This is why Archival Works will only deliver DV if a client specifically asks for it and is aware of the drawbacks and limitations of this legacy format

It is important to carefully consider the video format used for preservation and to regularly migrate content to newer formats to ensure long-term accessibility. The Library of Congress's Recommended Formats Statement provides valuable guidance for those responsible for preserving and providing access to video content.