MXF AS02 and IMF: What’s the Difference and Can They Work Together?By admin_lc | 07/02/15
If you read my previous posts about IMF, you will already know what it is and how it works. But one of the questions I often get is “how is IMF different from AS02 and will it replace it? After all, don’t they both claim to provide a solution to versioning problems?”. In a nutshell, the answer is yes, IMF and AS02 are different and no, IMF will not replace AS02; in fact the two complement and enhance each other. Let me explain:
MXF AS02 (for broadcast versioning) and IMF (for movie versioning) grew up at the same time. And while both had very similar requirements in the early stages, we soon ended up in a situation where the level of sophistication required by the broadcasters’ versioning process never really reached critical industry mass. Efforts were continually made to merge the MXF AS02 work and the IMF work to prevent duplication of effort and to ensure that the widest number of interoperable applications could be met with the minimum number of specifications.
When it came to merging the AS02 and IMF work, we looked at the question of what would be a good technical solution for all of the versioning that takes place in an increasingly complex value chain. It was clear that in the studio business there was a need for IMF, and that the technical solution should recognize the scale of the challenge.
It came down to a very simple technical decision, and a simple case of math. AS02 does all of its versioning using binary MXF files, while IMF does all of its versioning using human-readable XML files. There are maybe 20 or 30 really good MXF binary programmers in the world today; XML is much more generic, and there must be hundreds of thousands of top quality XML programmers out there. Given the growing amount of localized versioning that we are now faced with, it makes sense to use a more generic technology like XML to represent the various content versions whilst maintaining the proven AS02 media wrapping to store the essence components.
In a nutshell this is the main difference between AS02 and IMF. Both standards have exactly the same pedigree and aim to solve exactly the same problems, but IMF benefits from a more sophisticated versioning model and therefore requires a greater degree of customization – and XML is a better means of achieving this.
IMF is not going to replace AS02. Rather the goal is to get to a place where we have a standardized IMF package as a means of exchanging versioned packages within the workflow. IMF will actually enhance the AS02 bundles that represent componentized clips that are already ingested, transcoded and interchanged today.