Re: OpenTimelineIO meeting agenda 2019-09-05

Joshua Minor

We're looking for AAF expertise in these areas:

1. Our understanding of how to find the timecode associated with a MasterMob has some holes. We have encountered problems like this: and slowly improved based on test cases, but we are not confident in our understanding of how this is supposed to work. Specifically, we use pyaaf2's walk() method and this logic:
to find which segment of media is used in a clip. Most of our confusion revolves around the relationship between a MasterMob, FileSourceMob, PhysicalSourceMob and the various Timecode objects connected to them.

2. Similarly, we have some misunderstandings about how nested clips work, which leads to problems like this: We adopted a two-stage approach to parsing an AAF. First we transcribe the AAF structure verbatim into OTIO, then as a second pass, we simplify the structure into something that more closely resembles what the user sees in the UI of their NLE. This has been reasonably successful, but produces unexpected and undesirable results sometimes. We would rather have a clear understanding of the mapping between the AAF structure and the user's data model, so we can go to our simpler OTIO model in one step.

3. Non-linear timing effects. We have read the AAF Object Specification documentation on OperationDefinitions, and the AAF Edit Protocol documentation on Video Speed Control effects, but neither of these documents have details on the actual Motion Control effects that we find in AAFs exported from Media Composer. Specifically, we are trying to deeply understand the PARAM_SPEED_OFFSET_MAP_U, PARAM_SPEED_MAP_U, and PARAM_OFFSET_MAP_U parameters which seem to hold the critical information about non-linear time warps.

Any advice or expertise on any of these would be tremendously helpful.

Joshua Minor (he-him)
Pixar Studio Tools Story/Editorial/VR Previs Tech Lead

On Sep 5, 2019, at 1:29 PM, Michel Eid <michel.eid@...> wrote:

TX Joshua…
Quick note about:
- Autodesk Flame team has some AAF expertise. Michel will reach out to them to see if they can share any insight/advice.
As discussed, if you can provide me with a list of open questions regarding AAF, this would help me getting the information more rapidly.
From: <otio-discussion@...> on behalf of Joshua Minor <joshm@...>
Reply-To: "otio-discussion@..." <otio-discussion@...>
Date: Thursday, September 5, 2019 at 3:28 PM
To: "otio-discussion@..." <otio-discussion@...>
Subject: Re: [otio-discussion] OpenTimelineIO meeting agenda 2019-09-05
Here are my notes from today's TSC meeting.
Joshua Minor (Pixar)
Robyn Rindge (Pixar)
Eric Reinecke (Netflix)
John Mertic (Linux Foundation)
Michel Eid (Autodesk)
Josh Burnell (Dreamworks)
Sean Wallitsch (Dreamworks)
Next steps in ASWF process
- Meeting with Pixar legal and Linux Foundation legal scheduled for next week.
Topics: Switching to unmodified license, switching to minimal CLA, TSC charter, trademark transfer.
- License scan waiting until after license switch.
- OTIO website - we can talk with Emily Olin when we're ready for this.
Summary & discussion of current OTIO roadmap
- We are using Github's Project page to organize our near-term roadmap
- Main directions include: C++ API, Schema enhancements, AAF adapter, Integration with more 3rd party software
- C++ port was landed in master right after last release (beta 11)
- Pixar is nearly done integrating OTIO C++ into our in-house animation system, Presto.
- Autodesk provided feedback during development, but waiting until there are new features before switching from their in-house implementation.
- Looking for others to test & file bugs & feedback.
- Next release (beta 12) will include C++ core (and some stability improvements related AAF support)
- Some folks have noticed friction when updating to the latest (e.g. pip install's -e option doesn't work).
- Please file bugs & fixes to improve these quality of life issues, they will pay off when we do the next release :)
- Aiming for more robust AAF support.
- Working well for Pixar pipeline, but we have a lot of consistency in our media & compositions. Others finding issues.
- Some bugs are only repeatable with AAF files that cannot be shared publicly.
- Some technical documents provided by Avid are not approved for sharing publicly.
- Continuing discussion with Avid about this.
- Autodesk Flame team has some AAF expertise. Michel will reach out to them to see if they can share any insight/advice.
- Dreamworks working to switch to using OTIO AAF adapter. Seems to be going well.
- OTIO is missing a How-To document that explains how to use AAF in a pipeline.
- Autodesk has native OTIO support on their long term roadmap.
- For near-term Autodesk is committed to more engagement in discussion.
- OTIO plans to land the WIP OTIO RV plugin, aiming development towards the RV plugin rather than the RV adapter.
- Two types of schema improvements on the roadmap: new features & revisions to existing schema.
- Revisions are mainly:
Switching to integers instead of doubles for RationalTime
Revising the time composition model & API to better support time warps, transitions, and queries up/down the composition hierarchy
- Additions include a wide range of new features
Examples: Subtitles, Still Images, Image Sequences, Annotations, etc.
- Priority of these will be driven by community use cases - which ones do you need/want?
- Also heavily influenced by who is willing to do the work.
- Schema changes should be queued up so we don't change too many things at once.
- Integer-based RationalTime is likely to be first.
- Autodesk proposes a universal coordinate system for spatial attributes - especially media size/resolution and compositing effects.
- At some future TSC meeting Autodesk will teach us more about this proposal.
- Netflix is interested in helping to formalize the OTIO spec.
- Eric is now the point person for this. We expect more discussion after some upcoming vacation.
- This is listed on the roadmap project page, but not in active development.
- Volunteers are welcome to work on this :)
3rd Party Integrations
- Media Composer AAF support, and RV support mentioned earlier.
- There is some talk about Nuke Studio & Flix OTIO support - looking for contact/interest from Foundry.
- If there is an app or format that you want to have better OTIO support, please file an issue, or help us make contacts.
Let me know if I missed anything important, or if you have questions about any of this.
Joshua Minor (he-him)
OpenTimelineIO Technical Steering Committee Chairperson

On Sep 4, 2019, at 11:39 PM, Joshua Minor via Lists.Aswf.Io <> wrote:

This week's OpenTimelineIO Technical Steering Committee (TSC) meeting will cover the following topics:

- Summary & discussion of current OTIO roadmap.
- Progress update on AAF support.
- Progress update on RV support.
- Next steps in ASWF process.

Conference call details:

Joshua Minor (he-him)
OpenTimelineIO Technical Steering Committee Chairperson


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