Animation Shot Frame Ranges Changed

Status: Planned

Summary

This case is very similar to the Shots Added/Removed from the Cut Use Case. The editorial and animation departments are working with a sequence of shots simultaneously over the course of a few weeks. The initial delivery of rendered video clips from animation to editorial provides enough footage for the editor(s) to work with, at least as a starting point. As the cut evolves, the editor(s) may need more frames at the head or tail of some shots, or they may trim frames from the head or tail that are no longer needed. Usually there is an agreement that some extra frames, called handles, should be present at the head and tail of each shot to give the editors some flexibility. In the case where the editors need more frames than the handles provide, they might use a freeze frame effect, or a slow down effect to stretch the clip, or simply repeat a segment of a clip to fill the gap. This is a sign that new revisions of those shots should be animated and rendered with more frames to fill the needs of the cut. Furthermore, as the sequence nears completion, the cut becomes more stable and the cost of rendering frames becomes higher, so there is a desire to trim unused handles from the shots on the animation side. In both cases, we can use OTIO to compare the frame range of each shot between the two departments.

Example

Animation delivers the first pass of 100 shots to editorial. Editorial makes an initial cut of the sequence. In the cut, several shots are trimmed down to less than half of the initial length, but 2 shots need to be extended. Editorial exports an EDL or AAF of the sequence from Avid Media Composer and gives this cut to the animation department. Animation runs a Python script which compares the frame range of each shot used in the cut to the frame range of the most recent take of each shot being animated. Any shot that is too short must be extended and any shot that is more than 12 frames too long can be trimmed down. The revised shots are animated, re-rendered and re-delivered to editorial. Upon receiving these new deliveries, editorial will cut them into the sequence (see also Use Case: Conform New Renders into the Cut). For shots that used timing effects to temporarily extend them, those effects can be removed, since the new version of those shots is now longer.

Features Needed in OTIO

  • EDL reading
    • Clip names for video track
    • Source frame range for each clip
    • Timing effects
  • AAF reading
    • Clip names across all video tracks, subclips, etc.
    • Source frame range for each clip
    • Timing effects
  • Timeline should include (done)
    • a Stack of tracks, each of which is a Sequence
  • Sequence should include (done)
    • a list of Clips
  • Clips should include (done)
    • Name
    • Metadata
    • Timing effects
  • Timing effects
    • Source frame range of each clip as effected by timing effects.
  • Composition
    • Clips in lower tracks that are obscured (totally or partially) by overlapping clips in higher tracks are considered trimmed or hidden.
    • Visible frame range for each clip.

Features of Python Script

  • Use OTIO to read the EDL or AAF
  • Iterate through every Clip in the Timeline, printing its name and visible frame range