@carl here's the whiteboard from the design team summit conference on this feature

Maybe Timeline can become ContentTimeline and there can be a new DCPTimeline which uses TimelineView etc.

@carl

I guess the interactions that you want are:

• add a reel break at the playhead position
• move a reel break to the playhead position
• nudge reel breaks around, while looking at the preview
• snap some reel break to the start of a subtitle
• add reels every x minutes

Very impressed with the design team's Saturday Night Fever brainstorming dancefloor.

A note on "snap some reel break to the start of a subtitle":

My understanding is that it's unwise to put subtitles/captions near the start of a DCP. I have assumed that was due to a possible lag in subtitle data getting transmitted to wherever it needs to be so there may be a delay before they start displaying (I assume this would be more of a danger with CCAP captions where the chain from server to audience display is long).

I have also therefore assumed that it might also be a bad idea to put subs/captions close to start of a reel, in case the server/projector doesn't "look ahead" into the next reel and only starts transmitting captions for a reel when the reel starts.

We did have one report a few years ago that a DCP we made with CCAP captions did exhibit this problem - captions did not appear at start of each reel. However, it did turn out that that venue's closed captioning system had some systemic problems, so it was unclear if their report was valid, or a symptom of the other unrelated problems. However, as a precaution, we've tried to avoid captions near start of reels ever since.

Do you think this is a legitimate concern?

Either way, it's more common to make reel breaks on picture cuts, and they only sometimes correspond to subtitle/captions cuts.

So I wonder if it's a good idea to provide a feature to snap reel breaks to start of subtitles, as this might suggest to the user that this is the "right" way place to place reel breaks, when often it may not be.

One other thing: A nice timeline-based UI would of course be great, but for me at least, a simpler timecode-based interface (like the one for markers) would suffice. A "Place reel break at current playhead" button would give visual feedback, rather than having to do it with timecode alone. Moving/nudging reel breaks can be achieved by deleting the old reel break and adding another.

None of this is to say that your design isn't really nice! I'm just saying that, for me at least, having the ability to add custom reel breaks is more important than having a slick UI to do it. If the UI is going to be a fairly major job then, in my personal view, it'd be preferable to add the feature with a more basic interface at first, and then iterate on the UI later.

Maybe UI is simpler than I think, in which case feel free to ignore me. In fact, feel free to ignore me either way! Just giving my 2 cents opinion.

Do you think this is a legitimate concern?

Good point - SMPTE Bv2.1 "specifies" this and says that the first sub/caption in a reel should be at least 4 seconds in.

One other thing: A nice timeline-based UI would of course be great, but for me at least, a simpler timecode-based interface (like the one for markers) would suffice

Another good point. I'm hopeful that a DCP "reel" timeline can basically be a rehash of the content one (using lots of the same code) but let's see. I agree that making one on the markers timeline might be enough.

A tricky UI point here might be what you do when reel boundaries have been set up but then the content is changed somehow so that those reel boundaries become invalid.

Merged this in 2354c1fd781879d215834ebe54661f125fcb324e. There's probably some stuff missing but let's see what people think.