Allow generating a unique "thumbnail" to represent a project (timeline)
Submitted by Jeff F.T. @jeff
Assigned to Jeff F.T. @jeff
Description
Maybe we could find out a way to "thumbnail a project", to provide a visual representation for our welcome dialog (as part of bug #T3015) and (perhaps, optionally) Nautilus.
Here's an exerpt/summarized version of an IRC discussion around that:
<jimmac> in our weltanschauung mimetypes are not very relevant, we don't present the filesystem to the user anymore
<nekohayo> well, as long as Nautilus still exists...
<mclasen> there's certainly nothing wrong with providing a mime type icon
<jimmac> nothing wrong, sure
<jimmac> [but] i can imagine a thumbnail telling me way more about a sequence than a mimetype icon
<nekohayo> how do you fit a visual representation of 2 hours of timeline into a 128² or 256² space? (and how do you even represent that thing...)
<pippin> "visual rythm"? [...] I am referring to things like: http://moviebarcode.tumblr.com/
<pippin> you can also, instead of just using the same column of pixels throughout the video - scan right (and wrap around when you reach the rightmost one)
<pippin> jimmac: I've experimented with using such a thumbnail in the timeline scrollbars of video editors before. such visual rythm; shows the pace of cuts - other things like zooming in and out in the video/ and fades become very apparent
<nekohayo> project thumbnails would make sense for bug #T3015 I think, but probably not for pitivi project files in nautilus, which I just want them to "look different than plaintext files"
<jimmac> nekohayo, yea if you're falling back to nautilus, you lost :)
<nekohayo> I'm not "falling back" to it, but I'm using nautilus to actually do stuff it's meant for... like moving/renaming/deleting files :)
<nekohayo> pippin, the barcode/visual rhythm approach is very interesting I'd say... the problem is that it would be quite processing intensive, you would have to (frequently) play through the entire timeline to rip out frames and analyze them etc. There's the open question of "when should the thumbnail actually be updated (invalidated)" too
<pippin> nekohayo: the architectural impact is the same as for audio-mipmaps in DAWs
<pippin> a cached render of distilled information; that doesn't have to be up-to-date for the processed result; but it is nice that it is as immediate as possible
<nekohayo> well, imagine a 2 hours long timeline with 20-40 tracks/layers and hundreds of clips, in different file formats (some of which horribly slow to seek etc), and all of that with required 100% trust in the stuff below (GStreamer, gnonlin, etc.) being absolutely bulletproof AND superfast
I can't imagine things not going wrong, if you see what I mean
<pippin> I can eerily imagine that doing this with a gstreamer based stack is trickier than in the video editor I worked on ;p
<nekohayo> and at this point I'm wondering "wouldn't it be much faster and saner to actually take a screenshot of the timeline and save that straight to png?" (for project thumbnailer purposes of course, not a rhythm-scrollbar)... but I don't know, in a gtk4-wayland-enabled world, if that would be possible at all
<nekohayo> I've thought also of "seek to 20%, 40%, 60 and 80% of the timeline and grab the frame there, combine the 4 into a mosaic" too
Imported from https://bugzilla.gnome.org/show_bug.cgi?id=727319