Sync playback of multiple files

[memo]

Hi, I love this project and am happy to support it. I was wondering if you would consider synchronized playback of multiple files? This coud be either:

1. Multiple viewports (or windows) side by side playing back different videos synchronized, with a single or synchronized playhead and timeline - so if I pause/play or scrub in one viewport, it's reflected in the other.
2. In a single window, and pgup/pgdown switches between the different files - as it currently is, but with synchronized playhead. So play/pause/scrub is reflected in all open files (or at least those which are marked to be synced).
3. Same as 2, but with a draggable screen divider to compare two videos (I appreciate this is also a major UI addition as opposed to a more backend addition).

Even just having number two would be so useful for comparing takes!

[darbyjohnston]

Hi @memo! Those are good suggestions, unfortunately I have not had time to work on DJV lately. I do have a new project that supports A/B comparison with some of the features you listed:
https://github.com/darbyjohnston/tlRender

It's more of a library aimed at building playback applications, but does come with an example viewer if you don't mind compiling the source code. There is also a commercial application that uses the library and is free to download:
https://www.backlight.co/product/cinesync/download

[memo]

oh thanks, will check them both out.