Laggy proxy on save-load

When I start a new project, move a video onto the timeline and create a proxy for it, browsing through it and fastforwarding/browsing frames is very smooth. However when I save the .MLT and load it again (after closing just the project or whole Shotcut) it becomes laggy, as in it takes a while to load the specific frame after I select it on timeline. I thought I have to regenerate proxies after every closing but this does not help, it just stays laggy up until I drop a new video file onto the timeline and make a proxy for it (then it’s smooth only for the new clip).

Am I doing something wrong or is it a bug?

I’m on the newest, 23.11.29 version of Shotcut, no plugins and only a single clip in the timeline. I don’t have anything “enabled” in Settings → Proxy, I make them manually for every clip. They are saved in project folder.

Can you provide a screenshot of the video properties before and after saving the .mlt

First is before saving the project (I generated the proxy with “Make proxy” button, but it doesn’t shhow the “(PROXY)” in file’s name for some reason), second is after opening it again.
No difference between them from what I see yet browsing in the reloaded project takes way much more time than before.

The (Proxy) thingy shows up only whhen I generate it after choosing the option to create proxies automatically. The video is not added to the playist, only to the timeline, if this changes anythihng

That button creates a proxy but I’m not sure if that then gets used in the current project. How about just enabling Proxies from the outset? Maybe test it that way?


I did as you said, the proxy has been generated smoothly but now only the first couple of minutes is played in Shotcut, after certain point the timeline is progressing forward but the preview image is just stuck on a frame. Timeline pointer is showint the exact spot preview stops moving despite movement in timeline, no matter if I click anywhere else it’s just stuck, no sound or video.

When you brought the video into Shotcut did it ask you to convert it? If not, create a new project and then click the Convert button, play it and see if that improves playback

I only dragged the file from file explorer onto the timeline and it started making proxy immediately, nothing about conversion. Do I need to change anything in the Convert menu? Is it only for editing or does it replace the original clip in export? Should I convert the proxy or the original mp4?

I ended up deleting that possibly broken clip in project, saved the mlt, deleted the proxy mp4 file manually, reopened the project, dragged the original mp4 onto the timeline so the proxy was created automatically again and now it’s smooth before and after saving. Maybe the proxy was generated with a bug or something, I’m not sure how Shotcut makes them. I’d be grateful for more info about the Convert things from message above though :slight_smile:

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