Diagonal lines through media

[Spencer5D5E]

I have media in my timelines that is fine and as it should be...then all of a sudden when I open the project there are media clips with horizontal lines through part of if where the media drops out and is just black for the remainer of the clip. Sometimes I find that it is linked to the wrong clip, other times it is linked to the right clip but is not translated correctly in the project. 

I shot with a Canon C100 and I feel like part of the problem is the way the media is created/stored, being zipped in an AVCHD file. For instance, the AVCHD file, when unzipped by selecting "show package contents" I can see there are multiple media files in the 'STREAM' folder. In premiere it just references the one clip of the AVCHD file. Not sure if that has anything to do with the problem, but it is strange how Premiere handles those folders/files.

I'm running a MacBook Pro with Apple M2 Max chip, Sonoma 14.3 OS. With PremierePro 2024 version 24.1.0.

Any thoughts or ideas are much appreciate on how to fix this issue. 

[Bruce Bullis · Accepted solution]

We call those lines, "danger bars". 🙂

For media from cameras which create "spanned media" (if a file is >4gb, the camera spawns a new file to contain the next 4gb), it's important to use PPro's Media Browser to view and import that media. 

If you just drag-n-drop or use File --> Import, PPro will still successfully import the media files you're selecting...but only the Media Browser is smart enough to see the (camera-specific) metadata indicating whether those files were actually all part of the same asset. 

From personal experience; My old Panasonic would always generate files with the same name (00000.MTS), so I ended up with dozens of files with the same name, sometimes getting used in the same project. Under such conditions, it can be easy to relink media to the wrong instance of [files with the same name]; if there was more media in the first version of the file used, then the additional portions of media from that (re-linked) file will show 'danger bars' in the timeline.