Preview rendering failed, check your parameters

Hey, folks. I’m new here, so hopefully I’m logging this correctly. I’m working on a video in kdenlive, and when you start adding effects to a video, it slows to a crawl, so I added a preview zone to the section that plays back choppy, enabled proxy clips, and I told it to render. I then get the error listed in the title, and it lets me see additional details. When I expand the additional details, I get this:

[mp3 @ 0xa23740] Estimating duration from bitrate, this may be inaccurate[mp3 @ 0xa255c0] Estimating duration from bitrate, this may be inaccurate[swscaler @ 0x7f63051e4400] deprecated pixel format used, make sure you did set range correctly[swscaler @ 0x7f63051f1840] deprecated pixel format used, make sure you did set range correctly[swscaler @ 0x7f63051f1840] deprecated pixel format used, make sure you did set range correctly[swscaler @ 0x7f63051f1840] deprecated pixel format used, make sure you did set range correctly[swscaler @ 0x7f63051f1840] deprecated pixel format used, make sure you did set range correctly

That last line can actually repeat hundreds of times sometimes, but it doesn’t tell me much of anything as to what I’m doing wrong or what I can do to fix it. Googling that error tells me that it’s a warning, not an error, yet it’s certainly acting like an error. Is there anything actionable I can take away from this to fix my preview renders?

I think there are 2 issues. First there is a MP3 clip which is kind of “corrupt”. Second there seems to be a clip which have some format issue.
I suggest you convert both clips to an edit friendly format. Right click in the project bin the affected clip → Transcode to edit friendly format.

The only MP3 file I have in the project is now transcoded, and that warning is gone. However, the place where the preview rendering fails is still failing, and it’s not even on a clip that I imported. I have 3 PNG files that I added to the timeline, essentially a screenshot and two PNGs of a big arrow to point to things in the screenshot. Those are all fine. However, if I create a title clip with a caption for what I’m pointing at in the PNGs, the title clip (a thing created in kdenlive itself) is what causes the preview rendering error.

I ended up resolving this by updating from AppImage 23.04 to 24.02. I don’t usually like to do that mid-project, but it worked this time.