Recording pre-alarm frames are missing

[maddios]

Describe Your Environment

• Version of ZoneMinder [release version, development version, or commit]
  zm version, 1.36.33 (zoneminder_1.36.33~20230126.20-bionic_amd64.deb)
• How you installed ZoneMinder [e.g. PPA, RPMFusion, from-source, etc]
  installed by building from source via OS=ubuntu DIST=bionic utils/packpack/startpackpack.sh then dpkg the resulting build .deb file
• Full name and version of OS
  Ubuntu Bionic 18.04 LTS
• Browser name and version (if this is an issue with the web interface)
  Chrome 108.0.5359.125 (windows 11)

Describe the bug
The issue is since upgrading to 1.36.33 (last night) I noticed all my recorded videos have no frames until the first alarm frame. This was working fine with 1.36.32 (though I was having a separate login issue)
I have it setup to record 100 pre-alarm frames and 100 post-alarm frames. Those 100 pre-alarm frames are frozen and slightly garbled up, I can scrub within the 100 frames and the video is frozen (my camera records sound and I do hear the sound). As soon as the first alarm frame is hit the video is fine that, even any subsequent post alarm frames and secondary alarm frames.

PS: I git checked out 1.36.32 tag, rebuilt and dkpg downgraded to .32 and recordings work again. So I guess there indeed was/is some regression?

Steps to reproduce
Build from source the release_1.36 branch and install it.

Rolling back to 1.36.32 tag fixes the issue.

Debug Logs

Which are the relevant debug logs I should grab for this (zmc?)? I checked all my logs and there is nothing being logged at Error level.

[maddios]

Oh, another thing I just noticed, not sure if it's related but likely.

My camera stream is 5 fps, but the event list shows these bad recordings with WAY too many frames.

example: video duration 1 minute 40 seconds, but it's showing 1920 frames. Should be ~500.

After rolling back to .32 I'm again seeing sane frame counts.

[connortechnology]

Are the recordings done using passthrough? or jpegs?

Would need zmc logs at debug level 4.

[maddios]

These camera is setup as passthrough, jpeg frames disabled.

I'll try to reproduce this again and get you debug logs.