Hi and welcome to the forum
Most of times the culprit is indeed the disc.
Even if in past your drives were able to read these discs, a bad burned disc can happen anyway. If you are using dual layer discs, too bad there is only a brand that produces reliable media: Verbatim. All other brands have a huge variability in quality (never better than a Verbatim however).
Other than a low quality disc, also a wrong burning speed can cause a bad burn.
To exclude an issue in files (maybe clonedvd made some sort of error in compressing files), you can try to play the movie first from hard disk. If there is some sort of error on files, also playback from HDD will give problems. If playback from HDD is good, then the problem is the burned DVD.
What burner do you have? What discs are you using? What burning speed?