Timestamps unset?

[koberulz]

When trying to do anything in FFMPEG with my MKV rips, it gives me the error "Timestamps are unset in stream 0", followed by "pts has no value" repeatedly. I don't think I've ever seen this before so I'm guessing it's only an issue with the most recent version, because I've tried multiple discs and they're all behaving the same way.

As a result I'm unable to edit or convert my rips at all.

[Woodstock]

What type streams are being complained about? Some won't have timestamps (LPCM comes to mind).