I found that it only occurred with 'some' hap codecs... so you could try the others, however, recording to Hap isn't recommended as its is rather CPU heavy, and this may be why the speed isn't correct (frames may drop if not compressed in time).

 @callie 

Certainly this is a bug and we will fix it as soon as we can manage. However, it simply comes down to this: compressing a HAP frame generally takes way longer than a the the frame time to accomplish. In other words, if you're running at Isadora at 30fps the frame time is 1/30 = 0.033 seconds. If it takes 0.1 seconds to compress a frame, then 0.1 / 0.33 = approx 3 Isadora frames will pass before the next frame is compressed. Isadora should realize this and insert 3 frames of the same material, but instead it inserts 1 and when it plays back it's too fast. In the end, HAP is not a good codec for real time capture.

That's why @DusX is recommending the Blackmagic codecs, as they take far less time to compress and will thus should give you a proper frame rate when you play back the recording. Try them and let us know here how it works for you.

Best Wishes,
Mark

You can get the Desktop Video package at: https://www.blackmagicdesign.c...