I've got a video in the Video Editor workspace with a Transform effect strip to scale the video and a Speed Control effect strip to double the speed. I added these effects, then found the frames where I wanted the video to start and stop. I've positioned the video so that the start point is at Frame Start for the scene, and it starts there fine. But when I want to take frames off the end, the speed changes. If I turn off "Stretch to input strip length" in the Speed Control and then try to shorten the video, it randomly freezes at some seemingly arbitrary point about halfway through and doesn't finish. How can I avoid these issues?
The UI of the Speed Strips are super unintuitive. I've tried to address the subject matter here without any success: https://developer.blender.org/D6110
There are four ways to change the speed of the strip, using the speed strip options. I hope listing them here will help you and others out:
When "Scale to Length" is unselected, and behaves like the previous setting, but in frame numbers.