I don't misunderstand. The program already has seeking code, and if it needs to aim back slightly so that it can be more precise that's not a massive change to how it already works.
Efficiency is not as important as having the feature at all. "Go back 5 seconds and then run forward to the right frame" is a sufficient algorithm, as long as it can track and combine multiple presses of the previous-frame key. Improvements can come later. Maybe buffering, maybe tracking keyframes, maybe other things. But this is a big case of letting the perfect be the enemy of the good.
If it fails to find a keyframe, that sucks, but 99% of the time it'll work.
Efficiency is not as important as having the feature at all. "Go back 5 seconds and then run forward to the right frame" is a sufficient algorithm, as long as it can track and combine multiple presses of the previous-frame key. Improvements can come later. Maybe buffering, maybe tracking keyframes, maybe other things. But this is a big case of letting the perfect be the enemy of the good.
If it fails to find a keyframe, that sucks, but 99% of the time it'll work.