Compressed codecs can slow down your editing

Most lower to mid-range cameras record with codecs that use temporal compression, also known as long-GOP compression.

The simple explanation of a long-GOP is that, for each frame, the codec only captures what has changed between this frame and the previous frame. If the video doesn’t include a lot of motion, then this means that the new file can be a LOT smaller than the original. The difference between this frame and the last frame is just a few pixels, so all you need to store is a few pixels. That’s great!

The issue, however, is that these codecs tend only to work well when played forward. (If you’re curious why, read our the deep dive on codecs). That’s great for viewing on YouTube and your DVD player, but it’s not great for editing, because when you’re editing you’re often jumping around, or playing a clip backward. It takes a lot more processing power to do those things quickly with a long-GOP codec. A high-end computer might have no trouble, but even a mid-range computer will lag and stutter when you skim through the footage quickly or jump around.

Codecs that aren’t long-GOP (a.k.a. Intra-frame codecs), however, can play backwards just as easily as forwards, and even a mid-low-end computer can skip around very smoothly. If you’ve only ever edited clips straight from the camera, you not might realize what you’re missing.

The other thing that can cause issues with playback is raw video. Raw video needs to be converted before it can be displayed (sort of like a codec does), and some computers can’t decode the raw file fast enough, especially if it’s 4K. Ironically, both the low-end cameras and the highest-end cameras produce files that are hard to edit.