Codec
A codec is the way your video is packed and unpacked, so it can be stored and played back. It sets the balance between file size, quality and how hard your computer has to work with it. Well-known examples are ProRes, H.264 and H.265.
Codecs roughly fall into two groups: edit-friendly codecs like ProRes that play back easily but are large, and compact delivery codecs like H.264 that are small but heavier to edit. In DaVinci Resolve, Premiere Pro and Final Cut Pro you choose at export which codec fits your goal. For editing a light edit codec is nice, for the web a compact one. Tip: if your footage stutters while editing, transcode to an edit-friendly codec or work with proxies.
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