Stuff To Know About Codecs

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David Kong here with another video tutorial for you, this time on codecs. I’ve found a lot of confusion and mis-information around the internet about how codecs work, how the differ, and why those differences matter.

Hopefully, this video/post will clear those up. I know it’s long, but I really wanted to break it down and explain things thoroughly, rather than just skimming the surface like a lot of tutorials do. Codecs can sound impossibly complex when all you get is a bunch of numbers and acronyms, but the main concepts at work really aren’t that complicated.

I explain the concepts behind different types of codecs, but I also give some real-world examples which should help you understand how these algorithms work on a practical level, pulling frames into Photoshop to break them down and examine how our codecs have changed the image.

• What a codec is - And how it differs from a container.
• Different types of codecs – And why I frequently use 4 different codecs on a single project.
• Bit Depth – What it means and why it matters.
• Chroma Subsampling – 4:4:4, 4:2:2, and 4:2:0, and when it becomes an issue.
• Spatial Compression and Blocking – One of the most common artefacts you see with normal work.
• Temporal Compression – Long-GOP codecs, inter-frame compression, and ALL-I codecs.
• Lossless vs. Lossy compression – How image compression differs from data compression.
• Bit Rate – How to calculate bit rates and the differences between kbps/kBps/Mbps/MBps.
• Raw – Briefly, the difference between Raw, compressed, and uncompressed (this could have been a 40-minute tutorial on its own!)