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Advanced Topic 47 of 49 Graphics, Vision & Media

Video Codecs

Algorithms like H.264 compressing video.

How it works

Video codecs compress video by removing spatial and temporal redundancy. They split frames into blocks, predict them from neighboring pixels in intra frames or from other frames using motion estimation and compensation in inter frames, transform the residual with a DCT-like transform, quantize it and entropy code the result. Frames are organized into groups of pictures with I, P and B frames. Standards include H.264/AVC, H.265/HEVC, AV1 and VP9, each improving efficiency at the cost of encoding complexity. Rate control balances quality and bitrate, and containers package streams.

Where it is used

Streaming services, video calls, broadcasting, surveillance, game capture and storage rely on codecs, often with hardware encoders and decoders.

Common pitfall

Higher compression needs more encoding time and compute, and licensing and patents affect codec choice, with AV1 being royalty-free. Low bitrates cause blockiness and banding. Long GOPs make seeking and editing harder. Device support for decoding varies. Select codecs by audience devices, use constant rate factor or two-pass encoding and adaptive bitrate streaming.

Where it fits in the course

Video Codecs is topic 47 of 49 in Graphics, Vision & Media, rated Advanced. It follows Augmented and Virtual Reality. The next topic is Speech Recognition.

Practice and explore

How to study this topic

  1. Read the explanation above and restate the definition in your own words.
  2. Open the interactive lesson and answer its mini quiz.
  3. Read the common pitfall, then write a short example that avoids it.
  4. Check your understanding in the Graphics, Vision & Media quiz, and revisit the topic if you miss a question.

Frequently asked questions

What is Video Codecs?
Algorithms like H.264 compressing video. It belongs to Graphics, Vision & Media and is an advanced-level topic.
Where do people use Video Codecs?
Streaming services, video calls, broadcasting, surveillance, game capture and storage rely on codecs, often with hardware encoders and decoders.
What is the most common mistake with Video Codecs?
Higher compression needs more encoding time and compute, and licensing and patents affect codec choice, with AV1 being royalty-free.
What should I learn before this topic?
Start with Augmented and Virtual Reality, the topic just before it in Graphics, Vision & Media.
How can I practice it?
Answer the mini quiz in the interactive lesson, then take the Graphics, Vision & Media quiz.
Is Video Codecs hard to learn?
It is an Advanced topic. Expect to read the explanation more than once and to connect it with earlier topics. Working through a small example by hand helps most.
How long does it take to learn Video Codecs?
Most learners can read the explanation and finish the interactive lesson in under an hour. Fluency comes from applying the idea, so plan a few short practice sessions with the quiz.
Which topics are related to Video Codecs?
Augmented and Virtual Reality, Speech Recognition, SLAM are closely connected. The full list is in the related topics section of this page.
What should I study after Video Codecs?
Continue with Speech Recognition, the next topic in Graphics, Vision & Media.

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