THE VIDEO SHELF · image compression

JPEG DCT, Discrete Cosine Transform (JPEG Pt2)- Computerphile

Mike Pound explains the discrete cosine transform and how it underpins JPEG compression. It is part two of Computerphile's JPEG series.

Why HN readers recommended it

HN recommends it as an easy, clear intro to the DCT that finally made it click for several commenters.

This is a summary from the source dataset, not an endorsement by Hacker News or the video creator.

These counts and years describe the included Hacker News records; they are not YouTube views or the video’s publication date.

Excerpts from the recorded comments. Follow each source for the full comment and surrounding discussion.

There's a series of videos showing the algorithm: [LINK] I finally understood DCT after watching [VIDEO] And someone created a "JPEG to PNG" tool that "finds the smoothest possible picture that encodes to the given JPEG file": [LINK] . I tried it with some very …
netsharc on Hacker News · 2026-07
In How JPEG works: Interactively explore JPEG's lossy compression methods
Honestly this presentation didn't work for me. I was amazed at the spectacle and a few things like perfect math world vs pixels and multi-sampler helped explain a few things but over all it was all over the place and didn't seem to get to …
greggman on Hacker News · 2015-09
In The Pixel Factory
Pretty cool! I would add Computerphile's Youtube Video as a watch after this: [VIDEO] . This is a part of their 4-video series on JPEG: [LINK]
walagran on Hacker News · 2020-08
In Discrete Cosine Transform in Video Compression – Explain Like I'm Five

Summaries, classifications and recommendation records are from the HackerTube source dataset. Read about this library and its limitations.