How are Images Compressed? [46MB ↘↘ 4.07MB] JPEG In Depth

You've probably saved 1000s of JPEG images, but do you know what exactly JPEG does? Our smartphones and cameras save images in JPEG format, furthermore, the majority of images you see on the internet are saved using JPEG compression. This format is everywhere, but do you know exactly how it works? Well in this video we're going to explore the JPEG compression format. This is a rather complicated video, so it may take watching it a few times through to understand it all.

Script, Modeling, Animation: Teddy Tablante
Twitter: @teddytablante
Voice Over- Phil Lee
Nature Photography- Tobias Karlsson

Table of Contents:
00:00 - Intro into JPEG
01:24 - What does JPEG do?
02:35 - What are the Steps of JPEG?
04:06 - Color Space Conversion
06:06 - Discrete Cosine Transform
09:32 - Quantization
11:02- Run Length and Huffman Encoding
12:04 - H.264 Video Compression
13:25 - Rebuilding an Image
15:01 - Notes and Caveats on JPEG
17:06 - Sponsored by Brilliant
18:20 - Outro

Key Branches from this video are: How does a Camera Work? How do SSDs Work?

Erratum:
Tulips are not the same as Lillies.

Post with Adobe Premiere Pro

References:
A Trip Through the Graphics Pipeline 2011: Index

DCT (Discrete Cosine Transform)

H.264 is Magic

How JPEG Works

Jack, Keith. Video Demystified. Fifth Edition. Elsevier 2007.

JPEG 101 - How does JPEG Work?

JPEG: Image Compression Algorithm

What is H.264?

Wikipedia contributors. "Chroma Subsampling", "Chrominance", "Chroma Subsampling", "Discrete Cosine Transform", , "JPEG" , "
Wikipedia, The Free Encyclopedia. Wikipedia, The Free Encyclopedia, Visited December, 2021

Music Credits
Kindred

#JPEG #Camera #Picture

[jontrout]

It never ceases to amaze me how much computation goes into things we take for granted and how inconceivably fast it happens over and over again...

[ffk]

This channel is researching and (perfectly) presenting exactly what you think in your spare time

[microcolonel]

As somebody who has worked on JPEG implementations, I am still amazed by how perfect they got it on the first try. JPEG has been around for ages, and is still so good; only recently have meaningful replacements emerged, and JPEG still has some benefits over these.

[azharcassim]

Came across your channel this week. Must say that your explanations are exceptional in the sense that they convey technical details very clearly and also very quickly grab the attention of the viewer. Exceptional i tell you. Keep it up. You should he used as the benchmark for teachers and lecturers all around the world.

[DerpyNetworking]

You cover topics that I've always wanted to know and in the right amount of detail.🥰

[ariyagozlo]

as someone whos on youtube a lot, these still manage to be some of the best videos. The research, editing, the pace of the lesson. Thank you guys for the hard work

[levonja]

Up until now, I just thought JPEG lumps some similar colours together to save on file size. This was literally eye-opening. What an algorhythm!

[riddleraryan]

I am really amazed by the research and hard work you put into making this video. Subscribed !!

[iamtheusualguy]

I have a degree in computer science and I'm still amazed how good your channel is! Always wondered how JPEG compression worked. You have illustrated it in super simple terms and visualizations have as always been awesome! Happy to see more content like that, maybe more details on H.264.

[abbottabbott]

There's just nothing like these videos, really. I'm blown away every time. The voice-over and writing are just so far beyond anything else out there. I wish all information could be presented in this calm, clear, and concise manner than also somehow manages to never dumb it down.

[TheDarrenJones]

An absolute masterpiece of explanation. I've tried to understand how DCT works in JPEG before, and never understood the dry maths-only explanation. This video changed that and the image tables explained it perfectly. Thanks for filling in a gap that's been in my head for many years!

[theelephantintheroom]

Lol I just got shown this random channel with great quality narration, animation and explanation. Subscribed

[Slettador]

Great Video, just a little feedback on chroma subsampling: The reason why the human eye can perceive more luminance resolution than chroma isn't because of the number of rods vs cones. The rods are actually inactive in all but the darkest lit environments, and their density in the fovea i.e. the center of the visual field on the retina is actually rather low. So the RGB cone cells are solely responsible for tristimulus color vision.
The actual reason for the color resolution difference is because there is some amount of cell level processing happening in the eye before the signal reaches the visual nerve. This is very much analogous to the Lightness chroma separation done in digital images. Also, there is some correlation between spatial resolution of each of the red, green and blue cones in terms of the lightness but little correlation between them in terms of the color. Those effects together cause the lower chroma resolution of the human visual system.

[johelsen]

This is... AMAZING. It's probably almost impossible to explain this even just marginally better. The amount of well-considered effort you go through to make things more clear is extremely impressive. Subbed!

[anthonysaunders]

Digital imagery takes up a great deal of my time for what I do, and I know from practice what file formats and compression do, but I never really looked into how they work. Thank you!

[ReneHoffmann]

Incredibly well explained and visualized. Thank you so much!
I like the slower pace because it helps me to understand/think through what you say (but I'm no native speaker).

[kencarp]

Your videos are SPECTACULAR! It's obvious that you put a lot of work into them, and it shows. You seem to intuitively know how to achieve the perfect balance of technical detail and higher-level concepts to enable the viewer to develop a solid overall understanding of the subject matter. THANK YOU!

[CrashCarson]

WOW this is so detailed! So much more information than most videos will tell you. Down to a fundamental level, not just “it works better”. Thanks! I’ve been interested in how video/pictures are compressed

[VorpalMethod]

This is incredible. Easy like, easy subscribe. Time to go through your entire video history!

[Pasce]

I've just seen the video and realized that you released the video just two days after I submitted my bachelor thesis about forensic jpeg algorithms :D Would have been great to have these visualizations back then but nonetheless great and simple explanation with really good animations!