The Illustrated Guide to Video Formats: fifty years of video history | Hacker News Reader

The Illustrated Guide to Video Formats: fifty years of video history

archivesoftomorrow.com

120 pointsasicsp17 comments

Links to illustrations and data:

* https://github.com/ablwr/illustrations/tree/main/cables

* https://archivesoftomorrow.com/illustrations/video/

* https://archivesoftomorrow.com/data/video/

"UHF" connectors are very unfortunately named. They shouldn't be used for anything above 30 MHz (HF), but are often used on VHF (~150MHz) radios even though they have poor performance already at those frequencies:

https://www.hamradio.me/connectors/uhf-connector-test-result...

> The stunning result is all the UHF connectors in the test have worse performance than all the other connectors. One immediate conclusion concerning ‘UHF’ connectors is they will function at these higher frequencies, but one must decide if using the PL259 or SO239 is worth it in an age where its deficiencies have been made moot by ALL connector designs since WWII.

N connectors work excellent all the way up to ~1GHz and also have decent power ratings. Above that SMA/SMC is popular for low power applications, and waveguides for high power.

TNC connectors were popular in the 1980's for analog cell phones and 800MHz public safety radios.

The strangest video format I've worked with was a 1/4" open reel black & white format. I don't even know the time frame of when it was used, but the engineering staff had to dig up an old machine and restore it just to be able to playback the footage we received. It was the one and only job while work for that company that I ever saw it. Then again, there was a Fisher Price like toy camera that recorded similar b&w footage to an audio cassette.[0]

My favorite tape based trivia is that all but one tape format has the supply hub on the left side and the take up reel on the right. Only the 3/4 Umatic format has the supply reel on the right.

[0]https://www.youtube.com/watch?v=TCXJ5twf5tM

That's not quite true, Philips VCR (N1500/N1700) has the hubs stacked one on top of each other. I'm sure there was one other like that but I can't remember the name.

But which way did the tape wind? I've found no information in my brief searching about this format. I'll gladly add it to my list of right to left tape formats, but I'm seeing no such evidence.

Next up, Illustrated Guide to Video Codecs

01011010110011100101000111001010101010110101110001 or something

I _do_ want to do a history of video codecs (codec wars, etc) but I'll have to actually write words for that one :'-)

Another entertaining take from the perspective of consumers, while not just focusing on the typical VHS/Beta and newer stuff: "The Forgotten History of Home Video" by Cathode Ray Dude:

https://youtu.be/30Uc-JxJzYI

Does this book also explain NTSC and PAL formats? Or is that a different world?

Kind of hard to illustrate NTSC and PAL.

These are the physical media. The tapes were not concerned with the types of signals that went on them. This is showcasing the physical nature of the video formats.

If I were try to illustrate NTSC, the red would all be shifted to the right in the image in a blurry fasion. Not the hue itself shifted to the right, but the physical position of the red information ghosted to the right of the actual source in the image which would still be a shade of red, but most definitely, it wouldn't actually be red.

NTSC was also known as "Never The Same Colour".

NTSC and PAL were video encoding specs and also recording specs. The framerate and line resolution were part of the format, so PAL and NTSC recorders/tapes weren't compatible.

For capture, PAL is basically 576 interlaced at 50Hz. NTSC is 480 interlaced at a little less than 60Hz. The physical line count is higher - 625 for PAL, 525 for NTSC - but these extra lines are either blank or used for supporting data.

Most professional hardware could record/play either format, and a few systems could interconvert on the fly. But that took significant processing. The recordings themselves were one or the other.

This carried through to video recorded on disk. Consumer analog video capture cards tended to be PAL or NTSC, sold by region.

From BBC Engineering in the 1970s:

NTSC - "Never Twice the Same Colour" (US)

SECAM - "System Exactly Contrary to the American Method" (France)

PAL - "Perfection At Last" (UK - BBC of course)

Most people don't realize that PAL came 10 years after NTSC. It also did not have to worry about maintaining backwards compatibility with the pre-existing black&white only format that was only a couple of years old.

As much as I hate all of the pain that compatibility caused, it was an impressive feat of engineering. 30000/1001 was such a magic number that haunts me to this day.

> It also did not have to worry about maintaining backwards compatibility with the pre-existing black&white only format that was only a couple of years old.

The BBC was broadcasting TV shows in black and white, and they were being received, in black and white, on people's black and white televisions for many years before PAL was developed.

So yes of course compatibility was important, the existing sets continued to show (in black and white) newer colour shows, PAL is a method to encode colour on an existing black and white television signal just like NTSC. PAL isn't better because of somehow not worrying about backward compatibility, it's just a better technology.

It doesn't, it's a pretty simple book, intentionally. I had to remove a lot of more technical "fun facts" and replace them with something more historical / market-context-oriented so it would be fun for total novices (I had my mom tell me what was too confusing for her and swapped those out).

I think one of the best books out there for really getting into video (algorithms, et al) is Charles Poynton's Digital Video and HDTV.

I'm struggling to see who the intended audience is for this book.

Based on the preview, it appears to be 86 pages of illustrations in a cartoon style with a little bit of descriptive text in the form of 'fun facts.' It reminds me of the style of a children's pictorial encyclopedia.

This seems way too simple for a serious video geek, archivist, or historian, but who else will be interested in learning about dozens of historic video formats?

It's for funsies. Haven't you ever done something for funsies?

Mostly I just wanted to make some nice open-license illustrations and the book is just kind of a bonus. I'm not trying to make a buck; everything you need is available on the website.

I've been teaching archivists for a long time and everybody has to start somewhere. I think this is a good starting place, especially for folks that need to know how to figure out what something even is, or the potential content or historical context/era. Especially for folks that don't work with video often, they can get easily freaked out/overwhelmed. I think it's going to be either required or recommended reading for at least three archives courses this fall that I know about.

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