[HN Gopher] The Illustrated Guide to Video Formats: fifty years ...
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The Illustrated Guide to Video Formats: fifty years of video
history
Author : asicsp
Score : 106 points
Date : 2022-07-18 13:30 UTC (9 hours ago)
(HTM) web link (archivesoftomorrow.com)
(TXT) w3m dump (archivesoftomorrow.com)
| allturtles wrote:
| 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?
| [deleted]
| ablwr wrote:
| 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.
| dylan604 wrote:
| 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
| Gordonjcp wrote:
| 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.
| dylan604 wrote:
| 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.
| g-schro wrote:
| Does this book also explain NTSC and PAL formats? Or is that a
| different world?
| ablwr wrote:
| 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.
| dylan604 wrote:
| 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.
| TheOtherHobbes wrote:
| 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.
| taffronaut wrote:
| 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)
| dylan604 wrote:
| 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.
| tialaramex wrote:
| > 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.
| asicsp wrote:
| Links to illustrations and data:
|
| * https://github.com/ablwr/illustrations/tree/main/cables
|
| * https://archivesoftomorrow.com/illustrations/video/
|
| * https://archivesoftomorrow.com/data/video/
| kloch wrote:
| "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.
| dylan604 wrote:
| Next up, Illustrated Guide to Video Codecs
|
| 01011010110011100101000111001010101010110101110001 or something
| ablwr wrote:
| I _do_ want to do a history of video codecs (codec wars, etc)
| but I'll have to actually write words for that one :'-)
| h3mb3 wrote:
| 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
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(page generated 2022-07-18 23:01 UTC)