Characters, Symbols and the Unicode Miracle - Computerphile

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  • Опубликовано: 21 дек 2024

Комментарии • 622

  • @Jivvi
    @Jivvi 10 лет назад +8041

    Which side of a napkin is the back?

  • @Computerphile
    @Computerphile  11 лет назад +1479

    This was shot at the Marriott St Pancras Renaissance in London - kind thanks to them for allowing us to film there! >Sean

  • @AndreiZisu
    @AndreiZisu 10 лет назад +3809

    This guy just radiates enthusiasm

  • @tuberlook1
    @tuberlook1 11 лет назад +638

    It's rare to see a person who is knowledgeable, passionate and able to explain in a linear and easy to understand manner.

  • @praemdonck
    @praemdonck 8 лет назад +2294

    You forgot to mention that the great hacker behind the great hack is Ken Thompson, the genius behind unix

  • @MikkoRantalainen
    @MikkoRantalainen 8 лет назад +4227

    There's a saying that UTF-8 was successful because USA did not need to understand it. (Explanation: they could just keep using ASCII and magically they are compatible with UTF-8).

  • @pao_lumu
    @pao_lumu 8 лет назад +224

    3 years later, still quality.
    -Well, give-or-take a few leap seconds-

  • @coldfire6869
    @coldfire6869 Год назад +54

    Tom Scott explaining UTF-8 in some hotel lobby 9 years ago. Very nice!

  • @codeman99-dev
    @codeman99-dev 11 лет назад +773

    While designing ASCII they also chose "00110000" (48) for character zero. This is even more impressive than "a is 1" since you can then XOR any character with the value of character zero to find out if it's a decimal number (0 through 9)! :)
    In code example:
    char x = random(0, 128);
    if (x ^ '0' < 10) {
    // variable x is a decimal number character
    } else {
    // variable x is NOT a decimal number character
    }

  • @UteChewb
    @UteChewb 4 года назад +29

    Minor goof by Tom at 6:25 he writes 0110 0001 and writes 'A' when it should be 'a'. But a great video, and perhaps this is a deliberate mistake to see who was awake in class. I remember when I first read how unicode works I was blown away, but Tom's explanation is so much better than how I learnt it.

  • @dominiquestrauss-kahn2509
    @dominiquestrauss-kahn2509 9 лет назад +926

    Where is he presenting all this? That place looks rather pleasant.

  • @amykathleen2
    @amykathleen2 9 лет назад +305

    Just want to mention, not that people probably care, that Korean actually has a phonetic alphabet, unlike Chinese and Japanese. The letters do arrange into syllable blocks (e.g. ㅎ[h]+ㅏ[a]+ㄴ[n]+ㄱ[g]+ㅜ[u]+ㄱ[k]=한국[Hanguk, meaning Korea]), so I'm not sure if individual letters are encoded or if entire syllable blocks are encoded, but it is an alphabet nonetheless.

    • @SexyStarfleet
      @SexyStarfleet 9 лет назад +15

      I didn't know that. I remember studying Korea in world history and how it was very different from Japan and China. I guess I never thought about the language being that different. That's cool, and I'm sure it makes keyboards easy for you guys :)

    • @amykathleen2
      @amykathleen2 9 лет назад +46

      Yeah, it's pretty cool. I'm a Korean-language learner, and I mastered Korean touch-typing (on an American keyboard, no less) in about a month. :)
      The Korean alphabet, called Hangeul, was invented by a team of scholars led by King Sejong the Great in 1443 so Koreans wouldn't have to use Chinese characters to write anymore. Whenever I talk to a Korean and the topic of Chinese characters comes up, I always tell them, "I'm very grateful for King Sejong!"

    • @raizin4908
      @raizin4908 9 лет назад +76

      amykathleen2 You might not care, but Japanese texts have a large number of phonetic "letters" as well, unlike Chinese. Although it's technically not an alphabet but a syllabary. (Each "letter" signifying a syllable, rather than a "sound")
      Japanese uses a mix of phonetic and non-phonetic characters, and for a significant number of words both phonetic and non-phonetic spellings are common. It's also entirely possible to write any Japanese sentence fully in phonetic characters, but it's practically impossible to make a proper sentence without them. (Although it should be noted most sentences, especially more complex ones, would be significantly harder to read were they written fully phonetically.)
      In a modern Japanese sentence such as this:
      これは日本語での例文である。
      all the curly characters (これは での である) are phonetic, and the more rigid/angled characters (日本語 例文) are usually non-phonetic characters, often identical to characters used in Chinese (汉语 / 漢語). Although there's also a type of angled phonetic characters (カタカナ), which is usually reserved for loan words and foreign names and such.
      It's likely you already knew this, but I felt the need to clarify for interested uninformed passersby.

    • @amykathleen2
      @amykathleen2 9 лет назад +9

      Raizin Yes, I did know the basics. But I didn't know that the two syllabaries had different uses and different "kinds" of shapes, that's really interesting! Some of those angled phonetic characters really look a lot like Chinese characters - like 力 and 夕. I think if that syllabary was the more common one, I wouldn't be able to tell Chinese and Japanese writing apart, as my personal rule is "Japanese is the one with the squiggly characters," haha. Thank you for sharing that information! :D

    • @amykathleen2
      @amykathleen2 9 лет назад +28

      ***** The point I was trying to make is that, since not long after the Korean war, Korean has been written almost *exclusively* using a phonetic *alphabet*. Japanese usually uses a mix of Chinese characters and syllabic characters, while Chinese usually uses Chinese characters exclusively. In modern Korean, Chinese characters are only used in high-level texts, such as medical or legal journals. Everything else is written using the Korean alphabet (which, again, is *not* a syllabary, unlike bopomofo and kana, and is *not* based on borrowed letters, unlike pinyin). Many Koreans can't even write their own names using Chinese characters. So I made my comment to correct the fact that, in the video, he listed several alphabets (English, Cyrillic, Arabic), and then said, "Japanese, Chinese, and Korean characters." This is wrong; Korean uses an alphabet and should have been listed with the alphabets if it was to be listed at all.

  • @bloody_albatross
    @bloody_albatross 10 лет назад +145

    Another nice feature: Sorting UTF-8 strings under the assumption they are ASCII strings will sort them correctly in ascending codepoint order. For proper sorting in the context of a language you need of course much more complicated methods, but having some kind of sort that somehow makes sense for some technical applications that can be performed by something that was written for ASCII is already very nice.

  • @TheBoxOfBeats
    @TheBoxOfBeats 11 лет назад +874

    6:30 -- 01100001 is not 'A' and its not 65, its 97 / 'a' . Or am I wrong?

  • @devjock
    @devjock 10 лет назад +1246

    Are you listening to me Neo, or are you distracted by "Woman in the red jeans" 5:40
    Great explanation!

  • @benjaminfoo9270
    @benjaminfoo9270 11 лет назад +90

    I've never seen a guy explaining utf8 so well and so excited like this fellow here - really great job

  • @ACDCBoy62
    @ACDCBoy62 9 лет назад +862

    Hey, this video actually helped me fix a bug! I was trying to pass an ANSI filename to a function, and it would always fail. When I looked at the variable watch, the string showed up as a bunch of Chinese characters, so I was immediately able to recognize it was being reinterpret-casted to Unicode, rather than the proper typecast I assumed would happen!

  • @chandragie
    @chandragie Год назад +4

    This video showed up to me in Dec 2023, 10 years later from when this video launched. And I'm still amazed on how this guy explained it 👍👍

  • @mehrosenasir9974
    @mehrosenasir9974 2 года назад +5

    I remember when I watched this video for the first time back in 2018, didn't make any sense to me. Now I can understand how beautifully he explains the complete journey started from Ascii to UTF 8.

  • @douggwyn9656
    @douggwyn9656 9 лет назад +260

    The original version of UTF-8 was invented by Thompson and Pike for use in Plan 9 from Bell Labs. There were already ISO standards for character encoding; ISO 10646 is the master character compendium and assigns codes throughout a 31-bit range. I was impressed enough with the Plan 9 scheme that I promoted it in my C Standards column in the Journal of C Language Translation. The advantages of UTF-8 covered in this video helped its adoption by many applications needing to support an international character set. By the way, Plan 9 only implemented the 16-bit range, although the full scheme can encode any 31-bit pattern. The current IETF RFC3629 unnecessarily constrains UTF-8 to 16 bits. I'm at the beginning of the process of trying to undo those restrictions.

    • @iemobile930
      @iemobile930 9 лет назад +8

      This is interesting Doug. I plan to watch this later. Happy 4th to you too.

  • @Computerphile
    @Computerphile  11 лет назад +77

    There will be more with Tom :) >Sean

  • @squgeim
    @squgeim 10 лет назад +346

    Tom Scott is the James Grime of Computerphile!

  • @chlee-g5j
    @chlee-g5j 2 года назад +6

    Thank you for providing Korean subtitles. You explained it so well that I could understand it well. Thank you.

  • @rlamacraft
    @rlamacraft 11 лет назад +3

    Love this guy's enthusiasm and this type of video converting the odd bits of computing like how number phill covers the odd bits of maths rather than teach a full course in those subjects

  • @Computerphile
    @Computerphile  11 лет назад +13

    See the "extra bits" film for a further explanation! (link in the description) >Sean

  • @taserianAlephNull
    @taserianAlephNull 9 лет назад +122

    This was an excellent presentation. Thank you for making it so understandable!
    I do have a very minor quibble. At 7:18, there's an error; in a 2 byte Unicode character, having 11 bits available (5 from the header, and 6 from the continuation) will only allow you to get values up to 2048, not 4096.

  • @samuvisser
    @samuvisser 6 лет назад +3

    I watched this video like 5 times over a long period now. Keep coming back to it, I so love the explanation and the storytelling!

  • @dunx125
    @dunx125 11 лет назад +5

    This guy is brilliant at explaining things, please feature him more often!

  • @nameredacted1242
    @nameredacted1242 3 года назад +3

    For a restaurant setup, this is BIZARRELY informational and useful. So strange!!!

  • @Niki_0001
    @Niki_0001 11 лет назад +7

    It's always interesting to listen to someone who's that passionate, or at least sounds passionate. Even if you don't care about the subject at hand, it somehow becomes interesting when person speaking is passionate about it!

  • @DaChilla1
    @DaChilla1 9 лет назад +170

    Holy shit, this guy is freaking enthusiastic about it. But he has a point.... I only recently learned the way UTF-8 works and I gotta say, this is some freaking genius hack.

  • @LIES666
    @LIES666 11 лет назад +1

    It's always nice when you're watching one of Brady's channels and someone from a completely unrelated channel you subscribe to turns up.

  • @ButzPunk
    @ButzPunk 11 лет назад +4

    Finally, someone who loves UTF-8 and Unicode as much as me!

  • @lcdvasrm
    @lcdvasrm 9 лет назад +240

    cameraman, please take a seat

  • @megaelliott
    @megaelliott 10 лет назад +218

    UTF-8 is love, UTF-8 is life.

  • @lpatrasco
    @lpatrasco 5 лет назад +9

    Such an incredible enthusiasm just for UTF-8! I’d like to hear you speaking about quantum entanglement 🥴

  • @fabioampe
    @fabioampe 11 лет назад

    You talk with so much passion about the subject. I think that's really beautifull. I bet Even someone who doesn't understand a sh** about computers will know how important it was.

  • @joedeshon
    @joedeshon 5 лет назад +1

    Definitely one of my favorite Tom Scott videos!

  • @ZestyCrunchy
    @ZestyCrunchy 11 лет назад +1

    I've never seen someone that passionate about encoding characters.

  • @puncheex2
    @puncheex2 11 лет назад +2

    historical note: Before ASCII there was 5 bit teletype code (upper case only), binary coded decimal (BCD), which was a 6 bit code, and extended BCD interchange code (EBCDIC), an 8 bit code. BCD and EBCDIC were IBM standards adopted by the industry. All used the "trick" of having the letters in collating order; it was the basis for punch card computing.

  • @zdcyclops1lickley190
    @zdcyclops1lickley190 4 года назад +2

    I am certain that 99.99999 percent of all humans don't care about this at all. Nice video. Good camera work, a competent presenter, no unnecessary music. Good job.

  • @another-person-on-youtube
    @another-person-on-youtube 4 года назад +13

    This was unironically riveting for me. I'm amazed at the incredibly clever solutions that make up the foundations of mundane computer operation.

  • @lierdakil
    @lierdakil 7 лет назад +1

    "[...] we don't have mojibake, [...] we have something that nearly works" - Tom Scott, 2013.
    I absolutely adore this "nearly" thing.

  • @MrJekyllDrHyde1
    @MrJekyllDrHyde1 11 лет назад

    If you asked me to watch a UTF-8, I would have given it a pass... but with this guy, I could not stop watching.

  • @chridal
    @chridal 11 лет назад +11

    This guy is a LOT of fun. He's so enthusiastic! Please have him on again!

  • @lexbailey
    @lexbailey 11 лет назад

    This is one of the best computerphile videos. This is the sort of topic explained at the right level to be interesting to most people who (I suspect) subscribe here. Good work!

  • @iabervon
    @iabervon 11 лет назад +2

    Another tiny correction: at 1:53, he says a space is all zeros; actually, a space is 0100000 = 32 = 0x20. As he mentions later, all zeros is "end of string".

  • @GunjanBagayatkar
    @GunjanBagayatkar 10 лет назад +6

    Very interesting & informative video.
    Explained in detail and still very easy to understand.
    Thanks for uploading.
    Keep up the good work guys...

  • @solarisNT-v4j
    @solarisNT-v4j 2 года назад +1

    bingeing computerphile on halloween is a mood

  • @bulman07
    @bulman07 9 лет назад +203

    Was this filmed in the St Pancras Hotel?

    • @Computerphile
      @Computerphile  9 лет назад +148

      Yep

    • @Computerphile
      @Computerphile  7 лет назад +94

      ***** actually this is just their public bar, our filming location fell through and they were kind enough to let us film there. Anyone can go in >Sean

  • @diogoj95
    @diogoj95 11 лет назад +89

    5:38 i see what you did there xD

  • @xway2
    @xway2 11 лет назад

    This guy's personal channel is in the description. I just checked it out and it's really amazing. You should too.

  • @TheBreadCatt
    @TheBreadCatt 11 лет назад +1

    If you could do more with Tom Scott that would be amazing. I love his videos and these videos, so combining them is just awesome!

  • @veloxsouth
    @veloxsouth 11 лет назад

    This is the first computerphile video I didn't hate. Well done.

  • @DarrylCollins
    @DarrylCollins 10 лет назад +55

    Very interesting video explainer. I learnt something new today! (Particularly like the crash zoom at 5:42 to see girl in red pants!)

  • @manogilissen
    @manogilissen 10 лет назад +28

    7:17 Why does he say 4096? You can use 5+6 = 11 bits so wouldn't that be 2^11 = 2048?

  • @eduardobcastro14
    @eduardobcastro14 3 года назад +1

    These videos are great contributions to human knowledge

  • @shonari
    @shonari 2 года назад +2

    This is the simplest explanation of UTF-8 I've heard. Thank you!

  • @joeserneem853
    @joeserneem853 11 лет назад +16

    I really like Tom Scott's way of explaining.

  • @resonance2001
    @resonance2001 11 лет назад +2

    I like UTF-8 too. It's very useful. I quite like UTF-16 for encoding foreign words in RAM. I wrote a special text editor for writing in different languages and I found UTF-8 to be perfect for saving the text files.

  • @Dinoguy1000
    @Dinoguy1000 11 лет назад +29

    This makes me think of the error-checking header used in PNG files, really a quite clever piece of work that I'd love to see a video on. =)

  • @Carutsu
    @Carutsu 11 лет назад

    UTF has to be one o the most beautiful solutions I´ve ever seen. Loved it since I translated the unicode page.

  • @mathiasbynens
    @mathiasbynens 11 лет назад +2

    In practice, you’ll never really encounter UTF-8 byte sequences with 4 or 5 continuation bytes. In November 2003, UTF-8 was restricted by RFC 3629 to end at U+10FFFF, in order to match the constraints of the UTF-16 character encoding. This removed all 5- and 6-byte sequences, and about half of the 4-byte sequences, but it’s still enough to represent every possible Unicode symbol ever.

  • @qubei
    @qubei 11 лет назад +1

    The escape arrow (←) isn't from ASCII, it's in Code Page 437 (the MS DOS or OEM font) and shares the same position as ASCII's ESC code. In Unicode that arrow symbol is mapped to U+2190, which is 3 characters in binary: 11100010:10000110:10010000, and kept separate from the ESC control character (27 or 0x1B)

  • @m_jacko12
    @m_jacko12 11 лет назад

    this was one of the best videos on this channel, i loved it

  • @another-person-on-youtube
    @another-person-on-youtube 4 года назад

    One of the best parts of the video is that guy at the very end pondering whether that dude actually would or wouldn't be the last man on the moon.

  • @ronanderson1023
    @ronanderson1023 9 лет назад +2

    Thank you so much for sharing so much detailed information!
    I always thought of bits and bytes to be something i'll never be interester in, but frankly, this stuff is getting really interesting the more you into it.
    Greetings and all the best!

  • @Niosus
    @Niosus 11 лет назад

    Hacks can also be seen as a trick to circumvent limitations. The most important part is the fact that it was not intended to happen as you said. In code it usually refers to code that fixes an issue in a weird way. This can be good or bad just like any other piece of code. In this case it circumvents the limitations of backwards compatibility with ASCII in a very elegant way.

  • @jlamothe2
    @jlamothe2 5 лет назад +36

    Another advantage of UTF-8 that wasn't mentioned is that if you want to sort strings by Unicode value, you can just treat it as though each byte were a separate character, and it'll just work.
    The only real downside to UTF-8 is that you can't seek out a character at a specific index without walking the entire string character by character.

  • @DamoonBlu
    @DamoonBlu 2 года назад

    I don't even want to think about the stress of allocating every symbol with a number, but great video!

  • @KeianhhnaieK
    @KeianhhnaieK 2 года назад +1

    Nothing short of amazing.

  • @DynamixWarePro
    @DynamixWarePro 11 лет назад +4

    Would like to see more videos with Tom! BTW, I love these videos, but one thing I don't like so much is the camera movement at times, so if you don't use one, could you put the camera on a tripod for some parts of an interview? I know it wouldn't work when you have to look at something someone is writing or holding or doing, but for when the camera is focused on someone, it to me would be better to have the camera more stable.

  • @plutoniumseller
    @plutoniumseller 11 лет назад

    I have been waiting for something on Unicode/UTF-8. THANK YOU, COMPUTERPHILE!

  • @RedPandad
    @RedPandad 5 лет назад +11

    For the people wanting to know where this vid was taken it in a cafe called the booking office in St Pancras station I know because I have been there once it's pretty popular

  • @blindshiva2826
    @blindshiva2826 6 лет назад +10

    Thanks for the history lesson. It is always interesting to remember how we got to where we are today.

  • @arzenn_
    @arzenn_ 8 лет назад +22

    I learn more here than my software lessons

  • @raditz2488
    @raditz2488 5 лет назад

    In depth explanation. He also shares a cool way to remember what A's and a's codepoints are.

  • @harrytaller9403
    @harrytaller9403 6 лет назад

    thanx Computerphile for explaining utf8 , user tried to understand from wiki but could not do it, u make everything simple

  • @BGroothedde
    @BGroothedde 11 лет назад

    Man... I love these videos, I love all the videos by you.

  • @ElectricFury
    @ElectricFury 8 лет назад +59

    homework is to watch this

  • @Cathalion
    @Cathalion 9 лет назад +73

    Love the enthusiasm! :)

  • @mutoso0
    @mutoso0 11 лет назад

    By the way, the character he encodes into UTF-8 at 7:12 (Unicode character #434) is: Ʋ (U+01B2: LATIN CAPITAL LETTER V WITH HOOK)

  • @nedelkosm
    @nedelkosm 11 лет назад +1

    I prefer the way he does it now because it seems more realistic and more like a conversation. Zooming in on his face though is funny :)

  • @sonodrome
    @sonodrome 11 лет назад

    Hey Tom! Fancy seeing you here :) Great to see you on ye olde Computerphile.
    Maybe catch you at the next TDC! Loving the video empire Brady, thanks for bringing us a slice of Tom - Jim.

  • @freeman1884
    @freeman1884 4 года назад

    Patiently watched twice and understood it very well, thanks!

  • @unvergebeneid
    @unvergebeneid 11 лет назад

    Unicode is a beautiful beacon of hope for a united world and a celebration of the variety of writing systems our species developed. Go Unicode! ツ

  • @BGBTech
    @BGBTech 11 лет назад

    errm, C99 and C11 support unicode (more or less). C99 added wide characters and variable length arrays, and C11 was the one that added generics and similar.
    granted, when a lot of people think C, they think C89/C90.
    likewise, a certain major compiler still lacks support for many C99 and pretty much any C11 features.

  • @lambar0
    @lambar0 2 года назад +1

    Simply Elegant … clear explanation

  • @jdrejert
    @jdrejert 11 лет назад

    From Wikipedia: In modern computing terminology, a kludge (or often a "hack") is a solution to a problem, doing a task, or fixing a system that is inefficient, inelegant, or even unfathomable, but which nevertheless (more or less) works.

  • @aatheus
    @aatheus 11 лет назад

    That is actually a very good explanation of UTF-8! I had wondered how the continuation bytes worked for a long time.

  • @ScottLahteine
    @ScottLahteine 11 лет назад +1

    It's a hack specifically because it makes 7-bit ASCII into just another valid UTF-8 encoding. You can run a 7-bit plaintext file through a UTF-8 parser and it won't complain, because it's not a special case. It's a hack because it assigns a meaning to the high (eighth) bit in 8-bit ASCII encoding, which had just been an extraneous zero. Since that leading '0' in old ASCII files is a valid UTF-8 header, it makes all 7-bit ASCII files ever written instantly into valid UTF-8 files as well.

  • @sarahtonin58913
    @sarahtonin58913 5 лет назад +1

    You pronounced mojibake pretty well! For anyone who wants google translate or a Japanese English dictionary: もじばけ

  • @mightyNosewings
    @mightyNosewings 11 лет назад

    Unicode is a miracle in this sense: a lot of the time, standards don't get created, or a de facto standard with lots of ugly warts arises, or a bunch of companies try to create their own standards and everything becomes a huge mess.
    But in another sense, Unicode's success seems obvious in hindsight. If there's one thing that needs a clean, universal standard that everyone uses, it's text-data interchange. And the Web has become so important to modern civilization that a standard had to arise.

  • @dannygjk
    @dannygjk 11 лет назад +4

    Simply put, UTF-8 uses an indexing system, which is an old concept familiar
    to myself and any other programmer :)

  • @glitchsmasher
    @glitchsmasher 9 лет назад +68

    All 0s in ASCII is Nul. 32 (01 00000) is Space.

  • @AndersGustafsson87
    @AndersGustafsson87 11 лет назад

    Brady, please bring this guy on computerphile many more times! and nice restaurant btw :)

  • @puzzician
    @puzzician 8 лет назад +1

    Another quibble: he accidentally damns this with faint praise when he says "you have something at nearly works" right at the very end. He meant it nearly *works perfectly* but it does work excellently.

  • @policello1980
    @policello1980 5 лет назад

    Great video, I really like the close-discussion format !

  • @ChrisDuncanCodeCow
    @ChrisDuncanCodeCow 11 лет назад +1

    Thanks for this! Character encoding always confused me; this video explained UTF pretty well to me.

  • @cmroosen
    @cmroosen Год назад

    Great explanation, love his enthusiasm