How Lossless Compression Works: Lempel-Ziv

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  • Опубликовано: 11 дек 2024

Комментарии • 139

  • @maxthreshold
    @maxthreshold 4 года назад +32

    Ngl, I struggled to understand the core concept behind this algorithm. Even after watching so many "technical" videos here on youtube, I still couldn't wrap my head around it. But after watching the first 30 seconds of THIS video, it was crystal clear all of a sudden. I just love how you visually presented the inner workings of this algorithm!

    • @ArtOfTheProblem
      @ArtOfTheProblem  4 года назад +3

      woo! I'm thrilled to hear this. it's how I felt when I was researching this video.

  • @sourabhk2373
    @sourabhk2373 8 месяцев назад +1

    Thanks!

    • @ArtOfTheProblem
      @ArtOfTheProblem  8 месяцев назад

      Thank you kindly! I really appreciate this

    • @ArtOfTheProblem
      @ArtOfTheProblem  8 месяцев назад

      Just posted a new vid! ruclips.net/video/5EcQ1IcEMFQ/видео.html

    • @ArtOfTheProblem
      @ArtOfTheProblem  Месяц назад

      Finally have new video: ruclips.net/video/PvDaPeQjxOE/видео.html

  • @amankhunt3620
    @amankhunt3620 6 лет назад +48

    Always believed in your channel, first priority while searching for any topic

    • @ArtOfTheProblem
      @ArtOfTheProblem  6 лет назад +2

      thank you for the kind words, I will continue!

  • @Zeresrail
    @Zeresrail 4 года назад +7

    That was so easy to understand. Why can't my proffesor be this clear? Thanks a bunch!

  • @samarthtandale9121
    @samarthtandale9121 Год назад +4

    Wow! what a simple and intuitive explanation, excellent!

    • @ArtOfTheProblem
      @ArtOfTheProblem  Год назад

      thank you glad you found this, was it suggested or did you just discover it? I'm trying to learn

    • @samarthtandale9121
      @samarthtandale9121 Год назад

      @@ArtOfTheProblem I'm ur huge fan bro 🥺 ... Please remember me, I'm gonna meet u 1 day! Keep up the good work 💪😎💯

    • @GM_Blue
      @GM_Blue 14 дней назад +1

      @@ArtOfTheProblem Found this searching "lzma" on RUclips. Just an FYI.

    • @ArtOfTheProblem
      @ArtOfTheProblem  14 дней назад

      @@GM_Blue thanks!

  • @AntonFetzer
    @AntonFetzer 3 года назад +2

    Great explanation and example.
    It felt almost like ASMR to hear the algorithm play out in the example.

  • @siennahsu8990
    @siennahsu8990 4 года назад +2

    The topic is so well-explained. Can't believe the vid doesn't have more views!

    • @Waldemar_la_Tendresse
      @Waldemar_la_Tendresse 24 дня назад

      Yeah, RUclips is full of useless and boring 💩, that might be one reason.

  • @lightyearahead
    @lightyearahead 6 лет назад +10

    Great video as always.
    By the way, yesterday I had my exam. And I wrote answer on LZW compression.

  • @irvanicsmoke1132
    @irvanicsmoke1132 7 месяцев назад +1

    wowwwwww. I love watching this vid. Easy to undestand, clear, and fun! Thank you so much

    • @ArtOfTheProblem
      @ArtOfTheProblem  7 месяцев назад +1

      yes I loved making this! i was so confused when I first had to learn it

  • @Enigma758
    @Enigma758 3 года назад

    You have a talent for stating things clearly.

  • @fallacyz3r0
    @fallacyz3r0 5 лет назад +5

    Wow. Such an amazing explanation. I have an Information Theory exam in a few weeks and this really helped. (Along with your other videos!) Thanks a lot!

    • @ArtOfTheProblem
      @ArtOfTheProblem  5 лет назад +3

      excellent to hear, I was once in your position wanting this kind of help. please share with others.

    • @ArtOfTheProblem
      @ArtOfTheProblem  5 лет назад +3

      I remember trying to learn LempZiv and nothing...nothing...worked for me.

  • @ashayshirwadkar
    @ashayshirwadkar 5 лет назад +1

    Wow.. Great video. I am intrigued by how Lempel-Ziv came up with this. Simply beauty!!

  • @ee6lpzfzj023
    @ee6lpzfzj023 6 лет назад +8

    Great content, keep going! I like the style and how you bring up the philosophical side of information theory in your old videos. Nevertheless, this being more practical, it's equally interesting to watch.

    • @ArtOfTheProblem
      @ArtOfTheProblem  6 лет назад +1

      Thanks. yes these IEEE videos are very focused on concepts in specific academic papers. However I'm currently planing to do a new video series on AI which will follow the model in my "old" videos. Stay tuned!

  • @grjesus9979
    @grjesus9979 3 года назад +1

    Wow! I'm amazed for such quality of explanation, thank you!!

    • @ArtOfTheProblem
      @ArtOfTheProblem  3 года назад

      appreciate the feedback, stick around for more

  • @nyscersul42
    @nyscersul42 2 года назад +1

    You can tell as you were narrating it felt repetitive to use the same words for each step, during the compression explanation, repeatedly. But, it really did help for following the sequence. Another good video. :)

  • @yomanos
    @yomanos 6 лет назад +5

    This channel has great content. Keep it up Brit!

  • @DecedentoftheDecade
    @DecedentoftheDecade 6 лет назад +5

    Excellently made. Would be thrilled if you uploaded regularly (daily/weekly)

    • @ArtOfTheProblem
      @ArtOfTheProblem  6 лет назад +2

      Thank you. Monthly would be top speed for my style of production. You can make this a reality by supporting future work here: www.patreon.com/artoftheproblem

  • @anaswicaksono1123
    @anaswicaksono1123 Год назад

    this is concise and precise explanation, easy to understand, thanks a lot sir

  • @ashokrajur09
    @ashokrajur09 6 лет назад +1

    you are a very good teacher.. thanks for educating.. and god bless you to continue the good work

  • @albertologp5184
    @albertologp5184 Год назад

    Perfectly explained video. Congratulations!

  • @GegoXaren
    @GegoXaren 6 лет назад +2

    After 5 years since I requested it... Thank you!
    (it was in the comment section of the Makrov Chain videos I asked you to talk about this... Due to LZMA).

    • @ArtOfTheProblem
      @ArtOfTheProblem  6 лет назад +3

      Amazing...slow but steady :)

    • @MusicBent
      @MusicBent 6 лет назад +3

      Has it really been that long 😮 It’s so great that this channel hasn’t died, or sacrificed quality in the name of quantity!

  • @KishanKumar-mz3xr
    @KishanKumar-mz3xr 5 лет назад +1

    Wow amazing. It was very smooth teaching. Thank a lot.

  • @quantranminh1781
    @quantranminh1781 4 года назад

    Best explanation so far. Thank you

  • @furkanunluturk7785
    @furkanunluturk7785 4 года назад

    this video created such a great intuition in my mind. thank you!

  • @dragonsaige
    @dragonsaige 6 лет назад +3

    Always love the videos. Great work.

  • @nealski26
    @nealski26 9 месяцев назад +1

    Great description! Thanks.

    • @ArtOfTheProblem
      @ArtOfTheProblem  8 месяцев назад

      New video is up on Evolution of Intelligence ruclips.net/video/5EcQ1IcEMFQ/видео.html

  • @prateekthakur1347
    @prateekthakur1347 6 лет назад +3

    I love this channel.

  • @GiesbertNijhuis
    @GiesbertNijhuis 6 лет назад +1

    I really enjoyed this video. Thanks for making it.

  • @-tiktoktrend1212
    @-tiktoktrend1212 4 года назад +1

    wow, you made it so simple ! very easy to understand, thank you!

    • @ArtOfTheProblem
      @ArtOfTheProblem  4 года назад +1

      thrilled to hear it, made this video because I hadn't seen any others do it simply

  • @inarisound
    @inarisound 6 лет назад +8

    Fantastic, now I want to purchase my WinRAR activation

    • @ArtOfTheProblem
      @ArtOfTheProblem  6 лет назад +2

      Thank you for the feedback on the pacing I appreciate it.

  • @Denverse
    @Denverse 4 года назад +1

    Awesome Explanation!, Thank you!!!

  • @niua511
    @niua511 11 месяцев назад

    Amazing! I love your animation and background music. Keep going

  • @dyyno5578
    @dyyno5578 3 года назад

    Great explanation !

  • @alurma
    @alurma 6 лет назад +1

    Amazing! I always wondered how zip compression works. Thanks!!! :)

  • @PradeepBanerjeeKr
    @PradeepBanerjeeKr 4 года назад

    Simply awesome!

  • @HarriRobins
    @HarriRobins 6 лет назад +40

    This is very interesting. Or should I say, "This 3s very 3n1e8e4t10g" - oh, that hasn't compressed at all, I guess it gets better the more combinations there are.

    • @umnikos
      @umnikos 6 лет назад +2

      0b0e0t3e0r0u0s2z0i0v0c0o0m0p5e7s9o0n
      Huh, this is even longer than if it was uncompressed...

    • @jetison333
      @jetison333 6 лет назад +4

      I'm sure you could very easily construct a message that would be much longer compressed like this. However, the ,longer a message is, the better chance it has that it will have repeating content meaning easier to compress. Also a number has less data than a letter because there's only 9 numbers and 25 letters, so even if the message is the same length it has less information.

    • @inarisound
      @inarisound 6 лет назад +5

      @@umnikos don't forget that every message you type is actually binary and not what you initially see.

    • @umnikos
      @umnikos 6 лет назад

      @@inarisound yes, but then how do you transmit the numbers separately from the actual bits? They're both just 0s and 1s...

    • @HarriRobins
      @HarriRobins 6 лет назад

      I can't decrypt that, so I think you might have done something wrong.

  • @chris_1337
    @chris_1337 6 лет назад +1

    Awesome as always

  • @himanshukesarwani7446
    @himanshukesarwani7446 6 лет назад +1

    best videos for learning information theory concepts

  • @christianjansson6806
    @christianjansson6806 3 года назад

    Perfect. So next time I'll send a message containing only two letters, I'll contact you for a smart algorithm for compression!

  • @prachinainawa3055
    @prachinainawa3055 5 лет назад

    Unique explanation 😍

  • @justindie7543
    @justindie7543 6 лет назад +4

    Amazing, amazing, amazing. I have always wondered how compression works. Question though, why not send 3 1 (with a space to distinguish from 31) instead of 3A?

    • @MusicBent
      @MusicBent 6 лет назад +1

      Tommy Dies letters, numbers, and spaces are characters, quest like the buttons on your keyboard. They are all represented as bits (0 or 1) in the end. A common and simple translation is ASCII.

  • @fabricioalmeida351
    @fabricioalmeida351 5 лет назад

    Excellent!

    • @ArtOfTheProblem
      @ArtOfTheProblem  5 лет назад +1

      thanks for your feedback, stay tuned for more

  • @aronpop1447
    @aronpop1447 3 года назад

    you deserve more subscribers

  • @shirinmohebbi8624
    @shirinmohebbi8624 3 года назад

    thank you

  • @XanderGouws
    @XanderGouws 6 лет назад +3

    At 8:47, can't we write ABBA as 31, since ABB = 3, A = 1?

    • @MusicBent
      @MusicBent 6 лет назад +1

      Remember computers would be using only 1 and 0 s, not letters. In the video, the letters A and B are used to emphasize the difference between coded and uncoded parts of the message. You could replace all of the As with 0s and the Bs with 1s and it would still work. It just would be less clear in the video.

    • @griggiorouge
      @griggiorouge 6 лет назад

      @@MusicBent ok but then the question would be why didn't they code both the ABB and the A, and send it 31 and not 3A (meaning part coded and part not coded), I amnot sure if the guy making this video did that by mistake or the code has to be that way.

    • @MusicBent
      @MusicBent 6 лет назад

      andres martinez hey, I looked more closely at that part of the video and I guess I’m not sure either. I would assume the video is correct, but not explained clearly...
      The first four messages all are the same as the previous one except the last letter is new. The fifth message breaks this trend. Maybe that has something to do with it...

    • @griggiorouge
      @griggiorouge 6 лет назад +1

      @@MusicBent Hey, if you think about it, it can`t send the code 31 as it would be confused with the 31st sequence... and the same goes for 21 42 etc... so I guess each sequence has to be coded as part code (number) and part not code (letter: or original message).

    • @griggiorouge
      @griggiorouge 6 лет назад +2

      No you can`t because then you wouldn`t be able to use the code 31 for the 31st sequence, and so goes for the 42 41 32 etc... at 10:04 he says:
      "notice the sender is always adding what it hasn`t seen to a growing code book, and then sending that sequence in coded form, MINUS the last letter (!), that`s the trick."

  • @JobvanderZwan
    @JobvanderZwan 6 лет назад +1

    Technically the code-book is not empty at the start: it contains the letters. Or at least, the sender and receiver must agree on an alphabet

  • @paulstelian97
    @paulstelian97 4 года назад

    Funny how the numbers and letters are then compressed again using Huffman coding, which itself is also very interesting.

  • @alurma
    @alurma 6 лет назад +7

    But how do you differ between regular symbols and special code numbers, for example in binary? I tried this method as you descibed but message only got longer: 42 bits from 33 bits. In your example: what if 1 is also a symbol in angiven alphabet?

    • @MusicBent
      @MusicBent 6 лет назад

      The video used A and B for clarity, but everything would actually just be 1 and 0. Characters like a-z, A-Z, 0-9, etc could be encoded, using a simple scheme like ASCII which is still used today.

    • @MufinMcFlufin
      @MufinMcFlufin 2 года назад +1

      This implementation of the algorithm always results in the transmitted message alternating between an index and a character.

    • @techlon
      @techlon 6 месяцев назад

      for very small data sizes compression may yield worse results than not compressing at all. Also data with little to no repetition will compress very poorly

  • @FunkyDisco79
    @FunkyDisco79 25 дней назад +1

    1:30 and 2:30 Wrong code, it should be AAC.

  • @lucasantosmartins9084
    @lucasantosmartins9084 2 года назад

    wow thanks

  • @alan2here
    @alan2here 6 лет назад +2

    all anchors lost, not doing well since the amputation, my markets are too bad for quotation, everyone else inside giant fish, send help :-/

  • @KainniaK
    @KainniaK Год назад +1

    Lempel-Ziv is a very old and obsolete technique now that we have middle-out.

  • @jaypalsha1701
    @jaypalsha1701 4 года назад

    nice

  • @toyodathon08
    @toyodathon08 6 лет назад

    How do you delimit between symbols?

  • @mo5ch
    @mo5ch 6 лет назад +1

    If you have the last sequence ABA, why do you replace AB with the value in the lookup table, but not the last A?
    E.g. if we had ABAB, wouldn't we replace it with 22?

    • @WurstRELOADED
      @WurstRELOADED 6 лет назад +11

      The simple answer is "because that's how the algorithm is defined". You always find the longest sequence that is in your table already and add exactly one letter. If you would always compress multiple messages, then you would quickly run into trouble. For example, if your message is ABAABABBBABABA, then after the first two steps, your table would be "A-1, B-2". After that, you could "compress" the entire message as 112122212121. This wouldn't actually save you any space though, because you mapped one letter to one number.

    • @pedrostuginski7616
      @pedrostuginski7616 6 лет назад +2

      Basically because you don't have spaces, so you wouldn't be able to know if you have "two one" or "twenty-one". Remember that in a real system you just have 0 and 1.

  • @SetMyLife
    @SetMyLife 6 лет назад +1

    Awesome. You had actual A. Lempel as a consultant?

    • @ArtOfTheProblem
      @ArtOfTheProblem  6 лет назад +3

      That's correct, we were lucky to have the original authors participate in all the "information age" videos we've done together.

  • @julianmahler2388
    @julianmahler2388 3 года назад

    Very good explanation, thank you! However if you try the method on "TESTTESTTEST" it will make the dictionary ['T', 'ES', 'TT', 'EST', 'TE', 'ST'] and it'll never find out that compressing it as 3 * 'TEST' would be much more efficient? Or am I missing something?

    • @porglezomp7235
      @porglezomp7235 2 года назад +1

      Modern LZ approaches are able to have overlapping components-the codes are just described in terms of the previous values, so you could encode that as like
      4,0,8TEST, which says "take 4 literals, and starting from 0 symbols back, copy 8 symbols"
      so it would first write out:
      TEST
      ^
      and then copy 8 symbols,
      after 4: TESTTEST
      ^
      after 8: TESTTESTTEST
      ^

    • @FriedMonkey362
      @FriedMonkey362 Год назад

      T,1E,2S,3T,4,4,4 itls works efriencet and amXing

  • @Bc232klm
    @Bc232klm 6 лет назад +1

    Could you use names other than Alice or Bob?

    • @MusicBent
      @MusicBent 6 лет назад

      cubs0110 Adam and Betty
      Idk, apparently it’s just a tradition in computer / communication science

  • @flytape8490
    @flytape8490 5 лет назад

    Do bzip2 next

  • @griggiorouge
    @griggiorouge 6 лет назад

    1 person is nostalgic for the seamen

  • @kevinmaison9403
    @kevinmaison9403 6 лет назад +3

    ABBA is 4, Mamma Mia

  • @youralbaniandad8459
    @youralbaniandad8459 3 года назад

    thank you you saved my ass

    • @ArtOfTheProblem
      @ArtOfTheProblem  3 года назад

      happy to help, I remember this crushed me in school

  • @studentcommenter5858
    @studentcommenter5858 6 лет назад

    So basically they are finding prefix codes on the fly and sending them.

  • @MugiwaraSuponji
    @MugiwaraSuponji 5 лет назад +1

    If this series of videos was a psyop by IEEE Information Theory Society to steal away electrical engineers from other, non-information theory subdomains, well..........it might be working on me! :O

  • @LongfellowBrady
    @LongfellowBrady 3 месяца назад

    92286 Pasquale Camp

  • @1schwererziehbar1
    @1schwererziehbar1 6 лет назад

    I am very skeptical of the details of your example.

  • @MehrshadGolesorkhi
    @MehrshadGolesorkhi 6 лет назад +6

    Great, but jif? Really?

  • @harshedabdulla1269
    @harshedabdulla1269 16 дней назад +2

    thank you