p For those who like their PL History presented in avante guard beat poetry, a video of Steele amp; Gabriel's a href='http://blog.jaoo.dk/2008/11/21/art-and-code-obscure-or-beautiful-code/'50 in 50/a speech at JAOO is made to order. Or as the link says:/p blockquote p A fun, artistic and enlightning presentation full of interesting facts - and who better to do it than Richard P. Gabriel and Guy L. Steele (the great Quux). Nothing more to say than the rallying cry; More cowbell!/p/blockquote p Passing aside the Stephen Wright comic delivery of the two speakers, there are a lot of interesting thoughts, though very few are dwelled on. I think the most interesting things were the languages that they chose as expositions for the major ideas that they covered. Here's the ones that I picked out (though I ended up with only 49):/p blockquote table border='2'tr valign='top'td nowrapb Do Loops/b/tdtd Fortran (Pascal,APL)/tdtd nowrapb Guarded Commands/b/tdtd Algol-68/td/trtr valign='top'td nowrapb Array Origin/b/tdtd C, Fortan, Pascal, APL/tdtd nowrapb Extensible Language/b/tdtd PPL/td/trtr valign='top'td nowrapb Domain Specific Language/b/tdtd APT/tdtd nowrapb Structured Programming/b/tdtd BLISS, INTERCAL/td/trtr valign='top'td nowrapb Text vs. Environment/b/tdtd Algol-60, Lisp, Smalltalk/tdtd nowrapb Language as Educational Tool/b/tdtd Logo/td/trtr valign='top'td nowrapb Stack Machines/b/tdtd Befunge (SECD Machine, Forth)/tdtd nowrapb Formal Dynamic Semantics/b/tdtd SECD/td/trtr valign='top'td nowrapb Data Parallelism/b/tdtd APL/tdtd nowrapb Enumerated Types/b/tdtd Pascal/td/trtr valign='top'td nowrapb Coercion/b/tdtd PL/I (Fortran-V)/tdtd nowrapb Backtracking and Theorem Proving/b/tdtd Conniver (Prolog)/td/trtr valign='top'td nowrapb Hierarchical Records/b/tdtd COBOL/tdtd nowrapb Argument Handling/b/tdtd Common Lisp, Ada, Python (VB, C#, Suneido, PL/pgSQ)/td/trtr valign='top'td nowrapb Pointers amp; Lists/b/tdtd IPL-V/tdtd nowrapb Coding in Natural Language/b/tdtd Perligata (COBOL, Hypercard)/td/trtr valign='top'td nowrapb Parsing/b/tdtd Yacc (LR1, Recursive Descent)/tdtd nowrapb Computational Drama/b/tdtd Shakespeare/td/trtr valign='top'td nowrapb Linked Records/b/tdtd AED/tdtd nowrapb Reasoning/b/tdtd Prolog/td/trtr valign='top'td nowrapb Mathematical Syntax/b/tdtd MADCAP, MIRFAC, Kleerer-May System/tdtd nowrapb Type Declarators/b/tdtd C/td/trtr valign='top'td nowrapb Line Numbers/b/tdtd Basic (Focal, APL)/tdtd nowrapb Data Abstraction/b/tdtd CLU, Alphard/td/trtr valign='top'td nowrapb Visual Languages/b/tdtd Piet/tdtd nowrapb Dynamic vs. Lexical Scoping/b/tdtd Scheme/td/trtr valign='top'td nowrapb Pattern Matching amp; Replacement/b/tdtd COMIT, SNOBOL/tdtd nowrapb Knowledge Representation/b/tdtd KRL (Conniver, Microplanner)/td/trtr valign='top'td nowrapb Branding/b/tdtd Ada (COMIT, SNOBOL, TRAC)/tdtd nowrapb Stream Processing/b/tdtd Lucid/td/trtr valign='top'td nowrapb Dynamic Languages/b/tdtd AMBIT/L/tdtd nowrapb Generic Functions/b/tdtd Lisp/td/trtr valign='top'td nowrapb Program as Data/b/tdtd Lisp/tdtd nowrapb Reflection/b/tdtd Lisp/td/trtr valign='top'td nowrapb Macro Processor/b/tdtd TRAC, ML/I, Limp, M4/tdtd nowrapb Metacircular Interpreters/b/tdtd Lisp/td/trtr valign='top'td nowrapb Call By Name vs. Call By Value/b/tdtd C, Algol-60/tdtd nowrapb Functional Programming/b/tdtd KRC/td/trtr valign='top'td nowrapb Dangling Else/b/tdtd Algol-60/tdtd nowrapb Control Parallelism/b/tdtd Occam/td/trtr valign='top'td nowrapb Formal Static Semantics/b/tdtd Algol-68/tdtd nowrapb Domain Specific Languages/b/tdtd HQ9+, MUMBLE/td/trtr valign='top'td nowrapb Algebraic Formula Manipulation/b/tdtd Formac (Macsyma, Mathematica)/tdtd nowrapb Build Languages/b/tdtd Make, Ant, Rake (JCL)/td/trtr valign='top'td nowrapb Message Passing/b/tdtd Smalltalk (C++, C#, Java, Flavors, Common Loops, CLOS, Scheme, Dylan, Simula, Self)/tdtd nowrapb Scripting/b/tdtd Perl/td/trtr valign='top'td nowrapb Objects/b/tdtd Simula (Smalltalk, C++, Java)/tdtd nowrapb /b/tdtd /td/tr/table/blockquote

pimg src="http://cache.gawker.com/assets/images/gizmodo/2008/11/codecsarentgoodlkepancakes.jpg" width="807" height="414" style="display:block;float:none;" /Once upon time, video codecs and formats were really only the concern of AV nerds, anime freaks and hardcore not-so-legal movie downloaders. Now, even the most part-time of geeks has to deal with them, whether they're trying to stream a flick across their house with an Apple TV, dump some video onto their phone or just trying to grab last night's episode of Dexter because they, uh, forgot to renew their Showtime subscription that'll work in their media player. It's messy and annoying, but we're here to clean it up. Take a deep breath./p pYou might recall our discussion about a href="http://gizmodo.com/5048025/giz-explains-why-hd-video-downloads-arent-very-high-def"video bitrates earlier/a, or how much data is packed into a file. As a general rule, more bits per second translates into more betterer quality audio and video. The variable in thatmdash;the other part of the equationmdash;is how the content is compressed and de-compressed. Better compression techniquesmdash;the zen of knowing what bits of data to pull out to make big data chunks smallermdash;make for better quality video while taking up less space on your hard drive. Basically, the part you need to know is that codecs are the software that make that magic happen./p pstrongStandard Standards/strongbr bull; strongH.261/strong is not a term you have to worry about, but it's the technology a href="http://www.javvin.com/protocolH261.html"that most video standards and codecs/a were originally based on. Originating in 1990, it's the first major digital video compression standard, and like other "H" standards, it was developed by the International Telecommunication Union. This one was primarily for teleconferencing over ISDN lines, and as such, it looks like ass./p pbull; strongMPEG-1 Part 2/strong is another oldie, developed by the a href="http://www.chiariglione.org/mpeg/"Movie Picture Experts Group/a and approved in 1991. (All of the MPEG codecs we talk about, btw, will have an associated layer, since the video section is only part of the full standard, which includes audio and other stuff. MPEG-1 Layer 3, you probably know, is MP3.) Based quite a bit on H.261, a href="http://bmrc.berkeley.edu/frame/research/mpeg/mpeg_overview.html"MPEG-1 was designed to take VHS quality video/a and squeeze it down to a bit rate of about 1.5Mbps, optimized for CD transfers. No surprise, it's the standard used for all VCDs (which can play in most DVD players), but not a standard you would see hanging around today./p pbull; With strongMPEG-2 Part 2/strong, approved in 1994, we're finally talking decent vid. Also known as H.262, since it was developed jointly by the ITU-T and ISO, a href="http://www.bbc.co.uk/rd/pubs/papers/paper_14/paper_14.shtml"MPEG-2 is an extension of MPEG-1/a that delivers better resolution and higher bit rates (3-15Mbps for standard def and 15-30Mbps for HD). It's the video codec used by DVD and digital television, though now it's slowly being replaced by the more efficient MPEG-4, except on DVDs, where it'll ride out that disc format's lifetime./p pbull; bH.263/b is a href="http://www.phonescoop.com/glossary/term.php?gid=197"designed for sending video over crappy connections/a. So it's used to encode most Flash video and to send video over mobile networks./p pbull; strongMPEG-4/strong is where we really stand right now. It has a much broader scope than past MPEG standards, aiming to tackle both the low end (crappy cellphones on a crappy network) and the high end (Blu-ray). It's still developing, so it's not-so-coincidentally a href="http://www.m4if.org/mpeg4/"where this whole story gets messier/a. There are two relevant parts of the MPEG-4 standard for our myopic video purposes: Part 2 and Part 10mdash;which is also known as H.264 or Advanced Video Coding (AVC). To be clear though, even though they're both part of the MPEG-4 standard, they're itotally different formats/i. Nevertheless, both are more efficient at compression than past MPEG codecs, delivering better quality using less space./p pbull;Okay, so if you've ever frequented a Torrent site, you've actually watched tons of videos that use strongMPEG-4 Part 2/strong, though it's not like they would've had a flashing sign telling you so. MPEG-4 Part 2 actually a href="http://74.125.45.132/search?q=cache:2-AcZvq6F8YJ:www.mpegif.org/public/documents/vault/m4-out-30037.pdf+mpeg-4+profileshl=enct=clnkcd=4gl=usclient=firefox-a"has different "profiles"/amdash;the two that matter being Simple Profile, for low bitrate, low-res stuff, and Advanced Simple Profile. The latter profile is what's used by movies you would download in formats like DivX or XviD or 3ivxmdash;which are all codecs that are essentially just differing implementations of the MPEG-4 Part 2 standard./p pbull;strongMPEG-4 Part 10/strong, the other part, was actually co-devopled by MPEG and the ITU-T, so it's also knownmdash;in fact, more commonly knownmdash;as H.264. It's more efficient than MPEG-2 and MPEG-4 Part 2, delivering the same quality video in as little as half the space, making it suitable for the low and high-end. Because of this, it's quickly becoming a href="http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC_Products_and_Implementations"the standardest standard/a. It's part of the HD DVD and Blu-ray spec, replacing MPEG-2 in digital TV (like with satellite services and ATT's U-Verse IPTV) and supported by pretty much every portable video player on the planet from the iPod to the PSP. Apple has a decent, if Kool-Aid flavored, a href="http://www.apple.com/quicktime/technologies/h264/faq.html"FAQ about H.264/a./p pbull;strongVC-1/strong is essentially a a href="http://www.microsoft.com/windows/windowsmedia/howto/articles/vc1techoverview.aspx"Microsoft developed alternative video codec/a to H.264 released as a standard by the Society of Motion Picture and Television Engineers, though it descends from the same H.26X/MPEG family. (It essentially started life as WMV9, but then a href="http://www.eetimes.com/showArticle.jhtml?articleID=50500181"Microsoft shopped it to the SMPTE/a to make it an industry standard, and now it is.) It too, is part of the mandatory Blu-ray and HD DVD spec, and is the official video codec of the Xbox 360. It's pitch is the same as H.264'smdash;trying to deliver better quality using less space, like HD video in 6-8Mbps./p pstrongFree-Floating Codecs/strongbr Okay, so all that stuff up there are industry-wide standard video codecs. On top of emall of those/em, various entities love putting out their own spin on those standards. As we mentioned before, DivX (a href="http://www.divx.com/"proprietary/a) and a href="http://www.xvid.org/"XviD/a (open source), for instance, use MPEG-4 Part 2 (more specifically, MPEG-4 ASP) compression, meaning stuff that'll natively play back MPEG-4 ASP will also play back DivX. a href="http://gizmodo.com/gadgets/xbox-360-divx%5Cxvid-test/xbox-360-divxxvid-tested-it-plays-almost-everything-329769.php"Like the Xbox 360/a, for instance. There are a ton of MPEG-4 ASP-based codecs, actually, like FFmpeg, 3ivx and others, but DivX and XviD are the most common. Same deal with H.264: Some well known codecs that use it are Apple's Quicktime H.264, x264 and Nero Digital. You've also got Windows Media Video (WMV) codecs, which are Microsoft's proprietary twists on industry standards./p pstrongContainers aka Wrappers/strongbr Alright, well you've probably noticed that none of your video files have the extension .h264 or .vc1 or the like. That's because videos are packaged in a href="http://www.doom9.org/glossary.htm#Container"containers or wrappers/a that stuff things like the audio, navigational info, etc. along with the video in a single pretty file. Naturally, there are about as many of them as there are codecs. To be clear, you would take a video encoded with, say, H.264, and wrap it up as a .MP4 file./p pThe majors ones are:br bull;AVI (Audio Video Interleave) is a href="http://www.jmcgowan.com/avi.html#Definition"Windows' standard multimedia container/abr bull;MPEG-4 Part 14 (known to you as .mp4) is the a href="http://en.wikipedia.org/wiki/MP4"standardized container for MPEG-4/abr ·:FLV (Flash Video) is the a href="http://www.adobe.com/devnet/flv/"format used to deliver video through Flash Player/abr bull;MOV is Apple's QuickTime a href="http://www.apple.com/quicktime/"container format/abr bull;OGG is an a href="http://www.xiph.org/"open standard container/abr bull;MKV (Mastroska) a href="http://www.matroska.org/"is another open specification container/a that you've seen if you've ever downloaded animebr bull;VOB a href="http://www.afterdawn.com/glossary/terms/vob.cfm"stands for DVD Video Object/a. Guess what? It's DVD's standard container, and what you get when you rip a DVD.br bull;ASF is a a href="http://www.microsoft.com/windows/windowsmedia/format/asfspec.aspx"Microsoft format designed/a for WMV and WMA. (Files can end in .wmv or .asf)./p pSo, in order to play a video file, your setup has to be able to handle both the actual video codec, and the container. It's why you can try to play an AVI file and Windows Media Player laughs at you, even though it totally played one a minute agomdash; the container was no problem, it didn't have the right codec. Or conversely, even though an iPod could play back an H.264 encoded video, if it was wrapped up in MKV, it couldn't read it./p pOkay, my brain hurts. Hopefully this will make yours hurt less when it comes to dealing with pesky videos. If you'd like to do even more homework, Wikipedia, as always, has a href="http://en.wikipedia.org/wiki/Video_codecs"a more in-depth discussion/a. And Doom9 a href="http://www.doom9.org/index.html?/codecs-final-105-1.htm"is always an amazing resource/a for all things digital video./p pemSomething you still wanna know? Send any questions about codecs, kitties or pad thai (but not RealMedia) to tips@gizmodo.com, with "Giz Explains" in the subject line./em/p p[Image: a href="http://www.flickr.com/photos/siebeneinhalb-de/2385134555/"ME/a@Flickr]/p br style="clear: both;"/ a href="http://www.pheedo.com/feeds/ht.php?t=camp;i=8b16e36f57caf7463dda52b4758c5125amp;p=1"img style="border:0;" src="http://www.pheedo.com/feeds/ht.php?t=vamp;i=8b16e36f57caf7463dda52b4758c5125amp;p=1" border="0" //adiv class="feedflare" a href="http://feeds.gawker.com/~f/gizmodo/full?a=FxSbpUqh"img src="http://feedproxy.google.com/~f/gizmodo/full?d=120" border="0"/img/a a href="http://feeds.gawker.com/~f/gizmodo/full?a=6oQdGflA"img src="http://feedproxy.google.com/~f/gizmodo/full?d=41" border="0"/img/a a href="http://feeds.gawker.com/~f/gizmodo/full?a=qLBnOvuS"img src="http://feedproxy.google.com/~f/gizmodo/full?i=qLBnOvuS" border="0"/img/a a href="http://feeds.gawker.com/~f/gizmodo/full?a=pIR4dxIP"img src="http://feedproxy.google.com/~f/gizmodo/full?i=pIR4dxIP" border="0"/img/a /divimg src="http://feedproxy.google.com/~r/gizmodo/full/~4/q1B1QOVLsx0" height="1" width="1"/