{"id":3143,"date":"2011-02-08T22:40:23","date_gmt":"2011-02-09T06:40:23","guid":{"rendered":"http:\/\/multimedia.cx\/eggs\/?p=3143"},"modified":"2011-02-09T00:18:13","modified_gmt":"2011-02-09T08:18:13","slug":"googles-youtube-uses-ffmpeg","status":"publish","type":"post","link":"https:\/\/multimedia.cx\/eggs\/googles-youtube-uses-ffmpeg\/","title":{"rendered":"Google’s YouTube Uses FFmpeg"},"content":{"rendered":"

Controversy arose last week when Google accused Microsoft of stealing search engine results<\/a> for their Bing search engine. It was a pretty novel sting operation and Google did a good job of visually illustrating their side of the story on their official blog.<\/p>\n

This reminds me of the fact that Google’s YouTube<\/a> video hosting site uses FFmpeg<\/a> for converting videos. Not that this is in the same league as the search engine shenanigans (it’s perfectly legit to use FFmpeg in this capacity, but to my knowledge, Google\/YouTube has never confirmed FFmpeg usage), but I thought I would revisit this item and illustrate it with screenshots. This is not new information– I first empirically tested this fact 4 years ago<\/a>. However, a lot of people wonder how exactly I can identify FFmpeg on the backend when I claim that I’ve written code that helps power YouTube.<\/p>\n

Short Answer<\/strong>
\nHow do I know YouTube uses FFmpeg to convert multimedia? Because:<\/p>\n

    \n
  1. FFmpeg can decode a number of impossibly obscure multimedia formats using code I wrote<\/li>\n
  2. YouTube can transcode many of the same formats<\/li>\n
  3. I screwed up when I wrote the code to support some of these weird formats<\/li>\n
  4. My mistakes are still present when YouTube transcodes certain fringe formats<\/li>\n<\/ol>\n

    Longer Answer (With Pictures!)<\/strong>
    \nLet’s take a     video format named RoQ<\/a>, developed by noted game designer Graeme Devine<\/a>. Originated for use in the FMV-heavy game The 11th Hour<\/a>, the format eventually found its way into the Quake 3 engine as well as many games derived from the same technology.<\/p>\n

    Dr. Tim Ferguson reverse engineered the format (though it would later be open sourced along with the rest of the Q3 engine<\/a>). I wrote a RoQ playback system for FFmpeg, and I messed up in doing so. I believe my coding error helps demonstrate the case I’m trying to make here.<\/p>\n

    Observe what happened when I pushed the jk02.roq<\/a> sample through YouTube<\/a> in my original experiment 4 years ago:<\/p>\n


    \n\"\"
    \n<\/center><\/p>\n

    Do you see how the canyon walls bleed into the sky? That’s not supposed to happen. FFmpeg doesn’t do that anymore but I was able to go back into the source code history to find when it did do that:<\/p>\n


    \n\"\"
    \n<\/center><\/p>\n

    Academic Answer<\/strong>
    \nFFmpeg fixed this bug in June of 2007 (thanks to     Eric Lasota<\/a>). The problem had to do with premature colorspace conversion in my original decoder.<\/p>\n

    Leftovers<\/strong>
    \nI tried uploading the video again to see if the problem persists in YouTube’s transcoder. First bit of trivia: YouTube detects when you have uploaded the same video twice and rejects the subsequent attempts. So I created a double concatenation of the video and uploaded it. The problem is gone, illustrating that the backend is actually using a newer version of FFmpeg. This surprises me for somewhat esoteric reasons.<\/p>\n

    Here’s another interesting bit of trivia for those who don’t do a lot of YouTube uploading– YouTube reports format details when you upload a video:<\/p>\n


    \n\"\"
    \n<\/center><\/p>\n

    So, yep, RoQ format. And you can wager that this will prompt me to go back through the litany of unusual formats that FFmpeg supports to see how YouTube responds.<\/p>\n","protected":false},"excerpt":{"rendered":"

    Visual evidence that YouTube uses FFmpeg on its transcoding backend<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-3143","post","type-post","status-publish","format-standard","hentry","category-general"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t