Category Archives: General

Libav/FFmpeg and Google Summer of Code 2012

So, the projects are participating in the Google Summer of Code for the 2012 season. (While Libav is the project officially accepted to particular, I still refer to the projects because FFmpeg will also benefit).

Here are the students, projects, and mentors for this summer:

  1. Andrew D’Addesio is working on an Opus Decoder, mentored by Justin Ruggles
  2. Guillaume Martres is working on an HEVC video decoder, mentored by Mashiat Sarker Shakkhar
  3. Jan Ekström is working on an LGPL Ut Video encoder, mentored by Kostya Shishkov
  4. Jordi Ortiz is working to rewrite avserver, mentored by Luca Barbato
  5. Samuel Pitoiset is working on an RTMP[E|S|T|TE] protocol implementation, mentored by Martin Storsjö

Wish them luck– these are some ambitious projects.

Solving The XVD Puzzle

I downloaded a multimedia file a long time ago (at least, I strongly suspected it was a multimedia file which is why I downloaded it). It went by the name of ‘lamborghini_850kbps.vg2’. I have had it in my collection for at least 7 years. I couldn’t remember where I found it. I downloaded it before it occurred to me to take notes about this sort of stuff.

I found myself staring at the file again today and Googled the filename. This led me to a few Japanese sites which also contained working URLs for a few more .vg2 samples. Some other clues led me to a Russian language forum where someone had linked to a site that had Win32 codec modules that could process the files. The site was defunct but the Internet Archive Wayback Machine kept a copy for me, as well as copies of several more .vg2 samples from a defunct Japanese site previously involved with this codec.

Sometimes this internet technology works really well. But I digress.

Anyway, through all this, I finally found a clue: XVD. and wouldn’t you know, there is already a basic page on the MultimediaWiki describing the technology. In fact, while VG2 is a custom container, the MultimediaWiki states that the video component has a FourCC of VGMV, and there is already a file named VGMV.avi in the root V-codecs/ samples directory, something I vow to correct (that’s a big pet peeve of mine– putting samples in the root V-codecs/ or A-codecs/ directories).

XVD… XVD… XVD… why does that sound so familiar? Oh, of course; there is a company named XVD and they have an office in the Bay Area which I have passed on numerous occasions, like this morning:


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Someone originally connected with the multimedia technology in question operates a website which contains an unofficial history of the XVD tech. At first, I was wondering if the technology was completely defunct (and should therefore be open sourced). But if XVD’s solutions page (dated 2010) is to be believed, the technology is still in service, and purported to be better than H.264 and VC-1: “The current generation of XVD video compression technology provides better video quality at any given data rate than standards-based codecs (H.264 or VC-1) with four times lower encoding complexity (when compared with H.264 Main Profile).”

If they say so. For my part, I’m just happy that I have finally figured out what this lamborghini_850kbps.vg2 is so that I can properly catalog it on the samples site, which I have now done, along with other samples and various codecs modules.

This episode reminds me that there’s a branch office of Zygo Corporation close to my home (though the headquarters are far, far away). The companies you see in Silicon Valley. Anyway, long-time open source multimedia hackers will no doubt recognize Zygo from the ZyGo FourCC & video codec transported in QuickTime files that was almost decode-able using an H.263 decoder.



I may never learn what Zygo’s core competency actually is, but I will always remember their multimedia tech every time I run past their office.

G.I. Joe Custom Multimedia

I received this 3-disc set of G.I. Joe CD-ROMs today:



Copyright 2003, and labeled as PC ONLY. Each disc claims to have 2 episodes. So are these some sort of video discs? Any gaming elements? I dove in to investigate.

So, it turns out that there are some games on these discs, done in Flash Player (which tells me that these were probably available on the web at some point). Here’s a shooting gallery game from the first disc:



As promised by the CD-ROM copy, the menu does grant access to 2 classic G.I. Joe episodes. Selecting either one launches this:



Powered by C-ezy? Am I interpreting that correctly? Anyway, the video player goes fullscreen and looks fine (given the source material). I can’t capture screenshots and controls are limited to: space for pause, ESC to exit player, and up/down to control volume. No seeking and certainly no onscreen controls. Pretty awful player.

Studying the first disc, I find a 550 MB file with the name 5859Hasbro.egm. Coupled with ep58.cfg and ep59.cfg files in the same directory, I gather that the disc has G.I. Joe episodes 58 and 59 (though the exact episodes, “There’s No Place Like Springfield” parts 1 and 2, are listed on Wikipedia as being episodes 154 and 155; but who’s counting?). The cfg files contain this text:

ep58.cfg:
EGM_GIJOE.exe
5859Hasbro.egm /noend /track:0 /singletrack 

ep59.cfg:
EGM_GIJOE.exe
5859Hasbro.egm /noend /track:1 /singletrack

The big EGM file starts with the string “Egenie Player”. After that, I see absolutely no clues. The supporting EGM_GIJOE.exe file has some interesting strings: “Decore Bits Per Pixel” (I know I have seen “Decore” used to mean “decoding core” in some libraries), “Egenie Player – %s, Version:%s”, “4th June 2002”, a list of common FourCC tags seen in AVI files, “Brought to you by Martin, Patrick Bob and Bren” (do you suppose “Patrick Bob” is one person’s name?), a list of command line options…

Aha! A URL: http:\\www.e-genie.tv (yep, backslashes, not forward slashes). e-genie.tv seems to redirect to mygenie.tv, which… doesn’t appear to be strictly related to video technology these days.

WMA Lossless and ProRes Encoder

The projects (FFmpeg / Libav) just got a WMA lossless decoder. For those keeping score, this means that there are open source methods for decoding every single one of Microsoft’s proprietary audio codecs (Windows Media Audio, or WMA): WMA v1, WMA v2, WMA9/Pro, WMA Voice, and now WMA lossless. Currently, it’s only advertised to decode 16-bit audio (no 24-bit). Also, when I first tried it a few days ago, it didn’t decode the very end of the single sample file I concocted many years ago (luckynight.wma). But that might be cleared up by now.

Some other recent developments in the projects that I wanted to call out: An encoder for the Apple ProRes encoder from Kostya; XWD (X window dump) image decoding and encoding from Paul B. Mahol; a Sun rasterfile encoder from Aneesh Dogra.

And then there’s the new playback system for CDXL files, also courtesy of Paul B. Mahol. I wasn’t familiar with this format until I wrote this post, which is surprising, given the format’s vintage. This was a CD-ROM FMV format favored for Amiga computers. Here it is in all its 160x120x10fps glory:



That’s the amigaball.cdxl sample available in the repository. The sample is 3835910 bytes large and plays for about 24 seconds. This yields a data rate of about 159 kbytes/second. So, yeah, single-speed CD-ROM FMV.