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• FATE’s New Look

  4 août 2010, par Multimedia Mike — FATE Server

  The FATE main page exposes a lot of data. The manner in which it is presented has always been bounded by my extremely limited web development abilities. I wrestled with whether I should learn better web development skills first and allow that to inform any improved design, or focus on the more useful design and invest my web development learning time towards realizing that design.

  Fortunately, Mans solved this conundrum with an elegantly simple solution :

  
  
  

  The top of the page displays a status bar that illustrates — at a glance — how functional the codebase is. The web page source code identifies this as the failometer. It took me a few seconds to recognize what information that status bar was attempting to convey ; maybe it could use a succinct explanation.

  Mini-Book Review
  
  Before Mans took over, I thought about this problem quite a bit. I needed inspiration for creating a better FATE main page and aggregating a large amount of data in a useful, easily-digested form. Looking around the web, I see no shortage of methods for visualizing data. I could start shoehorning FATE data into available methods and see what works. But I thought it would be better to take a step back and think about the best way to organize the data. My first clue came awhile ago in the form of an xkcd comic : Blogofractal. Actually, the clue came from the mouseover text which recommended Edward Tufte’s "The Visual Display of Quantitative Information".

  
  
  

  I ordered this up and plowed through it. It’s an interesting read, to be sure. However, I think it illustrates what a book on multimedia and compression technology would look like if authored by yours truly— a book of technical curiosities from epochs past that discusses little in the way of modern practical application. Tufte’s book showed me lots of examples of infographics from decades and even centuries past, but I never concisely learned exactly how to present data such as FATE’s main page in a more useful form.

  Visualization Blog
  More recently, I discovered a blog called Flowing Data, authored by a statistics Ph.D. candidate who purportedly eats, sleeps, and breathes infographics. The post 11 Ways to Visualize Changes Over Time : A Guide offers a good starting point for creating useful data presentations.

  I still subscribe to and eagerly read Flowing Data. But I might not have as much use for data visualization now that Mans is on FATE duty.

• Sorenson Video 3 For Posterity

  12 août 2010, par Multimedia Mike — Software Museum

  On a recent dumpster dive, I procured a complete, never-been-opened copy of Sorenson Video 3 Professional Edition Compressor for Windows. And because I’m me, I thought it would be interesting to document it here :

  
  

  
  

  Not opened until now, anyway :

  
  
  

  I chuckled at the thought that I might open the user manual and find the complete data stream format listed therein. As expected, the guide offers a broad overview of video compression concepts (lossy vs. lossless, inter/intraframes, that kind of thing) and goes on to describe general guidelines for compressing different types of data. Then there is the feature reference. There are standard features and professional features (the latter includes things like bidirectional prediction, masking, and watermarking).

  I was hoping to figure out how to encode some video with this software. But I think I need full Quicktime Pro in order to do that. If you’re interested, here’s the user manual in PDF format : Sorenson Video 3 User Guide (626 Kbytes). Here’s an interesting claim from the chapter on audio compression :

  Most movies are made up of two parts, video and audio. Historically, the video portion of a digital movie was so large that the audio was only a minor piece of the puzzle. However, with Sorenson Video’s excellent compression capabilities it is possible to create a file where audio is the largest portion.

  I know it’s possible to do that, but is it really recommended ? I’m sure I have some samples in my vast repository where this is the case but it still doesn’t strike me as optimal for network delivery.

• New FATE Test Coverage System

  10 août 2010, par Multimedia Mike — FATE Server

  I’ve been feeling a bit scattered for the last week since I was fired from my volunteer position as the FFmpeg QA manager, wondering if there is anything I should attempt to do with the project. It can’t be denied that the new system is working well. But one area I’ve wondered about is test coverage.

  Under my old regime I tracked test coverage as a wiki page which was a highly flawed method— tedious and error-prone. There are those 2 adjectives again— tedious and error-prone ; whenever I see those, I search for automation methods. I think that might be more plausible thanks to the new FATE’s tighter integration with the FFmpeg build system.

  I don’t think anyone is working on this problem so I wanted to toss out a brainstorm :

  1. First, run ’ffmpeg -formats’, ’ffmpeg -codecs’, etc. and parse the output to collect a list of all the features (full list : -formats, -codecs, -bsfs, -protocols, -filters, -pix_fmts). Transform these lists into a standardized list of features, e.g., "DEVSD  ffvhuff         Huffyuv FFmpeg variant" represents features ’decode-video-ffvhuff’, ’encode-video-ffvhuff’, ’ffvhuff-horizband’, and ’ffvhuff-dr1’.
  2. Next, tag each individual test spec with the features that it exercises. E.g., test ’fate-vqa-cc’ exercises features ’demux-wsvqa’, ’decode-video-vqavideo’, and ’decode-audio-adpcm_ima_ws’.
  3. Finally, compare the data from parts 1 and 2. Print a list of all the features that are not exercised in FATE.

  I think a lot of this could be implemented at the GNU make level. Then again, I’m no expert on GNU make syntax so I may be overestimating its capabilities. Or there might be simpler ways to automatically track test coverage stats based on the improved testing infrastructure.