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• Writing A Dreamcast Media Player

  6 janvier 2017, par Multimedia Mike — Sega Dreamcast

  I know I’m not the only person to have the idea to port a media player to the Sega Dreamcast video game console. But I did make significant progress on an implementation. I’m a little surprised to realize that I haven’t written anything about it on this blog yet, given my propensity for publishing my programming misadventures.

  
  
  

  This old effort had been on my mind lately due to its architectural similarities to something else I was recently brainstorming.

  Early Days
  Porting a multimedia player was one of the earliest endeavors that I embarked upon in the multimedia domain. It’s a bit fuzzy for me now, but I’m pretty sure that my first exposure to the MPlayer project in 2001 arose from looking for a multimedia player to port. I fed it through the Dreamcast development toolchain but encountered roadblocks pretty quickly. However, this got me looking at the MPlayer source code and made me wonder how I could contribute, which is how I finally broke into practical open source multimedia hacking after studying the concepts and technology for more than a year at that point.

  Eventually, I jumped over to the xine project. After hacking on that for awhile, I remembered my DC media player efforts and endeavored to compile xine to the console. The first attempt was to simply compile the codebase using the Dreamcast hobbyist community’s toolchain. This is when I came to fear the multithreaded snake pit in xine’s core. Again, my memories are hazy on the specifics, but I remember the engine having a bunch of threading hacks with comments along the lines of “this code deadlocks sometimes, so on shutdown, monitor this lock and deliberately break it if it has been more than 3 seconds”.

  Something Workable
  Eventually, I settled on a combination of FFmpeg’s libavcodec library for audio and video decoders, xine’s demuxer library, and xine’s input API, combined with my own engine code to tie it all together along with video and output drivers provided by the KallistiOS hobbyist OS for Dreamcast. Here is a simple diagram of the data movement through this player :

  
  
  

  Details and Challenges
  This is a rare occasion when I actually got to write the core of a media player engine. I made some mistakes.

  xine’s internal clock ran at 90000 Hz. At least, its internal timestamps were all in reference to a 90 kHz clock. I got this brilliant idea to trigger timer interrupts at 6000 Hz to drive the engine. Whatever the timer facilities on the Dreamcast, I found that 6 kHz was the greatest common divisor with 90 kHz. This means that if I could have found an even higher GCD frequency, I would have used that instead.

  So the idea was that, for a 30 fps video, the engine would know to render a frame on every 200th timer interrupt. I eventually realized that servicing 6000 timer interrupts every second would incur a ridiculous amount of overhead. After that, my engine’s philosophy was to set a timer to fire for the next frame while beginning to process the current frame. I.e., when rendering a frame, set a timer to call back in 1/30th of a second. That worked a lot better.

  As I was still keen on 8-bit paletted image codecs at the time (especially since they were simple and small for bootstrapping this project), I got to use output palette images directly thanks to the Dreamcast’s paletted textures. So that was exciting. The engine didn’t need to convert the paletted images to a different colorspace before rendering. However, I seem to recall that the Dreamcast’s PowerVR graphics hardware required that 8-bit textures be twiddled/swizzled. Thus, it was still required to manipulate the 8-bit image before rendering.

  I made good progress on this player concept. However, a huge blocker for me was that I didn’t know how to make a proper user interface for the media player. Obviously, programming the Dreamcast occurred at a very low level (at least with the approach I was using), so there were no UI widgets easily available.

  This was circa 2003. I assumed there must have been some embedded UI widget libraries with amenable open source licenses that I could leverage. I remember searching and checking out a library named libSTK. I think STK stood for “set-top toolkit” and was positioned specifically for doing things like media player UIs on low-spec embedded computing devices. The domain hosting the project is no longer useful but this appears to be a backup of the core code.

  It sounded promising, but the libSTK developers had a different definition of “low-spec embedded” device than I did. I seem to recall that they were targeting something along with likes of a Pentium III clocked at 800 MHz with 128 MB RAM. The Dreamcast, by contrast, has a 200 MHz SH-4 CPU and 16 MB RAM. LibSTK was also authored in C++ and leveraged the Boost library (my first exposure to that code), and this all had the effect of making binaries quite large while I was trying to keep the player in lean C.

  Regrettably, I never made any serious progress on a proper user interface. I think that’s when the player effort ran out of steam.

  The Code
  So, that’s another project that I never got around to finishing or publishing. I was able to find the source code so I decided to toss it up on github, along with 2 old architecture outlines that I was able to dig up. It looks like I was starting small, just porting over a few of the demuxers and decoders that I knew well.

  I’m wondering if it would still be as straightforward to separate out such components now, more than 13 years later ?

  The post Writing A Dreamcast Media Player first appeared on Breaking Eggs And Making Omelettes.

• How you can use the Piwik AOM plugin to improve your data and make better online marketing decisions

  13 septembre 2017, par André Kolell — Plugins, AdWords, Bing, Case Study, Criteo, eccommerce tracking, Facebook Ads, how to install piwik analytics, how-to piwik, integration, piwik, Taboola

  Hi, this is André, one of the authors of the Piwik Advanced Online Marketing plugin, which has just hit 5,000 downloads on the Piwik marketplace. In this blog post I’ll show you how Piwik AOM improves your data and enables you to make better online marketing decisions.

  Piwik itself is excellent in tracking all kinds of visitor data, like where a visitor is coming from and what he’s doing on your page or app (pageviews, events, conversions). But what Piwik did not yet take a closer a look at, is how much you’ve invested into your marketing activities and how profitable they are.

  With the Piwik AOM plugin you can integrate data like advertising costs, advertising campaign names, ad impressions etc. from advertising platforms (such as Google AdWords, Microsoft Bing, Criteo, Facebook Ads and Taboola) and individual campaigns (such as such as cost per view/click/acquisition and fixed price per months deals) into Piwik and combine that data with individual Piwik visits.

  Piwik AOM adds a new marketing performance report to Piwik giving you a great overview of all your marketing activities with drill-down functionality :

  

   

  When taking a look at a specific visitor, Piwik AOM shows you the exact cost of acquiring a specific visit :

  

   

  Leveraging Piwik AOM’s full potential

  But although you can access Piwik AOM’s valuable data directly in the Piwik UI for ad-hoc analyses, Piwik AOM’s true strength comes into play when working with the raw data in an external business intelligence application of your choice, where you can further integrate Piwik AOM’s data with your most accurate backend data (like conversion’s contribution margins after returns, new vs. existing customer, etc.).

  Piwik AOM offers some API endpoints that allow you to fetch the data you need but you can also retrieve it directly from Piwik AOM’s aom_visits table, which includes all visits, all allocated advertising costs and advertising campaign details. As there is never data being deleted from aom_visits, the table can easily be connected to your ETL tool with its last update timestamp column. A third way to get data out of Piwik AOM is by developing your own Piwik plugin and listening to the AOM.aomVisitAddedOrUpdated event, which is posted whenever an aom_visits record is added or updated.

  Integrating Piwik AOM’s data with your backend data in the business intelligence application of your choice allows you to evaluate the real performance of your online marketing campaigns when applying different conversion attribution models, conduct customer journey analyses, create sophisticated forecasts and whatever you can think of.

  AOM Use case

  A company that followed this approach, is FINANZCHECK.de, one of Germany’s leading loan comparison websites. At the eMetrics summit 2016 in Berlin, Germany, I gave a talk about FINANZCHECK’s architectural online marketing setup. Until recently, FINANZCHECK used Pentaho data integration to integrate data from Piwik, Piwik AOM and additional internal tools like its proprietary CRM software into Jaspersoft, its data warehouse an BI solution. The enriched data in Jaspersoft was not only used for reporting to various stakeholders but also for optimising all kinds of marketing activities (e.g. bids for individual keywords in Google AdWords) and proactive alerting. Not long ago, FINANZCHECK started an initiative to improve its setup even further – I’ll hopefully be able to cover this in a more detailed case study soon.

  Roadmap

  In the past, we had the chance to make great progress in developing this plugin by solving specific requirements of different companies who use Piwik AOM. During the next months, we plan to integrate more advertising platforms, reimplement Facebook Ads, improve the support of individual campaigns and work on the general plugin stability and performance.

  Before you install Piwik AOM

  Before installing Piwik AOM, you should know that its initial setup and even its maintenance can be quite complex. Piwik AOM will heavily modify your Piwik installation and you will only benefit from Piwik AOM if you are willing to invest quite some time into it.

  If you are not familiar with Piwik’s internals, PHP, MySQL, database backups, cronjobs, creating API accounts at the advertising platforms or adding parameters to your advertising campaign’s URLs, you should probably not install it on your own (at least not in your production environment).

  Piwik AOM has successfully been tested with up to 25k visitors a day for a period of more than two years, running on an AWS server with 4 GB RAM, once CPU and a separate AWS RDS MySQL database.

  Ideas and Support

  If you have ideas for new features or need support with your Piwik AOM installation or leveraging your marketing data’s potential in general, feel free to get in touch with the plugin’s co-author Daniel or me. You can find our contact details on the plugin’s website http://www.advanced-online-marketing.com.

  How to get the Piwik AOM plugin ?

  The Piwik AOM plugin is freely available through the Piwik marketplace at https://plugins.piwik.org/AOM

  Did you like this article ? If yes do not hesitate to share it or give your feedback about the topic you would like us to write about.

• Open letter to the European Parliament’s LIBE committee

  28 novembre 2019, par Joselyn Khor — Uncategorized

  An open letter to the European Parliament’s LIBE committee

  

  In an effort to stem the tide of external control over user privacy, Matomo has rallied with other like-minded companies like Protonmail, NextCloud, Tutanota and Mailfence, to advocate for pro-privacy changes to the European Commission’s “e-evidence” proposal.

  Excerpt from the letter : 

  “The Commission’s e-evidence proposal threatens the competitive advantage European tech businesses have over their American counterparts by undermining the protections we can provide to our customers. It breaks with the long-standing rule that only trusted national judicial authorities can order companies to hand over customer data for criminal investigations. Instead, the Commission’s e-evidence proposal would allow any foreign law enforcement agency from across the EU to force us to hand out customer data without our own authorities doublechecking the foreign order.

  “Different from American Big Tech firms, European privacy tech companies lack the resources to verify the legality of each foreign order. Because of the way the e-evidence proposal is phrased, we would not even be able to properly authenticate foreign authorities to ensure that we are not replying to a malicious actor – let alone object to an order if we found it to be unwarranted.”

  Matomo Founder, Matthieu Aubry emphasises, “It is time that privacy-minded tech companies work together to defend their users, their businesses, and the values they are founded on. This is why we are supporting Privacy Tech Europe.”

  Read our open letter to members of the LIBE Committee in full.