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• Trolls in trouble

  6 juin 2013, par Mans — Law and liberty

  Life as a patent troll is hopefully set to get more difficult. In a memo describing patent trolls as a “drain on the American economy,” the White House this week outlined a number of steps it is taking to stem this evil tide. Chiming in, the Chief Judge of the Court of Appeals for the Federal Circuit (where patent cases are heard) in a New York Times op-ed laments the toll patent trolling is taking on the industry, and urges judges to use powers already at their disposal to make the practice less attractive. However, while certainly a step in the right direction, these measures all fail to address the more fundamental properties of the patent system allowing trolls to exist in the first place.

  System and method for patent trolling

  Most patent trolling operations comprise the same basic elements :

  1. One or more patents with broad claims.
  2. The patents of (1) acquired by an otherwise non-practising entity (troll).
  3. The entity of (2) filing numerous lawsuits alleging infringement of the patents of (1).
  4. The lawsuits of (3) targeting end users or retailers.
  5. The lawsuits of (3) listing as plaintiffs difficult to trace shell companies.

  The recent legislative actions all take aim at the latter entries in this list. In so doing, they will no doubt cripple the trolls, but the trolls will remain alive, ready to resume their wicked ways once a new loophole is found in the system.

  To kill a patent troll

  As Judge Rader and his co-authors point out in the New York Times, “the problem stems largely from the fact that, [...] trolls have an important strategic advantage over their adversaries : they don’t make anything.” This is the heart of the troll, and this is where the blow should be struck. Our weapon shall be the mightiest judicial sword of all, the Constitution.

  The United States Constitution contains (in Article I, Section 8) the foundation for the patent system (emphasis mine) :

  The Congress shall have Power [...] To promote the Progress of Science and useful Arts, by securing for limited Times to Authors and Inventors the exclusive Right to their respective Writings and Discoveries.

  Patent trolls are typically not inventors. They are merely hoarders of other people’s discarded inventions, and that allowing others to reap the benefits of an inventor’s work would somehow promote progress should be a tough argument. Indeed, it is the dissociation between investment and reward which has allowed the patent trolls to rise and prosper.

  In light of the above, the solution to the troll menace is actually strikingly simple : make patents non-transferable.

  Having the inventor retain the rights to his or her inventions (works for hire still being recognised), would render the establishment of non-practising entities, which most trolls are, virtually impossible. The original purpose of patents, to protect the investment of inventors, would remain unaffected, if not strengthened, by such a change.

  Links

  • Taking on Patent Trolls to Protect American Innovation
  • Fact Sheet : White House Task Force on High-Tech Patent Issues
  • Make Patent Trolls Pay in Court
  • Constitution of the United States

• bigbluebutton ...

  7 mars 2015, par signo

  ---

  Hello i have a BigBlueButton (0.9.0-beta (622)) installation on Debian Wheezy (7.8) all is ok except archiving recordings...

  in the log (/var/log/bigbluebutton/archive-488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.log) i have always same message :

  I, [2015-03-06T11:48:19.320704 #4550]  INFO -- : Archiving events for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.
  
  W, [2015-03-06T11:48:19.851280 #4550]  WARN -- : Failed to archive events for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675. Permission denied - /var/bigbluebutton/recording/raw/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/events.xml (complete error below...)

  but all directory are writable by right user (tomcat7).

  More Info :

  bbb packages installed

  ii  bbb-apps                              0.9.0-1ubuntu88               amd64        BigBlueButton applications for Red5
  
  ii  bbb-apps-deskshare                    0.9.0-1ubuntu25               amd64        BigBlueButton deskshare module for Red5
  
  ii  bbb-apps-sip                          0.9.0-1ubuntu19               amd64        BigBlueButton SIP module for Red5
  
  ii  bbb-apps-video                        0.9.0-1ubuntu18               amd64        BigBlueButton video module for Red5
  
  ii  bbb-client                            0.9.0-1ubuntu235              all          BigBlueButton Flash client
  
  ii  bbb-config                            0.9.0-1ubuntu42               all          BigBlueButton configuration
  
  rc  bbb-demo                              0.9.0-1ubuntu8                amd64        BigBlueButton API demos
  
  ii  bbb-freeswitch                        0.9.0-1ubuntu38               amd64        BigBlueButton build of FreeSWITCH 1.5.x
  
  ii  bbb-mkclean                           0.8.7-1                       amd64        tool to clean and optimize Matroska and WebM files
  
  ii  bbb-office                            0.9.0-1ubuntu6                amd64        BigBlueButton wrapper for LibreOffice
  
  ii  bbb-playback-presentation             0.9.0-1ubuntu11               amd64        BigBluebutton playback of presentation
  
  ii  bbb-record-core                       0.9.0-1ubuntu37               amd64        BigBlueButton record and playback
  
  ii  bbb-red5                              0.9.0-1ubuntu25               amd64        The Red5 server for bbb
  
  ii  bbb-swftools                          0.9.2-1ubuntu14               amd64        The swftools files for bbb
  
  ii  bbb-web                               0.9.0-1ubuntu54               all          BigBlueButton API
  
  ii  bigbluebutton                         0.9.0-1ubuntu2                amd64        Open source web conferencing platform (bbb)

  ---

  bbb-conf —check

  BigBlueButton Server 0.9.0-beta (622)
  
                      Kernel version: 3.16.0-4-amd64(64-bit)
  
                              Memory: 12044 MB
  
  
  
  /var/www/bigbluebutton/client/conf/config.xml (bbb-client)
  
          Port test (tunnel): 2xx.xxx.xxx.xx
  
                                Red5: 2xx.xxx.xxx.xx
  
                useWebrtcIfAvailable: true
  
  
  
  /opt/freeswitch/conf/sip_profiles/external.xml (FreeSWITCH)
  
                      websocket port: 5066
  
                      WebRTC enabled: true
  
  
  
  /etc/nginx/sites-available/bigbluebutton (nginx)
  
                         server name: 2xx.xxx.xxx.xx
  
                                port: 80
  
                      bbb-client dir: /var/www/bigbluebutton
  
  
  
  /var/lib/tomcat7/webapps/bigbluebutton/WEB-INF/classes/bigbluebutton.properties (bbb-web)
  
                        bbb-web host: 2xx.xxx.xxx.xx
  
  
  
  /usr/share/red5/webapps/bigbluebutton/WEB-INF/red5-web.xml (red5)
  
                    voice conference: FreeSWITCH
  
                       capture video: true
  
                     capture desktop: true
  
  
  
  /usr/local/bigbluebutton/core/scripts/bigbluebutton.yml (record and playback)
  
                       playback host: 2xx.xxx.xxx.xx
  
  
  
  
  
  * Potential problems described below **
  
      # IP does not match:
  
      #                           IP from ifconfig: 172.xx.xxx.xx
  
      #   /etc/nginx/sites-available/bigbluebutton: 2xx.xxx.xxx.xx
  
      # Error: Unable to connect to port 1935 (RTMP) 2xx.xxx.xxx.xx
  
  
  
      # Error: Unable to connect to port 9123 (desktop sharing) on 212.xxx.xxx.xx

  ---

  ls -l /var/freeswitch/meetings/

  -rw-r--r-- 1 freeswitch daemon 5139984 Mar  6 11:44 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675-81976383.wav

  ---

  ls -l /usr/share/red5/webapps/video/streams/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/

  -rw-rw-r-- 1 red5 red5 438342 Mar  6 11:44 320x240-cztd6nyzasaz_1-1425642114164.flv

  ---

  ls -l /usr/share/red5/webapps/video/streams/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/

  -rw-rw-r-- 1 red5 red5 438342 Mar  6 11:44 320x240-cztd6nyzasaz_1-1425642114164.flv

  ---

  cat /usr/share/red5/webapps/video/WEB-INF/red5-web.xml

  <bean class="org.bigbluebutton.app.video.VideoApplication">
  
          <property value="true"></property>
  
          <property ref="redisRecorder"></property>
  
  </bean>

  ---

  cat /usr/share/red5/webapps/deskshare/WEB-INF/red5-web.xml

   <bean class="org.bigbluebutton.deskshare.server.stream.StreamManager">
  
      
  
      
  
   </bean>

  ---

  bbb-record —watch

  Every 2.0s: bbb-record --list20                                                                                                                                   Fri Mar  6 11:53:58 2015
  
  
  
  Internal MeetingID                                               Time                APVD APVDE RAS Slides Processed            Published           External MeetingID
  
  ------------------------------------------------------  ---------------------------- ---- ----- --- ------ -------------------- ------------------  -------------------
  
  57d9849193299cebe9409d1c98d175958331d34a-1425642748807  Fri 6 Mar 11:52:28 GMT 2015   X                  5
  
  488052dc7c095c74bf8992ec51a66298db04b765-1425642166675  Fri 6 Mar 11:42:46 GMT 2015  XXX         X       6

  ---

  bbb-record —debug

  E, [2015-03-06T11:48:20.335578 #4548] ERROR -- : Sanity check failed on 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675

  ---

  cat /var/log/bigbluebutton/archive-488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.log

  # Logfile created on 2015-03-06 11:48:19 +0000 by logger.rb/31641
  
  I, [2015-03-06T11:48:19.320704 #4550]  INFO -- : Archiving events for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.
  
  W, [2015-03-06T11:48:19.851280 #4550]  WARN -- : Failed to archive events for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675. Permission denied - /var/bigbluebutton/recording/raw/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/events.xml
  
  I, [2015-03-06T11:48:19.851428 #4550]  INFO -- : Fetching the recording marks for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.
  
  I, [2015-03-06T11:48:19.851501 #4550]  INFO -- : Getting record status events
  
  W, [2015-03-06T11:48:19.851585 #4550]  WARN -- : Failed to fetch the recording marks for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675. Permission denied - /var/bigbluebutton/recording/raw/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/events.xml
  
  I, [2015-03-06T11:48:19.851645 #4550]  INFO -- : Archiving audio /var/freeswitch/meetings/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675*.wav.
  
  W, [2015-03-06T11:48:19.851920 #4550]  WARN -- : Failed to archive audio for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675. Permission denied - /var/bigbluebutton/recording/raw/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/audio
  
  I, [2015-03-06T11:48:19.851981 #4550]  INFO -- : Archiving presentation for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.
  
  W, [2015-03-06T11:48:19.852257 #4550]  WARN -- : Failed to archive presentations for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675. Permission denied - /var/bigbluebutton/recording/raw/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/presentation
  
  I, [2015-03-06T11:48:19.852322 #4550]  INFO -- : Archiving deskshare for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.
  
  W, [2015-03-06T11:48:19.852561 #4550]  WARN -- : Failed to archive deskshare for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675. Permission denied - /var/bigbluebutton/recording/raw/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/deskshare
  
  I, [2015-03-06T11:48:19.852620 #4550]  INFO -- : Archiving video for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675.
  
  W, [2015-03-06T11:48:19.852834 #4550]  WARN -- : Failed to archive video for 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675. Permission denied - /var/bigbluebutton/recording/raw/488052dc7c095c74bf8992ec51a66298db04b765-1425642166675/video

  ---

  all folder under /var/bigbluebutton/ have same rights (drwxrwxrwx tomcat7 tomcat7)

  ls -l /var/bigbluebutton/

  total 40
  
  drwxr-xr-x 3 tomcat7 tomcat7 4096 Mar  6 11:42 488052dc7c095c74bf8992ec51a66298db04b765-1425642166675
  
  drwxr-xr-x 3 tomcat7 tomcat7 4096 Mar  6 11:52 57d9849193299cebe9409d1c98d175958331d34a-1425642748807
  
  drwxrwxrwx 2 tomcat7 tomcat7 4096 Mar  3 15:52 blank
  
  drwxrwxrwx 2 tomcat7 tomcat7 4096 Feb 17 17:17 configs
  
  drwxrwxrwx 2 tomcat7 tomcat7 4096 Mar  3 15:57 deskshare
  
  drwxrwxrwx 2 tomcat7 tomcat7 4096 Mar  3 15:57 meetings
  
  drwxrwxrwx 3 tomcat7 tomcat7 4096 Mar  3 15:52 playback
  
  drwxrwxrwx 3 tomcat7 tomcat7 4096 Mar  3 15:57 published
  
  drwxrwxrwx 6 tomcat7 tomcat7 4096 Mar  3 15:57 recording
  
  drwxrwxrwx 2 tomcat7 tomcat7 4096 Mar  3 15:57 unpublished

  ---

• Making Sure The PNG Gets There

  14 juin 2013, par Multimedia Mike — General

  Rewind to 1999. I was developing an HTTP-based remote management interface for an embedded device. The device sat on an ethernet LAN and you could point a web browser at it. The pitch was to transmit an image of the device’s touch screen and the user could click on the picture to interact with the device. So we needed an image format. If you were computing at the time, you know that the web was insufferably limited back then. Our choice basically came down to GIF and JPEG. Being the office’s annoying free software zealot, I was championing a little known up and coming format named PNG.

  So the challenge was to create our own PNG encoder (incorporating a library like libpng wasn’t an option for this platform). I seem to remember being annoyed at having to implement an integrity check (CRC) for the PNG encoder. It’s part of the PNG spec, after all. It just seemed so redundant. At the time, I reasoned that there were 5 layers of integrity validation in play.

  I don’t know why, but I was reflecting on this episode recently and decided to revisit it. Here are all the encapsulation layers of a PNG file when flung over an ethernet network :

  
  
  

  So there are up to 5 encapsulations for the data in this situation. At the innermost level is the image data which is compressed with the zlib DEFLATE method. At first, I thought that this also had a CRC or checksum. However, in researching this post, I couldn’t find any evidence of such an integrity check. Further, I don’t think we bothered to compress the PNG data in this project long ago. It was a small image, monochrome, and transferring via LAN, so the encoder could get away with signaling uncompressed data.

  The graphical data gets wrapped up in a PNG chunk and all PNG chunks have a CRC. To transmit via the network, it goes into a TCP frame, which also has a checksum. That goes into an IP packet. I previously believed that this represented another integrity check. While an IP frame does have a checksum, the checksum only covers the IP header and not the payload. So that doesn’t really count towards this goal.

  Finally, the data gets encapsulated into an ethernet frame which has — you guessed it — a CRC.

  I see that other link layer protocols like PPP and wireless ethernet (802.11) also feature frame CRCs. So I guess what I’m saying is that, if you transfer a PNG file over the network, you can be confident that the data will be free of any errors.