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• Flash player seek not working when ffmpeg encoded with gop(-g) = 1 [migrated]

  3 mars 2015, par Brian

  I am trying to deliver video content with frame-by-frame viewing via the SMP Flash player. For encoding, I am using FFMPEG with the x264 video codec for files with .mp4 containers. I am using the latest ffmpeg build and using the OSMF SMP flash video player.

  I am taking a series of png files and creating a .mp4 file :

  ffmpeg -nostdin -loglevel warning  -i out.%d.png -g 1 -crf 15 -c:v libx264 -movflags faststart -pix_fmt yuv420p -r 24 out.mp4

  By encoding with the gop(-g) flag = 1, I am encoding to make each frame a keyframe. When I seek using the scrub bar of the SMP flash player, it always seeks to the start of the video. If I play and scrub/seek the video using the default HTML player, it works perfectly.

  When I encode with the gop(-g) flag = 2, the SMP Flash player scrubs/seeks and plays correctly.

  It looks like there may be some kind of bug or incompatibility with the Flash player. I have found this problem mentioned back in 2009. I think my only hope is to find a work around. Any suggestions ?

• Catalyst Open Source Academy

  16 janvier 2015, par Matthieu Aubry — Community

  The Open Source Academy is an initiative designed to provide training and work experience for young New Zealand technologists. Catalyst organises the Academy to show young technologists how to participate in open source communities and to fully explore their passion for IT through freely available open source tools.

  It has been running annually since 2011. We are proud that Piwik project could participate in the Academy again this year !

  What students got done

  It’s amazing what a few young students can get done in four days of participating in an open source project like Piwik ! They were able to quickly get started with Piwik, and continued to make useful contributions to the Piwik analytics platform.

  New Darkness theme

  Liam has created a new dark theme for Piwik called Darkness.

  

  To create the theme, Liam had to improve Piwik core stylesheets and created this pull request : Reuse the LESS variable for white color across all stylesheets.

  Accessibility improvements

  We were lucky to spend time with Julius, a Catalyst employee who is blind. He showed us in great detail how difficult and time consuming it can be for a blind user to use Piwik. For example we noticed how complicated it was for Julius to navigate the menus, to get to the main content, and to use the calendar and the Website selector. During this presentation we also noticed that Piwik was not yet usable with the keyboard.

  As a result of this session with Julius we got to work with the students to improve accessibility in Piwik.

  

  (photo source)

  List of accessibility improvements

  All these pull requests were created by the students and have been successfully merged into Piwik :

  • see the focus of menu items when tabbing through the page
  • Tweaks to improve accessibility (section around graph, better tooltip, set language in html)
  • Added h3 tags to widget headers
  • when main Menu is focused, display submenu
  • Add “Skip to content” feature when user presses tab key
  • Improved accessibility by putting offscreen text in the widget title

  To learn more about accessibility in Piwik check out this issue on our tracker.

  Summary

  Working with young students was fun and interesting. We were excited to see how much they got done in such a short time !

  At Piwik and Piwik PRO we are committed to building the best open analytics platform, and we will continue to support students who want to take part in the Piwik adventure.

  Be well,

• Problems accessing codecs with ggplot and gganimate

  19 décembre 2016, par noLongerRandom

  Using gganimate. Can’t figure out how to properly access functionality of ffmpeg, specifically I want to change the codec I’m using in the video file I’m outputting.

  # load packages
  
  library(ggplot)
  
  library(animation)
  
  library(gganimate)
  
  
  
  # Here's my data.frame
  
  myDf <- data.frame(
  
      year = c(1962, 1963, 1964, 1965, 1966, 1967, 1968, 1969, 1970, 1971, 1972, 1973, 1974, 1975, 1976, 1977, 1978, 1979, 1980, 1981, 1982, 1983, 1984, 1985, 1986, 1987, 1988, 1989, 1990, 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013, 2014), 
  
      bottom50 = c(0.195, 0.191, 0.187, 0.192, 0.196, 0.205, 0.207, 0.210, 0.209, 0.204, 0.203, 0.204, 0.205, 0.203, 0.202, 0.200, 0.200, 0.201, 0.199, 0.195, 0.190, 0.183, 0.179, 0.179, 0.177, 0.172, 0.169, 0.169, 0.168, 0.166, 0.158, 0.159, 0.158, 0.154, 0.151, 0.148, 0.149, 0.148, 0.146, 0.149, 0.148, 0.145, 0.142, 0.138, 0.135, 0.137, 0.137, 0.136, 0.130, 0.127, 0.123, 0.127, 0.125), top1 = c(0.126, 0.127, 0.129, 0.128, 0.126, 0.123, 0.122, 0.115, 0.110, 0.111, 0.111, 0.109, 0.106, 0.105, 0.105, 0.107, 0.108, 0.111, 0.107, 0.110, 0.112, 0.115, 0.125, 0.125, 0.122, 0.133, 0.149, 0.145, 0.145, 0.139, 0.150, 0.146, 0.147, 0.153, 0.160, 0.166, 0.169, 0.177, 0.183, 0.173, 0.171, 0.172, 0.183, 0.194, 0.201, 0.199, 0.195, 0.185, 0.198, 0.196, 0.208, 0.196, 0.202)
  
  )
  
  
  
  #Basic plot
  
  p <- ggplot(myDf, aes(x = year, y = bottom50, frame = year)) + 
  
      geom_line(color = "dodgerblue") + 
  
      geom_line(aes(y = top1), color = "darkred")

  The non-animated version gets me what I want :

  

  And I get an animation version output to video with :

  gganimate(p, interval = .1, title_frame = FALSE, "income.mp4")

  That’s fine, but I want to change some the output parameters, specifically : alter the dimensions, the frame rate, and use a different codec.

  # change some of the options
  
  ani.options(ani.height = 1080, ani.width = 1920, 
  
              interval = 0.04166667, other.opts = "-vcodec qtrle -f mov")
  
  # re-animate
  
  gganimate(p, title_frame = FALSE, "income.mov")

  That gives me the following error :

  Error in animation_saver(saver, filename) : 
  
    Don't know how to save animation of type mov

  I’m using ’.mov’ as my file extension because I’m trying to change to the Animation codec (so it’s no longer a .mp4 wrapper). I’ve got ffmpeg installed, so this is probably a syntax issue. But the documentation isn’t very clear here ; gganimate doesn’t have any documentation on changing codecs (or outputting any video besides an mp4), and the animation package is light on specifics as well.