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• Encode Frames to Video with C Library

  31 juillet 2018, par NetherGranite

  For the sake of continuity, let us assume "RGB values" are the following :

  typedef struct RGB {
  
      uint8_t r, g, b;
  
  } rgb;

  However, if you feel that a different color space is more appropriate for this question, please use that instead.

  How might I go about writing 2D arrays of RGB values to a video in C given an output format and framerate ?

  Before I continue, I should specify that I wish to be able to do this all within one program. I am trying to add functionality to an application that would allow it to compile videos frame by frame without having to leave it.

  Additionally, my needs for this functionality are extremely basic ; I simply need to be able to set individual pixels to certain colors.

  The closest I have come to a solution so far is the C library FFmpeg. Allow me to describe what I was able to learn on my own :

  After looking through its documentation, I came across the function avcodec_send_frame(avctx, frame), whose parameters are of the types AVCodexContext* and const AVFrame* respectively. If these are not the right tools for what I am trying to do, please ignore the rest of the question and instead point me towards what I should be using.

  However, I do not know which fields of avctx and frame must be set manually and which do not. The reason I assume some do not is because both are extremely large structures, but correct me if I am wrong.

  Question 1 : What values of an AVCodecContext and AVFrame must be set ? Of these, what is/are the recommended value(s) for each of them ?

  Additionally, I was only able to find instructions on how to initialize an AVFrame (using av_frame_alloc() and av_frame_get_buffer()) but not for an AVCodexConstant.

  Question 2 : Is there a proper way to initialize an AVCodexConstant ? And just in case, is the method of initializing an AVFrame described above correct ? Do any of the fields of either have a proper method of initialization ?

  Also, I was not able to find official documentation on how to take this AVCodexConstant (which I assume contains the video information) and turn it into a video. I apologize if the documentation for this is easy to find and I just missed it.

  Question 3 : How do I turn an AVCodexConstant into a file of a given format ?

  And, given my limited knowledge :

  Question 4 : Are there any other parts to this process that I am missing, and do I have any of the above parts wrong ?

  ---

  Please keep in mind that I found out about FFmpeg for the first time very recently, and as a result, I am a complete beginner to this. Additionally, my experience with C is very limited, so I would greatly appreciate it if you could note which files need to be included with #include.

  Feel free to even go as far as recommending something other than FFmpeg, just as long as it is written in C. I do not need power-user options, but I would greatly prefer flexibility in what audio and video file types the library can handle.

  ---

  Addressing Potential Duplicates

  I appologize for how long this section is ; I just want to have my bases covered. I heavily apologize, however, if this is in fact a duplicate of a question that I was just unable to find.

  • ffmpeg C API documentation/tutorial [closed] — This question was too open-ended and received answers pointing the asker towards a tutorial at dranger.com, a tutorial that confusingly muddied the waters by focusing heavily on a graphics library of choice. Please do not take this as me saying it is bad ; I am just enough of a beginner that I could not wade through it all.
  • Encoding frames to video with ffmpeg — Although this question seems to have been asking the same thing, it is geared towards Unreal Engine 4, and the asker provided sample code, making it difficult for me to understand which of parts of the accepted answer were necessary for me and which were not.
  • How to write frames to a video file ? — While this also asked the same thing, the accepted answer simply provides a command instead of an explanation of code.
  • YUV Raw frames to video stream — While the accepted answer for this question is a command, the question states that it is looking for a way to encode frames generated by C++ code. Is there some way to run commands in code that I haven’t been able to find ?
  • Converting sequenced frames to video — Not only is the asker’s code written in Python, but it also seems to use already-existing image files as frames.
  • How to write bitmaps as frames to H.264 with x264 in C\C++ ? — The accepted answer seems to describe a process that would take multiple applications, but I could be wrong as I am enough of a beginner that I am not sure exactly what it means other than Step 3.
  • How to write bitmaps as frames to Ogg Theora in C\C++ ? — Although it isn’t a problem that the question specifies the ogg format, it is a problem that the accepted answer suggests libtheora, which appears to only work with ogg files.

• Piwik 2.1 — Massive Performance and Reliability Improvements

  4 mars 2014, par Benaka M. — Community, Development

  We are very excited to announce the immediate availability of Piwik v2.1.0 !

  • Download Link
  • How to update Piwik ?
  • List of all tickets closed : Changelog

  Piwik 2.1 is the first release after our 2.0 release and it reflects the new direction Piwik is moving in : better performance, more reliability and a better overall open platform ! We also released more plugins on the marketplace as well as helped developers build exciting new plugins for Piwik.

  This 2.1.0 release contains several performance and reliability improvements to the archiving process and to the new device detection process introduced in Piwik 2.0. It also includes a new email report format (CSV), a new marketplace plugin and overall more than 80 improvements (source).

  Massive Performance Improvements to Archiving

  The biggest improvement this release brings to Piwik are the various performance improvements made to the Archiving Process. These improvements include the following :

  • The amount of memory used has been reduced in some cases by 80% or more ! What used to require 8GB of memory will now only require 1GB. Piwik engineers analysed Profiler XHProf reports of Piwik under high load and implemented several improvements to archiving.
  • The cron script you can setup to automatically process your reports will now create new processes to perform asynchronous archiving instead issuing CURL http requests. This change results in increases to the performance and reliability of the Archiving Process.

  Bug Fixes and Performance Improvements to Device Detection

  In Piwik 1.12 we introduced a new device detection feature that could detect much more information than what we used before. Piwik 2.1 includes several bug fixes and improvements to this feature (such as detecting dozens of new devices, brands and models for smartphones, tablets and other devices). To use this feature, go to “Settings” then “Plugins” then activate the DevicesDetection plugin.

  New Default MySQL Database Type (InnoDB)

  This change doesn’t affect our existing Piwik users, but it does reflect our commitment to performance and reliability. We’ve changed the default MySQL database type to be InnoDB instead of Myisam. This will allow new users to immediately gain the benefits in reliability offered by InnoDB.

  New Marketplace Plugin – HTTP Authentication

  We’re releasing a new plugin on the marketplace that will allow you to use the HTTP authentication services provided by your webserver. Learn more about this plugin on the marketplace.

  New Email Format for Scheduled Reports

  The last big change in this release is a new email report format. You can now get your email reports as CSV files as well as HTML and PDF reports.

  Other Improvements

  In addition to performance improvements and new plugins, this release contains a few other smaller improvements described below.

  Changing segments in the Embedded Dashboard

  The embedded dashboard is the powerful feature that lets you include the Piwik Dashboard without the top menu and Piwik branding, directly within your application !

  This dashboard will now include the segment selector allowing you to change the current segment and create new segments, just as you would in the normal dashboard view :

  

  Multiple Super Users

  It’s now possible for your Piwik to have more than one Super User and for Super Users to have aliases :

  

  Learn more in the User guide : Managing Super Users in Piwik.

  Smart App Banners for our Mobile Apps

  Finally, in accord with our commitment to providing great User Experience, we’ve added a smart banner to Piwik so users that view Piwik from a mobile device will be informed of our amazing (and free !) mobile apps (for both iOS and Android).

  Participate in Piwik

  Are you a talented developer or an experienced User Interface designer ? If you have some free time and if you want to contribute to one of the most awesome open source projects around, please get in touch with the Piwik team, or read this page to learn more ?

  Summary

  For the full list of changes in Piwik 2.1 check out the Changelog.

  Thank you to the core developers, all the beta testers and users, our official supporters, the translators & everyone who reported bugs or feature requests. Also thank you to the software we use, and the libraries we use.

  Many of the improvements in this release come from the efforts of Piwik PRO experts. If you are looking for help to make the most of your analytics data, contact Piwik PRO. Learn more about us here.

  If you like what you read, please tell your friends and colleagues or write on your website, blog, forums, stackoverflow, etc.

  Enjoy !

• Piwik 2.1 — Massive Performance and Reliability Improvements

  4 mars 2014, par Benaka M. — Community, Development

  We are very excited to announce the immediate availability of Piwik v2.1.0 !

  • Download Link
  • How to update Piwik ?
  • List of all tickets closed : Changelog

  Piwik 2.1 is the first release after our 2.0 release and it reflects the new direction Piwik is moving in : better performance, more reliability and a better overall open platform ! We also released more plugins on the marketplace as well as helped developers build exciting new plugins for Piwik.

  This 2.1.0 release contains several performance and reliability improvements to the archiving process and to the new device detection process introduced in Piwik 2.0. It also includes a new email report format (CSV), a new marketplace plugin and overall more than 80 improvements (source).

  Massive Performance Improvements to Archiving

  The biggest improvement this release brings to Piwik are the various performance improvements made to the Archiving Process. These improvements include the following :

  • The amount of memory used has been reduced in some cases by 80% or more ! What used to require 8GB of memory will now only require 1GB. Piwik engineers analysed Profiler XHProf reports of Piwik under high load and implemented several improvements to archiving.
  • The cron script you can setup to automatically process your reports will now create new processes to perform asynchronous archiving instead issuing CURL http requests. This change results in increases to the performance and reliability of the Archiving Process.

  Bug Fixes and Performance Improvements to Device Detection

  In Piwik 1.12 we introduced a new device detection feature that could detect much more information than what we used before. Piwik 2.1 includes several bug fixes and improvements to this feature (such as detecting dozens of new devices, brands and models for smartphones, tablets and other devices). To use this feature, go to “Settings” then “Plugins” then activate the DevicesDetection plugin.

  New Default MySQL Database Type (InnoDB)

  This change doesn’t affect our existing Piwik users, but it does reflect our commitment to performance and reliability. We’ve changed the default MySQL database type to be InnoDB instead of Myisam. This will allow new users to immediately gain the benefits in reliability offered by InnoDB.

  New Marketplace Plugin – HTTP Authentication

  We’re releasing a new plugin on the marketplace that will allow you to use the HTTP authentication services provided by your webserver. Learn more about this plugin on the marketplace.

  New Email Format for Scheduled Reports

  The last big change in this release is a new email report format. You can now get your email reports as CSV files as well as HTML and PDF reports.

  Other Improvements

  In addition to performance improvements and new plugins, this release contains a few other smaller improvements described below.

  Changing segments in the Embedded Dashboard

  The embedded dashboard is the powerful feature that lets you include the Piwik Dashboard without the top menu and Piwik branding, directly within your application !

  This dashboard will now include the segment selector allowing you to change the current segment and create new segments, just as you would in the normal dashboard view :

  

  Multiple Super Users

  It’s now possible for your Piwik to have more than one Super User and for Super Users to have aliases :

  

  Learn more in the User guide : Managing Super Users in Piwik.

  Smart App Banners for our Mobile Apps

  Finally, in accord with our commitment to providing great User Experience, we’ve added a smart banner to Piwik so users that view Piwik from a mobile device will be informed of our amazing (and free !) mobile apps (for both iOS and Android).

  Participate in Piwik

  Are you a talented developer or an experienced User Interface designer ? If you have some free time and if you want to contribute to one of the most awesome open source projects around, please get in touch with the Piwik team, or read this page to learn more ?

  Summary

  For the full list of changes in Piwik 2.1 check out the Changelog.

  Thank you to the core developers, all the beta testers and users, our official supporters, the translators & everyone who reported bugs or feature requests. Also thank you to the software we use, and the libraries we use.

  Many of the improvements in this release come from the efforts of Piwik PRO experts. If you are looking for help to make the most of your analytics data, contact Piwik PRO. Learn more about us here.

  If you like what you read, please tell your friends and colleagues or write on your website, blog, forums, stackoverflow, etc.

  Enjoy !