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• Tools for investigating video corruption — ffmpeg / libavcodec

  11 juillet 2013, par Gopherkhan

  In my current work I'm trying to encode some images to h264 video using the FFMPEG's C library. The resulting video plays fine in VLC, but has no preview image. The video can play in VLC and Mplayer on ubuntu, but won't play on Mac or PC (in fact, it causes a "VTDecoderXPCService quit unexpectedly" error on Mac).

  If I run the resulting file through FFMPEG using the command line, the resulting file has a preview image, and plays correctly everywhere.

  Apparently the file that I get out of the program is corrupt in some weird place, but I don't have any output during my compilation or run to indicate where. I can't share my code at the moment (work code isn't open source yet :-( ), but I have tried a number of things :

  1. Writing only header and trailer data (av_write_trailer) and no frames
  2. writing frames only minus the trailer (using avcodec_encode_video2 and av_write_frame)
  3. Adjusting our time_base and frame pts values to encode only one frame per second
  4. Removing all variable frame rate code
  5. Numerous other variants that I won't bother you with here

  In creating my project, I've also followed the following tutorials :

  • Dr. Anger's FFMPEG tutorial
  • FFmpeg's Own Tutorials
  • An older tutorial from FFmpeg

  And consulted the deprecated ffmpeg functions list

  And compiled FFMPEG on ubuntu according to the official doc

  But every run of the program runs into the exact same problem.

  My question is, is there anything obvious that causes a programmatic run of FFMpeg to differ from a console run (e.g., an incomplete finalization, some threading issues, etc.) ? Like some obvious reason that a console run could repair a corrupted file ? Or is there a decent tool/method for inspecting a video file and finding the point of corruption ?

• How to concatenate two videos w. ffmpeg — documented code not working

  2 mars 2014, par Jim Miller

  I'm trying to concatenate two videos with ffmpeg. Nothing fancy ; I just want one video that consists of video A immediately followed by video B.

  I've tried the code from How to concatenate (join, merge) media files on a freshly built and otherwise-working-fine install of ffmpeg 1.2.1 on Fedora 17, but the following error message appears :

  $ ffmpeg -i video_a.mov -i video_b.mov -filter_complex '[0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a]' -map '[v]' -map '[a]' output.mp4
  
  
  
  ffmpeg version N-54271-g7f866c1 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Jun 29 2013 11:05:42 with gcc 4.7.2 (GCC) 20120921 (Red Hat 4.7.2-2)
  
    configuration: --enable-gpl --enable-nonfree --enable-pthreads --enable-libx264 --enable-libfaac --extra-cflags=-I/usr/local/include --extra-ldflags=-L/usr/local/lib
  
    libavutil      52. 37.101 / 52. 37.101
  
    libavcodec     55. 17.100 / 55. 17.100
  
    libavformat    55. 10.100 / 55. 10.100
  
    libavdevice    55.  2.100 / 55.  2.100
  
    libavfilter     3. 77.101 /  3. 77.101
  
    libswscale      2.  3.100 /  2.  3.100
  
    libswresample   0. 17.102 /  0. 17.102
  
    libpostproc    52.  3.100 / 52.  3.100
  
  
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'v1221-MTQxMzcyNTIxODU2.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2013-03-28 20:34:59
  
      encoder         : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
      encoder-eng     : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
    Duration: 00:00:05.34, start: 0.000000, bitrate: 15837 kb/s
  
      Stream #0:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 221 kb/s
  
      Metadata:
  
        creation_time   : 2013-03-28 20:34:59
  
        handler_name    : Core Media Data Handler
  
      Stream #0:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 15512 kb/s, 29.81 fps, 30 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        creation_time   : 2013-03-28 20:34:59
  
        handler_name    : Core Media Data Handler
  
  
  
  Input #1, mov,mp4,m4a,3gp,3g2,mj2, from 'v1224-MTQxMzcyNTIxODg5.mov':
  
    Metadata:
  
      major_brand     : qt  
  
      minor_version   : 0
  
      compatible_brands: qt  
  
      creation_time   : 2013-03-28 20:36:28
  
      encoder         : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
      encoder-eng     : Mac OS X v10.8.3 (CMA 914, CM 926.87, x86_64)
  
    Duration: 00:00:04.13, start: 0.000000, bitrate: 15689 kb/s
  
      Stream #1:0(und): Audio: aac (mp4a / 0x6134706D), 44100 Hz, mono, fltp, 221 kb/s
  
      Metadata:
  
        creation_time   : 2013-03-28 20:36:28
  
        handler_name    : Core Media Data Handler
  
      Stream #1:1(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 15446 kb/s, 29.79 fps, 30 tbr, 600 tbn, 1200 tbc
  
      Metadata:
  
        creation_time   : 2013-03-28 20:36:28
  
        handler_name    : Core Media Data Handler
  
  
  
  Stream specifier ':0' in filtergraph description [0:0] [0:1] [1:0] [1:1] concat=n=2:v=1:a=1 [v] [a] matches no streams.

  A few other things to note :

  • The two videos I'm working with were shot with the same camera, so there shouldn't be any problems with aspect ratio or other gory video details.
  • I'm able to do other things with my ffmpeg installation, like convert one of those videos from .mov to .mp4 (yes, I had to recompile with faac...), which seems to vouch for both the ffmpeg and the video.
  • I've tried modifying the above invocation to produce a .mov file at the end, but I get the same error as before.
  • I've tried some stupid hacking tricks on the request above, like concatenating two copies of the same video, as well as some other invocations from other places around the web that involve filter_complex. Even on ones that were cited as working, I get the "matches no streams" message.

• What’s new in Piwik 2.16.0 ?

  1er février 2016, par Matthieu Aubry — About, Development, Uncategorized

  In this blog post we showcase what is new in Piwik 2.16.0 and why you should upgrade your Piwik to this latest release !

  Piwik 2.16.0 is currently in Release Candidate and you can already use it by following these simple instructions. Piwik 2.16.0 will be officially released in a few days.

  To see the list of all 250+ changes, read the Piwik 2.16.0 changelog.

  Long Term Support for Piwik 2.X

  Piwik 2.16.0 is our Long Term Support version for Piwik 2. Learn more about Piwik LTS.

  New : Custom Dimensions feature

  With Custom Dimensions you can assign any custom data to your visitors or actions (like pages, events, …) and then visualize the reports of how many visits, conversions, pageviews, etc. there were for each Custom Dimension. They are similar to Custom Variables see the comparison of Custom Dimensions and Custom Variables.

  The new Custom Dimensions plugin is available on the Piwik Marketplace.

  Learn more about creating, tracking, reporting, managing, segmenting custom dimensions in the Custom Dimensions user guide.

  

  

  

  View the list of all visitors who reached a specific goal

  All Goal reports now include a link below the Goal report summary, that lets you see in one click all users that have converted any of your Goals :

  

  Events reports : option to view all columns : min, max and avg values

  By default in Actions > Events report, the columns displayed are “Total events” (Total number of events) and “Total value” (the sum of event values). It is now possible to click on the footer icon to view more detailed columns about event values : minimum event value, maximum event value, and average event value.

  

  Allow zoom to country in realtime visitor map

  In the real time map in Piwik (which displays your users activity appearing in real time !), it is now possible to zoom on a given country :

  

  Export all Records : new ‘all’ option in the Row limit selector

  It is now possible to export all of the data in your reports directly from the user interface ! Select ‘all’ in the row limit selector before exporting your data reports :

  

  New themes on the Marketplace !

  Feel like a change of colors ? Try out the new community submitted Piwik Themes on the Marketplace ! Learn how to install a new theme in Piwik (in only a few clicks).

  

  Let Super User view and edit segments created by other users

  As a Super User of Piwik, it can be very useful to view all Custom Segments created by all users. Starting in Piwik 2.16.0 any Super User can now view all Segments for a given website in the Segment selector :

  • Segments that are shared with All users will now appear below a section “Shared with you :” (a segment can be shared to all users by any admin user by selecting “This segment is visible to All Users” in the Segment editor)
  • Segments that are not shared with anyone are now also visible under the section “Visible to you because you have Super User access :”

  

  New segment ‘deviceBrand’ to segment by Device Brand

  You can now segment by device brands such as Apple, Samsung, LG, Google, Nokia, Sony, Lenovo, Alcatel, etc. The complete list of device brands you can use is listed on the Segmentation developer guide.

  

  New segment ‘actionType’ to view only particular Actions types (pagesviews, downloads, outlinks, events…)

  Use the new “Action type” segment to view only particular actions such as : pageviews, contents, sitesearches, events, outlinks and downloads.

  

  New segment : ‘actionUrl’ to view any actions that matches a given URL

  Use the new “Action URL” segment to view any action that matches a given URL, whether they are Pageviews, Site searches, Contents, Downloads or Events.

  

  New segment operators : “Starts with” and “Ends with”

  The new segment operators “Starts with” and “Ends with” can come handy when creating Custom Segments, and complement well the existing segment operators : Contains, Does not contain, Equals, Not equals, Greater than or equal to, Less than or equal to.

  

  Learn more about Segmentation in our user guides or in the Segmentation developer guide.

  Making Piwik more accessible

  Web accessibility refers to the inclusive practice of removing barriers that prevent interaction with, or access to applications or websites, by people with disabilities. When sites are correctly designed, developed and edited, all users have equal access to information and functionality.

  In Piwik 2.16.0, and with the help of high school students from the Catalyst Academy, we have made several improvements that make Piwik more accessible :

  • Menu now include the ARIA metadata (to make menus easier to navigate and use)
  • Page titles and various key tooltips have been improved (to give a better context to the data)
  • Keyboard access has been much improvement and Piwik is starting to be usable with the keyboard ! (this is very useful as many users are not able to use a mouse, and they should be able to view Piwik reports with the keyboard only)
  • ‘Skip to main content’ link (when pressing the TAB key) now skips the cursor to the page content.
  • Search bar was further improved : try it by pressing the ‘f’ key (useful to open any Piwik report or page without using the mouse)

  New user preference : display times either as 24h format or AM/PM format

  Users can now select whether times should be displayed in 24h format (16:20) or in AM/PM format (4:20pm)

  

  Other admins and Super Users are not visible to users with ‘admin’ permissions anymore

  Piwik 2.16.0 just became even more respectful of your privacy : any user you created and assigned an “admin” permission will not be able to view all other usernames anymore. This change was requested by many Piwik users who rightfully preferred not to disclose all usernames to any ‘admin’ user.

  As a result of this change, when a user with ‘admin’ permission (admin user) wants to give additional permission to another user (target user), the admin user will now need to know the target username and enter it in the Manage Users interface :

  

  New Config file viewer

  A new menu entry Administration > Diagnostics > Config file, lets Super Users view all config values in the UI :

  This new screen serves several purposes :

  • help Piwik administrators discover and learn about all the possible config file settings that Piwik offers.
  • let Super Users and Admins easily view any overridden config.ini.php INI setting without having to open the config file on the server.

  

  New report ‘Personal settings > Custom Variables’ displays custom variable usage

  A new report visible to Super Users lets you see how your Custom Variables slots are being used, which ones are still unused, and how many times a given custom variable name was used.

  

  Learn more about Custom Variables.

  Improvements to Heartbeat feature to accurately count time spent on the last page

  The heartbeat feature which lets you accurately track how long do visitors spend on your website, has been improved in 2.16.0. If you would like to measure how long do people spend on your pages (even if they don’t interact with your website or app), then consider using the heartbeat feature. Learn more in our guide Accurately measure the time spent on each page.

  

  New AnonymousPiwikUsageMeasurement plugin
  

  AnonymousPiwikUsageMeasurement plugin was created for those who would like to measure how their Piwik services is being used. This plugin also sends anonymised tracking data to our demo-anonymous.piwik.org which will help us learn how your Piwik is used and how we could improve the application. Learn more about AnonymousPiwikUsageMeasurement plugin.

  

  Show a warning when Piwik is used as a SuperUser via HTTP

  It is highly recommended to use HTTPS (SSL) for your Piwik server. If you are logged in as a Super User and viewing any Administration pages, you will now see a warning notification message at the top of the screen inviting you to use HTTPS :

  

  MySQL 5.7+ support

  The awesome Piwik community has helped us identify several issues with MySQL 5.7 support and Piwik is now fully compatible with the latest MySQL version 5.7+. Piwik is officially compatible with MySQL >= 4.1 and up to Mysql 5.7 ! Piwik is also compatible with MariaDB.

  

  Better detection of new devices and robots

  Our Device Detector library can now detect many new types of devices : smart TVs, new tablets and mobile phones, and more. New bots were added to our list of bots to keep your analytics report meaningful.

  Learn more : What Device Detector is able to detect, About Device Detector.

  New Referrer Spammers

  Every week we keep updating our community-list of referrer spammers. More than 50 new spammers were added since the last Piwik release !

  Note that the list of referrer spammer is automatically updated every week in your Piwik, so you need to wait at most one week to benefit from the very latest list.

  Learn more about Stopping Referrer Spam in Analytics reports.

  

  Ability to support new SMS providers to send Scheduled Reports by text message

  When you create scheduled reports in Piwik, you can specify one or several email addresses (to send reports by email) and you can also configure phone numbers (so your reports are sent to your phone via text message). So far we only support one SMS Provider “Clockwork SMS” but it is now possible for anyone to create a very simple plugin that adds a new SMS Provider to Piwik.

  A new SMS Provider plugin was released on the Marketplace : FreeMobileMessaging. If you have a favorite SMS Provider, we encourage you to create a new plugin for it !

  Piwik PRO mentions

  A few new mentions of Piwik PRO were added into Piwik to let users know that they can get Professional Help, and additional services and products. For example a new widget was added to the default dashboard. If you provide your Piwik service to your own clients, maybe you would like to remove the Piwik PRO widget and other ads, see this FAQ : How do I remove from Piwik the links to “Piwik PRO” or to “Professional Services” ?

  Stability, Reliability and Performance

  Dozens of other bugs were fixed (including several Major bugs) and many small improvements are included in this release. All these changes make Piwik more stable and reliable, as well as easier to troubleshoot and maintain. We are proud to be able to offer Piwik 2.16.0 as our Long Term Support release !

  If you have any feedback, questions, suggestion, or bug to report, please join our Piwik Community Forums.

  We hope you will love this 2.16.0 release as much as we loved making it.

  Happy Analytics !