Sur d’autres sites (5546)

• Revision 6ce718eb18 : Merge "End of orientation zero group experiment" into experimental

  22 avril 2013, par Deb Mukherjee

  Changed Paths : Modify /vp9/decoder/vp9_decodframe.c Modify /vp9/encoder/vp9_encodemb.c Modify /vp9/encoder/vp9_rdopt.c Merge "End of orientation zero group experiment" into experimental

• Problems transcoding GoToMeeting output using FFmpeg

  20 avril 2014, par user3466413

  I’m having a nightmare of a time transcoding output from GoToMeeting, recorded using the latest OS X version, to something web-playable. No matter what settings I use, I end up with time syncing problems, at least with this particular recording.

  The .mov file looks like this. Note that it’s variable framerate, and because it’s mostly just a screencast of a PowerPoint presentation with occasional mouse movement, the output should be VFR too to produce a small file yet still preserve occasional motion.

  $ ffmpeg -i original.mov
  
  ffmpeg version N-58273-g18df75f Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Nov 19 2013 10:34:42 with Apple LLVM version 5.0 (clang-500.2.79) (based on LLVM 3.3svn)
  
    configuration: --enable-gpl --enable-version3 --enable-nonfree --enable-postproc --enable-libass --enable-libcelt --enable-libfaac --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-openssl --enable-libopus --enable-libschroedinger --enable-libspeex --enable-libtheora --enable-libvo-aacenc --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxvid --prefix=/usr/local
  
    libavutil      52. 53.100 / 52. 53.100
  
    libavcodec     55. 43.101 / 55. 43.101
  
    libavformat    55. 21.100 / 55. 21.100
  
    libavdevice    55.  5.100 / 55.  5.100
  
    libavfilter     3. 91.100 /  3. 91.100
  
    libswscale      2.  5.101 /  2.  5.101
  
    libswresample   0. 17.104 /  0. 17.104
  
    libpostproc    52.  3.100 / 52.  3.100
  
  [mov,mp4,m4a,3gp,3g2,mj2 @ 0x7f822980a000] decoding for stream 0 failed
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'original.mov':
  
    Metadata:
  
      major_brand     : qt
  
      minor_version   : 537199360
  
      compatible_brands: qt
  
      creation_time   : 2014-03-20 02:09:22
  
    Duration: 03:08:26.72, start: 0.000000, bitrate: 75 kb/s
  
      Stream #0:0(und): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv), 1368x728 [SAR 1:1 DAR 171:91], 20 kb/s, 0.60 fps, 600 tbr, 600 tbn, 1200 tbc (default)
  
      Metadata:
  
        creation_time   : 2014-03-20 02:09:22
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 16000 Hz, mono, fltp, 47 kb/s (default)
  
      Metadata:
  
        creation_time   : 2014-03-20 02:09:22
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:2(eng): Data: none (rtp  / 0x20707472), 6 kb/s
  
      Metadata:
  
        creation_time   : 2014-03-20 02:09:22
  
        handler_name    : Apple Alias Data Handler
  
      Stream #0:3(und): Data: none (rtp  / 0x20707472), 0 kb/s
  
      Metadata:
  
        creation_time   : 2014-03-20 02:09:22
  
        handler_name    : Apple Alias Data Handler

  The .mov file (which I unfortunately cannot publicly post) plays back properly in any application I use : VLC, Media Player Classic, and QuickTime. However, playing the transcoded output always exhibits the following symptoms :

  • Audio out of sync with what the video is showing, sometimes to the order of minutes off towards the end of this three hour recording
  • In the case of Media Player Classic, clicking a spot on the timeline actually moves the playhead to a spot on the timeline near where I clicked, but not directly on it.

  There are the arguments I’m using for a .mp4 encoding that is playable in all browsers that support H.264. Note that this is on Windows but Linux exhibits the same problems.

  ffmpeg.exe -y -i original.mov -i watermark.png -filter_complex "[0:v] crop=1184:720:178:6,scale=1184:720,setsar=1/1; [0:v][1:v] overlay=1242:648 [0:v]" -vcodec libx264 -acodec libvo_aacenc -q:a 80 -crf 30 -ac 1 -ar 16000 -strict -2 -profile:v baseline -level 3 outout.mkv

  The arguments, other than those that are self-explanatory or trivial :

  • -filter_complex : Crop excess letterboxing/pillarboxing from the video and set the aspect ratio to 1:1 for square pixels (something Safari needed), then overlay a watermark from a PNG and resize the output to 720p
  • -crf 30 : encode the video at constant quality, variable bitrate
  • -ac 1 -ar 16000 : encode with mono audio at 16 KHz
  • -strict -2 -profile:v baseline -level 3 : encode using FFmpeg’s "experimental" H.264 encoder using the Baseline level 3 profile for web compatibility

  Note that yes, this goes to an MKV container initially because, for some reason, encoding directly to a .mp4 container hangs FFmpeg. I then use -acodec copy -vcodec copy to copy the audio and video streams directly into a .mp4 container. Finally I pass the output through MP4Box to interleave it so it can be progressively downloaded.

  When transcoding, FFmpeg does drop frames, which I suspect is related to the problem, with output like this :

  FFmpeg: frame=  232 fps= 26 q=24.0 size=    5983kB time=00:32:44.57 bitrate=  24.9kbits/s dup=0 drop=1487

  When I then later attempt to mux it into the .mp4 container from this temporary .mkv container, I get a flood of warnings like this :

  [mp4 @ 0297cd00] Non-monotonous DTS in output stream 0:0; previous: 6341306, current: 6007024; changing to 6341307. This may result in incorrect timestamps in the output file.

  Now I wouldn’t be surprised if there is indeed some problem with the source file. However, if so, I need to definitively prove just how it’s broken.

  Any thoughts ?

• Berlin website owners need consent for using Google Analytics

  19 novembre 2019, par Joselyn Khor — Uncategorized

  Website owners in Berlin need consent for using Google Analytics

  According to the Berlin Data Protection Office, if you’re a website owner collecting and sending data to third-party services (like Google Analytics) who are also using that data “for own purpose uses” in Berlin, you are now required to ask for specific consent from visitors in order to collect that information. 

  This means you can only use Google Analytics or similar services once you’ve gotten consent from visitors. In contrast, Matomo does not use information from Cloud or On-Premise users for “own purpose uses”.

  Consent is also needed when keystrokes or mouse movements are recorded. That means you need users to consent to your usage of features like Heatmaps and Session Recordings.

  It’s advised that website owners in Berlin should check their websites for third-party content and tracking mechanisms. If you do use these third-party functions that require consent, you must either get consent or remove the functions. Consent is only effective if the visitor (whose data you’re collecting) is informed and agrees to their data being processed.

  Currently this applies to website owners in Berlin, and should likely be applied for the whole of Germany to be on the safe side.

  Further reading :

  • Learn more about Matomo’s Cloud Data Processing Agreement
  • Read about asking for consent in Matomo
  • To use Matomo Analytics and be compliant with the regulation we recommend you learn how to make Matomo GDPR compliant in 12 steps.

  And learn more about all the features in our GDPR user guide and privacy user guide. You can also learn more about GDPR through our blog posts.