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• HIK IP cameras changes chunks length while switching from day to night mode

  22 septembre 2022, par Klaus-Peter Eckert

  We are using ffmpeg to create a video playlist consisting of 2 sec chunks send by a HIKVISION DS-2CD2143G0-I IP camera. When the camera switches from day mode to night mode the length of the chunks changes from 2 to 4 sec. When the camera switches back to day mode the chunks again have a length of 2 sec.
This is an excerpt of a playlist :

  


  chunk-stream0-17750.m4s
#EXTINF:2.000000,
#EXT-X-PROGRAM-DATE-TIME:2022-09-19T22:26:59.418+0200
chunk-stream0-17751.m4s
#EXTINF:2.793047,
#EXT-X-PROGRAM-DATE-TIME:2022-09-19T22:27:01.418+0200
chunk-stream0-17752.m4s
#EXTINF:3.998984,
#EXT-X-PROGRAM-DATE-TIME:2022-09-19T22:27:04.211+0200
chunk-stream0-17753.m4s
#EXTINF:3.998984,
#EXT-X-PROGRAM-DATE-TIME:2022-09-19T22:27:08.210+0200
chunk-stream0-17754.m4s


  


  This is the call of ffmpeg (with APP_RECORDING_SEG_DUR = 2) :

  


  window_size = int(Settings.APP_RECORDING_PRE_DUR / Settings.APP_RECORDING_SEG_DUR)
# Command to start ffmpeg dash muxer
cmd = ''
cmd += f'ffmpeg -loglevel fatal -stimeout 1000000 -rtsp_transport tcp -i "{rtsp_url}" '
cmd += f'-map 0:0 -c:v:0 copy -movflags frag_keyframe+empty_moov -an -f dash -use_template 1 '
cmd += f'-use_timeline 0 -index_correction 0 -seg_duration {Settings.APP_RECORDING_SEG_DUR} '
cmd += f'-hls_playlist 1 -dash_segment_type mp4 -streaming 1 -remove_at_exit 1 '
cmd += f'-window_size {window_size} -extra_window_size {20 / Settings.APP_RECORDING_SEG_DUR} '
    cmd += f'{(self._target_path / playlist).as_posix()}'


  


  Has anybody observed a similar behaviour and knows how to stop the camera from changing the size of the video chunks ?

  


• ffmpeg produces extra frames after halving the framerate

  22 septembre 2022, par Korfoo

  I have a question about halving the framerate of a video using ffmpeg.
I have an input video with a framerate of 50fps and 6410 frames, ffprobe output :

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
  Metadata:
    major_brand     : M4V 
    minor_version   : 1
    compatible_brands: isomavc1mp42
    creation_time   : 2022-06-24T14:27:43.000000Z
  Duration: 00:02:08.20, start: 0.000000, bitrate: 12595 kb/s
  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 12202 kb/s, 50 fps, 50 tbr, 50k tbn, 100 tbc (default)
    Metadata:
      creation_time   : 2022-06-24T14:27:43.000000Z
      handler_name    : ETI ISO Video Media Handler
      vendor_id       : [0][0][0][0]
      encoder         : Elemental H.264
  Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 384 kb/s (default)
    Metadata:
      creation_time   : 2022-06-24T14:27:43.000000Z
      handler_name    : ETI ISO Audio Media Handler
      vendor_id       : [0][0][0][0]


  


  I want to change this to 25fps using the following ffmpeg command :

  


  ffmpeg -i input.mp4 -filter:v fps=25 25fps.mp4 


  


  One would expect the amount of frames in the output to be half the frames of the input file, 3205. But this transcode results in 3206 frames.

  


  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '25fps.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.76.100
  Duration: 00:02:08.24, start: 0.000000, bitrate: 3053 kb/s
  Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1920x1080 [SAR 1:1 DAR 16:9], 2917 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : ETI ISO Video Media Handler
      vendor_id       : [0][0][0][0]
  Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 129 kb/s (default)
    Metadata:
      handler_name    : ETI ISO Audio Media Handler
      vendor_id       : [0][0][0][0]


  


  How does this happen and why is there a frame extra ?

  


• Introducing Improvements to the Opt-Out Form Feature

  18 septembre 2022, par Ben — About

  Matomo includes a built-in opt-out form that you can add to your website so you can provide your visitors with the choice to opt-out of Matomo tracking. Up until Matomo 4.12.0 the built-in opt-out form relied on iFrame technology which has become increasingly problematic due to browser changes and restrictions on setting third-party cookies.

  With our privacy-first approach, we’ve known for some time that we would eventually need a new way to provide this important opt-out functionality that would work most reliably in the myriad of contexts our users rely on it for.

  Embedding the opt-out form

  Matomo 4.12.0 introduces an improved opt-out. This provides two new options for embedding the opt-out on your website, either using the Matomo tracker code or as self-contained code.

  

  As with the iFrame method, the built-in opt-out code can be styled in Matomo to match your website, and provides a snippet which you can add to your website to show the opt-out feature to your users.

  Find out how to customise the opt-out form.

  Customising the opt-out form

  

  What does this mean for existing opt-out forms ?

  Although it is no longer possible to generate new iFrame embed code using the Matomo UI, the underlying opt-out feature is still fully supported and any existing iFrame opt-out form code embedded in websites will still work as before. It is recommended to migrate to one of the new opt-out form options as browser support for the iFrame opt-out will continue to decrease.

  To read more in depth information about the new opt-out functionality please refer to our new developer documentation for tracking opt-out.