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• Evolution #4628 (En cours) : Intégrer la fonction slugify

  17 février 2021, par cedric -

  L’inconvénient de la nommer slufigy c’est le risque de collision.
  Je recherche dans mes mails d’il y a 4 ans pour trouver pourquoi, mais à l’époque, on avait switché de slugify vers filtre_slugify_dist et une définition optionnelle de la fonction slufigy() https://git.spip.net/spip-contrib-extensions/spip-bonux/commit/9987b6f429211364492560f63d66a73f3b5d41b2

  Ça m’embêterait de faire ça dans le core.

  Donc soit on y va

  • pour slufigy() tout court, au risque de la collision,
  • ou un spip_slugify() peut-être qui sera plus sur, mais on perd la compat automatique avec les appels existants (cela dit bonux peut gérer le mappage de l’ancien vers le nouveau)
  • ou alors un autre nom ?

  Faites vos jeux, rien ne va plus...

• ffmpeg : Apply a time-based expr to control intensity of lowpass, highpass, aphaser, or aecho [closed]

  17 mai 2024, par Wes Modes

  I am procedurally constructing complexFilters for ffmpeg via fluent-ffmpeg. My fluent-ffmpeg complex filters look like :

  


  {
   "filter": "volume",
   "options": {
       "volume": "min(1, max(0, ((cos(PI * t * 1 / 13) * 1 + cos(PI * t * 1 / 7) * 0.5 + cos(PI * t * 1 / 3) * 0.25) +
-0.5 ) * 0.75 * -1 + 0.5))",
       "eval": "frame"
    },
    "inputs": "track_1_output",
    "outputs": "track_1_adjusted"
},


  


  Note that I am using an expression to determine the volume dynamically.

  


  Here I'm testing on the command line, to understand the mysteries of lightly-documented ffmpeg filters. I'm fading in and out two sources, intertwined in the output. Now I want to apply lowpass, highpass, aphaser, and/or aecho to the transitions using a time-based expr.

  


  I've already succeeded using the volume filter to fade the sources in and out (Note that the sine has reversed polarity for the second volume filter) :

  


  # working fade in/out
ffmpeg -i knox.mp3 -i static.mp3 -filter_complex \
"[0:a] \
    volume = 'min(1, max(0, 0.5 + 0.5 * cos(PI * t / 5)))': eval=frame \
    [a0]; \
[1:a] \
    volume = 'min(1, max(0, 0.5 - 0.5 * cos(PI * t / 5)))': eval=frame \
    [a1]; \
[a0][a1]
    amix = inputs=2: duration=shortest" \
-c:a libmp3lame -q:a 2 output.mp3


  


  ffmpeg -filters says that lowpass has time-based support :

  


    T.. = Timeline support
 TSC lowpass           A->A       Apply a low-pass filter with 3dB point frequency.


  


  How can I similarly apply these other filters to source1 using a time-bassed expr ? I was unsuccessful in figuring out lowpass and highpass :

  


  # applying a lowpass filter
ffmpeg -i knox.mp3 -i static.mp3 -filter_complex \
"[0:a] \
    volume = 'min(1, max(0, 0.5 + 0.5 * cos(PI * t / 5)))': eval=frame, \
    lowpass=f=3000: mix='0.5 + 0.5 * cos(PI * t / 5)' \
    [a0]; \
[1:a] \
    volume = 'min(1, max(0, 0.5 - 0.5 * cos(PI * t / 5)))': eval=frame \
    [a1]; \
[a0][a1]
    amix = inputs=2: duration=shortest" \
-c:a libmp3lame -q:a 2 output.mp3


  


  With the resultant error :

  


  [Parsed_lowpass_1 @ 0x7f9a72005c00] [Eval @ 0x7ff7bec423d8] Undefined constant or missing '(' in 't/5)'
[Parsed_lowpass_1 @ 0x7f9a72005c00] Unable to parse option value "0.5 + 0.5 * cos(PI * t / 5)"
Error applying option 'mix' to filter 'lowpass': Invalid argument


  


  What complicated fffmpeg faerie magic is needed to make some of the filters other than volume controlled by a time-based expr ?

  


• Ffmpeg. Best way to rip dvd and convert mov into lossless mp4 that is playable in QuickTime on Mac ?

  19 octobre 2022, par Liam

  I’ve been ripping my collection of anime dvds with MakeMKV and converting them into .mp4 files using Ffmpeg.

  


  There are a couple things I need help with-
I’ve noticed that using the command ffmpeg -i input.mkv output.mp4 works in converting the mkv into a playable mp4 file in QuickTime player but that it has a smaller file size than the original MKV file.

  


  Does this indicate a loss in quality ?

  


  I’ve used another command
Ffmpeg -i input.mkv -c copy output.mp4

  


  to convert the MKV file into mp4 and the file is identical in size but will not play in QuickTime as the previous converted file did despite both being mp4.

  


  Does this mean that this mp4 file is just as recognisable as an mkv file ?

  


  I then did another command which may be the best as it plays in QuickTime but it resulted in by far the largest output file size.

  


  Ffmpeg -i input.mkv -crf 01 output.mp4

  


  The last command I used is almost the same as previous but doesn’t play in QuickTime for unknown reasons.

  


  Ffmpeg -i input.mkv -crf 00 output.mp4

  


  Results in huge file size and mp4 file which won’t play in QuickTime.

  


  Please can you shed some light on these issues and advise me on if these commands are best to use for lossless quality ?

  


  The Dvds and files are standard definition and animated in the 90s so that might be worth mentioning.