Recherche avancée

Sur d’autres sites (4475)

• headless chrome capture screen video or animation

  22 mai 2017, par t_io

  I try to capture some animations from a website and stitch them together using ffmpeg.
  As far as I understand the docs startScreencast is the way to go.

  If I understand that right I can start the screencast with

  await Page.startScreencast({format: 'png', everyNthFrame: 1});

  and listen to every incoming frame with

  Page.screencastFrame(image =>{
  
    const {data, metadata} = image;
  
    console.log(metadata);
  
  });

  But it’s never prints out something. So I assume it’s not called.

  I archived my goal with something like this :

  let counter = 0;
  
  while(counter < 500){
  
    await Page.startScreencast({format: 'png', everyNthFrame: 1});
  
    const {data, metadata} = await Page.screencastFrame();
  
    console.log(metadata);
  
    counter += 1;
  
  }

  Which feels like a non-performant hack.
  So any suggestions on how to use startScreencast and screencastFrame properly ?

• avformat/matroskaenc : Simplify writing Cues

  30 décembre 2019, par Andreas Rheinhardt

  avformat/matroskaenc : Simplify writing Cues
  When the Matroska muxer writes the Cues (the index), it groups index
  
  entries with the same timestamp into the same CuePoint to save space.
  
  But given Matroska's variable-length length fields, it either needs
  
  to have an upper bound of the final size of the CuePoint before writing it
  
  or the CuePoint has to be assembled in a different buffer, so that after
  
  having assembled the CuePoint (when the real size is known), the CuePoint's
  
  header can be written and its data copied after it.
  The first of these approaches is the currently used one. This entails
  
  finding out the number of entries in a CuePoint before starting the
  
  CuePoint and therefore means that the list is read at least twice.
  
  Furthermore, a worst-case upper-bound for the length of a single entry
  
  was used, so that sometimes bytes are wasted on length fields.
  This commit switches to the second approach. This is no longer more
  
  expensive than the current approach if one only resets the dynamic
  
  buffer used to write the CuePoint's content instead of opening a new
  
  buffer for every CuePoint : Writing the trailer of a file with 540.000
  
  CuePoints improved actually from 219054414 decicycles to 2164379394
  
  decicycles (based upon 50 iterations).
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskaenc.c

• How to escape characters in Windows batch file

  8 février 2017, par Tirafesi

  I’m trying to create a script to run a program that receives as an argument the name of a file. The problem I’m having is that the program doesn’t work if the filename has special characters in it.

  I found this post which helped me a bit. With a few modifications on that script I’m able to use the program with filenames containing [ and ].

  However, there are still some other special characters that cause the program to not run. Is it possible to create a batch for all special characters ? If not, I would at least need to be able to parse not only [ and ], but ' as well.

  This is what I have working at the moment. How can I at least add ' to this ?

  if not exist "mp4\" mkdir mp4
  
  setlocal disableDelayedExpansion
  
  for %%f in (*.mkv) do (
  
    set _a=%%~nf
  
    set _c=%%f
  
    setlocal enableDelayedExpansion
  
    set _b=!_a:[=\[!
  
    set _name=!_b:]=\]!
  
    set _d=!_c:[=\[!
  
    set _fullname=!_d:]=\]!
  
    "SOMEPATH\ffmpeg\bin\ffmpeg.exe" -i "%%f" -vf subtitles="!_name!.mkv:si=1" -c:v h264_qsv -c:a copy -map 0:v:0 -map 0:a:1 -q:v 6 -look_ahead 0 "mp4/%%~nf.mp4"
  
    endlocal
  
  )
  
  endlocal
  
  pause

  If you could explain the reasoning behind stuff that would be cool as well. I don’t understand much about scripting, but I would like to understand what’s going on in this batch...

  Oh, and here is the documentation for escaping characters in this program.