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• video to audio file convert & save through FFMPEG in node js

  17 juin 2015, par Nourin Hamid

  I am working on an FFMPEG on node js. I’d like to retrieve the audio track from a video file using node js. I would also like to save such file but I can’t figure out how.

  I though this line of code would help me :

  ffmpeg('/path/to/file.avi').noVideo();

  I have got this in npm package. I don’t quite understand how to work with this and how to actually save the audio file.

  Some other line of code that come in play :

  try {
  
      var process = new ffmpeg('/path/to/your_movie.avi');
  
      process.then(function (video) {
  
          // Callback mode
  
          video.fnExtractSoundToMP3('/path/to/your_audio_file.mp3', function (error, file) {
  
              if (!error)
  
                  console.log('Audio file: ' + file);
  
          });
  
      }, function (err) {
  
          console.log('Error: ' + err);
  
      });
  
  } catch (e) {
  
      console.log(e.code);
  
      console.log(e.msg);
  
  }

  My question is :

  How do I retrieve the audio from a FFMPEG video ? How do I save it ?

• avcodec/mqc : Hardcode tables to save space

  7 mai 2021, par Andreas Rheinhardt

  avcodec/mqc : Hardcode tables to save space
  mqc currently initializes three arrays at runtime ; each of them
  
  has 2 * 47 elements, one is uint16_t, two are uint8_t, so that their
  
  combined size is 8 * 47. The source data for these initializations
  
  is contained in an array of 47 elements of size six. Said array is
  
  only used in order to initialize the other arrays, so the savings
  
  are just 2 * 47B. Yet this is dwarfed by the size of the code for
  
  performing the initializations : It is 109B (GCC 10.2, x64, -O3 albeit
  
  in an av_cold function) ; this does not even include the size of the
  
  code in the callers. So just hardcode these tables.
  This also fixes a data race, because the encoder always initialized
  
  these tables during init, although they might already be used at the
  
  same time by already running encoder/decoder instances.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/j2kenc.c
  • [DH] libavcodec/jpeg2000dec.c
  • [DH] libavcodec/mqc.c
  • [DH] libavcodec/mqc.h

• x86inc : Improve SAVE/LOAD_MM_PERMUTATION macros

  22 avril 2018, par Henrik Gramner

  x86inc : Improve SAVE/LOAD_MM_PERMUTATION macros
  Use register numbers instead of copying the full register names. This makes it
  
  possible to change register widths in the middle of a function and keep the
  
  mmreg permutations intact which can be useful for code that only needs larger
  
  vectors for parts of the function in combination with macros etc.
  Also change the LOAD_MM_PERMUTATION macro to use the same default name as the
  
  SAVE macro. This simplifies swapping from ymm to xmm registers or vice versa :
      SAVE_MM_PERMUTATION
  
      INIT_XMM <cpuflags>
  
      LOAD_MM_PERMUTATION
  

  • [DH] common/x86/x86inc.asm