Recherche avancée

Sur d’autres sites (5469)

• how the packuswb instruction works ? (in low level bit operation)

  17 avril 2019, par MaikonNascimento

  Studying ffmpeg convertion from yuv to rgb , I came across the equation being implemented in assembly, yuv2rgb_template.c located in ffmpeg/libswscale/x86.

  I want to know how the instruction packuswb works ? Google says it :

  Converts 4 signed word integers from mm and 4 signed word integers from mm/m64 into 8 unsigned byte integers in mm using unsigned saturation.

      DEST[7:0] ← SaturateSignedWordToUnsignedByte DEST[15:0];
  
      DEST[15:8] ← SaturateSignedWordToUnsignedByte DEST[31:16];
  
      DEST[23:16] ← SaturateSignedWordToUnsignedByte DEST[47:32];
  
      DEST[31:24] ← SaturateSignedWordToUnsignedByte DEST[63:48];
  
      DEST[39:32] ← SaturateSignedWordToUnsignedByte SRC[15:0];
  
      DEST[47:40] ← SaturateSignedWordToUnsignedByte SRC[31:16];
  
      DEST[55:48] ← SaturateSignedWordToUnsignedByte SRC[47:32];
  
      DEST[63:56] ← SaturateSignedWordToUnsignedByte SRC[63:48];

  Since I dont know Assembly x86, it is even hard to simulate it or debug the current code.

  I want to know how they fit 16 bits in 8 bits ?

• FFMPEG - Palettegen for animations is not working

  18 juillet 2018, par deanhodges

  I have a script taken from the correct answer at https://superuser.com/questions/1002562/convert-multiple-images-to-a-gif-with-cross-dissolve, but I am getting no results.

  Even copying the code word for word does not work for me.

  However, if I run $ffmpeg = shell_exec("ffmpeg -i images/image001.jpg -vf palettegen palette_test.png"); on a single image, it works fine. But because I need it for an animation, I need to create a pallete for all images.

  Unless of course, on each image in the GIF sequence I can load a new palette ?

  $q = "ffmpeg -f image2 -framerate 0.5 -i ../view/client/files/".$dir."/%*.jpg -i palettePro.png -lavfi paletteuse -y .." . $save_path . '/' . $filename . " -report";

• SNAP : Simulation and Neuroscience Application Platform [closed]

  19 avril 2024, par S_S

  Is there any documentation/help manual on how to use SNAP (Simulation and Neuroscience Application Platform)1.

  



  I wanted to run the Motor Imagery sample scenario with a .avi file for the stimulus instead of the image. How can that be done ?

  



  The following error is obtained when using the AlphaCalibration scenario which gives code to play an avi file.Any help appreciated

  



  :movies:ffmpeg(warning): parser not found for codec indeo4, packets or times may be invalid.
:movies:ffmpeg(warning): max_analyze_duration 5000000 reached at 5000000
:movies(error): Could not open /e/BCI_Feb2014/SNAP-master/src/studies/SampleStudy/bird.avi
:audio(error): Cannot open file: /e/BCI_Feb2014/SNAP-master/src/studies/SampleStudy/bird.avi
:audio(error): Could not open audio /e/BCI_Feb2014/SNAP-master/src/studies/SampleStudy/bird.avi
:movies:ffmpeg(warning): parser not found for codec indeo4, packets or times may be invalid.
:movies:ffmpeg(warning): max_analyze_duration 5000000 reached at 5000000
:movies(error): Could not open /e/BCI_Feb2014/SNAP-master/src/studies/SampleStudy/bird.avi
:gobj(error): Texture "/e/BCI_Feb2014/SNAP-master/src/studies/SampleStudy/bird.avi" exists but cannot be read.
Traceback (most recent call last):
  File "E:\BCI_Feb2014\SNAP-master\src\framework\latentmodule.py", line 458, in _run_wrap
    self.run()
  File "modules\BCI\AlphaCalibration.py", line 30, in run
Exception during run():
    m = self.movie(self.moviefile, block=False, scale=[0.7,0.4],aspect=1.125,contentoffset=[0,0],volume=0.3,timeoffset=self.begintime+t*self.awake_duration,looping=True)
Could not load texture: bird.avi
  File "E:\BCI_Feb2014\SNAP-master\src\framework\basicstimuli.py", line 348, in movie
    tex = self._engine.base.loader.loadTexture(filename)
  File "E:\BCI_Feb2014\Panda3D-1.8.0\direct\showbase\Loader.py", line 554, in loadTexture
    raise IOError, message
IOError: Could not load texture: bird.avi