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• Ffmpeg color opacity

  19 janvier 2016, par Sandra

  I tried to rotate a video and keep the unused place due to the rotation transparent, to be able to overlay it later and to do that, I suppose that if the color was transparent is will be right ; and in the official page (https://www.ffmpeg.org/ffmpeg-filters.html#rotate) they said that you can give a color that ffmpeg would use in place of unused place due to the rotation of the video. So I tried, relatively to https://www.ffmpeg.org/ffmpeg-utils.html#Color to put a color with these commands

  ffmpeg -i video.mp4 -vf "rotate=PI/6:fillcolor=red@0.0" -acodec copy output.mp4

  and

  ffmpeg -i video.mp4 -vf "rotate=PI/6:fillcolor=red@0x00" -acodec copy output.mp4

  And it doesn’t work. The color remain opaque, and that whatever the value of the opacity (0.0 to 1.0)

  Any of you can know what is happened ?

• avcodec/libjxlenc : prevent color encoding from being set twice

  13 avril, par Leo Izen

  avcodec/libjxlenc : prevent color encoding from being set twice
  We currently populate the color encoding bundle and then check to see
  
  if there's an ICC profile to attach, and set the color encoding bundle
  
  in either case. The ICC profile overrides the color encoding bundle, so
  
  we should not calculate enum-based color encoding if we have an ICC
  
  profile present. Fixes several unnecessary warnings from being emitted.
  Signed-off-by : Leo Izen <leo.izen@gmail.com>
  

  • [DH] libavcodec/libjxlenc.c

• Display YUV420P video using OpenGLES on iPhone

  25 décembre 2014, par user3487978

  I am writing an app displaying YUV420p video using ffmpeg library on iPhone, every thing works fine, but the OpenGL color is a little strange, see picture, the bellow image is displaying using AVPicture in RGB format, above is using AVPicture in YUV format.
  any ideas ?

  my shader

  varying highp vec2 varTexcoord;
  
  uniform sampler2D SamplerY;
  
  uniform sampler2D SamplerUV;
  
  void main (void)
  
  {
  
      mediump vec3 yuv;
  
      lowp vec3 rgb;
  
      yuv.x = texture2D(SamplerY, varTexcoord).r;
  
      yuv.yz = texture2D(SamplerUV, varTexcoord).rg - vec2(0.5, 0.5);
  
      // Using BT.709 which is the standard for HDTV
  
      rgb = mat3(      1,       1,      1,
  
                  0, -.18732, 1.8556,
  
                  1.57481, -.46813,      0) * yuv;
  
      gl_FragColor = vec4(rgb,1.0);
  
  }

  Renderer :

  glActiveTexture(GL_TEXTURE0);
  
  glTexImage2D(GL_TEXTURE_2D,
  
               0,
  
               GL_LUMINANCE,
  
               (GLsizei)model.width,
  
               (GLsizei)model.height,
  
               0,
  
               GL_LUMINANCE,
  
               GL_UNSIGNED_BYTE,
  
               [model.y bytes]);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
  
  
  
  glActiveTexture(GL_TEXTURE1);
  
  glTexImage2D(GL_TEXTURE_2D,
  
               0,
  
               GL_LUMINANCE,
  
               (GLsizei)model.width/2,
  
               (GLsizei)model.height/2,
  
               0,
  
               GL_LUMINANCE,
  
               GL_UNSIGNED_BYTE,
  
               [model.uv bytes]);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
  
  glTexParameterf(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);