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• ffmpeg based JAVE video conversion taking a long time

  18 novembre 2015, par Deepak

  I am using ffmpeg to convert videos to mp4 format in my application I have used JAVE and Xuggler for the same. My issue is that, video conversions are taking way too much of time. For example, a 50MB video takes almost 2 hrs to complete the video conversion and upload the same. Also, when i play a video, it takes a longer time to play on safari on mac OS than chrome/firefox.

  What are the possible solutions for this ?
  How to optimize the conversion time/video buffering for playing the video faster

• Getting error during ogg to mp3 conversion

  8 novembre 2015, par user2659308

  I used RecordRTC and implemented with Angular.js, audio recording is working fine in Mozilla and recorded blob type is ogg, so I saving file in server in ogg format.

  But I need it in MP3 format as we have to support in different phone OS. So I further converting using ffmpeg :

  exec('/usr/bin/ffmpeg -i /var/www/dtswork/bluejaypt/us/bjaypt/uploads/index.ogg -acodec libmp3lame  /var/www/dtswork/bluejaypt/us/bjaypt/uploads/index.mp3 2>&1'))

  Using above command but it’s giving "/var/www/dtswork/bluejaypt/us/bjaypt/uploads/index.ogg : End of file".

• yuv to rgb conversion using OpenGL ES2.0 in android,

  8 octobre 2013, par 101110101100111111101101

  I have 2 questions about yuv to rgb conversion using OpenGL ES2.0 in android.

  First thing needs little background.

  -------BACK GROUND------

  When I put random data(YUVs one), It renders like good. (I'm not certain because data is
  random data.)

  however, When I put 'real' one, that is awkaward, important is 'render something'.

  I checked my codes(renderer, data parser, etc... every where), and no doubtful part , except for using GL_RGB parameters in method 'glRenderbufferStorage', 'glTexImage2D'...

  I changed that parameters many times which is in 'glRenderbufferStorage'(GL_RGBA4, GL_RGB565 etc... ). (current is GL_RGBA4)

  but no changed. (some parameters occur error, no rendering.)

  and 'glTexImage2D's parameters too. (current is GL_LUMINANCE.)

  Before Conversion : YUV420P (from ffmpeg pix_fmt_YUV420p) (16bpp, 2X2 Y4 Cb1 Cr1)
  After Conversion : RGB. (I don't know what's difference with RGB series... RGBA, RGB565 etc)
  Before decodedData : decoded linesize is 736 height is 480. (fixed)

  so 12*736*480/8 -> array size ;
  Y is 736 * 480
  U is arraysize * 1/4 ;
  V is arraysize * 1/4 ;

  ---------BACK GROUND END-----------

  I wondering GL_RGB or RGBA4 or RGB565 that parameters effect output data's result ?
  Not part of quality, but part of rendering or not.

  Second part is about fragment shader.

  My rendering engine structure has 3texture in fragment shader. (attach source below)

          "precision mediump float;               \n"
  
      "varying vec2 v_vTexCoord;          \n"
  
      "uniform sampler2D yTexture;        \n"
  
      "uniform sampler2D uTexture;        \n"
  
      "uniform sampler2D vTexture;        \n"
  
      "void main() {                      \n"
  
          "float y=texture2D(yTexture, v_vTexCoord).r;\n"
  
          "float u=texture2D(uTexture, v_vTexCoord).r;\n"
  
          "float v=texture2D(vTexture, v_vTexCoord).r;\n"
  
          "y=1.1643 * (y - 0.0625);\n"
  
          "u=u - 0.5;\n"
  
          "v=v - 0.5;\n"
  
          "float r=y + 1.5958 * v;\n"
  
          "float g=y - 0.39173 * u - 0.81290 * v;\n"
  
          "float b=y + 2.017 * u;\n"
  
          "gl_FragColor = vec4(r, g, b, 1.0);\n"
  
      "}\n";

  as you know, there are three texture, Ytex,Utex,Vtex.
  and then, it converts, and gl_FragColor = vec4(r,g,b,1.0) ;
  I don't know gl_FragColor = vec4(r,g,b,1.0) means.
  of cource, I know gl_FragColor is set, but How can I get actual r,g,b value ?
  it renders in texture automatically ?