Recherche avancée

Sur d’autres sites (8287)

• Conversion from Iphone Core Surface RGB Frame into ffmepg AVFarme

  10 mars 2015, par Raghu

  I am trying to convert Core Surface RGB frame buffer(Iphone) to ffmpeg Avfarme to encode into a movie file. But I am not getting the correct video output (video showing colors dazzling not the correct picture)

  I guess there is something wrong with converting from core surface frame buffer into AVFrame.

  Here is my code :

  Surface *surface = [[Surface alloc]initWithCoreSurfaceBuffer:coreSurfaceBuffer];
  
  [surface lock];
  
  unsigned int height = surface.height;
  
  unsigned int width = surface.width;
  
  unsigned int alignmentedBytesPerRow = (width * 4);
  
  if (!readblePixels) {
  
      readblePixels = CGBitmapAllocateData(alignmentedBytesPerRow * height);
  
      NSLog(@"alloced readablepixels");
  
  }
  
  unsigned int bytesPerRow = surface.bytesPerRow;
  
  void *pixels = surface.baseAddress;
  
  for (unsigned int j = 0; j < height; j++) {
  
      memcpy(readblePixels + alignmentedBytesPerRow * j, pixels + bytesPerRow * j, bytesPerRow);
  
  }
  
  
  
  pFrameRGB->data[0] = readblePixels; // I guess here is what I am doing wrong.
  
  pFrameRGB->data[1] = NULL;
  
  pFrameRGB->data[2] = NULL;
  
  pFrameRGB->data[3] = NULL;
  
  
  
  pFrameRGB->linesize[0] = pCodecCtx->width;
  
  pFrameRGB->linesize[1] = 0;
  
  pFrameRGB->linesize[2] = 0;
  
  pFrameRGB->linesize[3] = 0;
  
  
  
  
  
  sws_scale (img_convert_ctx, pFrameRGB->data, pFrameRGB->linesize,
  
         0, pCodecCtx->height,
  
         pFrameYUV->data, pFrameYUV->linesize);   

  Please help me out.

  Thanks,

  Raghu

• iPhone slow motion video transcode

  25 mai 2016, par coverboy

  I’m developing upload video (taken from iPhone) to my server.

  However, I have no idea how to implement.

  Any source code objective-c or swift will be welcomed.

  I have 120fps or 240fps video (It’s a slo-mo).
  When I playback these video on my iPhone6. I can see slo-mo effect.
  (I know playback frame rate is 30fps.)

  I want to convert that video before upload to my server, from 120/240 fps to 30fps video. (I mean not adjusting playback frame rate, it means video transcode to 30fps.)
  Additionally, I want to check slo-mo effect start-point and end-point.
  (Maybe iPhone record this information to video binary(it might be reside in file’s header.)

  Well, I guess if I use ffmpeg library, it should be easy(?).

  So any suggestions will be welcomed.

• 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);