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• How to extract orientation information from MOV videos created on the iPhone using ffmeg, ruby or objectivec ?

  5 octobre 2014, par Sid

  After surfing through tons of documentation on the web it seems that the iPhone always shoots the video at a 480x360 aspect ratio and applies a transformation matrix on the video track. (480x360 may change but its always the same for a given device)

  Here is a way of modifying the ffmpeg source within a iOS project and accessing the matrix http://www.seqoy.com/correct-orientation-for-iphone-recorded-movies-with-ffmpeg/

  Here is a cleaner way of finding the transformation matrix in iOS-4
  how to detect (iphone sdk) if a video file was recorded in portrait orientation, or landscape

  How can the orientation of the video be extracted in either of the options below -
  
   iOS 3.2
  
   ffmpeg (through the command line server side)
  
   ruby
  

  Any help will be appreciated.

• video playing sample on iPhone using libffmpeg

  6 mai 2014, par deimus

  can someone please provide a reference or an example on usage of libffmpeg library for playing video files not supported by apple.

  Let consider mkv file.
  I suppose the library decodes and passes the raw media data to AVFoundation objects to play it on device. Am I right ?

• video frames render slow using opengl and ffmpeg in iphone

  17 février 2012, par resident_

  I'm developing an video player for iPhone. I'm using ffmpeg libraries to decode frames of video and I'm using opengl 2.0 to render the frames to the screen.

  But my app is very slow render the frames and some videos played slowly.

  I have played AVI, MOV, FLV, MP4 and WMV, and only several AVI files are correct played.

  I don't have much idea of ffmpeg and opengl, and I have used a tutorials and examples until now. But I think that the problem can be two things :

  1. The render method is very slowly. I don't use correctly the glTexSubImage2D function.

  2. I don't scale the frames correctly. I don't use correctly the sws_getContext function.

  I'm here parts of my code, to see if anyone can help me.

  So I use sws_getContext

   ctx->p_sws_ctx = sws_getContext(ctx->p_video_ctx->width, 
  
                                  ctx->p_video_ctx->height, 
  
                                  ctx->p_video_ctx->pix_fmt, 
  
                                  ctx->p_video_ctx->width, 
  
                                  ctx->p_video_ctx->height,
  
                                  PIX_FMT_RGB565, SWS_FAST_BILINEAR, NULL, NULL, NULL);
  
  
  
  
  
  
  
  
  
  // Framebuffer for RGB data
  
  ctx->p_frame_buffer = malloc(avpicture_get_size(PIX_FMT_RGB565,
  
                                                  ctx->p_video_ctx->width, 
  
                                                  ctx->p_video_ctx->height));
  
  
  
  avpicture_fill((AVPicture*)ctx->p_picture_rgb, ctx->p_frame_buffer, PIX_FMT_RGB565, 
  
                 ctx->p_video_ctx->width, 
  
                 ctx->p_video_ctx->height);

  My render method of opengl 2.0

  - (void) render: (uint8_t*) buffer

  [EAGLContext setCurrentContext:context] ;

  glBindFramebuffer(GL_FRAMEBUFFER, defaultFramebuffer);
  
  glViewport(0, 0, backingWidth, backingHeight);
  
  
  
  glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
  
  
  
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  
  
  
  // OpenGL loads textures lazily so accessing the buffer is deferred until draw; notify
  
  // the movie player that we're done with the texture after glDrawArrays.          
  
  glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, mFrameW, mFrameH, GL_RGB,GL_UNSIGNED_SHORT_5_6_5, buffer);
  
  
  
  glDrawArrays(GL_TRIANGLE_STRIP, 0, 4);
  
  
  
  
  
  [moviePlayerDelegate bufferDone];
  
  
  
  glBindRenderbuffer(GL_RENDERBUFFER, colorRenderbuffer);
  
  [context presentRenderbuffer:GL_RENDERBUFFER];

  Someone, can I Help me ?

  Thanks,