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• How to stop ffmpeg automatically rotating (Iphone 13) videos

  22 juillet 2022, par VdGR

  I have a bunch of videos I want to merge into one video.
Therefore I used this ffmpeg command.

  


  ffmpeg -y -loglevel warning -f concat -safe 0  -i "filelist.txt" -c copy "merged.mov"


  


  When I open merged.mov all my videos are rotated -90 degerees but when I open my videos for example in vlc it has the right rotation.
What am I doing wrong ?

  


  I tried already adding the "-noautorotate" option but that does not seem to solve the problem.

  


• 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.