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• A random pixel on a frame. (ffmpeg)

  4 juin 2013, par Chris Russo

  Hello folks of SO !

  We're trying to do some very small and simple code in PHP to generate a variation of a video, using always the same file.

  The script would have to make a small pixel mark, on random or specific frame of the video file, and this would have to be streamed in real time.

  Here's some pseudo code to explain my idea :

  $frame = $_GET[frame];
  
  $videofile = 'video.avi';
  
  
  
  make_random_red_pixel_mark($videofile, $frame);

  Does anyone know if this is possible using ffmpeg ? As well, it is of extreamly importance for us, to execute this procedure as fast as possible.

  A solution that would imply reprocessing the whole video, won't be useful for our purposes. It should be something like a closed caption, or a quick image / overlay filter that could be applied without an entire video reprocessing. As well, we can't put the overlay using Javascript nor any HTML approach, since the actual manipulation has to be on the video file itself.

  The quality, and framerate of the original video, should be kept intact. Perhaps some other PHP module or software that could be execute from PHP using an exec() ?

  Any recommendation ?

  Thanks in advance !!
  Chris C. Russo

• How do I convert a 3D SBS dual-fisheye image to 3D SBS dual-equirectangular with only open-source tools ? [closed]

  21 octobre 2024, par Ethan T

  Canon has released a new 3D VR lens for their RF mount and I recently rented it to see what it's like to work with. Unfortunately, they charge a subscription fee for their conversion software, which I've also found to be inconveniently limited in real-world use cases. Thus I'm interested in an open-source approach to converting the video captured by this lens using something like ffmpeg.

  


  The video is dual-fisheye and the Canon tool produces dual-equirectangular side-by-side video. I would like to perform this same conversion in ffmpeg or a similarly-powerful open-source tool.

  


  Related questions exist but aren't quite correct. Most dual-fisheye input seems to be used to create 360-degree 2D video, not 3D SBS.

  


• How to pass command line arguments to FFMpeg in iOS

  23 septembre 2014, par Arif Nadeem

  This is a beginner question, since I am new to iOS(I started it today), so please pardon my ignorance and lack of iOS knowledge.

  After building and successfully using FFMpeg for Android I wanted to do the same for iOS.
  So I built FFMpeg successfully for iOS by following this link, but after all that pain I am confused as how to use FFMpeg in iOS, I mean how can I pass command line arguments to libffmpeg.a file ?

  I am assuming that there must be a way to run the .a file as an executable and then pass command line arguments and hope for FFMpeg to do the magic, I did the same in Android and it worked beautifully.

  I am also aware that I can use ffmpeg.c class and use its main method, but the question remains ; how do I pass those command line arguments ?

  Is there something I am supposed to be aware of here, is the thing what I am doing now correct or am I falling short on my approach ?

  I wanted to mix two audio files, so the command for doing that would be ffmpeg -i firstSound.wav -i secondSound.wav -filter_complex amix=inputs=2:duration=longest finalOutput.wav, how do I do the same in iOS ?

  Can someone please shed some light on this ?