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• FFmpeg - EXRs to MOV, repeating first 24 frames

  16 mai 2015, par JGazlyVFX

  I’m trying to convert EXRs to h264:MOV, in their native resolution. It will create the QT, but when I play back it back, it is looping the first 24 frames, over and over for what seems to be the duration of the frame sequence.

  Below is the command I’m running, Along with Output :

  /usr/bin/ffmpeg_build2/ffmpeg -start_number 001001 -r 24 -i /Volumes/storage/ff/plates/BC/BC0535/BC0535_ref2_20150408/2880x2160/EXR/BC0535_ref2.%06d.exr -vcodec libx264 -pix_fmt yuv420p -r 24 /Volumes/vfx_sftp/ff/ff_prod/TO_PROD/Fan4_BC_QT_PT2_20150515/BC0535_ref2_fr_20.mov

• ffplay how to change the seek interval

  29 janvier 2021, par oliopti

  I am completing a project in which I need to isolate single frames and their time stamps. I am using ffplay. using the "s" key I am able to stepwise move forward frame by frame. However when I try to move backwards a frame it jumps back 10 seconds. Is there a way to change this default based on my fps that the video was recorded at in order to jump back frame by frame ?
There seems to be a command including seek_interval, but limited documentation on how to implement this for a 25fps video file.
Thank you !

  


• Getting accurate time from FFMPeg with Objective C (Audio Queue Services)

  2 avril 2012, par Winston

  My iPhone app plays an audio file using FFMPeg.

  I'm getting the elapsed time (to show to user) from the playing audio (in minutes and seconds after converting from microseconds, given by FFMPeg) like so :

  AudioTimeStamp currentTimeStamp;
  
  AudioQueueGetCurrentTime (audioQueue, NULL, &currentTimeStamp, NULL);
  
  
  
  getFFMPEGtime = currentTimeStamp.mSampleTime/self.basicAudioDescription.mSampleRate;
  
  
  
  self.currentAudioTime = [NSString stringWithFormat: @"%02d:%02d",
  
                              (int) getFFMPEGtime / (int)60000000,
  
                              (int) ((getFFMPEGtime % 60000000)/1000000)];

  Everything works fine, but when I scrub back or forward to play another portion of the song, the elapsed time will go back to zero, no matter the current position. The timer will always zero out.

  I know I'm suposed to do some math to keep track of the old time and the new time, maybe constructing another clock or so, perhaps implementing another callback function, etc... I'm not sure what way I should go.

  My questions are :

  1) What's the best approach to keep track of the elapsed time when going back/forward in a song, avoiding the clock to always going back to zero ?

  2) Should I look deeply into FFMPeg functions or should I stick with Objective-C and Cocoa Touch for solving this problem ?

  Please, I need some advices/ideas from experienced programmers. I'm stuck. Thanks beforehand !