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• Speed advantage in combining FFmpeg filters ?

  4 mai 2020, par lach_codes

  I'm currently using five separate FFmpeg processes to do the following :

  



  

  1. trim & crop Vid B

  


  2. scale Vid B to height of Vid A

  


  3. combine Vid B & Vid A

  


  4. add a fade-in/fade-out to Combined Vid

  


  5. add an overlay to fade in/out vid

  


  



  I have them all set to ultrafast but it still takes a long time - about 40 seconds when each video is 10 seconds long.

  



  I initially explored combining some of the filters but couldn't get it working in the timeframe I had available. I also wasn't sure if the time spent figuring out how to combine all the filters would pay off in a faster processing time.

  



  Any thoughts/insights from you brilliant FFmpeg gurus ? Would this speed up processing, and if so, should I combine all the commands together or are there some I should combine and others I should leave separate ?

  



  Here are my current commands, all of which are working :

  



  // trimming 200ms off begining of vid B + cropping frame (note that I have previously retrieved dimensions and duration of both videos with ffprobe)
1. `ffmpeg -i vidB.mov -ss 200 -t ${vidB.duration} -async 1 -filter:v "crop=iw:${vidB.croppedHeight}:0:${vidB.offset}" -preset ultrafast -c:a copy croppedVidB.mov`

// scale Vid B up to Vid A's height
2. `ffmpeg -i croppedVidB.mov -vf scale=-2:${vidA.height} vidBScaled.mov`

// combine videos
3. `ffmpeg -i vidA.mov -i vidBScaled.mov -filter_complex "[0:v][1:v] hstack=inputs=2[v]; [0:a][1:a]amix[a]" -map "[v]" -map "[a]" -preset ultrafast -ac 2 combined.mov`

// add fade in & out
4. `ffmpeg -i combined.mov -sseof -1 -copyts -i combined.mov -filter_complex "[1]fade=out:0:30[t];[0][t]overlay,fade=in:0:30[v]; anullsrc,atrim=0:1[at];[0][at]acrossfade=d=1,afade=d=1[a]" -map "[v]" -map "[a]" -c:v libx264 -crf 22 -preset ultrafast -shortest fadeInOut.mov`

// add overlay
5. `ffmpeg -i fadeInOut.mov -i overlay.png -filter_complex overlay=W-w-10:H-h-10 -codec:a copy -preset ultrafast -async 1 overlay.mov`


  



  Thanks in advance for your thoughts !

  


• How to compile ffmpeg for an iphone application

  27 décembre 2012, par Swati

  I am trying to compile ffmpeg for my iphone app so that i can convert amr file to mp3

  I downloaded latest version of ffmpeg and tried to configure it via terminal on my mac.

  but i couldn't succeed, it always shows numerous errors :

  cannot find make command
  
  
  
  /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/gcc is unable to create an executable file.
  
  
  
  libavcodec.a    file not found
  
  libavfilter.a   file not found
  
  libavutil.a     file not found
  
  libswscale.a    file not found
  
  libavdevice.a   file not found
  
  libavformat.a   file not found
  
  libswresample.a file not found

  i tried following links :
  FFmpeg on iPhone

  FFmpeg on iPhone

  Using FFMPEG library with iPhone SDK for video encoding

  and many more...

  could not fins step by step instructions..
  Hope somebody can guide me with ffmpeg config

• iPhone video PHP upload. Windows to HTML5 tag

  21 août 2012, par zeshin

  As those of you with an iPhone know, the iCloud uploads all pictures and videos taken on the iPhone to the cloud and, thereafter, your home PC.

  I am uploading videos to my web page through a PHP function, which are then displayed as embedded HTML5 videos with the tag. The problem I am running into is that videos taken on the iPhone in portrait are showing up on both my PC and website in landscape view.

  Due to the fact that uploads come from multiple sources, I need a sever-side solution to recognize the orientation of the video and rotate it as needed.

  Does anyone know of a way to accomplish this without using additional plugins such as ffmpeg ?