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• ffmpeg-kit android : how to use -f concat -i input.txt with multiple file uris ?

  17 décembre 2023, par Robin

  I am trying to use ffmpeg-kit on Android.

  


  It says it can convert Storage Access Framework (SAF) Uris into paths that can be read or written by FFmpegKit.

  


  Reading a file :

  


  Uri safUri = intent.getData();
String inputVideoPath = FFmpegKitConfig.getSafParameterForRead(requireContext(), safUri);
FFmpegKit.execute("-i " + inputVideoPath + " -c:v mpeg4 file2.mp4");


  


  However, I am trying to use the concat mode with input.txt specifying the file list, like :

  


  file 'frame01.png'
duration 40ms
file 'frame02.png'
duration 40ms
file 'frame03.png'
duration 40ms
file 'frame04.png'
duration 40ms


  


  Then execute :

  


  ffmpeg -f concat -safe 0 -i input.txt -c:v libx264 -pix_fmt yuv420p output.mp4


  


  This worked fine if I copy/put all the files in app's local cache directory where all the files can be directly accessed by file path.

  


  However, if I let user to pick multiple files, which Android system will return a URI for each content, after I tried to convert the URI to 'saf file path' by the FFmpegKitConfig.getSafParameterForRead() method and put the path in the input.txt, it will give me error :

  


  [saf @ 0xb400007896b7e550] Protocol 'saf' not on whitelist 'file,crypto,data'!
[concat @ 0xb400007916b3c350] Impossible to open 'saf:1.png'


  


  It seems the concat mode cannot recognize the file path converted from an SAF uri.

  


  Is it a limitation of current ffmpeg-kit android impl or did I miss some parameters that should be specified ?

  


  Thanks a lot.

  


• create max quality Frame with FFMPEG from ProRes Clip

  5 août 2021, par Josef Zugarov

  I want to extract a frame from a ProRes Clip, recorded with a Blackmagic URSA Mini Pro 4.6K Gen 2 camera with ffmpeg.
I noticed the following : When I import the ProRes Clip into Davinci I can recover some highlights, which are out of the displayed range by lowering the gain paramater.
As you can see in the waveform the thrid peak has information in all channels.

  


  After I extracted the frame with ffmpeg, I couldn't recover the highlights anymore.
Waveform : Values are clipped till the fifth peak.

  


  I used the following command :
ffmpeg  -ss 00:00:01 -i 0volt.mov -vf zscale=t=input,zscale=c=input -frames:v 1  TIFFs\0volt.tiff -v verbose

  


  Here is the output of the ffmpeg command line : https://pastebin.com/a36ML3tL

  


  Do you have any hint, how the original quality and dynanmic range by extracting a TIFF-Frame with ffmpeg can be retained ?

  


  Thank you !

  


• fate : change the scenecut fate threshold

  21 juillet 2019, par Limin Wang

  fate : change the scenecut fate threshold
  why change .4 to .25, it's for :
  
  one scenecut(pkt_pts=20040) isn't detected by 0.4 threshold
  why not change to 0.3 instead of 0.25 :
  
  it will miss the scenecut(pkt_pts=20040) after applying the next
  
  patch which enables yuvj420
  for fate testing, it's better to catch all scenecut scenes.
  Reviewed-by : Marton Balint <cus@passwd.hu>
  
  Signed-off-by : Limin Wang <lance.lmwang@gmail.com>
  

  • [DH] tests/fate/filter-video.mak
  • [DH] tests/ref/fate/filter-metadata-scenedetect