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• Better way to use ffmpeg with vidstab and encoding 2 pass

  17 juin 2020, par Guillaume B.

  I scan old 8mm films
so I have folder with set of jpeg

  


  I transform them to films using ffmpeg ( I choose x264 2 pass encoding)

  


  //On all folder that start by 1 I launch the pass1 for x264

for f in 1*/ ; do cd "$f"; ffmpeg -y -r 18 -i img%05d.jpg -c:v libx264 -s 1200x898 -b:v 3000k -pass 1 -an -f mp4 /dev/null; cd ..; done

//On all folder that start by 1 I launch the pass2 x264

for f in 1*/ ; do cd "$f"; ffmpeg -y -r 18 -i img%05d.jpg -c:v libx264 -s 1200x898 -b:v 3000k -pass 2 ../"`echo ${PWD##*/}`.mp4"; cd ..; done


  


  —> Before I have set of folder with jpeg

  


  


  1965-FamilyStuff01\img1111.jpg,..,img9999.jpg

  


  1965-FamilyStuff02\img1111.jpg,..,img9999.jpg

  


  


  and I get

  


  


  1965-FamilyStuff01.mp4

  


  1965-FamilyStuff02.mp4

  


  


  then I discover vidstab that also need 2 pass

  


  // Stabilize every Video of a folder

  


  mkdir stab;for f in ./*.mp4 ; do echo "Stabilize $f" ; 
ffmpeg -i "$f" -vf vidstabdetect=shakiness=5:accuracy=15:stepsize=6:mincontrast=0.3:show=2 -y -f mp4 /dev/null; 
ffmpeg -i "$f" -vf vidstabtransform=smoothing=30:input="transforms.trf":interpol=linear:crop=black:zoom=0:optzoom=1,unsharp=5:5:0.8:3:3:0.4 -y "stab/$f" 
; done; rm transforms.trf;


  


  But I ask myself, that perhaps the order is not correct or perhaps there is a way to do the encoding with vidstab in less than 4 pass (2 pass for x264 encoding then 2 pass for vidstab)
or perhaps the order should be change to optimize quality of film output)

  


• libavcodec : add a new AV_CODEC_EXPORT_DATA_FILM_GRAIN flag and option

  12 novembre 2020, par Lynne

  libavcodec : add a new AV_CODEC_EXPORT_DATA_FILM_GRAIN flag and option
  This introduces a new field to allow decoders to export their film grain
  
  parameters.
  
  Will be used by the next patch.
  

  • [DH] doc/APIchanges
  • [DH] libavcodec/avcodec.h
  • [DH] libavcodec/options_table.h

• FFMPEG Dash with tiles of thumbnail images

  31 juillet 2020, par martyn Gilbert

  As of DASH-IF IOP version 4.2, section 6.2.6 defines the notion of image-based tracks in DASH :
https://dashif.org/docs/DASH-IF-IOP-v4.3.pdf.

  



  This is the ability to have an adaption set made up of mime type images that themselves are a strip of low resolution thumbnails. 
A player will use these thumbnails when the user hovers their mouse over the video timeline and get a 
preview of the the frame at that approximate timecode.

  



  Theo player website has a page dedicated to this function for playback :
https://www.theoplayer.com/blog/in-stream-thumbnail-support-dvr-dash-streams

  



  I need to generate a dash stream (not live) using ffmpeg that also contains these thumbnails. 
I already have an ffmpeg command that will generate the film strip of jpgs which outputs a thumbnail every 5 seconds of input video and joins 5 of these together in a single jpg :

  



  ffmpeg -i INPUT -q:v 20 -vf "select=not(mod(n\,125)),scale=480:270,tile=5x1" -vsync vfr output%d.jpg

  



  and the mpeg dash itself :

  



  ffmpeg -i INPUT -y -map 0 -acodec aac -ac 2 -ar 48000 -s 960x540 -vcodec libx264 -f dash -preset veryfast -b:v:2 1500k -seg_duration 2 output.mpd

  



  But I cannot find a way in ffmpeg to include the thumbnails in the dash mpd file.