Recherche avancée

Sur d’autres sites (8706)

• movenc : Add a flag for indicating a discontinuous fragment

  20 novembre 2014, par Martin Storsjö

  movenc : Add a flag for indicating a discontinuous fragment
  This allows creating a later mp4 fragment without sequentially
  
  writing the earlier ones before (when called from a segmenter).
  Normally when writing a fragmented mp4 file sequentially, the
  
  first timestamps of a fragment are adjusted to match the
  
  end of the previous fragment, to make sure the timestamp is the
  
  same, even if it is calculated as the sum of previous fragment
  
  durations. (And for the first packet in a file, the offset of
  
  the first packet is written using an edit list.)
  When writing an individual mp4 fragment discontinuously like this
  
  (with potentially writing the earlier fragments separately later),
  
  there’s a risk of getting a gap in the timeline if the duration
  
  field of the last packet in the previous fragment doesn’t match up
  
  with the start time of the next fragment.
  Using this requires setting -avoid_negative_ts make_non_negative
  
  (or -avoid_negative_ts 0).
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] libavformat/movenc.c
  • [DH] libavformat/movenc.h

• mov : Add an option to toggle dref opening

  15 janvier 2016, par Derek Buitenhuis

  mov : Add an option to toggle dref opening
  This feature is mostly only used by NLE software, and is
  
  both of dubious value being enabled by default, and a
  
  possible security risk.
  Signed-off-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavformat/isom.h
  • [DH] libavformat/mov.c
  • [DH] libavformat/version.h

• Overlaying one video on another one and making black pixels or green pixels transparent

  30 décembre 2017, par kostya572

  I found great answer here : https://stackoverflow.com/a/38581696/2337706

  It works only for black pixels. The result is not perfect. I guess if change the overlay background color to other color, e.g. green, red, blue the results would be better. How can I change the other background color ?

  Here is my working code :

  ffmpeg -y \
  
      -i video.webm -i overlay.mov \
  
      -filter_complex " \
  
          [0:v]setpts=PTS-STARTPTS[base]; \
  
          [1:v]crop=iw:0.50*ih,setpts=PTS-STARTPTS+0/TB, \
  
                   format=yuva420p,colorchannelmixer=aa=0.7[overlay]; \
  
       [base][overlay]overlay=x=(W-w)/2:y=0[v]" \
  
   -map "[v]" -map 0:a -c:a copy -c:v libvpx-vp9 -lossless 1 -threads 4 -quality realtime \
  
   -speed 8 -tile-columns 6 -frame-parallel 1 -vsync 2 -shortest output.webm

  The result :
  

  Need result :
  

  Or need result (if impossible first with good quality) :
  

  Thank you, sorry for the frequent questions on ffpmpeg topic.