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• How to accurately match an image to a video frame and exit with ffmpeg

  10 avril 2020, par Hans J

  In Bash,
I am trying to match an image to a frame in ffmpeg. I also want to exit the ffmpeg process when the match is found. Here is a (simplified version) of the code currently :

  



  ffmpeg --hide_banner -ss 0 -to 60 \
-i "video.mp4" -i "image.jpg" -filter_complex \
"blend=difference, blackframe" -f null - null 2>log.txt &
pid=$!
trap "kill $pid 2>/dev/null" EXIT
while kill -0 $pid 2>/dev/null; do
     # (grep command to monitor log file)
     # if grep finds blackframe match, return blackframe time
done


  



  To my understanding, if the video actually contains a blackframe I will get a false-positive. How can I effectively mitigate this ?

  



  While this is unnecessary to answer the question, I would like to exit the ffmpeg process without having to use grep to constantly monitor the log file, instead using pure ffmpeg

  



  Edit : I say this because while I understand the blend filter is computing the difference, I am getting a false positive on a blackframe in my video and I don't know why.

  



  Edit : A possible solution to this issue is to not use blackframe at all, but psnr (Peak Signal to Noise Ratio) but normal usage is by comparing two videos frame by frame, and I don't know how to effectively use it with an image as input.

  


• Read a growing MFX file for live streaming sports match file [closed]

  12 novembre 2024, par Sumit Chaudhary

  I'm struggling to read a growing MXF file in real time for a live sports streaming project in python. I can read the video in 5-minute chunks provided by the recording software, for the same match and I’m able to load the full file (around 750GB) once the match is over and file is complete. However, I need to process the file as it’s still growing. Any suggestions on how to approach this ?

  


• Revision 1790d45252 : Use variance metric for integral projection vector match This commit replaces t

  27 février 2015, par Jingning Han

  Changed Paths :
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/encoder/vp9_avg.c

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_pickmode.c

  
   Modify /vp9/encoder/x86/vp9_avg_intrin_sse2.c

  
  
  Use variance metric for integral projection vector match

  This commit replaces the SAD with variance as metric for the
  integral projection vector match. It improves the search accuracy
  in the presence of slight light change. The average speed -6
  compression performance for rtc set is improved by 1.7%. No speed
  changes are observed for the test clips.

  Change-Id : I71c1d27e42de2aa429fb3564e6549bba1c7d6d4d