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• FFMPEG Control Duration Of Video Watermark ? [duplicate]

  20 février 2017, par Briana Wilson

  This question already has an answer here :

  • ffmpeg watermark first 30 second
    
    4 answers
    

  So far I have this code which allows me to batch watermark videos using FFMPEG :

  for %%a in ("C:\filepath\*.mp4") do ffmpeg -i "%%a" -q 40 -s 640x480 -vf "movie=watermark.png [watermark]; [in][watermark] overlay=x=(main_w-overlay_w)/2:y=(main_h-overlay_h)/2 [out]" "C:\filepath\%%~na.mp4"

  What I’m trying to figure out is how I can control the duration of the watermark so that it appears 60 seconds into the video and disappears 15 seconds later.

  Any guidance or help in figuring this out would be greatly appreciated.

  P.S. I need the code to be able to be run in batch.

• YUV420p to other formats, color shift problems

  1er juin 2013, par Sam

  So I'm writing a color detection application using an AR Drone. The drone sends my python/opencv socket server an image from its camera in YUV420p format.

  What I do to access the image as an opencv IPLImage is the following (and yes this is inefficient but I didn't / don't want to have to write new conversion tools myself) :

  1. Save the yuv image to a file (some_image.yuv)
  2. subprocess.call(insert ffmpeg call here)
  3. Read the resultant file (bmp, png, it doesn't matter) back in using cv.LoadImage

  My problem right now is a very noticable color shift. I'm waving a red felt sheet in these pictures. The first one shows a heavy yellow tint. The second isn't as bad but is very rare — mostly when I have the red sheet it's heavily tinted.

  • Tinted image : http://i.stack.imgur.com/BQikM.png
  • Less-tinted image : http://i.stack.imgur.com/ezHyy.png

  I'm wondering both of these things :

  1. if there's either a better way to do this
  2. If the color tinting issue can be resolved

  My ffmpeg conversion line looks something like

  ffmpeg -s 640x480 -vcodec rawvideo -f rawvideo -pix_fmt yuv420p -i image.yuv -vcodec bmp -f image2 output.bmp

  I've also tried :

  ffmpeg -f rawvideo -s 640x480 -pix_fmt yuv420p -vf colormatrix=bt709:bt601 -i image.yuv -f image -vcodec png output.png

  The color shift is always there, unfortunately !

  The color shift is my big problem right now as I later convert the image to HSV and use thresholding to choose a color range that works for me.

• Revision 0ffa3836f3 : Adding a configure flag to control WebM container support Adding a —(enable|di

  14 mars 2014, par Vignesh Venkatasubramanian

  Changed Paths :
   Modify /configure

  
   Modify /examples.mk

  
   Modify /vpxdec.c

  
   Modify /vpxenc.c

  
  
  Adding a configure flag to control WebM container support

  Adding a —(enable|disable)-webm-io flag to control WebM container input and
  output support. For now, enabling WebM IO by default only when there is a C++
  compiler. Doing so because eventually we will move WebM IO to libwebm and it
  is built using C++.

  Change-Id : I210ac36c23528e382ed41d3c4322291720481492