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• How can start a process and stop the process if "error" string appear in the console output strings in one line commands set

  25 janvier 2018, par Thm Lee

  Now I want one line cmd commands set which start a process and monitor the consol output strings stream. And so if error message appear in the process’s console output, then could stop the process immediately.

  For example, I tried below commends sets, but failed. It seems find command didn’t get any strings streams in which search key word "error"

  ffmpeg "endcoding process options set" | find "error" && exit

  or,

  ffmpeg "endcoding process options set" 2>&1 find "error" && exit

  Is there any solutions about this ?

  Thanks in advance

• avcodec/xbmdec : convert() minor speed increase

  1er février 2021, par Jose Da Silva

  avcodec/xbmdec : convert() minor speed increase
  If we test for 0..9 first, we have tested for 10/16th of all possible
  
  characters first and avoid testing the remaining 6/16th of all possible
  
  characters, which can be either 6/16th lowercase or 6/16th uppercase.
  Signed-off-by : Joe Da Silva <digital@joescat.com>
  

  • [DH] libavcodec/xbmdec.c

• FFmpeg cannot extract correct first frame - always extract the second frame [closed]

  21 octobre 2024, par Cai Yu

  I am on macos Ventura 13.2.1, on Macbook Pro M1Max.

  


  The video is number counting animation video. From 2 to 125. The number on first frame is 2. The number on last frame is 125. The number plus one on each frame. You can download the video here.

  


  NOTE that :
First, you hit space bar to play it in Finder, you can see the first frame of the video is number 2.

  


  Second, in professional Video editing software - davinci resolve, on the timeline, you can see the first frame is number 2.

  


  Now I try to use FFmpeg to extract the first frame of the video.
First Try :

  


  ffmpeg -i /Users/chris/Downloads/2to125.mov -vframes 1 /Users/chris/Downloads/1.png


  


  The output png image is number 3. So it's actually the second frame.

  


  Second try :

  


  ffmpeg -i /Users/chris/Downloads/2to125.mov -frames:v 1 /Users/chris/Downloads/1.png


  


  The output png image is still the second frame - the number 3.

  


  Third try :

  


  ffmpeg -i /Users/chris/Downloads/2to125.mov -vf "select=eq(n\,0)" -q:v 3 /Users/chris/Downloads/1.png


  


  The output image is sitll the wrong second frame.

  


  NOTE that :

  


  first : all these three method are from internet. And a lot of people voted correct answer for this question.

  


  second : all their output on my system is the incorrect second frame, not the first frame.

  


  I cannot find what's wrong. Hope friend here help me.