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• Checking video integrity using ffmpeg with Python

  13 janvier 2020, par zion.b.

  I am trying to check video integrity and made it successfully using mac terminal with the line of code below :

  ffmpeg -v error -i filename.mp4 -f null - 2>error.log

  Now i am trying to do the same in python with no success making the cmd command. I try to do :

  cmds = ["ffmpeg", "-i","filename.mp4", "-v", "error", "-f", "null", "-", "2>", "error.log"]
  
  subprocess.Popen(cmds)

  But i am getting the error - 2>: Invalid argument

  I also tried also "2>error.log" instead of "2>", "error.log" but then im getting 2>error.log: Invalid argument

• avfilter/formats : Factor checking for mergeability out of ff_merge_*

  14 août 2020, par Andreas Rheinhardt

  avfilter/formats : Factor checking for mergeability out of ff_merge_*
  The callers of the ff_merge_*() functions fall into two categories with
  
  quite different needs :
  One caller is can_merge_formats() which only wants to test for mergeability
  
  without it merging anything. In order to do so, it duplicates the lists
  
  it intends to test and resets their owners so that they are not modified
  
  by ff_merge_*(). It also means that it needs to receive the merged list
  
  (and not only an int containing whether the lists are mergeable) to
  
  properly free it.
  The other callers want the lists to be actually merged. But given the
  
  fact that ff_merge_*() automatically updates the owners of the lists,
  
  they only want the information whether the merge succeeded or not ; they
  
  don't want a link to the new list.
  Therefore this commit splits these functions in two : ff_merge_*() for
  
  the latter callers and ff_can_merge_*() for the former.
  
  ff_merge_*() doesn't need to return a pointer to the combined list at all
  
  and hence these functions have been modified to return an int, which
  
  allows to distinguish between incompability and memory allocation failures.
  ff_can_merge_*() meanwhile doesn't modify its arguments at all obviating
  
  the need for copies. This in turn implies that there is no reason to
  
  return a pointer to the new list, as nothing needs to be freed. These
  
  functions therefore return an int as well. This allowed to completely
  
  remove can_merge_formats() in avfiltergraph.c.
  Notice that no ff_can_merge_channel_layouts() has been created, because
  
  there is currently no caller for this. It could be added if needed.
  Reviewed-by : Nicolas George <george@nsup.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavfilter/avfiltergraph.c
  • [DH] libavfilter/formats.c
  • [DH] libavfilter/formats.h

• How to extract good quality frames from a video and save them without compression ?

  13 août 2019, par Albert

  How can I use ffmpeg and only extract the frames that does not have artifacts (e.g. compression artifacts) from a video and save them with good quality in jpeg format .