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• avformat/matroskaenc : Move adding SeekEntry into end_ebml_master_crc32()

  27 avril 2020, par Andreas Rheinhardt

  avformat/matroskaenc : Move adding SeekEntry into end_ebml_master_crc32()
  Up until now, SeekEntries were already added before
  
  start_ebml_master_crc32() was even called and before we were actually
  
  sure that we really write the element the SeekHead references : After
  
  all, we might also error out later ; and given that the allocations
  
  implicit in dynamic buffers should be checked, end_ebml_master_crc32()
  
  will eventually have to return errors itself, so that it is the right
  
  place to add SeekHead entries.
  The earlier behaviour is of course a remnant of the time in which
  
  start_ebml_master_crc32() really did output something, so that the
  
  position before start_ebml_master_crc32() needed to be recorded.
  
  Erroring out later is also not as dangerous as it seems because in
  
  this case no SeekHead will be written (if it happened when writing
  
  the header, the whole muxing process would abort ; if it happened
  
  when writing the trailer (when writing chapters not available initially),
  
  writing the trailer would be aborted and no SeekHead containing the
  
  bogus chapter entry would be written).
  This commit does not change the way the SeekEntries are added for those
  
  elements that are output preliminarily ; this is so because the SeekHead
  
  is written before those elements are finally output and doing it
  
  otherwise would increase the amount of seeks.
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
  

  • [DH] libavformat/matroskaenc.c

• OpenCV build keeps failing with errors related to ffmpeg [closed]

  23 juillet 2024, par Aterox_os

  I am trying to install OpenCV on a Raspberry PI 4 with Raspbian Version 12. The default method via pip didnt work it kept failing to build the wheel. So I tried to install it manully.
I followed this guide. I change the swap size to 1024mb. I also tried to run just make without the -j4 parameter. But it didnt work. According to the error it seems like its an issue with the naming of the ffmpeg codec.
I could disable disable ffmpeg in the cmake command but I assume its fairly important for an computer vision library.
How can I fix it ?

  


  Here is the log of the cmake command (The same one as in the guide except WITH_QT=ON) :
Cmake log
And here is the make log :
Make log

  


  As mentioned I tried increasing the swap size and instead of running make -j4 I just ran make. I also tried the normal installation via pip install opencv-python. I also tried installing it with and without a virtual environment.

  


• libavfilter/vf_owdenoise.c : skip processing when strength is 0

  12 avril 2016, par Yuuki Galaxy

  libavfilter/vf_owdenoise.c : skip processing when strength is 0
  It is practical to de-noise only on luma while keeping chroma unchanged.
  However, libavfilter/vf_owdenoise.c always do the Wavelet transform/retransform on all 3 channels without check whether chroma_strength is 0.
  Thus I make this patch. De-noise on Y only for yuv420 is now 1.5 times faster.
  Signed-off-by : Yuuki Galaxy <galaxy001@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michael@niedermayer.cc>
  

  • [DH] libavfilter/vf_owdenoise.c