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• flac demuxer : parse the WAVEFORMATEXTENSIBLE_CHANNEL_MASK tag

  25 mai 2014, par Anton Khirnov

  flac demuxer : parse the WAVEFORMATEXTENSIBLE_CHANNEL_MASK tag
  It is used to store the channel mask for non-standard layouts.
  

  • [DBH] libavformat/flacdec.c

• how to us google ML kit Selfie segmentation in flutter to overlay segmented user on top of chosen image or video ? [closed]

  4 avril 2024, par Amr

  I'm working on implementing a virtual background feature using the Google ML Kit selfie segmentation Flutter plugin. The goal is to separate the user from the background live from the camera feed, overlay the user on a chosen image or video, and then create a new video combining these elements.

  


  Currently, I'm successfully obtaining the mask using the plugin. However, I'm concerned about performance issues if I directly copy pixels to achieve the overlay effect, especially in real-time scenarios.

  


  I'm looking for alternative approaches or best practices to efficiently achieve this functionality without sacrificing performance. Any insights or suggestions on how to approach this would be greatly appreciated.

  


  I thought about using ffmpeg but not sure how to take the user pixels from the camera feed, I am not a flutter developer so not sure how to do so.

  


• libavutil : Add wchartoutf8(), wchartoansi(), utf8toansi(), getenv_utf8(), freeenv_utf...

  20 juin 2022, par Nil Admirari

  libavutil : Add wchartoutf8(), wchartoansi(), utf8toansi(), getenv_utf8(), freeenv_utf8() and getenv_dup()
  wchartoutf8() converts strings returned by WinAPI into UTF-8,
  
  which is FFmpeg's preffered encoding.
  Some external dependencies, such as AviSynth, are still
  
  not Unicode-enabled. utf8toansi() converts UTF-8 strings
  
  into ANSI in two steps : UTF-8 -> wchar_t -> ANSI.
  
  wchartoansi() is responsible for the second step of the conversion.
  
  Conversion in just one step is not supported by WinAPI.
  Since these character converting functions allocate the buffer
  
  of necessary size, they also facilitate the removal of MAX_PATH limit
  
  in places where fixed-size ANSI/WCHAR strings were used
  
  as filename buffers.
  On Windows, getenv_utf8() wraps _wgetenv() converting its input from
  
  and its output to UTF-8. Strings returned by getenv_utf8()
  
  must be freed by freeenv_utf8().
  On all other platforms getenv_utf8() is a wrapper around getenv(),
  
  and freeenv_utf8() is a no-op.
  The value returned by plain getenv() cannot be modified ;
  
  av_strdup() is usually used when modifications are required.
  
  However, on Windows, av_strdup() after getenv_utf8() leads to
  
  unnecessary allocation. getenv_dup() is introduced to avoid
  
  such an allocation. Value returned by getenv_dup() must be freed
  
  by av_free().
  Because of cleanup complexities, in places that only test the existence
  
  of an environment variable or compare its value with a string
  
  consisting entirely of ASCII characters, the use of plain getenv()
  
  is still preferred. (libavutil/log.c check_color_terminal()
  
  is an example of such a place.)
  Plain getenv() is also preffered in UNIX-only code,
  
  such as bktr.c, fbdev_common.c, oss.c in libavdevice
  
  or af_ladspa.c in libavfilter.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DH] configure
  • [DH] libavutil/getenv_utf8.h
  • [DH] libavutil/wchar_filename.h