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• ffmpeg : playing media files does not release processor after media ends ?

  2 septembre 2017, par Blake Senftner

  I have a commercial C++ application which uses FFMPEG’s libav series of dlls to play media in a Windows application. I basically started with the dranger tutorial about two years ago, and created a library that can playback USB cameras, IP camera / online streams, and media files on disk. (http://dranger.com/ffmpeg/)

  My question is directed at anyone who has created their own similar library :

  I recently noticed after playing a video file from disk (as opposed to a live stream from USB or IP source), my 8 core i7 workstation will show 28-29% CPU usage after a media file has ended. My application can play an unlimited number of videos, and each "virtual video panel" (not a window, just a "virtual tab" created using wxWidgets that holds an OpenGL context that I use to glDrawPixels() to the visible app panel) will play any of the three media types fine (USB, IP stream or media file) and when I stop a USB or IP stream my application’s CPU usage drops to zero. But when I "stop" a media file playing or the media file ends on its own the CPU usage does not drop - until the application quits.

  Three media files playing will take my application to 80-83% CPU, and it never drops. UNLESS I reuse that same "virtual video panel" to play a USB or IP stream. If I stop those streams, CPU usage is released.

  MP4 (h264) video files exhibit this "holding a processor" problem.

  MP4 (mpeg2) files do not.

  MP4 (h265) files do not.

  MPG (mpeg1) files do not.

  ASF (MS MPEG-4 Video v3) files do not.

  MKV (vp8) files do not.

  MOV files using h265 do not, as well as MOV (h264) files do not.

  FLV (sorensen) files do not, as well as FLV (h264) files do not.

  So it is not just the h264 codec.

  Anyone know what is going on, and how I tell libav to release CPU usage when a media file is no longer playing ?

• Remove support for building for mingw32ce (Windows CE)

  30 août 2017, par Martin Storsjö

  Remove support for building for mingw32ce (Windows CE)
  The toolchain for this target is unmaintained since many years.
  While it has been continuously build tested on fate, it hasn’t
  
  actually been tested at runtime since many, many years (and back
  
  then, only a few codecs in libavcodec were tested).
  So far, keeping support for it has been mostly effortless, but
  
  the compiler does seem to have issues with dllimported data symbols,
  
  ending up as internal compiler errors in some cases. Instead of
  
  jumping through further hoops to work around that, just remove the
  
  target.
  Signed-off-by : Martin Storsjö <martin@martin.st>
  

  • [DBH] configure
  • [DBH] libavformat/os_support.h
  • [DBH] libavutil/file_open.c
  • [DBH] libavutil/wchar_filename.h
  • [DBH] tools/qt-faststart.c

• lavd : drop disabled v4l code

  3 septembre 2017, par Clément Bœsch

  lavd : drop disabled v4l code
  This code is disabled since 2012. V4L1 was dropped from the kernel more
  
  than 10 years ago.
  

  • [DH] configure
  • [DH] libavdevice/Makefile
  • [DH] libavdevice/alldevices.c
  • [DH] libavdevice/v4l.c