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• ffmpeg : Video duration confused for some players on Android

  2 juin 2021, par Radi Cho

  I am using ffmpeg to scale down and compress videos to be used in Android app.
The original files are played with no problem and have no metadata issues. When I re-encode them however, the Android player is able to play them, but displays wrong durations. My app is in production and it is using official player implementations, so I wonder if there is a way to fix the corruption using ffmpeg or adding some metadata to the generated files. Hopefully that's possible, but if not - any other possible fixes will be highly appreciated :)

  


  My ffmpeg command is complex, including scaling and encoding but I can confirm this issue is reproducible on my end with the simplest ffmpeg -i video.mp4 -c:v libx264 videogen.mp4 command.

  


  I'm leaving links to the two files if that's helpful for reference.

  


  

  • video.mp4

  


  • videogen.mp4

  


  


  Any ideas what could be causing this and how to fix it ?

  


  Player issues showcase :

  
video.mp4 (original)


  

  
videogen.mp4 (re-encoded)


  

  


• ffmpeg simple 5fps webcam capturing but results in poor performance

  16 septembre 2022, par irous

  I'm using Windows 10, intel core i5, 8GB ram. and download ffmpeg from official site : https://www.gyan.dev/ffmpeg/builds/

  


  I'm trying to capture 5fps video from webcam but the output fps is only 3.4 and speed is 0.668x. (I also tried with libx264 but the speed is same 0.5).
  
This is my command :

  


  ffmpeg ^
  -f dshow -r 5 -s 640x480 -i video="Sony Visual Communication Camera" ^
  -f rawvideo output.raw


  


  screenshot of console output :


  


  The cpu usage for above ffmpeg command is about 0.1% and also ram/disk usage is relatively low.
  
If I change the fps to 30 (-r 30), the output is : fps 7.9, speed 0.261x and CPU usage is still very low 0.1%.

  


  But I can easily record 30fps video with the same format yuyv422 in Directshow GraphEdit :


  


  So my question is why does ffmpeg show such poor performance even with 5fps video capturing ? If it can only produce 3.4 fps in the first case why it can output up to 7.9 fps in the latter case (when I set desired fps to 30) ? Did I mis-config ffmpeg ?
  
Any help is appreciated.

  


• Build PJSIP with video support on Windows 7, with MinGW

  3 juillet 2015, par Daniel V

  I’m trying to build PJSIP with video support for Windows OS, on my Windows 7 PC by using MinGW.
  Following the official guide from PJSIP :
  http://trac.pjsip.org/repos/wiki/Getting-Started/Autoconf#VideoSupportfor2.0andabove

  Building PJSIP without video support works as expected for me.

  • I’m using the latest PJSIP 2.2.1 from SVN
  • SDL2-devel-2.0.3-mingw.tar.gz (MinGW 32/64-bit)
  • ffmpeg-20140805-git-de41798-win32-dev

  I have added "#define PJMEDIA_HAS_VIDEO 1" in the config_site.h file
  and I’m building PJSIP with the following options :
  ./configure —with-ffmpeg="/c/PJSIP/ffmpeg" —with-sdl="/c/PJSIP/SDL"

  but I have the following compilation error for SDL :

  c:/PJSIP/SDL/lib/libSDL2main.a(SDL_windows_main.o): In function `console_main':
  
  /Users/slouken/release/SDL/SDL2-2.0.3-source/foo-x86/../src/main/windows/SDL_win
  
  dows_main.c:140: undefined reference to `SDL_main'
  
  collect2.exe: error: ld returned 1 exit status
  
  make[2]: *** [../bin/pjsua2-test-i686-pc-mingw32] Error 1
  
  make[2]: Leaving directory `/c/PJSIP/trunk/pjsip/build'
  
  make[1]: *** [pjsua2-test-i686-pc-mingw32] Error 2
  
  make[1]: Leaving directory `/c/PJSIP/trunk/pjsip/build'
  
  make: *** [all] Error 1

  The same error is available with SDL-2.0.2 too.