Sur d’autres sites (5670)

• FFMpegWriter() [Error 5] Access Denied

  8 juin 2016, par Guillermo

  So, I’m trying to save animations with the animation.save command. I installed ffmpeg in Windows 10 by placing a folder with its binaries in my drive C :\, I have also set the path in my system variables like C :\ffmpeg\bin, and finally, my code for the animation function saving looks like this

   if save=='True':
  
       mywriter = animation.FFMpegWriter()
  
       plt.rcParams['animation.ffmpeg_path'] = 'C:/ffmpeg/bin' 
  
       ani.save('mymovie.avi',writer=mywriter,fps=30)

  and all other kind of variants such as :

      mpl.animation.ffmpeg_path = r'C:\ffmpeg\bin' 
  
      mpl.animation.ffmpeg_path = 'C:\\ffmpeg\\bin' 

  No matter what I do, the result is always :

  File "<stdin>", line 2, in <module>
  
  File "Plot.py", line 168, in animate
  
  ani.save('mymovie.avi',writer=mywriter,fps=30)
  
  File "c:\users\guillermo\appdata\local\enthought\canopy\user\lib\site-packages\matplotlib\animation.py", line 801, in save
  
  with writer.saving(self._fig, filename, dpi):
  
  File "C:\Users\Guillermo\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.6.1.3253.win-x86_64\lib\contextlib.py", line 17, in __enter__
  
  return self.gen.next()
  
  File "c:\users\guillermo\appdata\local\enthought\canopy\user\lib\site-packages\matplotlib\animation.py", line 194, in saving
  
  self.setup(*args)
  
  File "c:\users\guillermo\appdata\local\enthought\canopy\user\lib\site-packages\matplotlib\animation.py", line 184, in setup
  
  self._run()
  
  File "c:\users\guillermo\appdata\local\enthought\canopy\user\lib\site-packages\matplotlib\animation.py", line 212, in _run
  
  creationflags=subprocess_creation_flags)
  
  File "C:\Users\Guillermo\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.6.1.3253.win-x86_64\lib\subprocess.py", line 710, in __init__
  
  errread, errwrite)
  
  File "C:\Users\Guillermo\AppData\Local\Enthought\Canopy\App\appdata\canopy-1.6.1.3253.win-x86_64\lib\subprocess.py", line 958, in _execute_child
  
  startupinfo)
  
  WindowsError: [Error 5] Access Denied
  
  </module></stdin>

  Any ideas ? :D

  ------------------------------------------------------------------------------

  EDIT : I will reference this answer as it is the one that helped me the best :
  http://stackoverflow.com/a/27017734/6050676

  It worked perfectly when using :

  plt.rcParams['animation.ffmpeg_path'] = 'C:\\ffmpeg\\bin\\ffmpeg.exe'  

• Can I access FFPlay.exe's STDIN in order to emulate a 'q' keypress ?

  28 novembre 2023, par couldabin

  I am writing a Win32 program that launches ffplay.exe. I would like to have my program send a quit message ('q') but cannot get ffplay to respond. I am using CreatePipe() to initialize read/write handles that are used by CreateProcess(), which launches ffplay.exe. Should I be able to make this work ? If I start ffplay manually from a command line, pressing 'q' works fine. I would like to emulate that with my Win32 program. To test my code, I substituted ffplay.exe with another console application that prompts the user for input, and it responds as expected.

  


• WinAPI multithreading access violation when writing in local variable

  26 février 2016, par JustPingo

  I’m making a multithreaded program using Visual C++, Win32 API (using _beginthread) that also uses FFmpeg (it is claimed to be thread-safe, and I’m using it only with one single thread anyway).

  Here is the part of my thread’s code that causes problems (everything is inside of the thread function) :

  Arena* arena = NULL;
  
  
  
  switch (task) {
  
      case TaskOne:
  
          arena = (Arena*) malloc(sizeof(Arena));
  
          for (uint i = 0; i < FIGHTSPERROUND; i++) {
  
              generateArena(arena, ARENAWALLSAMOUNT, ARENAWIDTH, ARENAHEIGHT, ARENAMAXENTITIES, 255);
  
              spawnPlayer(arena, playerOne, 3, 1, 0, 0, ARENAPLAYERLIFE);
  
              spawnPlayer(arena, playerTwo, 2, 2, ARENAWIDTH-1, ARENAHEIGHT-1, ARENAPLAYERLIFE);
  
  
  
              do {
  
                  tickArena(arena);
  
              } while ((result = getResult(arena)) == 0);
  
  
  
              switch (result) {
  
                  case 1: teamOneScore++; break;
  
                  case 2: teamTwoScore++; break;
  
                  default: break;
  
              }
  
  
  
              freeArena(arena);
  
              clearMemory(playerOne);
  
              clearMemory(playerTwo);
  
              clearBrain(playerOne);
  
              clearBrain(playerTwo);
  
          }
  
          threadTeamOneScore[threadID] = teamOneScore;
  
          threadTeamTwoScore[threadID] = teamTwoScore;
  
          break;
  
  
  
      default: break;
  
  }

  Here is how I generate my arena :

  void generateArena(Arena* arena, uint wallsAmount, uint xSize, uint ySize, uint maxEntities, uint maxTurns) {
  
      CasesTypes** map;
  
      map = (CasesTypes**) malloc(xSize * sizeof(CasesTypes*));
  
      memset(map, 0, xSize * sizeof(CasesTypes*));
  
      for (uint i = 0; i < xSize; i++) {
  
          map[i] = (CasesTypes*)malloc(ySize * sizeof(CasesTypes));
  
          memset(map[i], 0, ySize * sizeof(CasesTypes));
  
      }
  
  
  
      arena->map = map;
  
      arena->entities = (Entity*) malloc(maxEntities * sizeof(Entity));
  
      memset(arena->entities, 0, maxEntities * sizeof(Entity));
  
      arena->width = xSize;
  
      arena->height = ySize;
  
      arena->maxEntities = maxEntities;
  
      arena->maxTurns = maxTurns;
  
      arena->currentTurn = 0;
  
      arena->entitiesAmount = 0;
  
      for (uint i = 0; i < wallsAmount; i++)
  
          arena->map[random2(1, xSize-1)][random2(1, ySize-1)] = Wall;
  
  }

  This works as expected 4 times in 5.
  But sometimes, for some reason, arena = (Arena*) malloc(sizeof(Arena)); throws an access violation exception.

  For example, Visual Studio 2015’s debugger once said :
  Exception thrown at 0x77DBE389 (ntdll.dll) in MyProgram.exe: 0xC0000005: Access violation writing location 0x007C160F.

  When I used the debugger to find what ((void*) 0x007C160F) was, it always happened to be something similar to :

  avformat-57.dll!0x007c160f (load symbols for additional information)

  avformat is a part of FFmpeg. The address was different every times, but it always had something to do with FFmpeg.

  I can’t figure out what is causing the problem.
  If that can help, sometimes the arena also happens to get corrupted (some of its fields get extremely big while generating them with generateArena although it is never changed and only set once to an integer, this leads to a crash later).

  Thank you in advance !