Recherche avancée

Sur d’autres sites (9523)

• "The system cannot find the file specified" when animating with ffmpeg in matplotlib

  27 novembre 2019, par algol

  I am trying to generate a movie from a stack of numpy arrays using a function I have used on a different computer (a mac) on my home computer (Windows 10). Here is the function that I am using :

  def make_animation(frames,name): 
  
  
  
      plt.rcParams['animation.ffmpeg_path'] = u'C:\ffmpeg-20190320-0739d5c-win64-static\bin\ffmpeg.exe' 
  
      n_images=frames.shape[2] 
  
      assert (n_images>1)   
  
      figsize=(10,10)
  
      fig, ax = plt.subplots(figsize=figsize)
  
      fig.tight_layout()
  
      fig.subplots_adjust(left=0, bottom=0, right=1, top=1, wspace=None, hspace=None)
  
      #lineR, = ax.plot(xaxis_data[0],R_data[0],'c-',label="resources")
  
      img = ax.imshow(frames[:,:,0], animated = True)   
  
  
  
  
  
      def updatefig(img_num): 
  
  
  
          #lineR.set_data(xaxis_data[img_num],R_data[img_num],'r-')
  
  
  
          img.set_data(frames[:,:,img_num])
  
  
  
          return [img]
  
  
  
  
  
      ani = animation.FuncAnimation(fig, updatefig, np.arange(1, n_images), interval=50, blit=True)
  
      mywriter = animation.FFMpegWriter(fps = 20)
  
      #ani.save('mymovie.mp4',writer=mywriter)
  
  
  
      ani.save(f"D:\{name}.mp4",writer=mywriter)
  
  
  
      plt.close(fig)

  Here is the error that I am getting :

  Traceback (most recent call last):
  
  
  
    File "", line 1, in <module>
  
      make_animation(stack,'full_test')
  
  
  
    File "", line 27, in make_animation
  
      ani.save(f"D:\{name}.mp4",writer=mywriter)
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\site-packages\matplotlib\animation.py", line 1136, in save
  
      with writer.saving(self._fig, filename, dpi):
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\contextlib.py", line 112, in __enter__
  
      return next(self.gen)
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\site-packages\matplotlib\animation.py", line 228, in saving
  
      self.setup(fig, outfile, dpi, *args, **kwargs)
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\site-packages\matplotlib\animation.py", line 352, in setup
  
      self._run()
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\site-packages\matplotlib\animation.py", line 363, in _run
  
      creationflags=subprocess_creation_flags)
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\site-packages\spyder_kernels\customize\spydercustomize.py", line 143, in __init__
  
      super(SubprocessPopen, self).__init__(*args, **kwargs)
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\subprocess.py", line 775, in __init__
  
      restore_signals, start_new_session)
  
  
  
    File "C:\Users\~snip~\Anaconda3\lib\subprocess.py", line 1178, in _execute_child
  
      startupinfo)
  
  
  
  FileNotFoundError: [WinError 2] The system cannot find the file specified
  
  </module>

  I know this code basically works since I have used it before on another computer. My guess is that something about ffmpeg is messed up or something about the output path is wrong. I’m not sure what could be wrong with the ffmpeg since I definitely have it installed (via conda) and the path is pretty straightforward. On the other hand I’m not sure what could be wrong with the output path.

• lavc/lpc : exploit even symmetry of window function

  9 mars 2016, par Ganesh Ajjanagadde

  lavc/lpc : exploit even symmetry of window function
  Yields 2x improvement in function performance, and boosts aac encoding
  
  speed by 4% overall. Sample benchmark (Haswell+GCC under -march=native) :
  
  after :
  
  ffmpeg -i sin.flac -acodec aac -y sin_new.aac  5.22s user 0.03s system 105% cpu 4.970 total
  before :
  
  ffmpeg -i sin.flac -acodec aac -y sin_new.aac  5.40s user 0.05s system 105% cpu 5.162 total
  Reviewed-by : Rostislav Pehlivanov <atomnuker@gmail.com>
  
  Signed-off-by : Ganesh Ajjanagadde <gajjanag@gmail.com>
  

  • [DH] libavcodec/lpc.c

• Black screen when playing a video with ffmpeg and SDL on iOS

  1er avril 2012, par patrick

  I'm attempting to create a video player on iOS using ffmpeg and SDL. I'm decoding the video stream and attempting to convert the pixel data into a SDL_Surface and then convert that over to an SDL_Texture and render it on screen. However, all I'm getting is a black screen. I know the video file is good and can be viewed fine from VLC. Any idea what I'm missing here ?

  Initialization code :

      // initialize SDL (Simple DirectMedia Layer) to playback the content
  
      if( SDL_Init(SDL_INIT_VIDEO | SDL_INIT_AUDIO | SDL_INIT_TIMER) ) 
  
      {
  
          DDLogError(@"Unable to initialize SDL");
  
          return NO; 
  
      }
  
  
  
      // create window and renderer 
  
      window = SDL_CreateWindow(NULL, 0, 0, SCREEN_WIDTH, SCREEN_HEIGHT,
  
                                SDL_WINDOW_OPENGL | SDL_WINDOW_BORDERLESS |
  
                                SDL_WINDOW_SHOWN);
  
      if ( window == 0 ) 
  
      {
  
          DDLogError(@"Unable to initialize SDL Window");
  
      }
  
  
  
      renderer = SDL_CreateRenderer(window, -1, 0);
  
      if ( !renderer ) 
  
      {
  
          DDLogError(@"Unable to initialize SDL Renderer");
  
      }
  
  
  
      // Initialize the FFMpeg and register codecs and their respected file formats
  
      av_register_all();

  Playback code :
  AVFormatContext *formatContext = NULL ;

  DDLogInfo(@"Opening media file at location:%@", filePath);
  
  
  
  const char *filename = [filePath cStringUsingEncoding:NSUTF8StringEncoding];
  
  // Open media file
  
  if( avformat_open_input(&formatContext, filename, NULL, NULL) != 0 )
  
  {
  
      DDLogWarn(@"Unable to open media file. [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to open file.", @"Media playback failed, unable to open file.");
  
  
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_OPEN 
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Couldn't open file
  
  }
  
  
  
  // Retrieve stream information
  
  if( avformat_find_stream_info(formatContext, NULL) <= 0 )
  
  {
  
      DDLogWarn(@"Unable to locate stream information for file. [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to find audio/video stream information.", @"Media playback failed, unable to find stream information.");
  
  
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_FIND_STREAM
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO;  // Missing stream information
  
  }
  
  
  
  // Find the first video or audio stream
  
  int videoStream = -1;
  
  int audioStream = -1;
  
  
  
  DDLogInfo(@"Locating stream information for media file");
  
  
  
  for( int index=0; index<(formatContext->nb_streams); index++)
  
  {
  
      if( formatContext->streams[index]->codec->codec_type==AVMEDIA_TYPE_VIDEO ) 
  
      {
  
          DDLogInfo(@"Found video stream");
  
          videoStream = index;
  
          break;
  
      }
  
      else if( mediaType == AUDIO_FILE && 
  
              (formatContext->streams[index]->codec->codec_type==AVMEDIA_TYPE_AUDIO) )
  
      {
  
          DDLogInfo(@"Found audio stream");
  
          audioStream = index;
  
          break;
  
      }
  
  }
  
  
  
  if( videoStream == -1 && (audioStream == -1) )
  
  {
  
      DDLogWarn(@"Unable to find video or audio stream for file");
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to locate audio/video stream.", @"Media playback failed, unable to locate media stream.");
  
  
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_FIND_STREAM
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Didn't find a video or audio stream
  
  }
  
  
  
  // Get a pointer to the codec context for the video/audio stream
  
  AVCodecContext *codecContext;
  
  
  
  DDLogInfo(@"Attempting to locate the codec for the media file");
  
  
  
  if ( videoStream > -1 ) 
  
  {
  
      codecContext = formatContext->streams[videoStream]->codec;
  
  
  
  }
  
  else 
  
  {
  
      codecContext = formatContext->streams[audioStream]->codec;
  
  }
  
  
  
  // Now that we have information about the codec that the file is using,
  
  // we need to actually open the codec to decode the content
  
  
  
  DDLogInfo(@"Attempting to open the codec to playback the media file");
  
  
  
  AVCodec *codec;
  
  
  
  // Find the decoder for the video stream
  
  codec = avcodec_find_decoder(codecContext->codec_id);
  
  if( codec == NULL ) 
  
  {
  
      DDLogWarn(@"Unsupported codec! Cannot playback meda file [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unsupported file format. Cannot playback media.", @"Media playback failed, unsupported codec.");
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNSUPPORTED_CODEC
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Codec not found
  
  }
  
  
  
  // Open codec
  
  if( avcodec_open2(codecContext, codec, NULL) < 0 )
  
  {
  
      DDLogWarn(@"Unable to open codec! Cannot playback meda file [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Unable to open media codec. Cannot playback media.", @"Media playback failed, cannot open codec.");
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_LOAD_CODEC
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Could not open codec
  
  }
  
  
  
  // Allocate player frame
  
   AVFrame *playerFrame=avcodec_alloc_frame();
  
  
  
  // Allocate an AVFrame structure
  
  AVFrame *RGBframe=avcodec_alloc_frame();
  
  if( RGBframe==NULL )
  
  {
  
      // could not create a frame to convert our video frame
  
      // to a 16-bit RGB565 frame.
  
  
  
      DDLogWarn(@"Unable to convert video frame. Cannot playback meda file [File:%@]", filePath);
  
  
  
      NSString *failureReason = NSLocalizedString(@"Problems interpreting video frame information.", @"Media playback failed, cannot convert frame.");
  
      if ( error != NULL ) 
  
      {
  
          *error = [NSError errorWithDomain:MediaPlayerErrorDomain
  
                                       code:UNABLE_TO_LOAD_FRAME
  
                                   userInfo:[NSDictionary dictionaryWithObject:failureReason
  
                                                                        forKey:NSLocalizedFailureReasonErrorKey]];
  
      }
  
  
  
      return NO; // Could not open codec
  
  }
  
  
  
  int frameFinished = 0;
  
  AVPacket packet;
  
  
  
  // Figure out the destination width/height based on the screen size
  
  int destHeight = codecContext->height;
  
  int destWidth  = codecContext->width;
  
  if ( destHeight > SCREEN_HEIGHT || (destWidth > SCREEN_WIDTH) ) 
  
  {
  
      if ( destWidth > SCREEN_WIDTH ) 
  
      {
  
          float percentDiff = ( destWidth - SCREEN_WIDTH ) / (float)destWidth;
  
          destWidth  = destWidth  - (int)(destWidth * percentDiff );
  
          destHeight = destHeight - (int)(destHeight * percentDiff );
  
      }
  
  
  
      if ( destHeight > SCREEN_HEIGHT ) 
  
      {
  
          float percentDiff = (destHeight - SCREEN_HEIGHT ) / (float)destHeight;
  
          destWidth  = destWidth  - (int)(destWidth * percentDiff );
  
          destHeight = destHeight - (int)(destHeight * percentDiff );
  
      }
  
  }
  
  
  
  SwsContext *swsContext = sws_getContext(codecContext->width, codecContext->height, codecContext->pix_fmt, destWidth, destHeight, PIX_FMT_RGB565, SWS_BICUBIC, NULL, NULL, NULL);
  
  
  
  while( av_read_frame(formatContext, &packet) >= 0 ) 
  
  {
  
      // Is this a packet from the video stream?
  
      if( packet.stream_index == videoStream ) 
  
      {
  
          // Decode video frame
  
          avcodec_decode_video2(codecContext, playerFrame, &frameFinished, &packet);
  
  
  
          // Did we get a video frame?
  
          if( frameFinished != 0 ) 
  
          {
  
              // Convert the content over to RGB565 (16-bit RGB) to playback with SDL
  
  
  
              uint8_t *dst[3];
  
              int dstStride[3];
  
  
  
              // Set the destination stride
  
              for (int plane = 0; plane < 3; plane++) 
  
              {
  
                  dstStride[plane] = codecContext->width*2;
  
                  dst[plane]= (uint8_t*) malloc(dstStride[plane]*destHeight);
  
              }
  
  
  
              sws_scale(swsContext, playerFrame->data, 
  
                        playerFrame->linesize, 0, 
  
                        destHeight, 
  
                        dst, dstStride);
  
  
  
              // Create the SDL surface frame that we are going to use to draw our video
  
  
  
              // 16-bit RGB so 2 bytes per pixel (pitch = width*(bytes per pixel))
  
              int pitch = destWidth*2;
  
              SDL_Surface *frameSurface = SDL_CreateRGBSurfaceFrom(dst[0], destWidth, destHeight, 16, pitch, 0, 0, 0, 0);
  
  
  
              // Clear the old frame first
  
              SDL_RenderClear(renderer);
  
  
  
              // Move the frame over to a texture and render it on screen
  
              SDL_Texture *texture = SDL_CreateTextureFromSurface(renderer, frameSurface);
  
              SDL_SetTextureBlendMode(texture, SDL_BLENDMODE_BLEND);
  
  
  
              // Draw the new frame on the screen
  
              SDL_RenderPresent(renderer);
  
  
  
              SDL_DestroyTexture(texture);
  
              SDL_FreeSurface(frameSurface);
  
          }