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• Picturebox from AForge FFMPEG empty - C#/WinForms

  1er août 2017, par Jake Delson

  I’ve done a ton of research and looked at a lot of questions here but can’t seem to find anything to help me. I should preface I’m very new to C#, Windows Forms, and SO ! I’m a 1st year CompSci student coming from C++ experimenting with my own projects for the summer. I’m trying to display a series of bitmaps from a .avi using the AForge.Video.FFMPEG video file reader.

  It seems to be finding the file, getting its’ data (console prints dimensions, framerate, and codec) and creating the picturebox, but the picturebox comes up blank/empty. I get the bitmap from the frames of a .avi :

  From AForge example code here

  Then I’m trying to display it with a picture box :

  From MS example code here as well

  And here’s my code. Essentially a combination of the two :

      public class Simple : Form
  
  {
  
      Bitmap videoFrame;
  
  
  
      public Simple()
  
      {
  
          try
  
          {
  
              // create instance of video reader
  
              VideoFileReader reader = new VideoFileReader();
  
              // open video file
  
              reader.Open(@"C:\Users\User\Desktop\ScanTest3.AVI");
  
              // check some of its attributes
  
              Console.WriteLine("width:  " + reader.Width);
  
              Console.WriteLine("height: " + reader.Height);
  
              Console.WriteLine("fps:    " + reader.FrameRate);
  
              Console.WriteLine("codec:  " + reader.CodecName);
  
  
  
              PictureBox pictureBox1 = new PictureBox();
  
  
  
              // read 100 video frames out of it
  
              for (int i = 0; i < 100; i++)
  
              {
  
                  videoFrame = reader.ReadVideoFrame();
  
  
  
                  pictureBox1.SizeMode = PictureBoxSizeMode.StretchImage;
  
                  pictureBox1.ClientSize = new Size(videoFrame.Width, videoFrame.Height);
  
                  pictureBox1.Image = videoFrame;
  
  
  
                  // dispose the frame when it is no longer required
  
                  videoFrame.Dispose();
  
              }
  
  
  
              reader.Close();
  
          }
  
  
  
          catch
  
          {
  
              Console.WriteLine("Nope");
  
          }
  
  
  
      }
  
  }
  
  
  
  class MApplication
  
  {
  
      public static void Main()
  
      {
  
          Application.Run(new Simple());
  
      }
  
  }

  So that’s it pretty much. Just a blank picture box coming up, when it should have the first frame of the video, even though no exception caught (though I’m pretty confident I’m using the try/catch very poorly), and the console printing the correct data for the file :

  width:  720
  
  height: 480
  
  fps:    29
  
  codec:  dvvideo
  
  [swscaler @ 05E10060] Warning: data is not aligned! This can lead to a speedloss

  Though if anyone could tell me what that warning means, that would be great as well, but I’m mainly just lost as to why there’s no picture printing to the screen.

  Thanks !

• avcodec/mips/aaccoder_mips : Remove MIPS-specific aaccoder

  15 mars 2024, par Andreas Rheinhardt

  avcodec/mips/aaccoder_mips : Remove MIPS-specific aaccoder
  ff_aac_coder_init_mips() modifies a static const structure of
  
  function pointers. This will crash if the binary uses relro
  
  and is a data race in any case.
  Furthermore it points to a maintainability issue : The
  
  AACCoefficientsEncoder structures have been constified
  
  in commit fd9212f2edfe9b107c3c08ba2df5fd2cba5ab9e3,
  
  a Libav commit merged in 318778de9ebec276cb9dfc65509231ca56590d13.
  
  Libav did not have the MIPS-specific AAC code and so this was
  
  fine for them ; yet FFmpeg had them, but this was not recognized.
  Commit 75a099fc734a4ee2b1347d0a3d8c53d883b95174 points to another
  
  maintainability issue : Contrary to ordinary DSP code, this code
  
  here is way more complex and needs to be constantly kept in sync
  
  with the ordinary code which it mimicks and replaces. Said commit
  
  is the only commit actually changing aaccoder.c in the last few
  
  years and the same change has not been performed for the MIPS
  
  clone ; before that, it even happened several times that the mips
  
  code was broken due to changes of the generic code (see commits
  
  97437bd17a8c5d4135b2f3b1b299bd7bb72ce02c and
  
  de262d018d7d7d9c967af1dfd1b861c4b9eb2a60 or
  
  860dbe0275e57cbf4228f3f653f872ff66ca596b or
  
  933309a6ca0f18bf1d40e917fff455221f57fb4b or
  
  b65ffa316e377213c29736929beba584d0d80d7c). This might even lead
  
  to scenarios where someone changing non-dsp aacenc code would
  
  have to modify mips inline asm in order to keep them in sync.
  
  This is obviously a significant burden (if the AAC encoder were
  
  actively developed).
  Finally, the code does not even compile here due to errors like
  
  "Error : float register should be even, was 1".
  Reviewed-by : Lynne <dev@lynne.ee>
  
  Reviewed-by : Jean-Baptiste Kempf <jb@videolan.org>
  
  Signed-off-by : Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
  

  • [DH] libavcodec/aacenc.c
  • [DH] libavcodec/aacenc.h
  • [DH] libavcodec/mips/Makefile
  • [DH] libavcodec/mips/aaccoder_mips.c

• Python ImageIO WARNING:root:IMAGEIO FFMPEG_WRITER WARNING

  21 janvier 2018, par cavaler12345

  I’m working in python with some images and I’m trying to convert a series of images with size = 961x509 into an MP4 movie file. I’ve already did this and it’s working but I have a quite annoying problem with a warning which says something like this :

  WARNING:root:IMAGEIO FFMPEG_WRITER WARNING : input image is not
  divisible by macro_block_size=16, resizing from (509L, 961L) to (512L,
  976L) to ensure video compatibility with most codecs and players. To
  prevent resizing, make your input image divisible by the
  macro_block_size or set the macro_block_size to None (risking
  incompatibility). You may also see a FFMPEG warning concerning
  speedloss due to data not being aligned. [swscaler @ 04f8ac40]
  Warning : data is not aligned ! This can lead to a speedloss

  The problem that warning appears is my images resolution, that resolution should be divisible by 2, but mine it doesn’t. Is it there any possibility to just make this warning to don’t appear again ? Because I can’t change the size of my images and in the same time I don’t want to resize all of them.

  Here is my code :

  ready_images = []
  
  
  
  for img in videos['Images']:
  
      image = imageio.imread(img.fileName)
  
      ready_images.append(image)
  
  
  
  videoName = videos['Images'][0].gifLocationPath + "//" + videos['Name']
  
  imageio.mimwrite(videoName, ready_images, 'MP4')

  Is anyone here how has a solution for me ?

  UPDATE :

  If I’m gonna put macro_block_size to None in this way(That’s the only way I know) :

  ready_images = []
  
  
  
  for img in videos['Images']:
  
      image = imageio.imread(img.fileName)
  
      ready_images.append(image)
  
  
  
  video_name = videos['Images'][0].gifLocationPath + "//" + videos['Name']
  
  imageio.mimwrite(video_name, ready_images, 'MP4', macro_block_size = None)

  I will receive this error message :

  Error while opening encoder for output stream #0:0 - maybe incorrect
  parameters such as bit_rate, rate, width or height

  Traceback (most recent call last) : File "", line 146, in
  run() File "", line 136, in run
  for i, _ in tqdm(enumerate(pool.imap_unordered(generateGIFsWithThreads,
  videoList))) : File "", line 953, in iter
  for obj in iterable : File "", line 673, in next
  raise value IOError : [Errno 32] Broken pipe

  FFMPEG COMMAND : ffmpeg -y -f rawvideo -vcodec rawvideo -s 961x509
  -pix_fmt rgb24 -r 10.00 -i - -an -vcodec libx264 -pix_fmt yuv420p -crf 25 -v warning
  D :\work\hero_forge\build\win32\Documents\GIFs\CH3_M1_0.mp4

  FFMPEG STDERR OUTPUT :