Sur d’autres sites (9623)

• JAVE (Java Audio Video Encoder) library exception only on Linux (CentOS 7)

  13 octobre 2017, par Linu Radu

  I’m using JAVE (Java Audio Video Encoder) library and the developed application is on windows.
  On windows the conversion of an .mp3 file is working fine but when I deployed on linux (CentOS 7) an exception is thrown.

  As I understand JAVE has also a wrapper around an ffmpeg executable.

  Here is my code :

  try {
  
          File source = new File(sourceFile);
  
          File target = new File(targetFile);
  
  
  
          final AudioAttributes audio = new AudioAttributes();
  
          audio.setCodec("libmp3lame");
  
          audio.setBitRate(88000);
  
          audio.setChannels(2);
  
          audio.setSamplingRate(44100);   
  
  
  
          EncodingAttributes attrs = new EncodingAttributes();
  
          attrs.setFormat("mp3");
  
          attrs.setAudioAttributes(audio);
  
  
  
          Encoder encoder = new Encoder();
  
          encoder.encode(source, target, attrs);
  
  } catch (EncoderException ex) {
  
      throw ex;
  
  }

  Exception :

  ...
  
  
  
  Caused by: it.sauronsoftware.jave.EncoderException: Error while opening codec for output stream #0.0 - maybe incorrect parameters such as bit_rate, rate, width or height
  
      at it.sauronsoftware.jave.Encoder.encode(Encoder.java:926)
  
      at it.sauronsoftware.jave.Encoder.encode(Encoder.java:713)
  
      at com.hft2.ejb.util.Mp3JaveEncoder.encode(Mp3JaveEncoder.java:36)
  
      ... 206 more

  Update

  Here is the official page : http://www.sauronsoftware.it/projects/jave/

  Full exception log : https://jpst.it/1678l

  Does anyone have any idea ?

• ffmpeg c++/cli wrapper for using in c# . AccessViolationException after call dll function by it's pointer

  4 octobre 2017, par skynet_v

  My target is to write a c++/cli wrap arount ffmpeg library, using by importing ffmpeg functions from dll-modules.
  Later I will use this interface in c#.
  This is my challenge, don’t ask me why))

  So i’ve implemented Wrap class, which is listed below :

  namespace FFMpegWrapLib 
  
  {
  
      public class Wrap
  
      {
  
      private:
  
  
  
      public:
  
          //wstring libavcodecDllName = "avcodec-56.dll";
  
          //wstring libavformatDllName = "avformat-56.dll";
  
          //wstring libswscaleDllName = "swscale-3.dll";
  
          //wstring libavutilDllName = "avutil-54.dll";
  
  
  
          HMODULE libavcodecDLL;
  
          HMODULE libavformatDLL; 
  
          HMODULE libswsscaleDLL;
  
          HMODULE libavutilDLL;
  
  
  
          AVFormatContext     **pFormatCtx = nullptr;
  
          AVCodecContext      *pCodecCtxOrig = nullptr;
  
          AVCodecContext      *pCodecCtx = nullptr;
  
          AVCodec             **pCodec = nullptr;
  
          AVFrame             **pFrame = nullptr;
  
          AVFrame             **pFrameRGB = nullptr;
  
          AVPacket            *packet = nullptr;
  
          int                 *frameFinished;
  
          int                 numBytes;
  
          uint8_t             *buffer = nullptr;
  
          struct SwsContext   *sws_ctx = nullptr;
  
  
  
          void                Init();
  
          void                AVRegisterAll();
  
          void                Release();
  
          bool                SaveFrame(const char *pFileName, AVFrame * frame, int w, int h);
  
          bool                GetStreamInfo();
  
          int                 FindVideoStream();
  
          bool                OpenInput(const char* file);
  
          AVCodec*            FindDecoder();
  
          AVCodecContext*     AllocContext3();
  
          bool                CopyContext();
  
          bool                OpenCodec2();
  
          AVFrame*            AllocFrame();
  
          int                 PictureGetSize();
  
          void*               Alloc(size_t size);
  
          int                 PictureFill(AVPicture *, const uint8_t *, enum AVPixelFormat, int, int);
  
          SwsContext*         GetSwsContext(int, int, enum AVPixelFormat, int, int, enum AVPixelFormat, int, SwsFilter *, SwsFilter *, const double *);
  
          int                 ReadFrame(AVFormatContext *s, AVPacket *pkt);
  
          int                 DecodeVideo2(AVCodecContext *avctx, AVFrame *picture, int *got_picture_ptr, const AVPacket *avpkt);
  
          int                 SwsScale(struct SwsContext *c, const uint8_t *const srcSlice[], const int srcStride[], int srcSliceY, int srcSliceH, uint8_t *const dst[], const int dstStride[]);
  
          void                PacketFree(AVPacket *pkt);
  
          void                BufferFree(void *ptr);
  
          void                FrameFree(AVFrame **frame);
  
          int                 CodecClose(AVCodecContext *);
  
          void                CloseInput(AVFormatContext **);
  
          bool                SeekFrame(AVFormatContext *s, int stream_index, int64_t timestamp, int flags);
  
  
  
          Wrap();
  
          ~Wrap();
  
  
  
          bool                GetVideoFrame(char* str_in_file, char* str_out_img, uint64_t time);
  
      };
  
  
  
      public ref class managedWrap
  
      {
  
      public:
  
  
  
          managedWrap(){}
  
          ~managedWrap(){ delete unmanagedWrap; }
  
  
  
          bool GetVideoFrameToFile(char* str_in_file, char* str_out_img, uint64_t time)
  
          {
  
              return unmanagedWrap->GetVideoFrame(str_in_file, str_out_img, time);
  
          }
  
  
  
          static Wrap* unmanagedWrap = new Wrap();
  
      };
  
  }

  So the imports to libavcodec and etc. are succesful.
  The problem is in AccessViolationException during calling dll func, for example, in OpenInput (i.e. av_open_input in native ffmpeg library)

  The OpenInput func code is below :

  bool FFMpegWrapLib::Wrap::OpenInput(const char* file)
  
  {
  
      typedef int avformat_open_input(AVFormatContext **, const char *, AVInputFormat *, AVDictionary **);
  
  
  
      avformat_open_input* pavformat_open_input = (avformat_open_input *)GetProcAddress(libavformatDLL, "avformat_open_input");
  
      if (pavformat_open_input == nullptr)
  
      {
  
          throw exception("Unable to find avformat_open_input function address in libavformat module");
  
          return false;
  
      }
  
  
  
      //pin_ptr<avformatcontext> pinFormatContext = &amp;(new interior_ptr<avformatcontext>(pCodecCtx));
  
      pFormatCtx = new AVFormatContext*;
  
      //*pFormatCtx = new AVFormatContext;
  
  
  
  
  
      int ret = pavformat_open_input(pFormatCtx, file, NULL, NULL); // here it fails
  
  
  
      return ret == 0;
  
  }
  
  </avformatcontext></avformatcontext>

  So the problem, i think, is that class-fields of Wrap class are in secure memory. And ffmpeg works with native memory, initialising pFormatCtx variable by it’s address.
  Can I avoid this, or it is impossible ?

• Matplotlib : ValueError : I/O operation on closed file [duplicate]

  28 septembre 2017, par gopi

  This question is an exact duplicate of :

  • animation.FuncAnimation ValueError : I/O operation on closed file

  %matplotlib inline
  
  import math,os,sys,numpy as np
  
  from numpy.random import random
  
  from matplotlib import pyplot as plt, rcParams, animation, rc
  
  from __future__ import print_function, division
  
  from ipywidgets import interact, interactive, fixed 
  
  from ipywidgets.widgets import *
  
  rc('animation', html='html5')
  
  rcParams['figure.figsize'] = 3,3
  
  %precision 4
  
  np.set_printoptions(precision=4, linewidth=100)
  
  
  
  def lin(a,x,b): return a * x + b
  
  
  
  a = 3.
  
  b = 8.
  
  n = 30
  
  
  
  x = random(n)
  
  y = lin(a,x,b)
  
  
  
  plt.scatter(x,y)
  
  
  
  def sse(y, y_pred): return ((y-y_pred)**2).sum()
  
  def loss(y, a, x, b): return sse(y, lin(a, x, b))
  
  def avg_loss(y, a, x, b): return np.sqrt(loss(y, a, x, b)/n)
  
  
  
  a_guess = -1
  
  b_guess = 1
  
  avg_loss(y, a_guess, x, b_guess)
  
  
  
  lr = 0.01
  
  #d[(y-(a*x+b))**2, b] = 2 (y_pred - y)
  
  #d[(y -(a*x+b)) **2, a] = x * dy/db
  
  
  
  def upd():
  
      global a_guess, b_guess
  
      y_pred = lin(a_guess, x, b_guess)
  
      dydb = 2 * (y_pred - y)
  
      dyda = x * dydb
  
      a_guess -= lr*dyda.mean()
  
      b_guess -= lr*dydb.mean()
  
  
  
  
  
  fig = plt.figure(dpi=100, figsize=(5,5))
  
  plt.scatter(x,y)
  
  line, = plt.plot(x, lin(a_guess, x, b_guess))
  
  plt.close()
  
  
  
  def animate(i):
  
      line.set_ydata(lin(a_guess, x, b_guess))
  
      for i in range(10): upd()
  
      return line,
  
  
  
  
  
  ani = animation.FuncAnimation(fig, animate, np.arange(0, 40), interval=100)
  
  ani

  But when I run it I get the following error,

      ValueError Traceback (most recent call last)
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/IPython/core/formatters.pyc in __call__(self, obj)
  
      309             method = get_real_method(obj, self.print_method)
  
      310             if method is not None:
  
  --> 311                 return method()
  
      312             return None
  
      313         else:
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in _repr_html_(self)
  
     1233         fmt = rcParams['animation.html']
  
     1234         if fmt == 'html5':
  
  -> 1235             return self.to_html5_video()
  
     1236 
  
     1237 
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in to_html5_video(self)
  
     1207                                 bitrate=rcParams['animation.bitrate'],
  
     1208                                 fps=1000. / self._interval)
  
  -> 1209                 self.save(f.name, writer=writer)
  
     1210 
  
     1211             # Now open and base64 encode
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in save(self, filename, writer, fps, dpi, codec, bitrate, extra_args, metadata, extra_anim, savefig_kwargs)
  
     1061                         # TODO: See if turning off blit is really necessary
  
     1062                         anim._draw_next_frame(d, blit=False)
  
  -> 1063                     writer.grab_frame(**savefig_kwargs)
  
     1064 
  
     1065         # Reconnect signal for first draw if necessary
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/contextlib.pyc in __exit__(self, type, value, traceback)
  
       33                 value = type()
  
       34             try:
  
  ---> 35                 self.gen.throw(type, value, traceback)
  
       36                 raise RuntimeError("generator didn't stop after throw()")
  
       37             except StopIteration, exc:
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in saving(self, *args, **kw)
  
      287             yield self
  
      288         finally:
  
  --> 289             self.finish()
  
      290 
  
      291     def _run(self):
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in finish(self)
  
      307     def finish(self):
  
      308         'Finish any processing for writing the movie.'
  
  --> 309         self.cleanup()
  
      310 
  
      311     def grab_frame(self, **savefig_kwargs):
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/matplotlib/animation.pyc in cleanup(self)
  
      346     def cleanup(self):
  
      347         'Clean-up and collect the process used to write the movie file.'
  
  --> 348         out, err = self._proc.communicate()
  
      349         self._frame_sink().close()
  
      350         verbose.report('MovieWriter -- '
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in communicate(self, input, timeout)
  
      925 
  
      926         try:
  
  --> 927             stdout, stderr = self._communicate(input, endtime, timeout)
  
      928         finally:
  
      929             self._communication_started = True
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in _communicate(self, input, endtime, orig_timeout)
  
     1711             if _has_poll:
  
     1712                 stdout, stderr = self._communicate_with_poll(input, endtime,
  
  -> 1713                                                              orig_timeout)
  
     1714             else:
  
     1715                 stdout, stderr = self._communicate_with_select(input, endtime,
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in _communicate_with_poll(self, input, endtime, orig_timeout)
  
     1767             select_POLLIN_POLLPRI = select.POLLIN | select.POLLPRI
  
     1768             if self.stdout:
  
  -> 1769                 register_and_append(self.stdout, select_POLLIN_POLLPRI)
  
     1770                 stdout = self._fd2output[self.stdout.fileno()]
  
     1771             if self.stderr:
  
  
  
  /home/gopinath/Workspace/anaconda3/envs/py27/lib/python2.7/site-packages/subprocess32.pyc in register_and_append(file_obj, eventmask)
  
     1746             poller = select.poll()
  
     1747             def register_and_append(file_obj, eventmask):
  
  -> 1748                 poller.register(file_obj.fileno(), eventmask)
  
     1749                 self._fd2file[file_obj.fileno()] = file_obj
  
     1750 
  
  
  
  ValueError: I/O operation on closed file

  I almost tried everywhere and I couldn’t find a solution, I tried reinstalling ffmpeg from the sources, moved this file to the folder where I installed ffmpeg and gave a try.

  I’m using python 3.5,
  Ubuntu 16.04
  Anaconda 4.4
  Matplotlib 2.02

  actually this particular course was taught using python 2.7 so I created a virenv installed 2.7 along with all related dependencies. So will it be the problem ?? I mean using python 2.7 on top of 3.5 ?