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• What is the right way to clean memory in ffmpeg ?

  27 mars 2018, par hagor

  Hi i have a class with these fields :

  bool m_initializedAndRegistered = false;
  
      std::atomic <bool> m_recievingFrames = false;
  
      int m_init_frames = 10000;
  
      int m_capacity = 10;
  
      std::thread readingThread;
  
      std::string m_streamAdress;
  
      SwsContext *m_img_convert_ctx_ptr = NULL;
  
      AVFormatContext *m_format_ctx_ptr = NULL;
  
      AVFormatContext *m_output_ctx_ptr = NULL;
  
      AVCodecContext *m_codec_ctx_ptr= NULL;// = NULL;
  
      AVPacket m_packet;
  
      AVStream *m_stream_ptr = NULL;
  
      AVCodec *m_codec_ptr = NULL;
  
      AVFrame *m_picture_ptr = NULL;
  
      AVFrame *m_picture_rgb_ptr = NULL;
  
      int m_video_stream_index = -1;
  
      uint8_t *m_picture_buffer_ptr = NULL;
  
      uint8_t *m_picture_buffer_2_ptr = NULL;
  
      circ_buffer m_imageBuffer;
  
  </bool>

  is it a correct way to clean all memory or do I forget to clean something ?
  It seems that I have 0.2 MB memory leak when I do this :

  m_recievingFrames = false;
  
  readingThread.join();
  
  readingThread.~thread();
  
  
  
  while (m_imageBuffer.size() > 0)
  
  {
  
      m_imageBuffer.receive().release();
  
  }
  
  av_packet_unref(&m_packet);
  
  
  
  av_frame_free(&m_picture_ptr);
  
  
  
  av_frame_free(&m_picture_rgb_ptr);
  
  
  
  av_read_pause(m_format_ctx_ptr);
  
  avio_close(m_output_ctx_ptr->pb);
  
  avio_close(m_format_ctx_ptr->pb);
  
  
  
  avformat_close_input(&m_format_ctx_ptr);
  
  avformat_close_input(&m_output_ctx_ptr);
  
  avformat_free_context(m_output_ctx_ptr);
  
  avformat_free_context(m_format_ctx_ptr);
  
  
  
  m_video_stream_index = -1;
  
  av_free(m_picture_buffer_ptr);
  
  av_free(m_picture_buffer_2_ptr);
  
  
  
  avcodec_free_context(&m_codec_ctx_ptr);
  
  
  
  av_free(m_stream_ptr);
  
  sws_freeContext(m_img_convert_ctx_ptr);

  I used malloc in m_picture_buffer_ptr allocation, but I cant free() it, because I get a heap exception. Do I need manually clean all Info for streams as it is suggested here ?

  My work is based on this old ffmpeg streamer.
  I don’t do av_register_all() and avformat_network_init() on every streamer restart.
  What is a good way (tool) to find memory leaks ?

• Setting ffmpeg properly in ubuntu 16.04

  22 août 2017, par pro neon

  I am following this website for ffmpeg tutorial : http://dranger.com
  I tried to compile the programs after setting up ffmpeg in ubuntu by looking on some online videos but none of them worked. Some times GCC gives me undefined reference error and sometimes header not found error. I looked on some of the answers on SO that said that we need to do some change in the code as the new api is not backwards compatible but still GCC gives me undefined reference error.
  Here is the code that I am trying to compile :

      // tutorial01.c
  
  // Code based on a tutorial by Martin Bohme (boehme@inb.uni-luebeckREMOVETHIS.de)
  
  // Tested on Gentoo, CVS version 5/01/07 compiled with GCC 4.1.1
  
  // With updates from https://github.com/chelyaev/ffmpeg-tutorial
  
  // Updates tested on:
  
  // LAVC 54.59.100, LAVF 54.29.104, LSWS 2.1.101 
  
  // on GCC 4.7.2 in Debian February 2015
  
  
  
  // A small sample program that shows how to use libavformat and libavcodec to
  
  // read video from a file.
  
  //
  
  // Use
  
  //
  
  // gcc -o tutorial01 tutorial01.c -lavformat -lavcodec -lswscale -lz
  
  //
  
  // to build (assuming libavformat and libavcodec are correctly installed
  
  // your system).
  
  //
  
  // Run using
  
  //
  
  // tutorial01 myvideofile.mpg
  
  //
  
  // to write the first five frames from "myvideofile.mpg" to disk in PPM
  
  // format.
  
  
  
  #include <libavcodec></libavcodec>avcodec.h>
  
  #include <libavformat></libavformat>avformat.h>
  
  #include <libswscale></libswscale>swscale.h>
  
  
  
  #include 
  
  
  
  // compatibility with newer API
  
  #if LIBAVCODEC_VERSION_INT &lt; AV_VERSION_INT(55,28,1)
  
  #define av_frame_alloc avcodec_alloc_frame
  
  #define av_frame_free avcodec_free_frame
  
  #endif
  
  
  
  void SaveFrame(AVFrame *pFrame, int width, int height, int iFrame) {
  
    FILE *pFile;
  
    char szFilename[32];
  
    int  y;
  
  
  
    // Open file
  
    sprintf(szFilename, "frame%d.ppm", iFrame);
  
    pFile=fopen(szFilename, "wb");
  
    if(pFile==NULL)
  
      return;
  
  
  
    // Write header
  
    fprintf(pFile, "P6\n%d %d\n255\n", width, height);
  
  
  
    // Write pixel data
  
    for(y=0; ydata[0]+y*pFrame->linesize[0], 1, width*3, pFile);
  
  
  
    // Close file
  
    fclose(pFile);
  
  }
  
  
  
  int main(int argc, char *argv[]) {
  
    // Initalizing these to NULL prevents segfaults!
  
    AVFormatContext   *pFormatCtx = NULL;
  
    int               i, videoStream;
  
    AVCodecContext    *pCodecCtxOrig = NULL;
  
    AVCodecContext    *pCodecCtx = NULL;
  
    AVCodec           *pCodec = NULL;
  
    AVFrame           *pFrame = NULL;
  
    AVFrame           *pFrameRGB = NULL;
  
    AVPacket          packet;
  
    int               frameFinished;
  
    int               numBytes;
  
    uint8_t           *buffer = NULL;
  
    struct SwsContext *sws_ctx = NULL;
  
  
  
    if(argc &lt; 2) {
  
      printf("Please provide a movie file\n");
  
      return -1;
  
    }
  
    // Register all formats and codecs
  
    av_register_all();
  
  
  
    // Open video file
  
    if(avformat_open_input(&amp;pFormatCtx, argv[1], NULL, NULL)!=0)
  
      return -1; // Couldn't open file
  
  
  
    // Retrieve stream information
  
    if(avformat_find_stream_info(pFormatCtx, NULL)&lt;0)
  
      return -1; // Couldn't find stream information
  
  
  
    // Dump information about file onto standard error
  
    av_dump_format(pFormatCtx, 0, argv[1], 0);
  
  
  
    // Find the first video stream
  
    videoStream=-1;
  
    for(i=0; inb_streams; i++)
  
      if(pFormatCtx->streams[i]->codec->codec_type==AVMEDIA_TYPE_VIDEO) {
  
        videoStream=i;
  
        break;
  
      }
  
    if(videoStream==-1)
  
      return -1; // Didn't find a video stream
  
  
  
    // Get a pointer to the codec context for the video stream
  
    pCodecCtxOrig=pFormatCtx->streams[videoStream]->codec;
  
    // Find the decoder for the video stream
  
    pCodec=avcodec_find_decoder(pCodecCtxOrig->codec_id);
  
    if(pCodec==NULL) {
  
      fprintf(stderr, "Unsupported codec!\n");
  
      return -1; // Codec not found
  
    }
  
    // Copy context
  
    pCodecCtx = avcodec_alloc_context3(pCodec);
  
    if(avcodec_copy_context(pCodecCtx, pCodecCtxOrig) != 0) {
  
      fprintf(stderr, "Couldn't copy codec context");
  
      return -1; // Error copying codec context
  
    }
  
  
  
    // Open codec
  
    if(avcodec_open2(pCodecCtx, pCodec, NULL)&lt;0)
  
      return -1; // Could not open codec
  
  
  
    // Allocate video frame
  
    pFrame=av_frame_alloc();
  
  
  
    // Allocate an AVFrame structure
  
    pFrameRGB=av_frame_alloc();
  
    if(pFrameRGB==NULL)
  
      return -1;
  
  
  
    // Determine required buffer size and allocate buffer
  
    numBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,
  
                    pCodecCtx->height);
  
    buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
  
  
  
    // Assign appropriate parts of buffer to image planes in pFrameRGB
  
    // Note that pFrameRGB is an AVFrame, but AVFrame is a superset
  
    // of AVPicture
  
    avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,
  
           pCodecCtx->width, pCodecCtx->height);
  
  
  
    // initialize SWS context for software scaling
  
    sws_ctx = sws_getContext(pCodecCtx->width,
  
                 pCodecCtx->height,
  
                 pCodecCtx->pix_fmt,
  
                 pCodecCtx->width,
  
                 pCodecCtx->height,
  
                 PIX_FMT_RGB24,
  
                 SWS_BILINEAR,
  
                 NULL,
  
                 NULL,
  
                 NULL
  
                 );
  
  
  
    // Read frames and save first five frames to disk
  
    i=0;
  
    while(av_read_frame(pFormatCtx, &amp;packet)>=0) {
  
      // Is this a packet from the video stream?
  
      if(packet.stream_index==videoStream) {
  
        // Decode video frame
  
        avcodec_decode_video2(pCodecCtx, pFrame, &amp;frameFinished, &amp;packet);
  
  
  
        // Did we get a video frame?
  
        if(frameFinished) {
  
      // Convert the image from its native format to RGB
  
      sws_scale(sws_ctx, (uint8_t const * const *)pFrame->data,
  
            pFrame->linesize, 0, pCodecCtx->height,
  
            pFrameRGB->data, pFrameRGB->linesize);
  
  
  
      // Save the frame to disk
  
      if(++i&lt;=5)
  
        SaveFrame(pFrameRGB, pCodecCtx->width, pCodecCtx->height, 
  
              i);
  
        }
  
      }
  
  
  
      // Free the packet that was allocated by av_read_frame
  
      av_free_packet(&amp;packet);
  
    }
  
  
  
    // Free the RGB image
  
    av_free(buffer);
  
    av_frame_free(&amp;pFrameRGB);
  
  
  
    // Free the YUV frame
  
    av_frame_free(&amp;pFrame);
  
  
  
    // Close the codecs
  
    avcodec_close(pCodecCtx);
  
    avcodec_close(pCodecCtxOrig);
  
  
  
    // Close the video file
  
    avformat_close_input(&amp;pFormatCtx);
  
  
  
    return 0;
  
  }

  This is the command I use to compile :

  gcc -o tutorial01 tutorial01.c -lavformat -lavcodec -lswscale -lz

• How do I properly enable ffmpeg for matplotlib.animation ?

  9 novembre 2018, par spanishgum

  I have covered a lot of ground on stack so far trying to get ffmpeg going so I can make a timelapse video.

  I am on a CentOS 7 machine, running python3.7.0a0.

  python3
  
  >>> import numpy as np
  
  >>> np.__version__
  
  '1.12.0'
  
  >>> import matplotlib as mpl
  
  >>> mpl.__version__
  
  '2.0.0'
  
  >>> import mpl_toolkits.basemap as base
  
  >>> base.__version__
  
  '1.0.7'

  I found this github gist on installing ffmpeg. I used the chromium source, and installed without a prefix option (using the default).

  I have confirmed that ffmpeg is installed, although I don’t know anything about testing whether it works.

  which ffmpeg
  
  /usr/local/bin/ffmpeg
  
  
  
  ffmpeg -version
  
  ffmpeg version N-83533-gada281d Copyright (c) 2000-2017 the FFmpeg dev elopers
  
  built with gcc 4.8.5 (GCC) 20150623 (Red Hat 4.8.5-11
  
  configuration:
  
  libavutil      55. 47.100 / 55. 47.100
  
  libavcodec     57. 80.100 / 57. 80.100
  
  libavformat    57. 66.102 / 57. 66.102
  
  libavdevice    57.  2.100 / 57.  2.100
  
  libavfilter     6. 73.100 /  6. 73.100
  
  libswscale      4.  3.101 /  4.  3.101
  
  libswresample   2.  4.100 /  2.  4.100

  I tried to run a few sample examples I found online :

  [1] http://matplotlib.org/examples/animation/basic_example_writer.html

  [2] https://stackoverflow.com/a/23098090/3454650

  Everything works fine up until I try to save the animation file.

  [1]

   anim.save('basic_animation.mp4', writer = FFwriter, fps=30, extra_args=['-vcodec', 'libx264'])

  [2]

  im_ani.save('im.mp4', writer=writer)

  I found here that explictly setting the path to ffmpeg might be necessary so I added this to the top of the test scripts :

  plt.rcParams['animation.ffmpeg_path'] = '/usr/local/bin/ffmpeg'

  I tried a few more tweaks in the code but always get the same response, which I do not know how to begin deciphering :

  Traceback (most recent call last):
  
    File "testanim.py", line 27, in <module>
  
      writer.grab_frame()
  
    File "/usr/local/lib/python3.7/contextlib.py", line 100, in __exit__
  
      self.gen.throw(type, value, traceback)
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 256, in saving
  
      self.finish()
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 276, in finish
  
      self.cleanup()
  
    File "/usr/local/lib/python3.7/site-packages/matplotlib/animation.py", line 311, in cleanup
  
      out, err = self._proc.communicate()
  
    File "/usr/local/lib/python3.7/subprocess.py", line 836, in communicate
  
      stdout, stderr = self._communicate(input, endtime, timeout)
  
    File "/usr/local/lib/python3.7/subprocess.py", line 1474, in _communicate
  
      selector.register(self.stdout, selectors.EVENT_READ)
  
    File "/usr/local/lib/python3.7/selectors.py", line 351, in register
  
      key = super().register(fileobj, events, data)
  
    File "/usr/local/lib/python3.7/selectors.py", line 237, in register
  
      key = SelectorKey(fileobj, self._fileobj_lookup(fileobj), events, data)
  
    File "/usr/local/lib/python3.7/selectors.py", line 224, in _fileobj_lookup
  
      return _fileobj_to_fd(fileobj)
  
    File "/usr/local/lib/python3.7/selectors.py", line 39, in _fileobj_to_fd
  
      "{!r}".format(fileobj)) from None
  
  ValueError: Invalid file object: &lt;_io.BufferedReader name=6>
  
  </module>

  Is there something with my configuration that is malformed ? I searched google for this error for some time but never found anything relevant to animations / ffmpeg. Any help would be greatly appreciated.

  ---

  UPDATE :

  @LordNeckBeard pointed me here : https://trac.ffmpeg.org/wiki/CompilationGuide/Centos

  I ran into problems with installing the x264 encoding dependency. Some files in libavcodec/*.c (in the make output) were reporting undefined references to several functions. After a wild goose chase found this : https://mailman.videolan.org/pipermail/x264-devel/2015-February/010971.html

  To fix the x264 installation, I simply added some configure flags :

  ./configure --enable-static --enable-shared --extra-ldflags="-lswresample -llzma"

  ---

  UPDATE :

  So everything installed fine after fixing the libx264 problems. I went ahead and copied the ffmpeg binary from the ffmpeg_build folder into /usr/local/bin/ffmpeg.

  After running the script I was getting problems where ffmpeg could not find the libx264 shared object. I think I will have to recompile everything using different prefixes. My intuition tells me there are old files laying around after I have messed with everything, using some configuration that is broken.

  So I decided maybe I should just try to use NUX : http://linoxide.com/linux-how-to/install-ffmpeg-centos-7/
  I installed ffmpeg using the new rpm, but to no avail. I still was not able to run ffmpeg because of a missing shared object.

  Finally, instead of usiong files copied into my /usr/local/bin folder, I ran ffmpeg directly from the build bin directory. Turns out that this does work properly !

  So in essence, if I want to install ffmpeg system wide, I need to manually compile from sources again but using a nonlocal prefix.