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• Matplotlib can not save animation

  1er avril 2020, par Justin Furuness

  I have a matplotlib animation and it will not save. If I do not save it, it runs totally fine and without error. When I try to save it errors with a message that is not helpful. I have googled this error and checked everything, but I cannot seem to find an answer to this problem. I have installed ffmpeg. Am I doing something wrong that is obvious ? I am running on ubuntu 19.10 with matplotlib 3.2.1 if that matters.

  



  The code to save the animation is below :

  



      def run_animation(self, total_rounds):
        anim = animation.FuncAnimation(self.fig, self.animate,
                                       init_func=self.init,
                                       frames=total_rounds * 100,
                                       interval=40,
                                       blit=True)
#        Writer = animation.writers['ffmpeg']
#        writer = Writer(fps=15, metadata=dict(artist='Me'), bitrate=1800)
        anim.save('animation.mp4')


  



  The error traceback :

  



  2020-04-01 02:20:58,279-INFO: MovieWriter._run: running command: ffmpeg -f rawvideo -vcodec rawvideo -s 1200x500 -pix_fmt rgba -r 25.0 -loglevel error -i pipe: -vcodec h264 -pix_fmt yuv420p -y animation.mp4
Traceback (most recent call last):
  File "/home/anon/.local/lib/python3.7/site-packages/matplotlib/backend_bases.py", line 2785, in _wait_cursor_for_draw_cm
    self.set_cursor(cursors.WAIT)
  File "/home/anon/.local/lib/python3.7/site-packages/matplotlib/backends/backend_gtk3.py", line 468, in set_cursor
    self.canvas.get_property("window").set_cursor(cursord[cursor])
AttributeError: 'NoneType' object has no attribute 'set_cursor'


  



  Thanks a million for your help

  


• Trying to save frames as colored image using Ffmpeg in C++

  2 septembre 2021, par Tolga

  I am new to FFmpeg and I am trying to save the video frames as colored images. I have achieved saving them as grayscale using Netpbm, however, I need to save the frames as colored. I have tried implementing the code in this link.

  


  However, I get an error :

  


  'Exception thrown at 0x00E1FC4F (swscale-5.dll) in VideoDecoding2.exe:
 0xC0000005: Access violation writing location 0xCCCCCCCC.'


  


  Is there any way to improve this code or another way to save frames as colored ?

  


  Here is my code below.

  


  

  • src_pix_fmt is AV_PIX_FMT_YUV420p.

  


  • dst_pix_fmt is AV_PIX_FMT_RGB24.

  


  


  src_pix_fmt = avcc->pix_fmt;

src_width = avcc->width;
src_height = avcc->height;

dst_width = src_width;
dst_height = src_height;

numBytes = av_image_get_buffer_size(dst_pix_fmt, dst_width, dst_height, 0);

buffer = (uint8_t*)av_malloc(numBytes);

if ((ret = av_image_alloc(src_data, src_linesize, src_width, src_height, src_pix_fmt, 16)) < 0)
{
    printf("Couldn't allocate source image.\n");
    return 0;
}

av_image_fill_arrays(frameRGB->data, frameRGB->linesize, buffer, dst_pix_fmt, dst_width, dst_height, 0);

while (av_read_frame(avfc, packet) >= 0)
{
    ret = avcodec_send_packet(avcc, packet);
    if (ret < 0)
    {
        printf("Packets could not supplied to decoder.\n");
        return -1;
    }

    ret = avcodec_receive_frame(avcc, frame);
    printf("%d", ret);

    if (packet->stream_index == videoStream)
    {
        sws_ctx = sws_getContext(src_width, src_height, src_pix_fmt,
            dst_width, dst_height, dst_pix_fmt,
            SWS_BILINEAR, NULL, NULL, NULL);

        if (!sws_ctx)
        {
            printf("Cannot create scale context for conversion\n"
                "fmt:%s s:%dx%d --> fmt:%s s:%dx%d\n",
                av_get_pix_fmt_name(src_pix_fmt), src_width, src_height,
                av_get_pix_fmt_name(dst_pix_fmt), dst_width, dst_height);
            return 0;
        }

        sws_scale(sws_ctx, (const uint8_t* const*)frame->data, frame->linesize, 0, frame->height, dst_data, dst_linesize);

        FILE* f;
        char szFilename[32];
        int y;

        snprintf(szFilename, sizeof(szFilename), "frame%d.ppm", avcc->frame_number);
        fopen_s(&f, szFilename, "wb");
        
        if (f == NULL)
        {
            printf("Couldn't open file.\n");
            return 0;
        }
        
        fprintf(f, "P6\n%d %d\n255\n", dst_width, dst_height);

        for (y = 0; y < dst_height; y++)
            fwrite(frameRGB->data[0] + y * frameRGB->linesize[0], 1, dst_width * 3, f);
        
        fclose(f);
    }
}


  


• lavfi/delogo : option show shouldn’t affect band

  5 juillet 2013, par Jean Delvare

  lavfi/delogo : option show shouldn’t affect band
  Options "show" and "band" are unrelated and should thus be
  
  independent. However, setting "show" to 1 currently resets "band" to
  
  its default value of 4. While this is documented, this still
  
  surprising and confusing IMHO.
  Change this behavior and make "show" and "band" independent from each
  
  other. Update the documentation accordingly.
  Signed-off-by : Jean Delvare <khali@linux-fr.org>
  
  Reviewed-by : Stefano Sabatini <stefasab@gmail.com>
  
  Signed-off-by : Michael Niedermayer <michaelni@gmx.at>
  

  • [DH] doc/filters.texi
  • [DH] libavfilter/version.h
  • [DH] libavfilter/vf_delogo.c