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• How to save a vedostream on an event using ffmpeg

  26 janvier 2015, par Ludo

  I want to record short video sequences of an online stream (IP CCTV or Internet) on a defined event.

  For example : I want to have two minutes before and one minute after an event occures stored in a output file.

  Is it possible to do this using ffmpeg (avconv) and what are the parameters to use.

  Thanks for your help !

• speedhq : fix out-of-bounds write

  1er février 2017, par Steinar H. Gunderson

  speedhq : fix out-of-bounds write
  Certain alpha run lengths (for SHQ1/SHQ3/SHQ5) could be stored in
  
  both long and short versions, and we would only accept the short version,
  
  returning -1 (invalid code) for the others. This could cause an
  
  out-of-bounds write on malicious input, as discovered by
  
  Andreas Cadhalpun during fuzzing.
  Fix by simply allowing both versions, leaving no invalid codes
  
  in the alpha VLC.
  Signed-off-by : Andreas Cadhalpun <Andreas.Cadhalpun@googlemail.com>
  

  • [DH] libavcodec/speedhq.c
  • [DH] libavcodec/vlc.h

• sws_scale generates malformed video

  29 juillet 2024, par GiuTor

  I have to encode a series of frames from CAIRO_FORMAT_ARGB32 to AV_PIX_FMT_YUV420P with sws_scale. From the ffmpeg docs I came to know the AV equivalent of the source format is AV_PIX_FMT_ARGB so here is my code :

  


   // Set up conversion context
    img->sws_ctx = sws_getCachedContext(
        img->sws_ctx,
        img->video_size[0],
        img->video_size[1],
        AV_PIX_FMT_ARGB,
        img->video_size[0],
        img->video_size[1],
        AV_PIX_FMT_YUV420P,
        SWS_BILINEAR,
        NULL,
        NULL,
        NULL);

    width  = cairo_image_surface_get_width( surface );
    height = cairo_image_surface_get_height( surface );
    stride = cairo_image_surface_get_stride( surface );
    pix    = cairo_image_surface_get_data( surface );
    const int in_linesize[1] = { stride };
    
    sws_scale(  img->sws_ctx, (const uint8_t * const *) &pix, in_linesize, 0,
                img->video_size[1], img->video_frame->data, img->video_frame->linesize);
    img->video_frame->pts++;


  


  Sadly the video doesn't play and VLC shows a bunch of these useless messages :

  


  [h264 @ 0x7f6ce0cbc1c0] mmco: unref short failure
[h264 @ 0x7f6ce0c39a80] co located POCs unavailable
[h264 @ 0x7f6ce0c82800] co located POCs unavailable
[h264 @ 0x7f6ce0c9f400] mmco: unref short failure


  


  The encoding process runs just fine. I also tried with const int in_linesize[1] = 3 * width  ; Where am I wrong ?