Recherche avancée

Sur d’autres sites (11694)

• Error trying to install FFmpeg on Oracle Cloud VM Linux [closed]

  14 mai 2022, par lucasrvimieiro

  I'm trying to host a discord bot using Oracle Cloud but I need to install the FFmpeg extension for it to be able to play music. I have absolutely no experience with Linux at all but I was able to run the bot normally after a few tutorials. Everything is working fine except for the FFmpeg installation.

  


  I already tried following these guides :
https://computingforgeeks.com/how-to-install-ffmpeg-on-centos-rhel-8/
https://techviewleo.com/install-ffmpeg-on-rocky-almalinux-oracle-linux/

  


  However I keep getting the error :

  


  


  Errors during downloading metadata for repository 'nux-dextop' :

  


  

  • Status code : 404 for http://mirrors.coreix.net/li.nux.ro/nux/dextop/el7/aarch64/repodata/repomd.xml
(IP : xx.xx.xxx.xx)

  


  • Status code : 404 for http://li.nux.ro/download/nux/dextop/el7/aarch64/repodata/repomd.xml
(IP : xxx.xx.xx.xxx) Error : Failed to download metadata for repo
'nux-dextop' : Cannot download repomd.xml : Cannot download
repodata/repomd.xml : All mirrors were tried

  


  


  


  when executing :

  


  sudo dnf -y install ffmpeg


  


  I cannot find any solutions online. Is it even possible to install FFmpeg there ? The VM is running Oracle-Linux-8.5-aarch64-2022.04.04-0. I'm using Bitvise SSH Client to connect to the terminal.

  


• I need a compact c/c++ code for motion vectors extraction from mp4 file without frame decoding [on hold]

  23 mars 2018, par Andyrey

  I have searched a lot of answers on this kind of question. Many of them point out to code, presuming frame decoding :

  DCT coefficient and motion vector extraction in encoded domain ;
  https://github.com/vadimkantorov/mpegflow ;
  https://github.com/FFmpeg/FFmpeg/blob/master/doc/examples/extract_mvs.c.

  I implemented these codes in my program and saw they decode video frames, and then use frame side data for extracting motion vectors.

  Others give command lines for executing bynaries :

  Motion Vector extraction from encoded video file

  or just gives reference to huge set of library files with no idea what to do with them.

  What I badly need : code for extracting motion vectors from mp4 with no frame decoding (no pixel domain restoring). Is it possible ?

  From my 3rd reference I used code like next, where I suspect frame decoding happens :

  while (ret >= 0)
  
  {
  
      ret = avcodec_receive_frame(video_dec_ctx, frame);
  
     /*I omit some exclusion processing*/
  
      if (ret >= 0)
  
      {
  
          int i;
  
          AVFrameSideData *sd;
  
          video_frame_count++;
  
          sd = av_frame_get_side_data(frame, AV_FRAME_DATA_MOTION_VECTORS);
  
          if (sd)
  
          {
  
              const AVMotionVector *mvs = (const AVMotionVector *)sd->data;
  
              for (i = 0; i < sd->size / sizeof(*mvs); i++)
  
              {
  
                  const AVMotionVector *mv = &mvs[i];
  
                  printf("%d,%2d,%2d,%2d,%4d,%4d,%4d,%4d,0x%"PRIx64"\n",
  
                  video_frame_count, mv->source,
  
                  mv->w, mv->h, mv->src_x, mv->src_y,
  
                  mv->dst_x, mv->dst_y, mv->flags);
  
              }
  
          } 
  
          av_frame_unref(frame);
  
      }
  
  }

• avformat/mov_chan : make iso_channel_position table more compact

  3 juin 2024, par Marton Balint

  avformat/mov_chan : make iso_channel_position table more compact
  Signed-off-by : Marton Balint <cus@passwd.hu>
  

  • [DH] libavformat/mov_chan.c