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• Strange performance of avcodec_decode_video2

  26 janvier 2014, par John Simpson

  I am developing an Android video player. I use ffmpeg in native code to decode video frame. In the native code, I have a thread called decode_thread that calls avcodec_decode_video2()

  int decode_thread(void *arg) { 
  
     avcodec_decode_video2(codecCtx, pFrame, &frameFinished,pkt);
  
  }

  I have another thread called display_thread that uses aNativeWindow to display a decoded frame on a SurfaceView.

  The problem is that if I let the decode_thread run continuously without a delay. It significantly reduces the performance of avcodec_decode_video2(). Sometimes it takes about 0.1 seconds to decode a frame. However if I put a delay on the decode_thread. Something likes this.

  int decode_thread(void *arg) { 
  
      avcodec_decode_video2(codecCtx, pFrame, &frameFinished,pkt);
  
      usleep(20*1000);
  
  }

  The performance of avcodec_decode_video2() is really good, about 0.001 seconds. However putting a delay on the decode_thread is not a good solution because it affects the playback. Could anyone explain the behavior of avcodec_decode_video2() and suggest me a solution ?

• Change ffmpeg output directory

  6 mai 2019, par Filip

  Im using ffmpeg to compress footage and i want to compess the footage of a specific day but when i overwrite the files it outputs a empty stream because it writes as it reads at the same time so i want to rename the output file. Find will give the full path which is necessary but i don’t know how to change the actual file name, rather than the path.

  Any suggestions ?

  find /home/server/recordings/compress -name '*.mp4' -print0 | xargs -0 -I{} ffmpeg -i {}  -c:v libx265 -preset fast -crf 25 -x265-params "vbv-maxrate=1500:vbv-bufsize=1000" -c:a aac {}

• Streaming desktop screen over the internet using ffmpeg

  22 janvier 2014, par user2944822

  I am a newbie in ffmpeg. I am trying to stream my Desktop screen over the internet using ffmpeg. This is the server configuration.

  Port 8090                      # Port to bind the server to
  
  BindAddress 0.0.0.0
  
  MaxHTTPConnections 2000
  
  MaxClients 1000
  
  MaxBandwidth 10000             # Maximum bandwidth per client
  
                             # set this high enough to exceed stream bitrate
  
  CustomLog -
  
  NoDaemon                       # Remove this if you want FFserver to daemonize after start
  
  
  
  <feed>               # This is the input feed where FFmpeg will send
  
     File ./feed1.ffm            # video stream.
  
     FileMaxSize 1G              # Maximum file size for buffering video
  
     ACL allow 127.0.0.1         
  
  </feed>
  
  
  
  <stream>              # Output stream URL definition
  
     Feed feed1.ffm              # Feed from which to receive video
  
     Format webm
  
  
  
     # Audio settings
  
     NoAudio
  
     #AudioCodec vorbis
  
     #AudioBitRate 64             # Audio bitrate
  
  
  
     # Video settings
  
     VideoCodec libvpx
  
     VideoSize 720x576           # Video resolution
  
     VideoFrameRate 25           # Video FPS
  
     AVOptionVideo flags +global_header  # Parameters passed to encoder
  
                                     # (same as ffmpeg command-line parameters)
  
     AVOptionVideo cpu-used 0
  
     AVOptionVideo qmin 10
  
     AVOptionVideo qmax 42
  
     AVOptionVideo quality good
  
     AVOptionAudio flags +global_header
  
     PreRoll 15
  
     StartSendOnKey
  
     VideoBitRate 400            # Video bitrate
  
  </stream>
  
  
  
  <stream>            # Server status URL
  
     Format status
  
     # Only allow local people to get the status
  
     ACL allow localhost
  
     ACL allow 192.168.0.0 192.168.255.255
  
  </stream>
  
  
  
  <redirect>    # Just an URL redirect for index
  
     # Redirect index.html to the appropriate site
  
     URL http://www.ffmpeg.org/
  
  </redirect>

  Server starts without showing any problem.

  Input stream is as follows :
  ffmpeg -f x11grab -r 25 -s 1366x768 -i :0.0 http://xxx.xxx.xxx.xxx:8090/feed1.ffm

  I get always core dumped. Please help me out or point me to any tutorial which can help me in this context.

  Regards
  Dheeraj