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• avcodec/mpegaudio_tablegen : more dynamic table creation speedups

  28 novembre 2015, par Ganesh Ajjanagadde

  avcodec/mpegaudio_tablegen : more dynamic table creation speedups
  This further speeds up runtime initialization, with identical generated tables.
  Sample benchmark (x86-64, Haswell, GNU/Linux) :
  old :
  
  34441423 decicycles in mpegaudio_tableinit,    8192 runs,      0 skips
  new :
  
  10776291 decicycles in mpegaudio_tableinit,    8192 runs,      0 skips
  Most low hanging fruit is taken care of here. For some idea, note that
  
  83,064 array elements totalling 233,722 bytes need to be initialized.
  
  Thus, with this patch, we average 12.9 cycles per element or 4.6
  
  cycles per byte.
  Reviewed-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  
  Signed-off-by : Ganesh Ajjanagadde <gajjanagadde@gmail.com>
  

  • [DH] libavcodec/mpegaudio_tablegen.h

• FFmpeg -filter_complex_script crop & blurbox with time based values

  6 juin 2021, par user1503606

  I am trying to create a script that will move a blur boxed across a video based on x and y cords in a text script.

  


  I can easily create a blur box with the following ffmpeg command.

  


  ffmpeg -y -i pex.mp4 -filter_complex_script cropblur.txt -map "[v]" out_crop.mp4


  


  The cropblur.txt has the following.

  


  [0:v]crop=400:400:300:350,boxblur=10[fg]; [0:v][fg]overlay=300:350:enable='between(t\,0\,5)'[v]


  


  This creates this.

  


  

  


  What I want is the blur box to move across where the lady is running.

  


  

  


  She obviously runs out from where the box is positioned.

  


  I can create a script where I can track the correct x and y positions for the blox using jquery ui or something I just dont understand how to implement this in a filter_complex_script.

  


  I thought it would be a simple as just appending to the script something like this.

  


  [0:v]crop=400:400:300:350,boxblur=10[fg]; [0:v][fg]overlay=300:350:enable='between(t\,0\,2)'[v]
[0:v]crop=200:200:200:360,boxblur=10[fg]; [0:v][fg]overlay=300:350:enable='between(t\,2\,3)'[v]
[0:v]crop=200:200:200:370,boxblur=10[fg]; [0:v][fg]overlay=300:350:enable='between(t\,3\,4)'[v]
[0:v]crop=200:200:200:380,boxblur=10[fg]; [0:v][fg]overlay=300:350:enable='between(t\,4\,5)'[v]


  


  Changing the time and the x position based on the incremented time.

  


  If I run this script I get this error.

  


  No output pad can be associated to link label '0:v'


  


  Obviously I am doing something wrong but I cannot find any documentation that really helps me understand how to do this https://ffmpeg.org/ffmpeg.html the official docs dont really help.

  


  I could do it by running multiple passes like this.

  


  ffmpeg -y -i pex.mp4 -filter_complex "[0:v]crop=400:400:300:350,boxblur=10[fg]; [0:v][fg]overlay=300:350:enable='between(t\,0\,2)'[v]" -map "[v]" out_crop.mp4 && ffmpeg -y -i out_crop.mp4 -filter_complex "[0:v]crop=200:200:200:360,boxblur=10[fg]; [0:v][fg]overlay=300:350:enable='between(t\,2\,3)'[v]" -map "[v]" out_crop2.mp4


  


  I Would just really like to understand how to use the filter complex scripts in this way ?

  


  Any help would be great.

  


  Thanks

  


• FFMpeg Add Background Music to Video

  10 juillet 2021, par Hossein

  I wanna add a background music on my video.
I tried this command

  


  ffmpeg -i video.mkv -i audio.m4a -filter_complex "[0:a][1:a]amerge=inputs=2[a]" -map 0:v -map "[a]" -c:v copy -ac 2 output.mkv


  


  It worked but when music ended, My Video Sound end too.
I want to repeate the background music until video end.
And if I can change background music volume it will be awosome