Blog de François Becker

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mercredi 30 septembre 2015

Compress a MP4 video using ffmpeg

This is the two-pass command, using a 2048k video bitrate:

ffmpeg -y -i <input>.mp4 -c:v libx264 -preset medium -b:v 2048k -pass 1 -c:a libfdk_aac -b:a 128k -f mp4 /dev/null && ffmpeg -i <input>.mp4 -c:v libx264 -preset medium -b:v 2048k -pass 2 -c:a libfdk_aac -b:a 128k <output>.mp4

samedi 21 mars 2015

Automate Octave script execution on save on Mac OS X

Let's say the octave script you are working on is located in ~/Documents/script.m . On save, you want it to be automagically executed by octave, including persistent figures.

Let's create a watchdog script ~/Documents/watchdog.sh:

#!/bin/bash
while true
do
  ATIME=`ls -al ~/Documents/script.m`
  if [[ "$ATIME" != "$LTIME" ]]
  then
    echo "Running octave script"
    echo "script" > ~/Documents/OCTAVEPIPE
    LTIME=$ATIME
  fi
  sleep 1
done

Make it executable: chmod u+x ~/Documents/watchdog.sh

Don't launch it yet. We are missing the OCTAVEPIPE pipe. Create it with mkpipe ~/Documents/OCTAVEPIPE

Launch the watchdog in a shell: ~/Documents/watchdog.sh or ./watchdog.sh if you are in the same directory.

In another shell, cd to /Documents/OCTAVEPIPE) | octave --interactive

Now edit and save your octave script, it shoud be executed after less than 1 second.