Calls avconv on all mkv container files found in the folder on which it is run.

avconv-bash-script.sh

# assumes that all subtitles have been removed
# and only one audio stream (and it is located at 0:1)

# TODO: add support for all subtitle and audio tracks

for file in *.mkv
do
  # extract and convert audio
  echo Extracting audio from "$file"
  avconv -i "$file" -map 0:1 -c:a aac -b:a 160k -strict experimental audio_$(basename "$file" .mkv).m4a

  # 1st pass video
  echo Performing first pass of video for "$file"
  avconv -i "$file" -c:v libx264 -preset medium -b:v 1024k -pass 1 -s 720x480 -f  null -

  # 2nd pass video
  echo Performing second pass of video for "$file"
  avconv -i "$file" -map 0:0 -c:v libx264 -preset medium -b:v 1024k -pass 2 -s 720x480 video_$(basename "$file" .mkv).mov

  # combine video and audio
  echo Muxing video and audio for "$file"
  avconv -i video_$(basename "$file" .mkv).mov -i audio_$(basename "$file" .mkv).m4a -c copy remuxed_"$file"

  # cleaning up folder
  echo Cleaning up all temporary files for "$file"
  find . -name "*.m4a" -type f -delete
  find . -name "*.mov" -type f -delete
  find . -name "*.log" -type f -delete
  find . -name "*.mbtree" -type f -delete
done

for file in *.mov
do
  # Rename all .mov files to mkv ones.
  # Do this outsite of the above loop, so that the above loop
  # isn't called recursively forever.
  mv "$file" basename("$file", .mov).mkv
done