Shell Programming and Scripting

#!/bin/bash

find . -type f | grep .mkv$ | while read file
do
 echo $file
 ## Gather some information about the file
 directory=`dirname "$file"`
 title=`basename "$file" .mkv`
 tracks=`mkvinfo "$file" | grep "Track type" | sed 's/.*: //'`
 maxarray=`mkvinfo "$file" | grep "Track number" | sed 's/.*: //' | tail -n 1`

 ## Put each of the tracks from the file into an array
 n=1
 for i in $tracks; do track[$n]=$i ; let n=n+1 ; done

 ## Loop through each track to figure out what codec it is
 ## Then store it in an array with the same location as the track
 codecs=`mkvinfo "$file" | grep "Codec ID" | sed 's/.*: //'`
 n=1
 for i in $codecs; do
  if [ "$i" == "V_MPEG4/ISO/AVC" ]; then
   type[$n]='264'
  elif [ "$i" == "A_DTS" ]; then
   type[$n]='dts'
  elif [ "$i" == "A_AC3" ]; then
   type[$n]='ac3'
  elif [ "$i" == "A_AAC" ]; then
   type[$n]='aac'
  elif [ "$i" == "S_TEXT/UTF8" ]; then
   type[$n]='srt'
  else
   echo "Track type unknown."
  fi
  let n=n+1;
 done;

 ## Loop through the file types and create an array with the file name and track type
 n=1
 for i in "${type[@]}"; do trcktitle[$n]="${title}.$i"; let n=n+1; done

 ## Loop through the track file names and search for names that are the same
 ## If they are the same, then change the file name with an incremental number
 ## This is done so that when extracting the tracks, each track has it's own file name
 ## To prevent overwriting tracks of the same type that were already extracted
 n=1
 for i in "${trcktitle[@]}"; do
  q=0
  z=1
  for p in "${trcktitle[@]}"; do
   if [ "$i" == "$p" ]; then
    if [ -n "$sametitle" ]; then
     sametitle=("${sametitle[@]}" "$z")
    else
     sametitle=("$n" "$z");
    fi
    let q=q+1
   fi
  let z=z+1
  done
  if [ $q -gt 1 ]; then
   t=0
   for i in "${sametitle[@]}"; do
    trcktitle[$i]="${title}${t}.${type[$i]}"
    let t=t+1
   done
  fi
  q=0
  let n=n+1
  unset sametitle
 done

 ## Let's figure out the FPS of the video track
 ## Some MKV files don't always put the video track in the same location, so we gather all the FPS information in the file
 ## Then we figure out which FPS belongs to the video track
 ## This is done by looping through both the FPS array and the type array
 ## Assigning the same location in each array based on file type
 ## If the type is SRT, move on in the type array but stay at the same location in the FPS array
 ## If AC3, AAC, or DTS, move in in both arrays; if 264 (the video track) assign FPS from array to vfps and leave the loop
 trckfps=`mkvinfo "$file" | grep duration | sed 's/.*(//' | sed 's/f.*//'`
 n=1
 for i in ${trckfps[@]}; do fps[$n]=$i; let n=n+1; done
 if [ ${#type[@]} != ${#fps[@]} ]; then
  n=1
  z=1
  for i in ${type[@]}; do
   if [ "$i" == "srt" ]; then
    let n=n+1
   elif [ "$i" == "264" ]; then
    vfps=${fps[$z]}
    break
   else
    let z=z+1
    let n=n+1
   fi
  done
 else
  n=1
  for i in ${type[@]}; do
   if [ "$i" == "264" ]; then
    vfps=${fps[$n]}
    break
   fi
   let n=n+1
  done
 fi

 ## Create the options for the MKVEXTRACT command. This will put the track titles in the correct location with track position and type
 n=1
 while [ $n -le $maxarray ]; do
  if [ -n "$extract" ]; then
   extract=" ${extract} ${n}:\"${trcktitle[$n]%.*}\".${type[$n]}"
  else
   extract="mkvextract tracks \"${file}\" ${n}:\"${trcktitle[$n]%.*}\".${type[$n]}"
  fi
  let n=n+1
 done
 echo $extract
 echo `$extract`

 ## If the type that was extracted is AC3 or DTS, we need to convert it to AAC before putting everything back together in the MP4 container
# n=1
# for i in ${type[@]}; do
#  if ([ "$i" == "ac3" ] || [ "$i" == "dts" ]); then
#   old=${trcktitle[$n]}
#   trcktitle[$n]=$old.aac
#   ffmpeg -i "$old" -acodec libfaac -ab 576k "${trcktitle[$n]}"
#  fi
#  let n=n+1
# done
 #echo $old
 #echo ${trcktitle[@]}

 ## Create all the options that go into the MP4Box command
 ## Loop through each track title and add it to the input array
# n=1
# while [ $n -le $maxarray ]; do
#  if [ -n "$input" ]; then
#   input=" $input -add \"${trcktitle[$n]}\""
#  else
#   input="-add \"${trcktitle[$n]}\""
#  fi
#  let n=n+1
# done
 #echo $input

 ## Let's put everything back togehter into an MP4 file
# MP4Box -new "${directory}/${title}".mp4 $input -fps $vfps

 ## Now we need to clean up our mess
 ## Delete all of the track title files that we extracted from the MKV file
# for i in ${trcktitle[@]}; do
#  rm -f "$i"
# done

 ## If there is an MP4 file created, then let's go ahead and delete the original MKV file
 ## I would leave this commented so you can test the MP4 file for quality, then delete the original yourself
 #if [ -f "${directory}/${title}.mp4 ]; then
  #rm -f "$file"
 #fi

 ## Let's clean up some of the variables we used so they dont get reused in the next file
 n=""
 file=""
 directory=""
 title=""
 tracks=""
 maxarray=""
 codecs=""
 unset type
 unset trcktitle
 extract=""
 input=""

done

$ export PS4="
--->DEBUG: "

$ cat a.sh
#! /bin/bash

echo Hello World
date
cal

$ bash -x a.sh

--->DEBUG: echo Hello World
Hello World

--->DEBUG: date
Wed May  9 08:08:22 SGT 2012

--->DEBUG: cal
      May 2012
Su Mo Tu We Th Fr Sa
       1  2  3  4  5
 6  7  8  9 10 11 12
13 14 15 16 17 18 19
20 21 22 23 24 25 26
27 28 29 30 31