Script to convert video to mp4 in a way that is playable on the Kindle Fire. Prereqs: Compile the latest ffmpeg and x264 encoder. On Ubuntu, this worked well: https://ffmpeg.org/trac/ffmpeg/wiki/UbuntuCompilationGuide

ConvertToMP4_KindleFire.sh

#!/bin/bash

## Convert input files $name.* into $name.mp4, suitable for playing 
## in Kindle Fire.

usage="$0 file1 [file2 ...]"

if [ -z "$1" ]
then
    echo $usage
    exit 1
fi

audio="libmp3lame"
for ifile in "$@"
do
    ofile="${ifile/.*/.mp4}"
    echo "Convert from $ifile to $ofile"
    echo ffmpeg -i $ifile -acodec $audio -ab 96k  -vcodec libx264  -f mp4  $ofile 
    ffmpeg -i $ifile -acodec $audio  -ab 96k  -vcodec libx264  -f mp4  $ofile 
done