h264encode: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On CentOS possible default full paths are:

/usr/bin/h264encode - from package: libva-utils

You may install the required package with command yum install {package}

Error in other languages:
h264encode: bevel nie gevind nie
h264encode: comandă negăsită
h264encode: comando não encontrado
h264encode: commande introuvable
h264encode: command not found
h264encode: käsku ei ole
h264encode: không tìm thấy lệnh
h264encode: komanda nerasta
h264encode: Kommando nicht gefunden.
h264encode: kommandot finns inte
h264encode: komut yok
h264encode: nie znaleziono polecenia
h264encode: níor aimsíodh an t-ordú
h264encode: no se encontró la orden
h264encode: no s'ha trobat l'ordre
h264encode: opdracht niet gevonden
h264encode: parancs nem található
h264encode: perintah tidak ditemukan
h264encode: príkaz nenájdený
h264encode: příkaz nenalezen
h264encode: команда не найдена
h264encode: командата не е открита
h264encode: 命令找不到
h264encode: コマンドが見つかりません