dirac_YUV422ItoYUV420I: 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/dirac_YUV422ItoYUV420I - from package: dirac

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

Error in other languages:
dirac_YUV422ItoYUV420I: bevel nie gevind nie
dirac_YUV422ItoYUV420I: comandă negăsită
dirac_YUV422ItoYUV420I: comando não encontrado
dirac_YUV422ItoYUV420I: commande introuvable
dirac_YUV422ItoYUV420I: command not found
dirac_YUV422ItoYUV420I: käsku ei ole
dirac_YUV422ItoYUV420I: không tìm thấy lệnh
dirac_YUV422ItoYUV420I: komanda nerasta
dirac_YUV422ItoYUV420I: Kommando nicht gefunden.
dirac_YUV422ItoYUV420I: kommandot finns inte
dirac_YUV422ItoYUV420I: komut yok
dirac_YUV422ItoYUV420I: nie znaleziono polecenia
dirac_YUV422ItoYUV420I: níor aimsíodh an t-ordú
dirac_YUV422ItoYUV420I: no se encontró la orden
dirac_YUV422ItoYUV420I: no s'ha trobat l'ordre
dirac_YUV422ItoYUV420I: opdracht niet gevonden
dirac_YUV422ItoYUV420I: parancs nem található
dirac_YUV422ItoYUV420I: perintah tidak ditemukan
dirac_YUV422ItoYUV420I: príkaz nenájdený
dirac_YUV422ItoYUV420I: příkaz nenalezen
dirac_YUV422ItoYUV420I: команда не найдена
dirac_YUV422ItoYUV420I: командата не е открита
dirac_YUV422ItoYUV420I: 命令找不到
dirac_YUV422ItoYUV420I: コマンドが見つかりません