This is  a quick guide to installing the following in CentOS 7:

• ffmpeg

• flvtool2

• mp4box

• imagemagick

CentOS 7 requires a tweak to the process I'd used for CentOS 6. The links below are generally suitable for EL7.

Installing ffmpeg

If you don't have the EPEL repo installed already:

sudo yum -y install epel-release

Import a repo from Nux (this is third party, obviously):

sudo rpm --import http://li.nux.ro/download/nux/RPM-GPG-KEY-nux.ro
sudo rpm -Uvh http://li.nux.ro/download/nux/dextop/el7/x86_64/nux-dextop-release-0-5.el7.nux.noarch.rpm

Install ffmpeg from this repo:

sudo yum -y install ffmpeg ffmpeg-devel

Confirm it's working:

ffmpeg

ffmpeg reporting back

flvtool2

This is easiest to grab via RubyGems.

Install Ruby and RubyGems

yum install -y ruby rubygems

And then it's a simple gem install:

gem install flvtool2

And we're done.

flvtool2 - done.

mp4box (GPAC)

This one is quite easy on CentOS 7:

yum install -y gpac mediainfo

imagemagick

This package is much more common, so the install is also more straightforward.

Install any prerequisites:

yum install -y gcc php-devel php-pear

Install the package itself:

yum install -y ImageMagick ImageMagick-devel

Install it into PHP:

pecl install imagick
echo "extension=imagick.so" > /etc/php.d/imagick.ini

Finishing up.

Last, but not least:

service httpd restart