yamdi is a metadata injector for FLV files like flvtool2.
To install yamdi, run
cd /usr/local/src
wget http://hivelocity.dl.sourceforge.net/sourceforge/yamdi/yamdi-1.4.tar.gz
tar -zxvf yamdi-1.4.tar.gz
cd yamdi-1.4
gcc yamdi.c -o yamdi -O2 -Wall
mv yamdi /usr/bin/
yamdi 1.4 is latest version at the time of installation. You need to check if a newer version is available for download at yamdi site http://yamdi.sourceforge.net/