yamdi is a metadata injector for FLV files like flvtool2, but much faster and better than flvtool2.

To install, download latest yamdi from

yamdi - Yet Another MetaData Injector for FLV

Code:
cd /usr/local/src
wget -c http://hivelocity.dl.sourceforge.net...mdi-1.4.tar.gz
tar -zxvf yamdi-1.4.tar.gz
cd /usr/local/src/yamdi-1.4
gcc yamdi.c -o yamdi -O2 -Wall
mv yamdi /usr/bin/