EVENTUALLY !!! The problem was definitely the external libx264. Most likely not properly compiled by I.
So ... for those who are in the same trouble, instead of resolving it I went another way : - Went to the configure file of hvirtual/quicktime/ffmpeg - modify the default options in the configure file (one being x264) - dont forget to enable gl - back to the main directory, ran ./configure without options (though I did export CFLAGS="-fPIC") - all config Ok - make - couple of libs such libtiff and a couple of devel packages (used synaptic) - make install - ldconfig to make sure Et Voila ..... Champagne this evening !! Thanks all for your help and time. Cheers Edouard
