i am using debian and i change complety my browswer .
can someone tell me on debian testing how to make opera recognze the H.264
i just search many times but nothing
Install chromium-codecs-extra (I think that's the correct name, may have the first two words swapped). It has been discussed several times, though usually in relation to *buntu of course.
Debian does not package chromium-ffmpeg-codecs(-extra) from chromium's source.
Instead, it relies on 3 of ffmpeg's libraries to provide the needed html5 support which are: libavcodec(-extra), libavformat and libavutil, and these are direct dependencies of the chromium package.