.htaccess - Rewrite with htaccess -

here i'm trying do. i've got these urls, old form , new form

site.com/video.php -> site.com/video site.com/index.php?cat_id=1 -> site.com/some-cat-name 

here htaccess file working if 1 of last 2 commented.

options +followsymlinks rewriteengine on rewritebase /  rewriterule ^\.htaccess$ - [f] rewritecond $1   !^(index\.php|img|js|css|admin|robots\.txt) rewriterule ^video$   /videos.php/$1 [l]  #rewriterule ^(.*)$   /index.php/$1 [l]  

if 2 active server returns error 500

rewriterule ^video$   /videos.php/$1 [l]  rewriterule ^(.*)$   /index.php/$1 [l]  

my logic if first matched video in url redirect videos.php , forget under line, seems in other way. can 1 explain how have predifined urls , others go on index.php, tnx in advanced.

you getting 500 (internal server error) because rule looping in rule:

rewriterule ^(.*)$   /index.php/$1 [l]  

to fix rule have .htaccess this:

options +followsymlinks rewriteengine on rewritebase /  rewriterule ^\.htaccess$ - [f]  rewritecond %{request_filename} !-f rewritecond $1   !^(index\.php|img|js|css|admin|robots\.txt) rewriterule ^video$   /videos.php/$1 [l]   # ignore existing files , directories rewrite rewritecond %{request_filename} !-f rewritecond %{request_filename} !-d rewriterule ^(.*)$   /index.php/$1 [l]