buffer problem

[mm580486]

hi guys
i have a problem on youtube-dl.rb gem when i want download a big video ( 1/5gb) from youtube my ram is crashed ( i have 4 gb ram on server) because after download video i see ram graph and up to 2gb after download again ram up to 3 and again 4 and as a result server crashed

now i use memory_profiler gem this awesome but after download video ram up to 1.100 mb and again 1.200 mb ....... and again up to 4 and again crashed
also after complete download ram buffer not start to flush buffer