Questions specific to the IDE belong in its dedicated forum.
I haven't done anything with video in Flex, but I am quite familar with the closed captioning domain. My research indicates that Adobe's Open Source Media Framework project is the way to go as it provides a captioning plug-in. The documentation, at least out of what I've found on the project site so far, sucks though.
This covers how to actually use the captioning plug-in:
http://books.google.com/books?id=sJl-nUYdZjgC&pg=PA289&lpg=PA289&dq=osmf+captions&source=b l&ots=OnHHbUl_aZ&sig=uAr3nnnfgJtE0vxgQ9EA6xdPO0g&hl=en&ei=BxszTPa-F4ublgeu2LyjBg&sa=X&oi=b ook_result&ct=result&resnum=5&ved=0CCkQ6AEwBA
You can use the FLVPLayback & the FLVPlaybackCaptioning component within Flex 3; haven't tried it in FB4.
thanks for your reply.
could u send me that sample code in flex 3.
Ping Bing with "FLVPlayback" and you'll find some examples.