Chain two spawned processes

[Max Lapshin]

Hi everyone. I cannot find solution for a problem: I need to spawn two
processes (ffmpeg and x264) and chain their input and output.
Shell command looks like:   ffmpeg ... | x264

If I've made program in C, I would make pipe(), then two fork() and
exec in each fork with reopening fds.
It seems, that there is no way to do it in erlang, using existing
functions. I haven't found any pipe() call in otp sources.