Bug#898575: In-memory cache grows almost without bound

[Juliusz Chroboczek <jch@irif.fr>]

> That's correct. The --cache option only affects the stream cache (which
> is correctly disabled by that option). The issue here was the size of
> the demuxer cache (which caches already demuxed packets).

This is completely unintuitive, and undocumented.  From the manual page:

       --cache=<kBytes|yes|no|auto>
              Set the size of the cache in kilobytes, disable it with  no,  or
              automatically  enable  it  if  needed with auto (default: auto).

The manual page needs fixing, at the very least.