Wrap around behavior is enforced manually and we use the values in
arithmetic involving negative integers.
Change-Id: I199706b6f3af91f4fb6fe2ef302fbbc6d0cf5785
the lookahead buffer allocation is deferred to receipt of the first
frame to allow profile changes. if the encoder was flushed before
supplying any frames the encoder would crash trying to dereference the
NULL buffer. vp8 is unaffected.
fixes mozilla bug:
https://bugzilla.mozilla.org/show_bug.cgi?id=1237848
Change-Id: Icee4b64de760476eee0d33b568f0a1010335ff13
