Relax constraints on Y4M header parsing

Previous parser assumed that the header would not exceed
80 characters. However, with latest FFMPEG changes, the header
of Y4M files can exceed this limit.

New parser can parse an arbitrarily long header, as long each
tag is 255 or less characters.


Change-Id: I9e6e42c50f4e49251dd697eef8036485ad5a1228
1 file changed