Don't swap back un-deblocked lines for intra prediction when

at slice boundaries for deblocking-type 2 content.

This is needed for slice based threading only and doesn't do much
good or bad otherwise.
Patch by Andreas Oman %andreas A olebyn P nu%
Original thread:
date: Jun 18, 2007 1:21 PM
subject: Re: [FFmpeg-devel] [PATCH] h264 parallelized,

Originally committed as revision 9380 to svn://svn.ffmpeg.org/ffmpeg/trunk