Prefix "DECLARE_ALIGNED" to avoid conflict with definition in ffmpeg.
Merge pull request #23 from fancycode/ffmpeg_reserved_name

Prefix "DECLARE_ALIGNED" to avoid conflict with definition in ffmpeg.
Fixed stack memory that is one byte too small.
Use cached value instead of looking it up.
Merge pull request #24 from fancycode/refpic_alloca_size

Fixed stack memory that is one byte too small.