Merge pull request #1574 in FS/freeswitch from fs-11189-av-fix to master

* commit 'be782776b535c52f49f0d64145ee9dc3e12e4d19':
  FS-11189 add back default flags LOOP_FILTER and PSNR for H264
  FS-11189 set default cpu string to cpu/2/4 if not configured
  FS-11189 add helper functions and macros to dump encoder context params
  FS-11189 add default av conf to vanilla
  FS-11189 use AV_INPUT_BUFFER_PADDING_SIZE instead of FF_INPUT_BUFFER_PADDING_SIZE in newer ffmpeg