Give HandbrakeCLI a path to a file or a directory and it will generate better-compressed "{.}-handbrake.mp4" files next to each video.

HandbrakeCLI-recursive

#!/bin/bash

# brew install handbrake parallel ffmpeg

usage()
{
    echo 1>&2 "Usage:" "$0" 'path/to/video/dir1 [path/to/video/dir2 ...]'
    exit -1
}

if [ $# -lt 1 ]
then
    usage
fi

find "$@" \( -iname '*.mov' -or -iname '*.mpg' -or -iname '*.mpeg' -or \
  -iname '*.mp4' -or -iname '*.webm' -or -iname '*.avi' -or -iname '*.wmv' \
  -or -iname '*.mkv' -or -iname '*.m4v' \) -print0 | \
  parallel -0 --tty \
    "ffmpeg -i '{}' -vcodec copy -acodec copy -metadata:s:v:0 rotate=0 \
      '{.}-unrotated.mov' && \
    HandBrakeCLI -i '{.}-unrotated.mov' -o '{.}-unrotated-handbrake.mp4' -O \
      --preset 'Normal' --crop 0:0:0:0 && \
    ffmpeg -i '{.}-unrotated-handbrake.mp4' -vcodec copy -acodec copy \
      -metadata:s:v:0 rotate=\`mediainfo --Inform=\"Video;%Rotation%\" '{}'\` \
      '{.}-handbrake.mp4' && \
    rm '{.}-unrotated-handbrake.mp4'  '{.}-unrotated.mov' "