All this works in a simpler way for me. If you save file as .flv you can even watch video when it is downloading.
Code:
ffmpeg -i "https://nbcmpx-vh.akamaihd.net/i/video/1000/467/170704_3545906_Today___Aug_08__2017_,25,40,18,12,7,4,2,00.mp4.csmil/master.m3u8?hdnea=st=1502351375~exp=1502364005~acl=/i/video/1000/467/170704_3545906_Today___Aug_08__2017_*~id=7819d6d4-426c-402f-bf69-8d2c4edb62ab~hmac=a5f13890c6f702e5c2f63f99a291f503eaff2f6e772bd914ecc00b0c19ffd886" -c:v copy -c:a aac ou1tput.flv