{"ns":"yt","el":"embedded","cpn":"fj5N7RQFc6yYBeFN","docid":"XHzMosZGE_s","ver":2,"referrer":"https://www.youtube.com/feed/subscriptions?flow=2","cmt":"373.484","plid":"AAUpKLiDy81e85HL","ei":"-l6VVqyoHMnrqgX_oqOIBw","fmt":"298","fs":"0","rt":"75.125","of":"sJOkGdGWdH8pnk758J_QgQ","adformat":null,"content_v":null,"euri":"https://www.youtube.com/watch?v=XHzMosZGE_s","subscribed":"1","lact":1,"live":null,"cl":"111891359","mos":0,"osid":null,"state":"9","vm":"CAEQAQ","volume":75,"c":"WEB","cver":"html5","cplayer":"UNIPLAYER","cbr":"Firefox","cbrver":"43.0","cos":"Windows","cosver":"6.1","hl":"en_US","cr":"US","len":"1370.047","fexp":"9416126,9420452,9422596,9423662","afmt":"140","vct":"373.484","vd":"1370.047","vpl":"370.573-373.484,","vbu":"370.010-373.800,","vpa":false,"vsk":false,"ven":false,"vpr":1,"vrs":2,"vns":2,"vec":null,"vvol":0.75,"lct":"373.484","lsk":false,"lmf":false,"lbw":"327680.000","lhd":"0.835","ltd":"21966.802","laa":"itag=140,seg=37,range=5911218-5943962,time=372.1-374.1","lva":"itag=298,seg=73,range=117725025-118565624,time=371.9-373.9","lar":"itag=140,seg=37,range=5878427-5943962,time=370.0-374.1","lvr":"itag=298,seg=74,range=118975842-119406224,time=374.9-376.0","lvh":"r8---sn-vgqsenld","lab":"0.000-3.878,370.010-374.027,","lvb":"369.867-373.800,","debug_videoId":"XHzMosZGE_s","cgr":true,"debug_playbackQuality":"hd720","debug_date":"Tue Jan 12 2016 15:17:28 GMT-0500 (Eastern Standard Time)"}

lga25s21 (71.76.0.0/15)

Time Warner Cable, SC, USA
Can't stream smoothly above 240p in either Chrome or Firefox. However, the constant stuttering is dependent on stream host. Kept refreshing until it changed to r6---sn-ab5l6nls, which works fine @ 1080p.