This is normal. within your network, you have unlimited upload speed, its as fast as your router. But once you go remote, the upload speed is limited by your internet provider. Most limit the speed to about 280-340. You have to pay extra for more upload speed. Or just get used the the decent but less than perfect picture. I got used to it.
As Perterla mentioned, you will need to improve the upload speed at home to get a better bit rate remotely, check also this article