Is live streaming of legal television channels?

Hello friends,
I would like to know if "Live Streaming" is legal or illegal. I have seen many websites that broadcast live sports and other channels, including pay-per-view channels / movies and some software such as TVU and SopCast that help you broadcast any channel you want.

Is this illegal?

If so, who is to blame?
1. Software providers (SOPCAST, TVU, etc.) that allow people to broadcast television channels.
2. The issuers that use the software to transmit the TV channels …

Is live streaming of legal television channels?