트위치 공식 입장: https://blog.twitch.tv/en/2019/01/31/co-streaming-on-twitch-92c49ece7293/
https://www.twitch.tv/creatorcamp/en/connect-and-engage/mix-it-up/
Co-Streaming
With co-streaming, you can connect with your community around other shared interests beyond what you normally stream. By adding your facecam and commentary on top of Twitch-licensed premium content available to co-stream, you can put your unique spin on a broadcast other than your own.
Co-streaming is enabled for a lot of special events throughout the year for conventions like TwitchCon, marathons, sporting events, and award shows. For the full rundown on how to co-stream, you can check out this help article.
Note: Co-streaming is not permitted by all channels, and streamers should refer directly to the channel page for specific permissions and restrictions.
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