4music, the music TV channel launched last August by UK broadcaster Channel 4, and Box TV Network, has already captured 20% of all UK music TV viewing for 16-34 year-olds, it claimed today.The channel is apparently the 25th most-watchec channel in the UK, and in Freeview homes, it’s the 12th most popular. However, head of T4 and music Neil McCallum says 4music isn’t stopping there.”Our stated aim internally is that we want to be in the Top 10 digital channels,” he said at a press event this morning. When we think about competition, it’s nothing to do with MTV2 or MTV Base or Amp, Flaunt or other music channels. We’re talking about ITV2, BBC 3, Sky One, Living and Dave.”McCallum also drew a direct comparison between 4music and MTV One. “Our channel is very much about music: it’s 90% music skewed, compared to MTV One which is less than 5%,” he said.