We often earn money from youtube channel by showing ads from adsense and suppose if someone want to earn bitcoin by showing ads on their youtube videos then is there any alternative ad network which provide ads for youtube channel?
Hm... No? Youtube adsense is owned by Google and they are paying with USD. If you want to earn Bitcoin with your Videos, I think you should find a new way like joining Video campaigns on Bitcointalk.
That's the right suggestion. If you're good in making videos get enrolled to the video creation campaign and earn through it. Else the only way is to get paid in terms of USD for your contents on YouTube channel and later convert it to bitcoin and hold it.