This answer is specific to the Maryland legislative process.
Bill Introduction & Committee Process
The first step of the process is to have the bill introduced. In my state, it's considered poor taste to deny a bill introduction (although I can't say for sure that norm extends to other states).
Maryland has some restrictions on bills based on when they are introduced. Any bill may be freely introduced in the first 90 days of the year (January 11 - April 10, 2017). However, any bill introduced after the first 24 or 31 days (depending on which chamber we are talking about) must first go through a rules committee.
I haven't been able to find committee rules on the Maryland General Assembly's website, but in the states I am familiar with there is no requirement for the committee to vote on the bill. Many (perhaps most) bills die in committee without any action.
Although the committee chair has a lot of discretionary authority, the rest of the committee can force issues through. However, this requires support within the committee. Committee assignments are determined by chamber leadership, so it's possible that the relevant committees are strongly for or against any particular bill. This would make it difficult for a bill to be forced through a community.
Rules in the state of Maryland require a committee to work a bill before it goes to the rest of the chamber. If a bill can't get through its committee, it won't have a chance to be voted on in the rest of the legislature.
The issue they are talking about in the video is House Joint Resolution #6 (HJ6). This resolution would ask for a Constitutional convention to be convened to discuss voting and electoral changes.
The resolution has 61 sponsors (of the 141 members of the House). However, only 7 of those sponsors are on the House Rules committee (it has 24 members total).
HR6 was introduced February 10, and the committee scheduled it's hearing on March 10. Maryland's electronic system includes no updates since then, so it's likely dead in committee. However, Maryland doesn't include meeting agendas or other information online, so I can't tell for sure what happened at that meeting.