As the saying goes, you think you know, but you have no idea. Such is the case of the hardcore punk scene of the 1980s, a dirty and rebellious time for America's youth and part of music's history that will never be relived and impossible to fully understand.

But much like the music itself American Hardcore , a documentary by director Paul Rachman – inspired by the book of the same name – is an intense and raw illustration of this lost genre.

Grainy concert footage and colorful interviews with originators of the genre (Black Flag, Bad Brains, Minor Threat to name a few), help to retell the rise and fall of hardcore, explain its sociological influence and how its musical impact is still felt today.

The outlet for unleashing aggression and rage for the Reagan-era misfits is often remembered by outsiders as being nothing more than sites of violence and brutality. Though violence did ensue and eventually helped hardcore's decline, Rachman shows that the hardcore punk scene was much more than that.

This subculture put a great emphasis on the do-it-yourself punk ethic. With no label support or radio play many bands had to rely on themselves to get their name out. They made their own records, flyers and booked their own tours through an informal network of like-minded people.

The straight edge way of life, which was particularly popular on the east coast, also stemmed from hardcore.

While the majority of the video footage is extremely rough in quality, and the cut-and-paste fan zine graphics are at first hard to get used to, they work well for the nature of the documentary and actually help to visualize the stripped-down sense of culture.

Though the film is a cohesive who, what, when and where account of events, American Hardcore does fail to address the fact that Bad Brains, one of the most influential bands of the genre was African-American – a largely excluded race in a scene of mostly middle-class white teenagers.

It also skims over how female population is largely lacking from the genre.

Even so, hardcore had an influence on American culture that is still felt. Punk music as we know it today – often a sugar coated, commercialized and symbolized by studded belts and eyeliner, exactly what hardcore's creators were retaliating against – is deeply rooted in hardcore. American Hardcore is an important lesson on the punk community.

Grade: B

American Hardcore releases in theaters Sept. 29.