The best documentaries usually turn out to be the ones with the best stories and characters. A keen documentarian will always relish coming across a great untold yarn that can unfold with colour and candour on screen. Get a person with a store of such tales talking on camera, and it’s game on.

Not surprisingly, music has long been a rich source for such films. Given the often outlandish figures to be found in front of the microphone – not to mention the gallery of charlatans, rogues and chancers who run the show offstage – and the scope for once-in-a-lifetime performances, it pays to keep the cameras rolling when musicians are playing and talking.

From the evergreen Stop Making Sense , which captured Talking Heads in full flow at the height of their powers, to Standing In the Shadows Of Motown , focusing on the seminal soul label's house band, The Funk Brothers, and the recently reissued Charlie i s m y Darling , about The Rolling Stones's Irish dates in 1965, a rich, vibrant canon of music has been developing for some time. And it is growing constantly, as film-makers find new subjects to cover and angles to take. As the OneTwoOneTwo film festival at Dublin's Lighthouse Cinema last autumn showed, the field of music films now covers a multitude, from insights into how some record stores are coping with music-retail pessimism ( Sound i t Out ) to the enigmatic Detroit musician Sixto Rodriguez and his surprise cult success in South Africa ( Searching for Sugar Man ).

The recent South By Southwest (SXSW) film festival in Austin, Texas, which celebrated its 20th anniversary as a well-regarded offshoot of the music festival of the same name, featured some exceptional music stories.

Certainly, Good Ol ' Freda is a story that hasn't been told before. Dublin-born Freda Kelly took a job as a teenager in Liverpool in 1962 answering fan mail for a band called The Beatles and now, years later, she talks for the first time about what it was like to work as the secretary to the band and their manager, Brian Epstein.

As Kelly talks about those wild years, which involved dealing with correspondence from the band’s fanatical following and keeping many secrets, it’s clear that the main reason the band employed her for so long was because she was loyal and discreet.

She is obviously still held in high regard by the band’s estate, given the ease with which the director, Ryan White, was able to tap their music for his charming, warm-hearted profile. Usually, gaining permission from Apple Corps for access to The Beatles’s music for something like this an impossible task. Kelly says she decided it was time to tell her story now, so that her grandson would know what she had been up to way back then. Fans of The Beatles, and even curious pop fans, should be glad that she's decided to talk.

Sometimes the hardest question a musician has to answer is why he or she makes music in the first place. The Punk Syndrome focused on Pertti Kurikan Nimipäivät, a four-piece Finnish punk rock band, talking about the motivation behind their angry, wild, headstrong music.

What initially made the band’s story worthy of Jani-Petteri Passi and Jukka Kärkkäinen’s cameras and attention is that the band consists of a pair of autistic musicians and another duo who have Down syndrome.

It soon becomes clear, however, that that their story goes beyond such labelling. It’s to Passi’s and Karkkainen’s credit that they skilfully elicit the liberating, powerful tones of the story and capture how the quartet’s huge passion for punk rock helps them rage against several machines.

Just where did Kathleen Hanna disappear to over the past few years? That’s the question Sini Anderson set out to answer, tracing what happened to the fiery figurehead for the Riot Grrrl movement and musician with Bikini Kill and Le Tigre after she seemingly dropped out of sight in 2005.

An advanced case of Lyme disease caused Hanna to quit music performances, but Anderson’s documentary shows that the singer and activist has lost little of her zest for art and politics. The most affecting scenes, though, come in the archival footage of vintage Hanna performances shot at the outset of her career, when she and Bikini Kill were producing audacious, powerful, thought-provoking performances. The good new is Hanna is again making music, this time with The Julie Ruin.

There were bona-fide stars in the SXSW big screen mix too. You can imagine a large, appreciative audience out there for Stevie Nicks's In Your Dreams , about her collaborative album with Dave Stewart, especially given the renewed interest in Fleetwood Mac and their upcoming world tour.

Dave Grohl comes across as hugely enthusiastic and fired up in Sound City as he talks to musicians such as Paul McCartney, Barry Manilow, Neil Young and others who have used the Los Angeles recording studio of the same name. Meanwhile, there will also be plenty of takers for the Green Day-focused brace of Broadway Idiot and Cuatro!

Funk and soul have long been the meat and drink of great documentaries, though often with a greater focus on the could-have-beens than on those who found success. Muscle Shoals took a long, evocative look at the Alabama town that has produced some of the most exciting soul music of all time. With contributions from Keith Richards, Aretha Franklin, Clarence Carter and many more, Greg Camalier's film documented how the town, and especially Fame Studios, became such a magnet for soul men and women.

As an author, Nelson George is known for his astute observations on black music though books on hip-hop, Motown and Russell Simmons. His Finding the Funk documentary, narrated by the multitaskers' multitasker, Questlove from the Roots, looked at the origins of the sound and how funk has changed as it travelled from city to city.

Many Irish live-music fans will already be familiar with the cast of eight brothers in the Hypnotic Brass Ensemble. Reuben Atlas's documentary, Brothers Hypnotic , tells the story of their rise from the south side of Chicago and especially the part their father, the influential jazz trumpeter Kelan Phil Cohran, has played in informing their musicianship and mindset.

Some of these films will, we hope, show up on a big screen or at a discerning film festival in the near future.