I love the idea of wha this app is doing, and so many of the options in this space are laggy and painful, so I'm very interested in this rewrite. That said, as a photographer a lot of my media is stored as RAWs, and it's not clear whether that's supported (or perhaps its exclusion from the list of "all major image and video formats" suggests that it's not)?
Does your product have docs/a support forum/other place these kinds of details would be covered?
As someone who's never given a speech at a conference before, but is very interested in sharing his newfound knowledge and love of Python, is there anywhere people would recommend reading up on the form or content of such a proposal?
I'll echo Simon - just submit a short proposal (I've posted 3 :-). New speakers are encouraged as they help the community to grow. Consider adding a Poster Proposal as a backup so you could still talk about your subject even if you don't get a speaking slot. The Poster sessions last year were huge and very good.
You might be over-thinking things a bit... depending on the conference, a talk proposal often only needs to be a couple of paragraphs. You don't need to have planned the talk out in detail - just an explanation of what it is you intend to talk about and some background on your experience with the topic.
Does your product have docs/a support forum/other place these kinds of details would be covered?