I had a wonderful thought yesterday whilst listening to a podcast with Joe Rogan and Andreas Antonopoulos. They were speaking about Chirp.
Chirp is a service which can encode any piece of data into a 20 tone audio clip which can be decoded by any Chirp client to link to the original data. It’s a pretty cool cross platform communication tool as it stands, but I have another interesting use for it: audio syncing with unique identifiers.
So what the hell am I talking about?
First we start with the problem – audio and video is recorded on separate devices, this is because single purpose devices tend to do one thing really well, and things that do both video and audio tend to do either one, or the other, or both – badly. By using the on-board terrible audio on most modern cameras, and a digital audio recorder of some sort – we have what is commonly referred to as “Dual system sound”.
Applications such as Pluraleyes have been developed specifically to work with film productions using dual system sound. They take a list of files and try to pair them together by listening (or examining the data rather) and moving the files around until they match. Trouble is, if you’ve got several takes of the same scene – things can sound rather similar between takes and you can end up waiting an age for the synchronising process to work correctly and it can sometimes fail to find a match completely.
Enter – Chirp. Instead of using a clapper board like in traditional sync sound productions, we use a unique chirp at the beginning or end of the takes in order for Pluraleyes to identify each pair and sync them correctly. What I suggested doing here was simply making a new chirp note with each take number, and broadcasting it to the dual system sound devices at the beginning of each take. It is important to note that both camera and sound devices must be able to hear the chirp simultaneously for this to work. So if you’re shooting in a loud environment this might not work and a clapper board or timecode jamming would be better suited.
Theoretically you could then use your Chirp app to identify which slate and take something was just by playing back the original chirp. Now I’m thinking I should’ve left an easter egg in the video. Next time.
Anyway – how cool is this app?
