Automatic Audio Syncing / Fingerprinting

I just re-read this
> http://pipapo.org/pipawiki/Lumiera/DesignProcess/DelectusShotEvaluator
>   
and thought that this is interesting point:

---
The application should be smart enough to fill in audio if the existing 
source is missing. For example, in a recent project I was working on a 
camera op accidently set the shotgun mike to test mode, ruining about 
10% of the audio for the gig. I was running sound, and luckily I had a 
backup copy of the main audio being recorded. This application should, 
when told that these two are of the same event at the same time, 
seamlessly overlay the backup audio over the section of the old audio 
that has been marked bad and not even play the bad audio. This is just 
background noise, and streamlining the immense task of sorting through 
footage needs to be simplified as much as possible.
---

Because still, at least in lower budget productions for flexibility 
reasons (no cables to the camera etc), external audio (Flash-Recorder / 
DAT) without TC sync is used. Even the more professional Prosumer 
cameras / Audio Equipment lack possibilities to sync for Freerun or 
other sync strategies. On the other hand, at least in video, often 
external Sound recorders and camera mic record the same sound from 
different perspectives. So, automatic syncing where possible by creating 
audio fingerprints could be nice. I dont know if this is what the part 
in the document referred to.