The availability of Nokia Pro Camera for selected existing Nokia Lumia devices had more of an effect than just giving a fancy new UI, smart cropping of stills and stereo audio capture when capturing video. Nokia Pro Camera's video capture frame rate is now more stable than that from the Windows Phone default Camera application, meaning less audio/video sync issues when handling the video files later on under Windows or Mac OS. 

Here's the Quicktime Player movie inspector on a video shot today using the default Windows Phone Camera application, which has remained essentially unchanged for years:

Note the frame rate of '29.56' (frames per second). This actually varies from clip to clip and even within a clip (by up to 0.1fps), making video editing (I use iMovie 12 on the Mac) somewhat hit and miss - I've had audio/video sync errors on numerous occasions in the final render and it has had me tearing my hair out.

[ignore the 'current size' readout, by the way, that's just the size of the playback window on my set-up at that instant]

Happily, in addition to confirming the new, higher quality, stereo audio capture, have a look at this inspector on a video shot with Nokia Pro Camera:

Notice the frame rate of '30.01' fps. Not that you can tell from a single screenshot, but I took ten videos and all of them had the identical frame rate. I then assmbled them in various combinations in iMovie 12 and rendered the result several times at full 1080p. The result? Not the slightest sign of audio sync issues.

Nokia, like Apple, have expertise in video capture, and it does seem as though it has been Microsoft's Camera application that has been the weak link all this time - Nokia Pro Camera, debuted on the Lumia 1020, encodes video faster and more reliably, even on older devices like the Lumia 920 being used for these tests.

So... another vote of confidence in this new generation of Nokia-written Windows Phone code? Comments welcome.