N64 AVI Dumping Audio Fix

There is audible crackling produced in AVI dumps of N64 games. It seems to be circumstantial and is not present in some games and some situations, whilst in some its subtle, and then in others it's noticeable and intrusive.

Attached, is a savestate for Banjo-Tooie (U). If you start the selected cutscene (King Jingaling Gets Zapped), one such crackle is present during the fade-in and should immediately be noticable.
TooieCinema.zip

A potentially more prominent example is in the fourth gameplay demo. If you leave the title screen on long enough, brief gameplay demos cycle through in batches of three. The fourth demo exhibits quite a lot of the problem within the first ten seconds when dumped to video. Attached is a savestate for that, too.
TooieDemo.zip

As of Bizhawk 1.12.1, there was a fix labelled "fix audio in AVI recording" for N64 Hawk. I had a look and it appeared to be a fix for this issue, but with the above examples it would seem that the issue is alive and well in Bizhawk 1.13.0. Using alternate sync fixes a majority of these cases (and has done since it was implemented) and is a completely viable solution to this problem (although at the expensive of a change in how the video is saved), but I assumed this fix was for this particular issue.

Reproduce the crackling with the attached TooieCinema.zip and TooieDemo.zip savestates while recording N64 gameplay to AVI, then compare the normal and alternate sync paths. Done means the supplied cutscenes and gameplay demo no longer produce audible crackling under the normal AVI recording path.