It does seem like audio frame sync is there to stop the emulator throwing away a few ms of samples because the mixer buffer is full, and once the mixer is full it'll probably stay close to full as it clearly isn't draining quick enough.
The dropping of sound samples causes audible pops (especially on lightly loaded things, eg the system menu)
I suspect that the mixer buffer being full is an indication that samples are coming out of the emulator quicker than they should be, and that somewhere there's a missing feedback loop.
At a guess it's something to do with the AudioInterface updating consumed samples on a timer, and so when it interrupts the CPU to say I've consumed the samples it's a fraction early. It might work better if was actually tied into the Mixer code which actually consumes the samples... However, that might upset the code that "DMAs" the samples to the mixer buffer on a 4khz timer (unless that's also part of what's wrong?)
However, this is all speculation on my part based on what I see happening, and a lack of detailed knowledge of all these areas. Certainly any insight as to am I completely mad to be looking at those areas would be appreciated.
The dropping of sound samples causes audible pops (especially on lightly loaded things, eg the system menu)
I suspect that the mixer buffer being full is an indication that samples are coming out of the emulator quicker than they should be, and that somewhere there's a missing feedback loop.
At a guess it's something to do with the AudioInterface updating consumed samples on a timer, and so when it interrupts the CPU to say I've consumed the samples it's a fraction early. It might work better if was actually tied into the Mixer code which actually consumes the samples... However, that might upset the code that "DMAs" the samples to the mixer buffer on a 4khz timer (unless that's also part of what's wrong?)
However, this is all speculation on my part based on what I see happening, and a lack of detailed knowledge of all these areas. Certainly any insight as to am I completely mad to be looking at those areas would be appreciated.