MPC-HC Frame Step messed up by LAV bitstreaming

[Frankenscript]

Hi folks,

I recently did a fresh Win7sp1 x64 installation on my PC, and installed the latest stable build (1.7.0, from September 29). It had been more than a year since I updated MPC-HC.

One of the things I like to do is frame-step one frame at a time through action sequences. I always configure the right arrow key to do this for me. Other than this I go with very default settings for MPC-HC. No external filters or anything exotic.

When I set the frame step key up in MPC-HC 1.7, initially it worked fine. But I noticed with the default configuration I was only getting stereo PCM output (via SPDIF) to my AVR. I configured the LAV audio filter to bitstream AC-3 and DTS (which are all my old AVR can deal with). Bingo. Proper AC-3 and DTS output to the AVR.

But, after doing that adjustment, frame-by-frame stepping is now very jerky. One or two steps might be OK then it will suddenly jerk forward several frames. It's unusable.

Turning off bitstreaming in the LAV Audio Filter properties solves the problem, at the cost of surround sound.

What's the proper fix for this?

Thanks in advance!

Marc