Here is a playlist of my tests for reference .
Thanks for your help, but unfortunately the pictures in Norman's initial post of this thread are gone. Could these be reinserted?
Here are some screenshots showing the fast decode settings in the VirtualDub 2 dialogs.
Select the x264 8-bit encoder. Force keyframes every 8 frames. Then in "configure" choose the typical settings as previously discussed. It can be hard to see, the extra command line option is listed as "--bframes 0". Two dashes.
For audio choose full processing mode. Make sure conversion is set to 16-bit. Sometimes VirtualDub auto selects 32-bit float.
For the audio encode settings choose AAC. Then a bitrate per channel of 96k. This is per channel. This results in a 192Kbps overall audio bitrate for the typical stereo audio stream.