Sound issue in x264 MP4 converted from miniDV AVI PCM source

[daveb_89]

I just started experimenting with converting files from old digital camcorder

I used a Pinnacle usb device to import some AVI files from miniDV cassette

I then used Handbrake to create x264 MP4s , trying to get to grips with deinterlacing, quality, speed etc

First one was 15 minutes long and worked fine

Next one was 60 minutes and initially seemed ok - picture quality is absolutely fine but I realised that about 50 minutes in the sound is very distorted, "robotic" like it's being played through a voice changer

The sound in source AVI plays absolutely fine in VLC and Windows media player

I tried encoding into MP3 instead of AAC but it had the same issue

I tried AVC Any Video Converter to create an audio only WAV file, same thing

I looked in the Handbrake log files and the only thing that looked obviously weird was several messages "time went backwards" !?

MediaInfo shows audio stream in AVI is PCM 024 KB/s 32 khz 16 bit 2 channels

Any suggestions how to work around this?