After trying various players, and converting the media file to various formats, it continued to not play with sound. I continued by trying other media files that I had on my laptop, they appeared to play fine. Eventually I noticed a light crackle after a fairly low quality conversion, which was a hint that is might have to do with audio channels. At this point I tried using mono output in VLC and the sound came out clear.
After making a tree of files that would not play properly in the same way, I converted the whole batch of videos using the following bit of shell code. The codecs I used are ones that stock windows understands.
# low quality mono (256kb) #ABR=64kb #VBR=192kb # medium quality mono (512kb) #ABR=64kb #VBR=448kb # high quality mono (1024kb) ABR=64kb VBR=960kb find . -type d -print | while read x ; do mkdir -p ../out/"$x" done find . -type f | while read file ; do ffmpeg -i "$file" -acodec wmav2 -vcodec msmpeg4v2 -ab $ABR -b $VBR -ac 1 "../out/$file.avi" < /dev/null done