[ATrpms-users] ffmpeg audio conversion problem at low bitrates

[John Pilkington]

I'm running the ATrpms build of ffmpeg under CentOS 5.  Mytharchive uses 
ffmpeg to convert the mp2 audio streams from dvb to ac3 before writing 
to DVD.  On the main audio streams this is ok, but some programmes 
include a 64kb/s mono stream intended for the visually impaired: I have 
  not been able to play this properly after conversion to ac3 and I 
haven't found any references to a problem.

The wish to convert to ac3 is really to workaround DVD player 
shortcomings, and is suggested on the Mytharchive wiki.

The command used in mytharchive is

ffmpeg -v 0 -y -i '/pathto/stream0.mp2' -f ac3 -ab 192k -ar 48000 
'/pathto/stream0.ac3'

but I find the same problem with other (fairly) plausible-looking 
command lines too.

I see that the ATrpms packages relating to ac3/a52 audio are related to 
decoding only.  Could that be what's wrong, or has anyone any other ideas?

John P