Burning DVD from flv format - video/audio sync problem

I recently recorded three one-hour duration programmes from BBC iPlayer in Replay Media Catcher (selecting the 'Do not convert option') and then burned to DVD in Replay Converter, selecting 'Burn to CD/DVD' with 'Burn to DVD-PAL' target format.

One of these three had serious audio sync problems. At the start of the programme the lip-sync delay was up to half a second. Throughout the programme the delay increased, and at the end was several seconds. Another programme recorded some months ago had a similar serious audio sync delay.

Accessing the Troubleshooter function recommended in the online user instructions by right-clicking on the file in the 'Files to convert window of Replay Converter, I couldn't find an explanation of the options available for selection, ie:-
Conversion Method: With DirectShow/Without Direct/Show
Sync options: No change/Automatically Re-sync (Only start of audio is corrected)/Automatically Re-sync (All audio corrected)/Resync video by amount in seconds.

I can't find information about the significance of these choices. With my problem on the rogue recording I will try reconverting/burning with the 'All audio corrected option, but any light anyone can throw on these options would be helpful.