[FFmpeg-user] how to make ffmpeg automatically choose the apt bitrate for transcoding favoring quality over size

[Ramprasad N]

Hi,
I have a video in x264 format and need to convert to xvid for playback in
dvd player via USB.
I dont care much about the output filesize, it is ok if the size increases,
i want to preserve as much quality as possible.
basically i dont want to manually set any overall bitrate.
Is it possible to let ffmpeg.exe choose some bitrate as it deems fit and do
the transcoding?
Thanks