I have extracted a 5.1 AC3 file from an AVI movie, it's bitrate is 448 kbps. The AC3 plays fine on Media Player (with appropriate plug-in).

However when I reload this AC3 into BeSweet and convert it to 384 kbps, with the "Create 5.1 AC3" option ticked, the resultant AC3 file plays back very choppy. With the option unticked, the playback is fine but obviouslt lacks the 5.1 I require. Does anyone know the cause of this, and how I can create non-choppy 5.1 AC3? Is there any other setting I may be missing out?

Thanks.