Common bitrate for 5.1 AC3 stream

[ookzDVD]

Dear forum,

I want to ask about common bitrate for 5.1 AC3 stream,
is it 448 ? or 384 ? or I can low it down ?

Thank you.

[DJ Bobo]

448kbps is minimum to get full bandwidth up to 20KHz
Anything lower will result in lower quality and earlier frequency cut.

[canadian_fbi]

since ac3machine came out, i transcode any 448 kbps AC3 files to 384. 448 is probably overkill for me, and the extra 64 kbps come in handy.

[ookzDVD]

@canadian_fbi,

Thank you.

I also have the same opinion, I think 448 is too big for me,
about 500mb for 130mins movie. With 384 I could save about
70mb for the video. ;)

[DJ Bobo]

then keep in mind that you're lowering the quality quite much because of recompressing an already highly compressed file (448kbps has not even 96kbps per channel and this is not even MP3) and that you got frequencies only up to 18KHz with 384kbps...

[ookzDVD]

@DJ Bobo,

Thank you, I'll use the 384 for movie with few of actions mostly
and lots of people's dialogue. For action movie, sure I'll stay
with 448.