ABR and CBR query

[JimmyBarnes]

Hi

Have just started playing with BeSweet v1.3b12 to create mp3s from AC3s.

This puzzles me:

When I make an mp3 using ABR (average bitrate) specific sounds do not appear at the same times as in the mp3 using CBR (constant bitrate)- they are many seconds displaced (not sure if the displacement is constant, or if it varies).

Yet when I mux the ABR.mp3 with corresponding video, audio and video seem to be in sync! :confused:

Presumably ABR is superior to CBR :confused:

Any help appreciated

thanx
JB

[pacohaas]

did you actually time the audio or just look at what WiMP said? try playing it under a decent mp3 player like xmms or winamp and see what it says then. I'm sure the length is the same, just WiMP has no clue how to get the timecode from VBR files (of which ABR is a subset). It just looks at the first frame and assumes the rest of the file is that bitrate and calculates the time as if it were CBR, so it's no surprise that it's wrong almost every time.

in short, you yourself said it worked when muxed, so don't worry about it.

[JimmyBarnes]

Originally posted by pacohaas
did you actually time the audio or just look at what WiMP said? try playing it under a decent mp3 player like xmms or winamp and see what it says then.

I did use WinAMP - that's how I found the apparent discrepancy.

JB

[Sven Bent]

i have never noticed this.

do yuo have some downloadable test ?

[DSPguru]

this simply a problem of WMP, read the latest Q over the audio faqs.

[MaTTeR]

One more reason for me to add to my list why I don't use WiMP:rolleyes:

Hope Doom doesn't see this thread:D

[Hanty]

Presumably ABR is superior to CBR

It is, but for none of the problems you encountered.
The encoding method abr contra cbr has really nothing to do with the sync of the audio.

[pacohaas]

but you guys...he said he used winamp and not WiMP.

[gnoshi]

I believe the only time winamp really gives accurate lengths of files is, well, never. The only way to actually tell the length is to play from start to finish and watch the time as it ticks over.
That is my experience anyway.

gnoshi

Maybe I'm wrong. It is possible. Maybe not. Equally likely. Good luck.