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View Full Version : AutoGK and CBR/VBR audio


bollemanneke
2nd June 2009, 21:23
Hi!

I'm a great fan of AutoGK, but there's something I don't understand...

What does VBR (variable bitrate) mean?
a. The MP3 auido kbps will differ throughout the whole movie, depending on the noise of the movie scenes.
2. The other settings, such as resolution, target quality etc. will decide the kbps, which will be used troughout the whole ovie without changing?

BigDid
2nd June 2009, 22:53
Hi,

It's not really VBR, it's ABR; see lame infos here:
http://lame.sourceforge.net/about.php
http://lame.sourceforge.net/abr.php

So when you choose Lame-MP3 176-ABR and you get an average of 160Kbps (example) it is "roughly" equivalent to 176CBR in quality.
Knowing that the averaged audio bitrate may vary from movie to movie this is why the mp3 encoding is done before the video encodes so that the size of the audio is used to calculate the size of the video (for 2 pass)
Hence, everything else (resolution, matrix resizer...) will be calculated last in AGK.

Hope it gives clues to your questions.

Did