[MPlayer-users] Vbitrate not responding on lavc encoding

[Rich Felker]

On Wed, Jul 13, 2005 at 08:04:51AM -0500, cothrige wrote:
> > if the file is smaller than the requested size, it simply means lavc
> > could not use the requested number of bits within the constraints you
> > specified. perhaps lower the minimum quantizer to 1. also you really
> > should always use 2pass mode. 1pass will give very low quality.
> 
> But, why would a file which yesterday could be encoded at a vbitrate
> of 2200 today only be able to be encoded at 900?  Everything is
> identical, including the command line flags and the original source.
> Using a dvd which can be encoded with "-ovc copy" at 5400 I can only

-ovc is NOT encoding, it's copying.

> get 900 with lavc.  That can't be right.  And certainly I should be
> getting a different result with such diverse vbitrate settings as 1800
> and 16000, and yet the final result is virtually identical, both in
> quality and size.

no, you should not. lavc can't use more bits than are useful. what do
you want it to do...just throw in millions of useless zeros for you to
make the file bigger?!

> Yes, I do agree about 2pass.  It much improves the results.  But, I
> did not use it for these tests in order to gain some speed as I was
> doing several encodes in a row.  But, as things stand right now I
> cannot use mencoder to get a useable final product at all and so
> basic quality is not a big issue.  A file at 900 vbitrate, whether at
> 1pass or 2pass, is not good enough for me to want to keep
> unfortunately.

if there's any use for the extra bits, it should be full size after 2
passes. try this and if you still have problems report back. also like
i said you can lower the minimum quantizer.

rich