[MPlayer-users] reducing size of files while conserving the audio/video quality

D Richard Felker III dalias at aerifal.cx
Mon Aug 25 17:28:53 CEST 2003


On Mon, Aug 25, 2003 at 03:10:52PM +0900, Maximo Ramos wrote:
> [Automatic answer: RTFM (read DOCS, FAQ), also read DOCS/bugreports.html]
> Time to reply!
> 
> Citando a  D Richard Felker III (dalias at aerifal.cx):
> > Getting a CDR drive would be a much better choice. Reencoding will
> > damage quality quite a bit -- you'll have to make the movie look
> > significantly worse to get any significant reduction in size.
> 
> I already have a CDR :) but I want to stop this burning madness!!
> And some files are way too huge, with mounstrous resolutions!!
> 
> Do you agree that a 20 minutes show like SouthPark takes 250MB in 352x240
>  MPEG format? 

It most definitely should not, BUT (and this is the important part),
if your source material is MPEG1 at 352x240, it's probably full of
compression artifacts. Therefore, if you reencode, lots of bits will
be wasted storing these artifacts, meaning that unless you use very
high bitrate, the quality will be very bad when reencoding.

In this case, the best solution is not to create/download/whatever
352x240 mpeg1 files, but instead get good mpeg4's to begin with...

> > > I choosed vbitrate 800 because according with the man page that's the minimum, 
> > 
> > No, it says it's the default. 800 is actually much higher than you'll
> > normally use in practice!!
>  
> oops! yes, my bad! but after doing some tests with very high quality mpeg
> files (recorded somewhere from a HDTV signal), if I choose something lower
> than 1800 I get too much pixelation.

Well if you want to make these significantly smaller, you're going to
have to use much lower bitrate -- probably 500-600. Also, don't go
crazy with the audio bitrate. ABR or VBR averaging 100-128 kbit/sec is
a plenty for movies where most of the time you don't have music
anyway.

Rich



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