[MPlayer-dev-eng] [PATCH] fix for -srate bug

[D Richard Felker III]

On Tue, Oct 19, 2004 at 10:27:27PM +0100, Ed Wildgoose wrote:
> 
> >you insist on quality, yet you're not using overlay?!?
> >i hope you know that all of the non-overlay vo drivers do not sync to
> >vblank, so you'll get horrible tearing. that's a much worse offense
> >than slight distortion in resampling, in fact it makes things
> >unwatchable...
> > 
> >
> 
> I have no idea what output driver I am using.  I think I forced "noxv" 
> in order to get the software scaler to work, and "sws=10".  The monitor 
> refresh rate is exactly 50 Hz
> 
> I have to be honest, I can't see any tearing on either 50Hz or 60Hz 
> stuff.

look closer, it's definitely there. there's no way to avoid it,
regardless of what your refresh rate is, without waiting for vsync to
flip the page. with overlay this is done in hardware. otherwise you
need a vo driver that can do it in software, and afaik none of them
can since it usually requires root/kernel privs.

> >>The CPU requirements seem unusually low in your case, but perhaps this 
> >>is because of the integer optimisation?  For comparison, Brutefir 
> >
> >well i also said my case is 2-channel only.
> 
> Can you please tell me how to setup the same setup as you have?  I would 
> like to test it?

mplayer some_48000hz_file.avo -af resample=44100:0:1 -af-adv force=3

(the af-adv thing is to disable all auto-filtering so double filters
don't get loaded or other nonsense -- libaf behavior is very broken!)

> Sure, that's fair enough.  If you have low CPU then basically you can't 
> do high quality resampling!  Seems fair enough really.  In any case, 
> most people shouldn't need to be resampling - I guess the most common 
> need would be playing CD audio out via some external decoder that only 
> supports 48Khz..?  I think most people though can probably just output 
> at the right rate?

no, total opposite. playing dvd on some output that only support
44100.

> I'm still trying to understand your 1-2%cpu case.  If you mean that it's 
> 1-2% when doing linear interpolation then we are talking completely 
> poles apart.

my claim was that full quality resample takes 1-2% additional cpu time
over linint.

> high quality resampling code burns a ton of CPU (which I would expect it 
> to), but the quality is loads better, but I *think* still audibly lower 
> quality (I have only tested briefly you see)

huh? it hardly burns any for me.

rich