[MPlayer-users] Suggested Low Bitrate Encoding Options

[RC]

On Mon, 27 Aug 2007 23:38:07 -0700
Corey Hickey <bugfood-ml at fatooh.org> wrote:

> That surprises me. I'm curious to try encoding your test clip. Can you
> post it somewhere, or make a representative sample that is large
> enough?

It's a 5 minute, 300MB vob.  I'm willing to upload it if you'll provide
a place.  Though I think you'd do just as well to test any other
fast-action video.  In fact my other test clips are just high bitrate
HD videos (some animation, some not).  All the settings I've used
(*_mask, quant, etc.) seem to have exactly the same effect with all my
tested content.

The only reason I really prefer this particular clip is because it's D1,
so much faster to encode than HD clips.  Also, the relatively high 6000K
bitrate prevents source artifacts which seriously limiting testing the
encoding quality of my other DVDs (mostly 4000K).

> > sc_factor=6 has nominal effect.  Perhaps just barely lower quality,
> > if anything.
> 
> Er... I think it's your imagination, unless your mencoder is rather
> old.  sc_factor doesn't do anything as of ffmpeg r6876.

First, I did try to stress that any difference (if any existed) was very
tiny. Trying to spot changes so small, I wouldn't be surprised if I had
imagined the difference (or rather if my eyes changed something, or if
some random CPU slowdown or strange hardware glitch might have caused
some barely perceptible change).  All other options had effects far more
visible.

HOWEVER, and more importantly, the sc_factor6 file is 0.01MB larger, so
they weren't entirely the same file.  Taking the time to look back
through my encoding script, it seems that when I added sc_factor=6 to
the -lavcopts, I somehow accidentally removed vqcomp=0.6 in the process.
 I checked the script for all my other encodes, and fortunately the
mistake was limited to just that one file.