[MEncoder-users] Mencoder vs. hardware based devices...

[RC]

On Tue, 21 Jun 2005 22:17:54 -0400
Brian Keener <keenerb at roleplayga.org> wrote:

> I was looking at new hard drives at my local store, and I saw some 
> inexpensive PVR devices (PVR-250 and PVR-150 from Hauppauge), and the 
> thought crossed my mind that they might be adequate for my purposes.
> 
> Can mencoder give significantly better quality than one of these 
> stand-alone devices?

Better?  How?

Hardware MPEG encoders need much higher bitrates to give decent quality
output.  If you're not concerned about bitrate, and just want to use
the MPEG hardware for the first capture (which you're going to re-
encode later) then they work just fine for the job.

I have a PVR-250 myself, and I was quite disappointed with the fact
that it barely looked any better than BTTV card captures with mencoder
(better color, slightly less noise) while needing about 2GBs/Hour to
really look good and not break-up during motion (720x480).

As for 352x240, it captures in MPEG-1, and looks horendous.  I guess
the card doesn't have very good quality scaling, so you get more
aliasing than you can stand, and a very dark picture for some reason.

This is using the Linux IvyTV drivers (ivtv) and the Hauppauge PVR-250.

> My disk space restricts me to capturing at 352x480 or 352x240 

Why's that?  Are you using some lossless codec like Huffyuv for the
initial capture?  Using either lavc's mpeg2 or mpeg4 codec with
keyint=1 will give you very fast encoding, and using far less space
than any lossless codec.  Also use something like "vqscale=2" (as
opposed to using "vbitrate=") for live captures.