[MEncoder-users] Authoring for DVD - qpel?

[RC]

On Sat, 29 Sep 2007 18:33:02 +0100
"Ross Clement" <rossclement at gmail.com> wrote:

> I would guess (please correct me if I'm wrong) that motion
> compensation will improve encoding quality considerably.

With modern video codecs, you would have to go to great lengths to
disable "motion compensation".  And BTW, motion _estimation_ (m.e.) is
the more common term.

So your answer is:  No.

> From poking through the docs, it seems that "qpel" is the lavc option
> I should try. My current plan is to go back and re-do some encodes
> using this option and see if the result looks better at the same bit
> rate.

With MPEG-2, I expect qpel will cause artifacts, as you DVD player
doesn't know how to handle it.  That's assuming mencoder doesn't return
an error and prevent you from even trying it.

And more to the point, qpel doesn't enable motion estimation, it just
enables an extra TYPE/METHOD (ie. quarter-pixel).  

The option to change/disable motion compesation is actually 'vme', but
it's most certainly enabled by default.

> Are there any more sophisticated experiments I should try (e.g.
> varying other parameters related to motion compensation)?

You might see some noticable gains by increasing the default diamond
size...  See dia and predia.

Besides that, you should just try the typical recomendations for
improving video quality...