[MEncoder-users] Tutorial?

[Aaron Digulla]

Phil Ehrens wrote:

> Before you can happily go and convert some arbitrary dvd to divx
> you need to learn what a dvd is and what divx is. You can follow
> any one of the many HOWTO's out there, and it *might* work with
> your dvd... Or it might fail utterly. Video is not as simple as
> you think. I have been doing one particular kind of conversion
> for 3 years now, and I still need to sit down and do some tests
> before I can let my script fly merrily along overnight.

I wonder if this wasn't something that can be improved. (Sidenote: I
don't know anything about dvd or xvid stuff, so I'm also one of those
that struggle endlessly with mencoders many options :-)

I think the main goal is always the same: Encode some video with the
best quality at the least usage of bits/s.

I also see that almost no one ever uses the fixed quality options.

What is missing to turn mencoder into an automated system to encode
video without having the user worry about thousands of options? Surely
during encoding, mencoder will notice if it simply cannot create a good
looking result?

As I see it, there are two maxima and everyone is attracted to one of
them: There is the goal for best quality and on the other hand, the need
to fit the video on a CD (ie. fixed size). A third goal might be to
conform to a certain video output format (like SVCD or DVD).

Some random thoughts:

- Send mencoder over the input to cut it into "scenes" (ie. blocks which
probably need the same encoding parameters for best results)
- Run some test encodings on each scene to determine the best encoding
parameters towards the goal (quality or size). Just encode 5 to 10
images in each scene.
- For fixed bitrate, do another run (this is the old first pass)
- Encode the video for real

Since most users of mencoder have no idea of the impact of most options,
I think this might give much better results for the average user. Even a
script like mencoder -identify which just runs some tests to determine
good parameters would help a lot.

Regards,

-- 
Aaron "Optimizer" Digulla a.k.a. Philmann Dark
"It's not the universe that's limited, it's our imagination.
Follow me and I'll show you something beyond the limits."
http://www.philmann-dark.de/