Re: [Mjpeg-users] Success: DV to DivX via mjpegtools and mencoder

[Bryan J. O. <b...@op...>]

Just a few notes on your process.

There are 2 things I would move from the mjpeg tools and into the mencoder
command: the deinterlacing and the scaling.  It is much faster in my
experience because you are not spawning off 2 more processes and the 
quality is amazing.  You can look at my perl scripts if you want to see 
how I do it.  I don't concern myself so much with fitting stuff on CDR's 
because I want good quality and I burn my files to DVD-R's to archive 
them.  I also don't use the smil tools yet, but that is an easy switch 
out.

Here are my scripts:
http://www.bopfer.com/scripts/VideoEncoding/

-Bryan Opfer 

On Tue, 12 Nov 2002, Robert Kesterson wrote:

> 
> OK, I've spent the last couple of weeks trying every option known to man
> to get high quality DivX files out of my DV captures.  And I think I
> finally have it all figured out.
> 
> I still want to write a Perl script to automate this, but here's the gist
> of it:
> 
> Capture the DV.  Create the edit list in Kino and save as SMIL format.
> Then do a three-pass encode with mencoder with mjpegtools for the
> preprocessing, like so:
> 
> rm -f frameno.avi
> sml2wav editlist.smil >audiofile.wav
> smil2yuv editlist.smil | yuvdenoise -I | mencoder -audiofile audio.wav \
>    -ovc frameno -o frameno.avi -fps 29.97 -ofps 29.97 -oac mp3lame \
>    -lameopts br=128:vbr=2:q=0:vol=2 -
> 
> This will pull the audio and write it to "frameno.avi" as a variable
> bitrate stream with best quality and a slight volume boost.  When this run
> of mencoder finishes, it will print out what video bitrate to use for the
> next steps, depending on what size of CD your target is.  Let's say for
> the sake of example that we want a 700 MB disk and mencoder suggests a
> bitrate of 804.  
> 
> Now to get a good quality DivX of a 90-minute movie onto a single CD, you
> aren't going to be able to go full resolution (704x480).  In my case, I'm
> working from a VHS tape -- there is a slight black border around the
> active frame, and the top and bottom few pixels are just "tape noise".  So
> I use mjpegtools filters to crop that out, reducing the number of pixels
> on screen.  Then I reduce the pixel count further by reducing to a height
> of 350 lines instead of 480 and reducing the horizontal accordingly.
> 
> So the next step would be:
> 
> smil2yuv editlist.smil | yuvdenoise -I | \
>     yuvscaler -v 0 -I USE_688x464+8+8 -O SIZE_528x352 -m BICUBIC | \
>     mencoder -ovc lavc -lavcopts \
>        vcodec=mpeg4:vhq:keyint=60:vqcomp=0.8:vqmin=2:vqmax=31:\
>        vpass=1:vbitrate=804 -oac copy -fps 29.97 -ofps 29.97 \
>        -o /dev/null -
> 
> This makes the first pass through the video, gathering statistics for the
> actual encoding pass.  The output of this pass isn't used, so it's sent to
> /dev/null and discarded.  The statistics file is all that is needed.  Note
> that the -oac copy causes mencoder to copy from frameno.avi that was
> created in the first pass, earlier.
> 
> Now to make the final encoding pass, repeat the preceding command, but
> change it to do pass 2, and give it an output filename.  Like so:
> 
> smil2yuv editlist.smil | yuvdenoise -I | \
>     yuvscaler -v 0 -I USE_688x464+8+8 -O SIZE_528x352 -m BICUBIC | \
>     mencoder -ovc lavc -lavcopts \
>        vcodec=mpeg4:vhq:keyint=60:vqcomp=0.8:vqmin=2:vqmax=31:\
>        vpass=2:vbitrate=804 -oac copy -fps 29.97 -ofps 29.97 \
>        -o VideoFile_Divx.avi -
> 
> Like I said, this can all be put into a script to automate it, but these
> are the steps.  The combination of the reduction in frame size and the
> encoding parameters result in a very good quality encoding -- no
> discernible block noise or compression artifacts in the two samples I've
> tried so far.  And they come out to *just* fill a CD (or two, if that's
> what you're targeting).
> 
> This definitely is not a speedy process -- I get from 12 to 15 frames per
> second on my Athlon XP 1600+ -- but the results are outstanding.  I have
> several hundred training videos that I need to archive, and from what I've
> seen so far, this method will do a *great* job of preserving these videos.
> 
> The combination of the ADVC-100, Kino, MJpegtools and Mencoder *rocks*!! 
> :-)  :-)   :-)
> 
> --
>   Robert Kesterson
>   ro...@ro...
> 
> 
> 
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