[mythtv-users] why are the mythtv stream files different fromstandard codecs?

[Rob Snow]

Mike,

I've not tried to make a VCD out of any of these, so I can't help you there.

As far a recommended parameters for a 1hr, keep this in mind: (video bitrate 
+ audio bitrate) * hours = ~1600 to fit on a 700MB CD.  So for 1hour you 
could probably try something around 1420Kbs video and 160Kbs audio. 
(1420+160)*1.0 = 1580.

As you see, in this script it's (464+80)*3 = 1632, but you'll notice that 
you generally don't end up with 80kbs on the audio. (I think I get around 
72kbs or maybe a bit lower...been a week or so since I tweaked it.)

Conversely, if you have a 2.5hr movie you want to burn you could turn it 
around to get a general idea of what to encode with: 1600/2.5 = 640 ... 
maybe 545 video and 96 for audio to get you in the ballpark.

-Rob


On Sun, 6 Apr 2003 11:09:16 -0700, Michael Peay wrote
> Rob-
> Thanks for posting this script! This is the closest I've gotten to 
> producing a VCD. I have two questions:
> 
> What are your recommended paramater changes for a 1 hour disk?
> What's the next step to produce a VCD? I tried vcdimager but it 
> wants mpg input not avi.
> 
> I like your system. Ultimately, looking at the rest of your scripts 
> would help me (and probably others) in this effort.
> 
> Thanks,
>     --Mike
> 
> On Saturday, April 5, 2003, at 01:38 PM, Rob Snow wrote:
> 
> > Here is what I use for one of my scripts, this one is designed to put 
> > 3hr's
> > of DIVX on one CD.  You might want to adjust the audio/video ratio's 
> > if you
> > are doing something with nice audio.
> >
> > I have 2hr/3hr/4hr/6hr scripts that I use to convert my 2Kbps MPEG4 
> > .nuv
> > default captures to something that I can actually carry around on the
> > laptop, burn to CD for my wife or family since .nuv is useless to them.
> >
> > I use a cron job with a find /e/store -mtime +2 to get anything I 
> > haven't
> > already deleted in 2 days and convert it and rename it using the other
> > script I previously posted to name it by extracting the Title:subtitle 
> > from
> > the database.
> > (ie. 1059_213412431432_243132412314.nuv --> SG-1:Emancapation.avi)
> >
> > I just need to write another script to delete the .nuv and database 
> > entries
> > from Myth once it's done.
> >
> > I should probably up the 2Kbps MPEG4 to around 4Kbps (~2GB/hr) since 
> > they
> > are going to be converted pretty quickly to something else.
> >
> > -Rob
> >
> >
> > ########## INCLUDE 2hr-2pass ##########
> >
> > #!/bin/sh
> > rm -f *.log
> > echo got $1
> > path=$1
> > echo path=${path}
> > root=${path%.*}
> > echo root=${root}
> > noroot=${root##/*/}
> > echo noroot=${noroot}
> >
> > # First pass, note it's without vhq and v4mv
> > ./mencoder-cvs -idx $root.nuv -fps 30 -oac mp3lame -lameopts
> > vbr=3:br=80:mode=1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=464:vpa
> > ss=1 -vop lavcdeint,scale=320:240 -aspect 4:3 -o $noroot.avi
> >
> > # Second pass with vhq and v4mv
> > ./mencoder-cvs -idx $root.nuv -fps 30 -oac mp3lame -lameopts
> > vbr=3:br=80:mode=1 -ovc lavc -lavcopts vcodec=mpeg4:vbitrate=464:vhq
> > :v4mv:vpass=2 -vop lavcdeint,scale=320:240 -aspect 4:3 -o $noroot.avi
> >
> > ############# end include #############
> 
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