[geeks] I haven't gotten into this yet but I need some advice

[Joshua D Boyd]

On Fri, Apr 12, 2002 at 10:48:27AM -0700, David Passmore wrote:

> I have been archiving video for several years in many different formats, and
> I can only give you one piece of advice: you should make your best effort to
> record the first time in the format that you want the video to stay in
> forever. If it is destined for DVD, record straight to MPEG-2. You don't
> necessarily have to burn it to DVD right away. Recompression sucks.

Or, record straight to uncompressed.  Now cost effective, but it gets rid of
the recompression problems.  The problem with mpeg 2 is that even cuts only
editing requires some amount of recompression due to needing to regenerate
the P and B frames on either side of the edit.  

Furthermore, DVDs don't take just any sequence of frame types, they only take 
a specific stream at a specifica data rate, and if your initial MPEG2 stream 
isn't the same, then your are going to have to recompress.  I believe the 
stream is IBPBPBP..., and the BP sequence repeats 7 times before the next I 
frame (so, potentially a cut could mean having to recompress 28 frames of 
video since all the B and P frames need redone).

Anyway, if you capture to the specific style of MPEG2 used by DVDs, then the
damage of cuts only editing is fairly limited.  And, I think most capture
programs set the MPEG2 defaults properly.  But, command line generation 
programs (like are used to stitch a lot of TGAs together) often don't get put
together in the right format.  Blech.

And what really sucks is when people put out a file that consists of a wierd
blend of mpeg1 and 2.

-- 
Joshua D. Boyd