[mythtv-users] DVD Authoring and MythTV Archive howto (writing one...)

[Cory Papenfuss]

On Mon, 28 Mar 2005, Jeff Simpson wrote:

> While the outline looks good, I don't think the organization of the
> writeup was ever the brick wall preventing anything. The real lack is
> in decent software applications to do the job.(ie, I think we should
> be looking for people who can fix the missing parts rather than
> re-write up the workarounds)
>
> but while we're at it, add these utilities to the toolbox, these are
> all I use to make dvds out of PVR-350 NUVs:
>
> nuvexport (using avidemux2, MPEG2->MPEG2 cut option)
> dvdstyler (for making dvd iso)
> k3b (for burning dvd)
>
 	I'll agree to this.  The problem with "one-touch" dvd authoring 
from ivtv-captured files is that they're not consistent.  Some procedures 
work well for some, and not for others.  Two big problems are:

1. No lossless MPEG2 cutting that does not break streams.  This would 
ideally be rolled into MythTV so when commercials are cut out of an MPEG2 
stream, the losslessly-cut MPEG2 stream is what remains.  Current somewhat 
working methods include:
 	A. avidemux: cut/demux/remux (what nuvexport does).  This method 
works most of the time, but breaks when a capture does not have a constant 
A/V offset throughout.
 	B. gopdit/gopchop: cuts in-place.  This method works somewhat, but 
the "correctness" of the resulting stream hasn't been fully verified. 
There are some details (timestamp manipulation, open/closed GOPs, "broken" 
GOPs, etc) that need to be investigated.

2. No MythTV support for MPEG2->MPEG2 cutting.  Ideally, one would want to 
apply a cutlist to a capture to save the master footage on the backend 
with commercials removed.  Since this tool doesn't yet exist properly, 
it's not rolled into MythTV proper... see #1 above.

 	Lather, rinse, repeat.

 	One other point to note is that the ivtv does a *horrible* job of 
producing low-mid quality captures.  If one is trying to build a 
broadcast-quality archive DVD, they cannot record at a low enough bitrate 
to do so straight off the card without crappy quality.  I use a 2-pass 
transcode to get very acceptable 2.2 Mbps 352x480 archival DVDs.  Roughly 
760MB per 42-minute show.  That's 6 "hour-long" shows on one DVD.  If you 
try to capture at that directly, it'll look horrible.

  -Cory

*************************************************************************
* Cory Papenfuss                                                        *
* Electrical Engineering candidate Ph.D. graduate student               *
* Virginia Polytechnic Institute and State University                   *
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